0bd48d4db6010b5cbdc5106322cb7d15baa2ebff
[platform/upstream/libsolv.git] / src / problems.c
1 /*
2  * Copyright (c) 2007-2009, Novell Inc.
3  *
4  * This program is licensed under the BSD license, read LICENSE.BSD
5  * for further information
6  */
7
8 /*
9  * problems.c
10  *
11  */
12
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <unistd.h>
16 #include <string.h>
17 #include <assert.h>
18
19 #include "solver.h"
20 #include "solver_private.h"
21 #include "bitmap.h"
22 #include "pool.h"
23 #include "util.h"
24 #include "evr.h"
25 #include "solverdebug.h"
26
27 /**********************************************************************************/
28
29 /* a problem is an item on the solver's problem list. It can either be >0, in that
30  * case it is a update/infarch/dup rule, or it can be <0, which makes it refer to a job
31  * consisting of multiple job rules.
32  */
33
34 static void
35 solver_disableproblem(Solver *solv, Id v)
36 {
37   int i;
38   Id *jp;
39
40   if (v > 0)
41     {
42       if (v >= solv->infarchrules && v < solv->infarchrules_end)
43         {
44           Pool *pool = solv->pool;
45           Id name = pool->solvables[-solv->rules[v].p].name;
46           while (v > solv->infarchrules && pool->solvables[-solv->rules[v - 1].p].name == name)
47             v--;
48           for (; v < solv->infarchrules_end && pool->solvables[-solv->rules[v].p].name == name; v++)
49             solver_disablerule(solv, solv->rules + v);
50           return;
51         }
52       if (v >= solv->duprules && v < solv->duprules_end)
53         {
54           Pool *pool = solv->pool;
55           Id name = pool->solvables[-solv->rules[v].p].name;
56           while (v > solv->duprules && pool->solvables[-solv->rules[v - 1].p].name == name)
57             v--;
58           for (; v < solv->duprules_end && pool->solvables[-solv->rules[v].p].name == name; v++)
59             solver_disablerule(solv, solv->rules + v);
60           return;
61         }
62       solver_disablerule(solv, solv->rules + v);
63       return;
64     }
65   v = -(v + 1);
66   jp = solv->ruletojob.elements;
67   if (solv->bestrules_info)
68     {
69       int ni = solv->bestrules_up - solv->bestrules;
70       for (i = 0; i < ni; i++)
71         {
72           int j = solv->bestrules_info[i];
73           if (j < 0 && jp[-j - solv->jobrules] == v)
74             solver_disablerule(solv, solv->rules + solv->bestrules + i);
75         }
76     }
77   for (i = solv->jobrules; i < solv->jobrules_end; i++, jp++)
78     if (*jp == v)
79       solver_disablerule(solv, solv->rules + i);
80 }
81
82 /*-------------------------------------------------------------------
83  * enableproblem
84  */
85
86 static void
87 solver_enableproblem(Solver *solv, Id v)
88 {
89   Rule *r;
90   int i;
91   Id *jp;
92
93   if (v > 0)
94     {
95       if (v >= solv->infarchrules && v < solv->infarchrules_end)
96         {
97           Pool *pool = solv->pool;
98           Id name = pool->solvables[-solv->rules[v].p].name;
99           while (v > solv->infarchrules && pool->solvables[-solv->rules[v - 1].p].name == name)
100             v--;
101           for (; v < solv->infarchrules_end && pool->solvables[-solv->rules[v].p].name == name; v++)
102             solver_enablerule(solv, solv->rules + v);
103           return;
104         }
105       if (v >= solv->duprules && v < solv->duprules_end)
106         {
107           Pool *pool = solv->pool;
108           Id name = pool->solvables[-solv->rules[v].p].name;
109           while (v > solv->duprules && pool->solvables[-solv->rules[v - 1].p].name == name)
110             v--;
111           for (; v < solv->duprules_end && pool->solvables[-solv->rules[v].p].name == name; v++)
112             solver_enablerule(solv, solv->rules + v);
113           return;
114         }
115       if (v >= solv->featurerules && v < solv->featurerules_end)
116         {
117           /* do not enable feature rule if update rule is enabled */
118           r = solv->rules + (v - solv->featurerules + solv->updaterules);
119           if (r->d >= 0)
120             return;
121         }
122       solver_enablerule(solv, solv->rules + v);
123       if (v >= solv->updaterules && v < solv->updaterules_end)
124         {
125           /* disable feature rule when enabling update rule */
126           r = solv->rules + (v - solv->updaterules + solv->featurerules);
127           if (r->p)
128             solver_disablerule(solv, r);
129         }
130       return;
131     }
132   v = -(v + 1);
133   jp = solv->ruletojob.elements;
134   if (solv->bestrules_info)
135     {
136       int ni = solv->bestrules_up - solv->bestrules;
137       for (i = 0; i < ni; i++)
138         {
139           int j = solv->bestrules_info[i];
140           if (j < 0 && jp[-j - solv->jobrules] == v)
141             solver_enablerule(solv, solv->rules + solv->bestrules + i);
142         }
143     }
144   for (i = solv->jobrules; i < solv->jobrules_end; i++, jp++)
145     if (*jp == v)
146       solver_enablerule(solv, solv->rules + i);
147 }
148
149
150 /*-------------------------------------------------------------------
151  * turn a problem rule into a problem id by normalizing it
152  */
153 static Id
154 solver_ruletoproblem(Solver *solv, Id rid)
155 {
156   if (rid >= solv->jobrules && rid < solv->jobrules_end)
157     rid = -(solv->ruletojob.elements[rid - solv->jobrules] + 1);
158   else if (rid >= solv->bestrules && rid < solv->bestrules_up && solv->bestrules_info[rid - solv->bestrules] < 0)
159     rid = -(solv->ruletojob.elements[-solv->bestrules_info[rid - solv->bestrules] - solv->jobrules] + 1);
160   else if (rid > solv->infarchrules && rid < solv->infarchrules_end)
161     {
162       Pool *pool = solv->pool;
163       Id name = pool->solvables[-solv->rules[rid].p].name;
164       while (rid > solv->infarchrules && pool->solvables[-solv->rules[rid - 1].p].name == name)
165         rid--;
166     }
167   else if (rid > solv->duprules && rid < solv->duprules_end)
168     {
169       Pool *pool = solv->pool;
170       Id name = pool->solvables[-solv->rules[rid].p].name;
171       while (rid > solv->duprules && pool->solvables[-solv->rules[rid - 1].p].name == name)
172         rid--;
173     }
174   return rid;
175 }
176
177 /*-------------------------------------------------------------------
178  * when the solver runs into a problem, it needs to disable all
179  * involved non-pkg rules and record the rules for solution
180  * generation.
181  */
182 void
183 solver_recordproblem(Solver *solv, Id rid)
184 {
185   Id v = solver_ruletoproblem(solv, rid);
186   /* return if problem already countains our rule */
187   if (solv->problems.count)
188     {
189       int i;
190       for (i = solv->problems.count - 1; i >= 0; i--)
191         if (solv->problems.elements[i] == 0)    /* end of last problem reached? */
192           break;
193         else if (solv->problems.elements[i] == v)
194           return;
195     }
196   queue_push(&solv->problems, v);
197 }
198
199 /*-------------------------------------------------------------------
200  * this is called when a problem is solved by disabling a rule.
