Imported Upstream version 2.28.0
[platform/upstream/git.git] / builtin / diff.c
index 42ac803..cb98811 100644 (file)
@@ -6,6 +6,7 @@
 #define USE_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
 #include "config.h"
+#include "ewah/ewok.h"
 #include "lockfile.h"
 #include "color.h"
 #include "commit.h"
 #include "log-tree.h"
 #include "builtin.h"
 #include "submodule.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 
 #define DIFF_NO_INDEX_EXPLICIT 1
 #define DIFF_NO_INDEX_IMPLICIT 2
 
 static const char builtin_diff_usage[] =
-"git diff [<options>] [<commit> [<commit>]] [--] [<path>...]";
+"git diff [<options>] [<commit>] [--] [<path>...]\n"
+"   or: git diff [<options>] --cached [<commit>] [--] [<path>...]\n"
+"   or: git diff [<options>] <commit> [<commit>...] <commit> [--] [<path>...]\n"
+"   or: git diff [<options>] <commit>...<commit>] [--] [<path>...]\n"
+"   or: git diff [<options>] <blob> <blob>]\n"
+"   or: git diff [<options>] --no-index [--] <path> <path>]\n"
+COMMON_DIFF_OPTIONS_HELP;
 
 static const char *blob_path(struct object_array_entry *entry)
 {
@@ -254,6 +261,108 @@ static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv
        return run_diff_files(revs, options);
 }
 
+struct symdiff {
+       struct bitmap *skip;
+       int warn;
+       const char *base, *left, *right;
+};
+
+/*
+ * Check for symmetric-difference arguments, and if present, arrange
+ * everything we need to know to handle them correctly.  As a bonus,
+ * weed out all bogus range-based revision specifications, e.g.,
+ * "git diff A..B C..D" or "git diff A..B C" get rejected.
+ *
+ * For an actual symmetric diff, *symdiff is set this way:
+ *
+ *  - its skip is non-NULL and marks *all* rev->pending.objects[i]
+ *    indices that the caller should ignore (extra merge bases, of
+ *    which there might be many, and A in A...B).  Note that the
+ *    chosen merge base and right side are NOT marked.
+ *  - warn is set if there are multiple merge bases.
+ *  - base, left, and right point to the names to use in a
+ *    warning about multiple merge bases.
+ *
+ * If there is no symmetric diff argument, sym->skip is NULL and
+ * sym->warn is cleared.  The remaining fields are not set.
+ */
+static void symdiff_prepare(struct rev_info *rev, struct symdiff *sym)
+{
+       int i, is_symdiff = 0, basecount = 0, othercount = 0;
+       int lpos = -1, rpos = -1, basepos = -1;
+       struct bitmap *map = NULL;
+
+       /*
+        * Use the whence fields to find merge bases and left and
+        * right parts of symmetric difference, so that we do not
+        * depend on the order that revisions are parsed.  If there
+        * are any revs that aren't from these sources, we have a
+        * "git diff C A...B" or "git diff A...B C" case.  Or we
+        * could even get "git diff A...B C...E", for instance.
+        *
+        * If we don't have just one merge base, we pick one
+        * at random.
+        *
+        * NB: REV_CMD_LEFT, REV_CMD_RIGHT are also used for A..B,
+        * so we must check for SYMMETRIC_LEFT too.  The two arrays
+        * rev->pending.objects and rev->cmdline.rev are parallel.
+        */
+       for (i = 0; i < rev->cmdline.nr; i++) {
+               struct object *obj = rev->pending.objects[i].item;
+               switch (rev->cmdline.rev[i].whence) {
+               case REV_CMD_MERGE_BASE:
+                       if (basepos < 0)
+                               basepos = i;
+                       basecount++;
+                       break;          /* do mark all bases */
+               case REV_CMD_LEFT:
+                       if (lpos >= 0)
+                               usage(builtin_diff_usage);
+                       lpos = i;
+                       if (obj->flags & SYMMETRIC_LEFT) {
+                               is_symdiff = 1;
+                               break;  /* do mark A */
+                