201  * It calls disableproblem and then re-enables policy rules
202  */
203 void
204 solver_fixproblem(Solver *solv, Id rid)
205 {
206   Id v = solver_ruletoproblem(solv, rid);
207   solver_disableproblem(solv, v);
208   if (v < 0)
209     solver_reenablepolicyrules(solv, -v);
210 }
211
212 /*-------------------------------------------------------------------
213  * disable a set of problems
214  */
215 void
216 solver_disableproblemset(Solver *solv, int start)
217 {
218   int i;
219   for (i = start + 1; i < solv->problems.count - 1; i++)
220     solver_disableproblem(solv, solv->problems.elements[i]);
221 }
222
223 /*-------------------------------------------------------------------
224  * try to fix a problem by auto-uninstalling packages
225  */
226 Id
227 solver_autouninstall(Solver *solv, int start)
228 {
229   Pool *pool = solv->pool;
230   int i;
231   int lastfeature = 0, lastupdate = 0;
232   Id v;
233   Id extraflags = -1;
234   Map *m = 0;
235
236   if (!solv->allowuninstall && !solv->allowuninstall_all)
237     {
238       if (!solv->allowuninstallmap.size)
239         return 0;               /* why did we get called? */
240       m = &solv->allowuninstallmap;
241     }
242   for (i = start + 1; i < solv->problems.count - 1; i++)
243     {
244       v = solv->problems.elements[i];
245       if (v < 0)
246         extraflags &= solv->job.elements[-v - 1];
247       if (v >= solv->updaterules && v < solv->updaterules_end)
248         {
249           Rule *r;
250           Id p = solv->installed->start + (v - solv->updaterules);
251           if (m && !MAPTST(m, v - solv->updaterules))
252             continue;
253           if (pool->considered && !MAPTST(pool->considered, p))
254             continue;   /* do not uninstalled disabled packages */
255           if (solv->bestrules_info && solv->bestrules_end > solv->bestrules)
256             {
257               int j;
258               for (j = start + 1; j < solv->problems.count - 1; j++)
259                 {
260                   Id vv = solv->problems.elements[j];
261                   if (vv >= solv->bestrules && vv < solv->bestrules_end && solv->bestrules_info[vv - solv->bestrules] == p)
262                     break;
263                 }
264               if (j < solv->problems.count - 1)
265                 continue;       /* best rule involved, do not uninstall */
266             }
267           /* check if identical to feature rule, we don't like that (except for orphans) */
268           r = solv->rules + solv->featurerules + (v - solv->updaterules);
269           if (!r->p)
270             {
271               /* update rule == feature rule */
272               if (v > lastfeature)
273                 lastfeature = v;
274               /* prefer orphaned packages in dup mode */
275               if (solv->keep_orphans)
276                 {
277                   r = solv->rules + v;
278                   if (!r->d && !r->w2 && r->p == p)
279                     {
280                       lastfeature = v;
281                       lastupdate = 0;
282                       break;
283                     }
284                 }
285               continue;
286             }
287           if (v > lastupdate)
288             lastupdate = v;
289         }
290     }
291   if (!lastupdate && !lastfeature)
292     return 0;
293   v = lastupdate ? lastupdate : lastfeature;
294   POOL_DEBUG(SOLV_DEBUG_UNSOLVABLE, "allowuninstall disabling ");
295   solver_printruleclass(solv, SOLV_DEBUG_UNSOLVABLE, solv->rules + v);
296   /* should really be solver_fixproblem, but we know v is an update/feature rule */
297   solver_disableproblem(solv, v);
298   if (extraflags != -1 && (extraflags & SOLVER_CLEANDEPS) != 0 && solv->cleandepsmap.size)
299     {
300       /* add the package to the updatepkgs list, this will automatically turn
301        * on cleandeps mode */
302       Id p = solv->rules[v].p;
303       if (!solv->cleandeps_updatepkgs)
304         {
305           solv->cleandeps_updatepkgs = solv_calloc(1, sizeof(Queue));
306           queue_init(solv->cleandeps_updatepkgs);
307         }
308       if (p > 0)
309         {
310           int oldupdatepkgscnt = solv->cleandeps_updatepkgs->count;
311           queue_pushunique(solv->cleandeps_updatepkgs, p);
312           if (solv->cleandeps_updatepkgs->count != oldupdatepkgscnt)
313             solver_disablepolicyrules(solv);
314         }
315     }
316   return v;
317 }
318
319
320 /*-------------------------------------------------------------------
321  * enable weak rules
322  *
323  * Reenable all disabled weak rules (marked in weakrulemap)
324  *
325  */
326
327 static void
328 enableweakrules(Solver *solv)
329 {
330   int i;
331   Rule *r;
332
333   if (!solv->weakrulemap.size)
334     return;
335   for (i = 1, r = solv->rules + i; i < solv->learntrules; i++, r++)
336     {
337       if (r->d >= 0) /* already enabled? */
338         continue;
339       if (!MAPTST(&solv->weakrulemap, i))
340         continue;
341       solver_enablerule(solv, r);
342     }
343   /* make sure broken orphan rules stay disabled */
344   if (solv->brokenorphanrules)
345     for (i = 0; i < solv->brokenorphanrules->count; i++)
346       solver_disablerule(solv, solv->rules + solv->brokenorphanrules->elements[i]);
347 }
348
349
350 /*-------------------------------------------------------------------
351  *
352  * refine_suggestion
353  *
354  * at this point, all rules that led to conflicts are disabled.
355  * we re-enable all rules of a problem set but rule "sug", then
356  * continue to disable more rules until there as again a solution.
357  */
358
359 /* FIXME: think about conflicting assertions */
360
361 static void
362 refine_suggestion(Solver *solv, Id *problem, Id sug, Queue *refined, int essentialok)
363 {
364   Pool *pool = solv->pool;
365   int i, j;
366   Id v;
367   Queue disabled;
368   int disabledcnt;
369
370   IF_POOLDEBUG (SOLV_DEBUG_SOLUTIONS)
371     {
372       POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "refine_suggestion start\n");
373       for (i = 0; problem[i]; i++)
374         {
375           if (problem[i] == sug)
376             POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "=> ");
377           solver_printproblem(solv, problem[i]);
378         }
379     }
380   queue_empty(refined);
381   if (!essentialok && sug < 0 && (solv->job.elements[-sug - 1] & SOLVER_ESSENTIAL) != 0)
382     return;
383   queue_push(refined, sug);
384
385   /* re-enable all problem rules with the exception of "sug"(gestion) */
386   solver_reset(solv);
387
388   for (i = 0; problem[i]; i++)
389     if (problem[i] != sug)
390       solver_enableproblem(solv, problem[i]);
391   if (sug < 0)
392     solver_reenablepolicyrules(solv, -sug);
393
394   /* here is where the feature rules come into play: if we disabled an
395    * update rule, we enable the corresponding feature rule if there is
396    * one. We do this to make the solver downgrade packages instead of
397    * deinstalling them */
398   if (sug >= solv->updaterules && sug < solv->updaterules_end)
399     {
400       /* enable feature rule */
401       Rule *r = solv->rules + solv->featurerules + (sug - solv->updaterules);
402       if (r->p)
403         solver_enablerule(solv, r);
404     }
405
406   enableweakrules(solv);
407
408   /* disabled contains all of the rules we disabled in the refinement process */
409   queue_init(&disabled);
410   for (;;)
411     {
412       int nother, nfeature, nupdate, pass;
413       queue_empty(&solv->problems);
414       solver_reset(solv);
415       /* we set disablerules to zero because we are only interested in
416        * the first problem and we don't want the solver to disable the problems */
417       solver_run_sat(solv, 0, 0);
418
419       if (!solv->problems.count)
420         {
421           POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "no more problems!\n");
422           break;                /* great, no more problems */
423         }
424       disabledcnt = disabled.count;
425       nother = nfeature = nupdate = 0;
426       for (pass = 0; pass < 2; pass++)
427         {
428           /* start with 1 to skip over proof index */
429           for (i = 1; i < solv->problems.count - 1; i++)
430             {
431               /* ignore solutions in refined */
432               v = solv->problems.elements[i];
433               if (v == 0)
434                 break;  /* end of problem reached */
435               if (!essentialok && v < 0 && (solv->job.elements[-v - 1] & SOLVER_ESSENTIAL) != 0)
436                 continue;       /* not that one! */
437               if (sug != v)
438                 {
439                   /* check if v is in the given problems list
440                    * we allow disabling all problem rules *after* sug in
441                    * pass 2, to prevent getting the same solution twice */
442                   for (j = 0; problem[j]; j++)
443                     if (problem[j] == v || (pass && problem[j] == sug))
444                       break;
445                   if (problem[j] == v)
446                     continue;
447                 }
448               if (v >= solv->featurerules && v < solv->featurerules_end)
449                 nfeature++;
450               else if (v > solv->updaterules && v < solv->updaterules_end)
451                 nupdate++;
452               else
453                 nother++;
454               queue_push(&disabled, v);
455             }
456           if (disabled.count != disabledcnt)
457             break;
458         }
459       if (disabled.count == disabledcnt)
460         {
461           /* no solution found, this was an invalid suggestion! */
462           POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "no solution found!\n");
463           refined->count = 0;
464           break;
465         }
466       if (!nother && nupdate && nfeature)
467         {
468           /* got only update rules, filter out feature rules */
469           POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "throwing away feature rules\n");
470           for (i = j = disabledcnt; i < disabled.count; i++)
471             {
472               v = disabled.elements[i];
473               if (v < solv->featurerules || v >= solv->featurerules_end)
474                 disabled.elements[j++] = v;
475             }
476           disabled.count = j;
477           nfeature = 0;
478         }
479       if (disabled.count == disabledcnt + 1)
480         {
481           /* just one suggestion, add it to refined list */
482           v = disabled.elements[disabledcnt];
483           if (!nfeature && v != sug)
484             queue_push(refined, v);     /* do not record feature rules */
485           solver_disableproblem(solv, v);
486           if (v < 0)
487             solver_reenablepolicyrules(solv, -v);
488           if (v >= solv->updaterules && v < solv->updaterules_end)
489             {
490               Rule *r = solv->rules + (v - solv->updaterules + solv->featurerules);
491               if (r->p)
492                 solver_enablerule(solv, r);     /* enable corresponding feature rule */
493             }
494         }
495       else
496         {
497           /* more than one solution, disable all */
498           /* do not push anything on refine list, as we do not know which solution to choose */
499           /* thus, the user will get another problem if he selects this solution, where he
500            * can choose the right one */
501           IF_POOLDEBUG (SOLV_DEBUG_SOLUTIONS)
502             {
503               POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "more than one solution found:\n");
504               for (i = disabledcnt; i < disabled.count; i++)
505                 solver_printproblem(solv, disabled.elements[i]);
506             }
507           for (i = disabledcnt; i < disabled.count; i++)
508             {
509               v = disabled.elements[i];
510               solver_disableproblem(solv, v);
511               if (v >= solv->updaterules && v < solv->updaterules_end)
512                 {
513                   Rule *r = solv->rules + (v - solv->updaterules + solv->featurerules);
514                   if (r->p)
515                     solver_enablerule(solv, r);
516                 }
517             }
518         }
519     }
520   /* all done, get us back into the same state as before */
521   /* enable refined rules again */
522   for (i = 0; i < disabled.count; i++)
523     solver_enableproblem(solv, disabled.elements[i]);
524   queue_free(&disabled);
525
526   /* reset policy rules */
527   for (i = 0; problem[i]; i++)
528     solver_enableproblem(solv, problem[i]);
529   solver_disablepolicyrules(solv);
530   /* disable problem rules again */
531   for (i = 0; problem[i]; i++)
532     solver_disableproblem(solv, problem[i]);
533   POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "refine_suggestion end\n");
534 }
535
536
537 /*-------------------------------------------------------------------
538  * sorting helper for problems
539  *
540  * bring update rules before job rules
541  * make essential job rules last
542  */
543
544 static int
545 problems_sortcmp(const void *ap, const void *bp, void *dp)
546 {
547   Queue *job = dp;
548   Id a = *(Id *)ap, b = *(Id *)bp;
549   if (a < 0 && b > 0)
550     return 1;
551   if (a > 0 && b < 0)
552     return -1;
553   if (a < 0 && b < 0)
554     {
555       int af = job->elements[-a - 1] & SOLVER_ESSENTIAL;
556       int bf = job->elements[-b - 1] & SOLVER_ESSENTIAL;
557       int x = af - bf;
558       if (x)
559         return x;
560     }
561   return a - b;
562 }
563
564 /*
565  * convert a solution rule into a job modifier
566  */
567 static void
568 convertsolution(Solver *solv, Id why, Queue *solutionq)
569 {
570   Pool *pool = solv->pool;
571   if (why < 0)
572     {
573       why = -why;
574       if (why < solv->pooljobcnt)
575         {
576           queue_push(solutionq, SOLVER_SOLUTION_POOLJOB);
577           queue_push(solutionq, why);
578         }
579       else
580         {
581           queue_push(solutionq, SOLVER_SOLUTION_JOB);
582           queue_push(solutionq, why - solv->pooljobcnt);
583         }
584       return;
585     }
586   if (why >= solv->infarchrules && why < solv->infarchrules_end)
587     {
588       Id p, name;
589       /* infarch rule, find replacement */
590       assert(solv->rules[why].p < 0);
591       name = pool->solvables[-solv->rules[why].p].name;
592       while (why > solv->infarchrules && pool->solvables[-solv->rules[why - 1].p].name == name)
593         why--;
594       p = 0;
595       for (; why < solv->infarchrules_end && pool->solvables[-solv->rules[why].p].name == name; why++)
596         if (solv->decisionmap[-solv->rules[why].p] > 0)
597           {
598             p = -solv->rules[why].p;
599             break;
600           }
601       if (!p)
602         return;         /* false alarm */
603       queue_push(solutionq, SOLVER_SOLUTION_INFARCH);
604       queue_push(solutionq, p);
605       return;
606     }
607   if (why >= solv->duprules && why < solv->duprules_end)
608     {
609       Id p, name;
610       /* dist upgrade rule, find replacement */
611       assert(solv->rules[why].p < 0);
612       name = pool->solvables[-solv->rules[why].p].name;
613       while (why > solv->duprules && pool->solvables[-solv->rules[why - 1].p].name == name)
614         why--;
615       p = 0;
616       for (; why < solv->duprules_end && pool->solvables[-solv->rules[why].p].name == name; why++)
617         if (solv->decisionmap[-solv->rules[why].p] > 0)
618           {
619             p = -solv->rules[why].p;
620             break;
621           }
622       if (!p)
623         return;         /* false alarm */
624       queue_push(solutionq, SOLVER_SOLUTION_DISTUPGRADE);
625       queue_push(solutionq, p);
626       return;
627     }
628   if (why >= solv->updaterules && why < solv->updaterules_end)
629     {
630       /* update rule, find replacement package */
631       Id p, pp, rp = 0;
632       Rule *rr;
633
634       /* check if this is a false positive, i.e. the update rule is fulfilled */
635       rr = solv->rules + why;
636       FOR_RULELITERALS(p, pp, rr)
637         if (p > 0 && solv->decisionmap[p] > 0)
638           return;       /* false alarm */
639
640       p = solv->installed->start + (why - solv->updaterules);
641       if (solv->decisionmap[p] > 0)
642         return;         /* false alarm, turned out we can keep the package */
643       rr = solv->rules + solv->featurerules + (why - solv->updaterules);
644       if (!rr->p)
645         rr = solv->rules + why;
646       if (rr->w2)
647         {
648           int mvrp = 0;         /* multi-version replacement */
649           FOR_RULELITERALS(rp, pp, rr)
650             {
651               if (rp > 0 && solv->decisionmap[rp] > 0 && pool->solvables[rp].repo != solv->installed)
652                 {
653                   mvrp = rp;
654                   if (!(solv->multiversion.size && MAPTST(&solv->multiversion, rp)))
655                     break;
656                 }
657             }
658           if (!rp && mvrp)
659             {
660               /* found only multi-version replacements */
661               /* have to split solution into two parts */
662               queue_push(solutionq, p);
663               queue_push(solutionq, mvrp);
664             }
665         }
666       queue_push(solutionq, p);
667       queue_push(solutionq, rp);
668       return;
669     }
670   if (why >= solv->bestrules && why < solv->bestrules_end)
671     {
672       int mvrp;
673       Id p, pp, rp = 0;
674       Rule *rr;
675       /* check false positive */
676       rr = solv->rules + why;
677       FOR_RULELITERALS(p, pp, rr)
678         if (p > 0 && solv->decisionmap[p] > 0)
679           return;       /* false alarm */
680       /* check update/feature rule */
681       p = solv->bestrules_info[why - solv->bestrules];
682       if (p < 0)
683         {
684           /* install job */
685           queue_push(solutionq, 0);
686           queue_push(solutionq, solv->ruletojob.elements[-p - solv->jobrules] + 1);
687           return;
688         }
689       if (solv->decisionmap[p] > 0)
690         {
691           /* disable best rule by keeping the old package */
692           queue_push(solutionq, SOLVER_SOLUTION_BEST);
693           queue_push(solutionq, p);
694           return;
695         }
696       rr = solv->rules + solv->featurerules + (p - solv->installed->start);
697       if (!rr->p)
698         rr = solv->rules + solv->updaterules + (p - solv->installed->start);
699       mvrp = 0;         /* multi-version replacement */
700       FOR_RULELITERALS(rp, pp, rr)
701         if (rp > 0 && solv->decisionmap[rp] > 0 && pool->solvables[rp].repo != solv->installed)
702           {
703             mvrp = rp;
704             if (!(solv->multiversion.size && MAPTST(&solv->multiversion, rp)))
705               break;
706           }
707       if (!rp && mvrp)
708         {
709           queue_push(solutionq, SOLVER_SOLUTION_BEST);  /* split, see above */
710           queue_push(solutionq, mvrp);
711           queue_push(solutionq, p);
712           queue_push(solutionq, 0);
713           return;
714         }
715       if (rp)
716         {
717           queue_push(solutionq, SOLVER_SOLUTION_BEST);
718           queue_push(solutionq, rp);
719         }
720       return;
721     }
722   if (why >= solv->blackrules && why < solv->blackrules_end)
723     {
724       queue_push(solutionq, SOLVER_SOLUTION_BLACK);
725       assert(solv->rules[why].p < 0);
726       queue_push(solutionq, -solv->rules[why].p);
727     }
728   if (why >= solv->strictrepopriorules && why < solv->strictrepopriorules_end)
729     {
730       queue_push(solutionq, SOLVER_SOLUTION_STRICTREPOPRIORITY);
731       assert(solv->rules[why].p < 0);
732       queue_push(solutionq, -solv->rules[why].p);
733     }
734 }
735
736 /*
737  * convert problem data into a form usable for refining.
738  * Returns the number of problems.
739  */
740 int
741 solver_prepare_solutions(Solver *solv)
742 {
743   int i, j = 1, idx;
744
745   if (!solv->problems.count)
746     return 0;
747   queue_empty(&solv->solutions);
748   queue_push(&solv->solutions, 0);      /* dummy so idx is always nonzero */
749   idx = solv->solutions.count;
750   queue_push(&solv->solutions, -1);     /* unrefined */
751   /* proofidx stays in position, thus we start with 1 */
752   for (i = 1; i < solv->problems.count; i++)
753     {
754       Id p = solv->problems.elements[i];
755       queue_push(&solv->solutions, p);
756       if (p)
757         continue;
758       /* end of problem reached */
759       solv->problems.elements[j++] = idx;
760       if (i + 1 >= solv->problems.count)
761         break;
762       /* start another problem */
763       solv->problems.elements[j++] = solv->problems.elements[++i];  /* copy proofidx */
764       idx = solv->solutions.count;
765       queue_push(&solv->solutions, -1); /* unrefined */
766     }
767   solv->problems.count = j;
768   return j / 2;
769 }
770
771 /*
772  * refine the simple solution rule list provided by
773  * the solver into multiple lists of job modifiers.
774  */
775 static void
776 create_solutions(Solver *solv, int probnr, int solidx)
777 {
778   Pool *pool = solv->pool;
779   Queue redoq;
780   Queue problem, solution, problems_save, branches_save, decisionq_reason_save;
781   int i, j, nsol;
782   int essentialok;
783   unsigned int now;
784   int oldmistakes = solv->cleandeps_mistakes ? solv->cleandeps_mistakes->count : 0;
785   Id extraflags = -1;
786
787   now = solv_timems(0);
788   queue_init(&redoq);
789   /* save decisionq, decisionq_why, decisionmap, and decisioncnt */
790   for (i = 0; i < solv->decisionq.count; i++)
791     {
792       Id p = solv->decisionq.elements[i];
793       queue_push(&redoq, p);
794       queue_push(&redoq, solv->decisionq_why.elements[i]);
795       queue_push(&redoq, solv->decisionmap[p > 0 ? p : -p]);
796     }
797
798   /* save problems queue */
799   problems_save = solv->problems;
800   memset(&solv->problems, 0, sizeof(solv->problems));
801
802   /* save branches queue */
803   branches_save = solv->branches;
804   memset(&solv->branches, 0, sizeof(solv->branches));
805
806   /* save decisionq_reason */
807   decisionq_reason_save = solv->decisionq_reason;
808   memset(&solv->decisionq_reason, 0, sizeof(solv->decisionq_reason));
809
810   /* extract problem from queue */
811   queue_init(&problem);
812   for (i = solidx + 1; i < solv->solutions.count; i++)
813     {
814       Id v = solv->solutions.elements[i];
815       if (!v)
816         break;
817       queue_push(&problem, v);
818       if (v < 0)
819         extraflags &= solv->job.elements[-v - 1];
820     }
821   if (extraflags == -1)
822     extraflags = 0;
823   if (problem.count > 1)
824     solv_sort(problem.elements, problem.count, sizeof(Id), problems_sortcmp, &solv->job);
825   queue_push(&problem, 0);      /* mark end for refine_suggestion */
826   problem.count--;
827 #if 0
828   for (i = 0; i < problem.count; i++)
829     printf("PP %d %d\n", i, problem.elements[i]);
830 #endif
831
832   /* refine each solution element */
833   nsol = 0;
834   essentialok = 0;
835   queue_init(&solution);
836   for (i = 0; i < problem.count; i++)
837     {
838       int solstart = solv->solutions.count;
839       refine_suggestion(solv, problem.elements, problem.elements[i], &solution, essentialok);
840       queue_push(&solv->solutions, 0);  /* reserve room for number of elements */
841       for (j = 0; j < solution.count; j++)
842         convertsolution(solv, solution.elements[j], &solv->solutions);
843       if (solv->solutions.count == solstart + 1)
844         {
845           solv->solutions.count--;      /* this one did not work out */
846           if (nsol || i + 1 < problem.count)
847             continue;                   /* got one or still hope */
848           if (!essentialok)
849             {
850               /* nothing found, start over */
851               POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "nothing found, re-run with essentialok = 1\n");
852               essentialok = 1;
853               i = -1;
854               continue;
855             }
856           /* this is bad, we found no solution */
857           /* for now just offer a rule */
858           POOL_DEBUG(SOLV_DEBUG_SOLUTIONS, "nothing found, already did essentialok, fake it\n");
859           queue_push(&solv->solutions, 0);
860           for (j = 0; j < problem.count; j++)
861             {
862               convertsolution(solv, problem.elements[j], &solv->solutions);
863               if (solv->solutions.count > solstart + 1)
864                 break;
865             }
866           if (solv->solutions.count == solstart + 1)
867             {
868               solv->solutions.count--;
869               continue;         /* sorry */
870             }
871         }
872       /* patch in number of solution elements */
873       solv->solutions.elements[solstart] = (solv->solutions.count - (solstart + 1)) / 2;
874       queue_push(&solv->solutions, 0);  /* add end marker */
875       queue_push(&solv->solutions, 0);  /* add end marker */
876       queue_push(&solv->solutions, problem.elements[i]);        /* just for bookkeeping */
877       queue_push(&solv->solutions, extraflags & SOLVER_CLEANDEPS);      /* our extraflags */
878       solv->solutions.elements[solidx + 1 + nsol++] = solstart;
879     }
880   solv->solutions.elements[solidx + 1 + nsol] = 0;      /* end marker */
881   solv->solutions.elements[solidx] = nsol;
882   queue_free(&problem);
883   queue_free(&solution);
884
885   /* restore decisions */
886   memset(solv->decisionmap, 0, pool->nsolvables * sizeof(Id));
887   queue_empty(&solv->decisionq);
888   queue_empty(&solv->decisionq_why);
889   for (i = 0; i < redoq.count; i += 3)
890     {
891       Id p = redoq.elements[i];
892       queue_push(&solv->decisionq, p);
893       queue_push(&solv->decisionq_why, redoq.elements[i + 1]);
894       solv->decisionmap[p > 0 ? p : -p] = redoq.elements[i + 2];
895     }
896   queue_free(&redoq);
897
898   /* restore decision reasons */
899   queue_free(&solv->decisionq_reason);
900   solv->decisionq_reason = decisionq_reason_save;
901
902   /* restore problems */
903   queue_free(&solv->problems);
904   solv->problems = problems_save;
905
906   /* restore branches */
907   queue_free(&solv->branches);
908   solv->branches = branches_save;
909
910   if (solv->cleandeps_mistakes)
911     {
912       if (oldmistakes)
913         queue_truncate(solv->cleandeps_mistakes, oldmistakes);
914       else
915         {
916           queue_free(solv->cleandeps_mistakes);
917           solv->cleandeps_mistakes = solv_free(solv->cleandeps_mistakes);
918         }
919     }
920
921   POOL_DEBUG(SOLV_DEBUG_STATS, "create_solutions for problem #%d took %d ms\n", probnr, solv_timems(now));
922 }
923
924
925 /**************************************************************************/
926
927 unsigned int
928 solver_problem_count(Solver *solv)
929 {
930   return solv->problems.count / 2;
931 }
932
933 Id
934 solver_next_problem(Solver *solv, Id problem)
935 {
936   if (!problem)
937     return solv->problems.count ? 1 : 0;
938   return (problem + 1) * 2 - 1 < solv->problems.count ? problem + 1 : 0;
939 }
940
941 unsigned int
942 solver_solution_count(Solver *solv, Id problem)
943 {
944   Id solidx = solv->problems.elements[problem * 2 - 1];
945   if (solv->solutions.elements[solidx] < 0)
946     create_solutions(solv, problem, solidx);
947   return solv->solutions.elements[solidx];
948 }
949
950 Id
951 solver_next_solution(Solver *solv, Id problem, Id solution)
952 {
953   Id solidx = solv->problems.elements[problem * 2 - 1];
954   if (solv->solutions.elements[solidx] < 0)
955     create_solutions(solv, problem, solidx);
956   return solv->solutions.elements[solidx + solution + 1] ? solution + 1 : 0;
957 }
958
959 unsigned int
960 solver_solutionelement_count(Solver *solv, Id problem, Id solution)
961 {
962   Id solidx = solv->problems.elements[problem * 2 - 1];
963   solidx = solv->solutions.elements[solidx + solution];
964   return solv->solutions.elements[solidx];
965 }
966
967 Id
968 solver_solutionelement_internalid(Solver *solv, Id problem, Id solution)
969 {
970   Id solidx = solv->problems.elements[problem * 2 - 1];
971   solidx = solv->solutions.elements[solidx + solution];
972   return solv->solutions.elements[solidx + 2 * solv->solutions.elements[solidx] + 3];
973 }
974
975 Id
976 solver_solutionelement_extrajobflags(Solver *solv, Id problem, Id solution)
977 {
978   Id solidx = solv->problems.elements[problem * 2 - 1];
979   solidx = solv->solutions.elements[solidx + solution];
980   return solv->solutions.elements[solidx + 2 * solv->solutions.elements[solidx] + 4];
981 }
982
983
984 /*
985  *  return the next item of the proposed solution
986  *  here are the possibilities for p / rp and what
987  *  the solver expects the application to do:
988  *    p                             rp
989  *  -------------------------------------------------------
990  *    SOLVER_SOLUTION_INFARCH       pkgid
991  *    -> add (SOLVER_INSTALL|SOLVER_SOLVABLE, rp) to the job
992  *    SOLVER_SOLUTION_DISTUPGRADE   pkgid
993  *    -> add (SOLVER_INSTALL|SOLVER_SOLVABLE, rp) to the job
994  *    SOLVER_SOLUTION_BEST          pkgid
995  *    -> add (SOLVER_INSTALL|SOLVER_SOLVABLE, rp) to the job
996  *    SOLVER_SOLUTION_BLACK         pkgid
997  *    -> add (SOLVER_INSTALL|SOLVER_SOLVABLE, rp) to the job
998  *    SOLVER_SOLUTION_JOB           jobidx
999  *    -> remove job (jobidx - 1, jobidx) from job queue
1000  *    SOLVER_SOLUTION_POOLJOB       jobidx
1001  *    -> remove job (jobidx - 1, jobidx) from pool job queue
1002  *    pkgid (> 0)                   0
1003  *    -> add (SOLVER_ERASE|SOLVER_SOLVABLE, p) to the job
1004  *    pkgid (> 0)                   pkgid (> 0)
1005  *    -> add (SOLVER_INSTALL|SOLVER_SOLVABLE, rp) to the job
1006  *       (this will replace package p)
1007  *
1008  * Thus, the solver will either ask the application to remove
1009  * a specific job from the job queue, or ask to add an install/erase
1010  * job to it.
1011  *
1012  */
1013
1014 Id
1015 solver_next_solutionelement(Solver *solv, Id problem, Id solution, Id element, Id *p, Id *rp)
1016 {
1017   Id solidx = solv->problems.elements[problem * 2 - 1];
1018   solidx = solv->solutions.elements[solidx + solution];
1019   if (!solidx)
1020     return 0;
1021   solidx += 1 + element * 2;
1022   if (!solv->solutions.elements[solidx] && !solv->solutions.elements[solidx + 1])
1023     return 0;
1024   *p = solv->solutions.elements[solidx];
1025   *rp = solv->solutions.elements[solidx + 1];
1026   return element + 1;
1027 }
1028
1029 void
1030 solver_take_solutionelement(Solver *solv, Id p, Id rp, Id extrajobflags, Queue *job)
1031 {
1032   int i;
1033
1034   if (p == SOLVER_SOLUTION_POOLJOB)
1035     {
1036       solv->pool->pooljobs.elements[rp - 1] = SOLVER_NOOP;
1037       solv->pool->pooljobs.elements[rp] = 0;
1038       return;
1039     }
1040   if (p == SOLVER_SOLUTION_JOB)
1041     {
1042       job->elements[rp - 1] = SOLVER_NOOP;
1043       job->elements[rp] = 0;
1044       return;
1045     }
1046   if (rp <= 0 && p <= 0)
1047     return;     /* just in case */
1048   if (rp > 0)
1049     p = SOLVER_INSTALL|SOLVER_SOLVABLE|SOLVER_NOTBYUSER|extrajobflags;
1050   else
1051     {
1052       rp = p;
1053       p = SOLVER_ERASE|SOLVER_SOLVABLE|extrajobflags;
1054     }
1055   for (i = 0; i < job->count; i += 2)
1056     if (job->elements[i] == p && job->elements[i + 1] == rp)
1057       return;
1058   queue_push2(job, p, rp);
1059 }
1060
1061 void
1062 solver_take_solution(Solver *solv, Id problem, Id solution, Queue *job)
1063 {
1064   Id p, rp, element = 0;
1065   Id extrajobflags = solver_solutionelement_extrajobflags(solv, problem, solution);
1066   while ((element = solver_next_solutionelement(solv, problem, solution, element, &p, &rp)) != 0)
1067     solver_take_solutionelement(solv, p, rp, extrajobflags, job);
1068 }
1069
1070
1071 /*-------------------------------------------------------------------
1072  *
1073  * find problem rule
1074  */
1075
1076 static void
1077 findproblemrule_internal(Solver *solv, Id idx, Id *reqrp, Id *conrp, Id *sysrp, Id *jobrp, Id *blkrp, Id *scprp, Map *rseen)
1078 {
1079   Id rid, d;
1080   Id lreqr, lconr, lsysr, ljobr, lblkr, lscpr;
1081   Rule *r;
1082   Id jobassert = 0;
1083   int i, reqset = 0;    /* 0: unset, 1: installed, 2: jobassert, 3: assert */
1084   int conset = 0;       /* 0: unset, 1: installed */
1085
1086   /* find us a jobassert rule */
1087   for (i = idx; (rid = solv->learnt_pool.elements[i]) != 0; i++)
1088     {
1089       if (rid < solv->jobrules || rid >= solv->jobrules_end)
1090         continue;
1091       r = solv->rules + rid;
1092       d = r->d < 0 ? -r->d - 1 : r->d;
1093       if (!d && r->w2 == 0 && r->p > 0)
1094         {
1095           jobassert = r->p;
1096           break;
1097         }
1098     }
1099
1100   /* the problem rules are somewhat ordered from "near to the problem" to
1101    * "near to the job" */
1102   lreqr = lconr = lsysr = ljobr = lblkr = lscpr = 0;
1103   while ((rid = solv->learnt_pool.elements[idx++]) != 0)
1104     {
1105       assert(rid > 0);
1106       if (rid >= solv->learntrules)
1107         {
1108           if (MAPTST(rseen, rid - solv->learntrules))
1109             continue;
1110           MAPSET(rseen, rid - solv->learntrules);
1111           findproblemrule_internal(solv, solv->learnt_why.elements[rid - solv->learntrules], &lreqr, &lconr, &lsysr, &ljobr, &lblkr, &lscpr, rseen);
1112         }
1113       else if ((rid >= solv->jobrules && rid < solv->jobrules_end) || (rid >= solv->infarchrules && rid < solv->infarchrules_end) || (rid >= solv->duprules && rid < solv->duprules_end) || (rid >= solv->bestrules && rid < solv->bestrules_end) || (rid >= solv->yumobsrules && rid < solv->yumobsrules_end))
1114         {
1115           if (!*jobrp)
1116             *jobrp = rid;
1117         }
1118       else if (rid >= solv->updaterules && rid < solv->updaterules_end)
1119         {
1120           if (!*sysrp)
1121             *sysrp = rid;
1122         }
1123       else if (rid >= solv->blackrules && rid < solv->blackrules_end)
1124         {
1125           if (!*blkrp)
1126             *blkrp = rid;
1127         }
1128       else if (rid >= solv->strictrepopriorules && rid < solv->strictrepopriorules_end)
1129         {
1130           if (!*scprp)
1131             *scprp = rid;
1132         }
1133       else
1134         {
1135           assert(rid < solv->pkgrules_end);
1136           r = solv->rules + rid;
1137           d = r->d < 0 ? -r->d - 1 : r->d;
1138           if (!d && r->w2 < 0)
1139             {
1140               /* prefer conflicts of installed packages */
1141               if (solv->installed && !conset)
1142                 {
1143                   if (r->p < 0 && (solv->pool->solvables[-r->p].repo == solv->installed ||
1144                                   solv->pool->solvables[-r->w2].repo == solv->installed))
1145                     {
1146                       *conrp = rid;
1147                       conset = 1;
1148                     }
1149                 }
1150               if (!*conrp)
1151                 *conrp = rid;
1152             }
1153           else
1154             {
1155               if (!d && r->w2 == 0 && reqset < 3)
1156                 {
1157                   if (*reqrp > 0 && r->p < -1)
1158                     {
1159                       Pool *pool = solv->pool;
1160                       Id op = -solv->rules[*reqrp].p;
1161                       if (op > 1 && pool->solvables[op].arch != pool->solvables[-r->p].arch &&
1162                           pool->solvables[-r->p].arch != pool->noarchid)
1163                         continue;       /* different arch, skip */
1164                     }
1165                   /* prefer assertions */
1166                   *reqrp = rid;
1167                   reqset = 3;
1168                 }
1169               else if (jobassert && r->p == -jobassert)
1170                 {
1171                   /* prefer rules of job assertions */
1172                   *reqrp = rid;
1173                   reqset = 2;
1174                 }
1175               else if (solv->installed && r->p < 0 && solv->pool->solvables[-r->p].repo == solv->installed && reqset <= 1)
1176                 {
1177                   /* prefer rules of job installed package so that the user doesn't get confused by strange packages */
1178                   *reqrp = rid;
1179                   reqset = 1;
1180                 }
1181               else if (!*reqrp)
1182                 *reqrp = rid;
1183             }
1184         }
1185     }
1186   if (!*reqrp && lreqr)
1187     *reqrp = lreqr;
1188   if (!*conrp && lconr)
1189     *conrp = lconr;
1190   if (!*jobrp && ljobr)
1191     *jobrp = ljobr;
1192   if (!*sysrp && lsysr)
1193     *sysrp = lsysr;
1194   if (!*blkrp && lblkr)
1195     *blkrp = lblkr;
1196   if (!*scprp && lscpr)
1197     *scprp = lscpr;
1198 }
1199
1200 /*
1201  * find problem rule
1202  *
1203  * search for a rule that describes the problem to the
1204  * user. Actually a pretty hopeless task that may leave the user
1205  * puzzled. To get all of the needed information use
1206  * solver_findallproblemrules() instead.
1207  */
1208
1209 Id
1210 solver_findproblemrule(Solver *solv, Id problem)
1211 {
1212   Id reqr, conr, sysr, jobr, blkr, srpr;
1213   Id idx = solv->problems.elements[2 * problem - 2];
1214   Map rseen;
1215   reqr = conr = sysr = jobr = blkr = srpr = 0;
1216   map_init(&rseen, solv->learntrules ? solv->nrules - solv->learntrules : 0);
1217   findproblemrule_internal(solv, idx, &reqr, &conr, &sysr, &jobr, &blkr, &srpr, &rseen);
1218   map_free(&rseen);
1219   /* check if the request is about a not-installed package requiring a installed
1220    * package conflicting with the non-installed package. In that case return the conflict */
1221   if (reqr && conr && solv->installed && solv->rules[reqr].p < 0 && solv->rules[conr].p < 0 && solv->rules[conr].w2 < 0)
1222     {
1223       Pool *pool = solv->pool;
1224       Solvable *s  = pool->solvables - solv->rules[reqr].p;
1225       Solvable *s1 = pool->solvables - solv->rules[conr].p;
1226       Solvable *s2 = pool->solvables - solv->rules[conr].w2;
1227       Id cp = 0;
1228       if (s == s1 && s2->repo == solv->installed)
1229         cp = -solv->rules[conr].w2;
1230       else if (s == s2 && s1->repo == solv->installed)
1231         cp = -solv->rules[conr].p;
1232       if (cp && s1->name != s2->name && s->repo != solv->installed)
1233         {
1234           Id p, pp;
1235           Rule *r = solv->rules + reqr;
1236           FOR_RULELITERALS(p, pp, r)
1237             if (p == cp)
1238               return conr;
1239         }
1240     }
1241   if (reqr)
1242     return reqr;        /* some requires */
1243   if (conr)
1244     return conr;        /* some conflict */
1245   if (blkr)
1246     return blkr;        /* a blacklisted package */
1247   if (srpr)
1248     return srpr;        /* a strict repo priority */
1249   if (sysr)
1250     return sysr;        /* an update rule */
1251   if (jobr)
1252     return jobr;        /* a user request */
1253   assert(0);
1254   return 0;
1255 }
1256
1257 /*-------------------------------------------------------------------*/
1258
1259 static void
1260 findallproblemrules_internal(Solver *solv, Id idx, Queue *rules, Map *rseen)
1261 {
1262   Id rid;
1263   while ((rid = solv->learnt_pool.elements[idx++]) != 0)
1264     {
1265       if (rid >= solv->learntrules)
1266         {
1267           if (MAPTST(rseen, rid - solv->learntrules))
1268             continue;
1269           MAPSET(rseen, rid - solv->learntrules);
1270           findallproblemrules_internal(solv, solv->learnt_why.elements[rid - solv->learntrules], rules, rseen);
1271           continue;
1272         }
1273       queue_pushunique(rules, rid);
1274     }
1275 }
1276
1277 /*
1278  * find all problem rule
1279  *
1280  * return all rules that lead to the problem. This gives the user
1281  * all of the information to understand the problem, but the result
1282  * can be a large number of rules.
1283  */
1284
1285 void
1286 solver_findallproblemrules(Solver *solv, Id problem, Queue *rules)
1287 {
1288   Map rseen;
1289   queue_empty(rules);
1290   map_init(&rseen, solv->learntrules ? solv->nrules - solv->learntrules : 0);
1291   findallproblemrules_internal(solv, solv->problems.elements[2 * problem - 2], rules, &rseen);
1292   map_free(&rseen);
1293 }
1294
1295 const char *
1296 solver_problemruleinfo2str(Solver *solv, SolverRuleinfo type, Id source, Id target, Id dep)
1297 {
1298   Pool *pool = solv->pool;
1299   char *s;
1300   Solvable *ss;
1301   switch (type)
1302     {
1303     case SOLVER_RULE_DISTUPGRADE:
1304       return pool_tmpjoin(pool, pool_solvid2str(pool, source), " does not belong to a distupgrade repository", 0);
1305     case SOLVER_RULE_INFARCH:
1306       return pool_tmpjoin(pool, pool_solvid2str(pool, source), " has inferior architecture", 0);
1307     case SOLVER_RULE_UPDATE:
1308       return pool_tmpjoin(pool, "problem with installed package ", pool_solvid2str(pool, source), 0);
1309     case SOLVER_RULE_JOB:
1310       return "conflicting requests";
1311     case SOLVER_RULE_JOB_UNSUPPORTED:
1312       return "unsupported request";
1313     case SOLVER_RULE_JOB_NOTHING_PROVIDES_DEP:
1314       return pool_tmpjoin(pool, "nothing provides requested ", pool_dep2str(pool, dep), 0);
1315     case SOLVER_RULE_JOB_UNKNOWN_PACKAGE:
1316       return pool_tmpjoin(pool, "package ", pool_dep2str(pool, dep), " does not exist");
1317     case SOLVER_RULE_JOB_PROVIDED_BY_SYSTEM:
1318       return pool_tmpjoin(pool, pool_dep2str(pool, dep), " is provided by the system", 0);
1319     case SOLVER_RULE_PKG:
1320       return "some dependency problem";
1321     case SOLVER_RULE_BEST:
1322       if (source > 0)
1323         return pool_tmpjoin(pool, "cannot install the best update candidate for package ", pool_solvid2str(pool, source), 0);
1324      return "cannot install the best candidate for the job";
1325     case SOLVER_RULE_PKG_NOT_INSTALLABLE:
1326       ss = pool->solvables + source;
1327       if (pool_disabled_solvable(pool, ss))
1328         return pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), " is disabled");
1329       if (ss->arch && ss->arch != ARCH_SRC && ss->arch != ARCH_NOSRC &&
1330           pool->id2arch && pool_arch2score(pool, ss->arch) == 0)
1331         return pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), " does not have a compatible architecture");
1332       return pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), " is not installable");
1333     case SOLVER_RULE_PKG_NOTHING_PROVIDES_DEP:
1334       s = pool_tmpjoin(pool, "nothing provides ", pool_dep2str(pool, dep), 0);
1335       return pool_tmpappend(pool, s, " needed by ", pool_solvid2str(pool, source));
1336     case SOLVER_RULE_PKG_SAME_NAME:
1337       s = pool_tmpjoin(pool, "cannot install both ", pool_solvid2str(pool, source), 0);
1338       return pool_tmpappend(pool, s, " and ", pool_solvid2str(pool, target));
1339     case SOLVER_RULE_PKG_CONFLICTS:
1340       s = pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), 0);
1341       s = pool_tmpappend(pool, s, " conflicts with ", pool_dep2str(pool, dep));
1342       return pool_tmpappend(pool, s, " provided by ", pool_solvid2str(pool, target));
1343     case SOLVER_RULE_PKG_OBSOLETES:
1344       s = pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), 0);
1345       s = pool_tmpappend(pool, s, " obsoletes ", pool_dep2str(pool, dep));
1346       return pool_tmpappend(pool, s, " provided by ", pool_solvid2str(pool, target));
1347     case SOLVER_RULE_PKG_INSTALLED_OBSOLETES:
1348       s = pool_tmpjoin(pool, "installed package ", pool_solvid2str(pool, source), 0);
1349       s = pool_tmpappend(pool, s, " obsoletes ", pool_dep2str(pool, dep));
1350       return pool_tmpappend(pool, s, " provided by ", pool_solvid2str(pool, target));
1351     case SOLVER_RULE_PKG_IMPLICIT_OBSOLETES:
1352       s = pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), 0);
1353       s = pool_tmpappend(pool, s, " implicitly obsoletes ", pool_dep2str(pool, dep));
1354       return pool_tmpappend(pool, s, " provided by ", pool_solvid2str(pool, target));
1355     case SOLVER_RULE_PKG_REQUIRES:
1356       s = pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), " requires ");
1357       return pool_tmpappend(pool, s, pool_dep2str(pool, dep), ", but none of the providers can be installed");
1358     case SOLVER_RULE_PKG_SELF_CONFLICT:
1359       s = pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), " conflicts with ");
1360       return pool_tmpappend(pool, s, pool_dep2str(pool, dep), " provided by itself");
1361     case SOLVER_RULE_YUMOBS:
1362       s = pool_tmpjoin(pool, "both package ", pool_solvid2str(pool, source), " and ");
1363       s = pool_tmpjoin(pool, s, pool_solvid2str(pool, target), " obsolete ");
1364       return pool_tmpappend(pool, s, pool_dep2str(pool, dep), 0);
1365     case SOLVER_RULE_BLACK:
1366       return pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), " can only be installed by a direct request");
1367     case SOLVER_RULE_STRICT_REPO_PRIORITY:
1368       return pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), " is excluded by strict repo priority");
1369     case SOLVER_RULE_PKG_CONSTRAINS:
1370       s = pool_tmpjoin(pool, "package ", pool_solvid2str(pool, source), 0);
1371       s = pool_tmpappend(pool, s, " has constraint ", pool_dep2str(pool, dep));
1372       return pool_tmpappend(pool, s, " conflicting with ", pool_solvid2str(pool, target));
1373     default:
1374       return "bad problem rule type";
1375     }
1376 }
1377
1378 /* convenience function */
1379 const char *
1380 solver_problem2str(Solver *solv, Id problem)
1381 {
1382   Id type, source, target, dep;
1383   Id r = solver_findproblemrule(solv, problem);
1384   if (!r)
1385     return "no problem rule?";
1386   type = solver_ruleinfo(solv, r, &source, &target, &dep);
1387   return solver_problemruleinfo2str(solv, type, source, target, dep);
1388 }
1389
1390 const char *
1391 solver_solutionelement2str(Solver *solv, Id p, Id rp)
1392 {
1393   Pool *pool = solv->pool;
1394   if (p == SOLVER_SOLUTION_JOB || p == SOLVER_SOLUTION_POOLJOB)
1395     {
1396       Id how, what;
1397       if (p == SOLVER_SOLUTION_JOB)
1398         rp += solv->pooljobcnt;
1399       how = solv->job.elements[rp - 1];
1400       what = solv->job.elements[rp];
1401       return pool_tmpjoin(pool, "do not ask to ", pool_job2str(pool, how, what, 0), 0);
1402     }
1403   else if (p == SOLVER_SOLUTION_INFARCH)
1404     {
1405       Solvable *s = pool->solvables + rp;
1406       if (solv->installed && s->repo == solv->installed)
1407         return pool_tmpjoin(pool, "keep ", pool_solvable2str(pool, s), " despite the inferior architecture");
1408       else
1409         return pool_tmpjoin(pool, "install ", pool_solvable2str(pool, s), " despite the inferior architecture");
1410     }
1411   else if (p == SOLVER_SOLUTION_DISTUPGRADE)
1412     {
1413       Solvable *s = pool->solvables + rp;
1414       if (solv->installed && s->repo == solv->installed)
1415         return pool_tmpjoin(pool, "keep obsolete ", pool_solvable2str(pool, s), 0);
1416       else
1417         return pool_tmpjoin(pool, "install ", pool_solvable2str(pool, s), " from excluded repository");
1418     }
1419   else if (p == SOLVER_SOLUTION_BEST)
1420     {
1421       Solvable *s = pool->solvables + rp;
1422       if (solv->installed && s->repo == solv->installed)
1423         return pool_tmpjoin(pool, "keep old ", pool_solvable2str(pool, s), 0);
1424       else
1425         return pool_tmpjoin(pool, "install ", pool_solvable2str(pool, s), " despite the old version");
1426     }
1427   else if (p == SOLVER_SOLUTION_BLACK)
1428     {
1429       Solvable *s = pool->solvables + rp;
1430       return pool_tmpjoin(pool, "install ", pool_solvable2str(pool, s), 0);
1431     }
1432   else if (p > 0 && rp == 0)
1433     return pool_tmpjoin(pool, "allow deinstallation of ", pool_solvid2str(pool, p), 0);
1434   else if (p == SOLVER_SOLUTION_STRICTREPOPRIORITY)
1435     {
1436       Solvable *s = pool->solvables + rp;
1437       return pool_tmpjoin(pool, "install ", pool_solvable2str(pool, s), " despite the repo priority");
1438     }
1439   else if (p > 0 && rp > 0)
1440     {
1441       const char *sp = pool_solvid2str(pool, p);
1442       const char *srp = pool_solvid2str(pool, rp);
1443       const char *str = pool_tmpjoin(pool, "allow replacement of ", sp, 0);
1444       return pool_tmpappend(pool, str, " with ", srp);
1445     }
1446   else
1447     return "bad solution element";
1448 }
1449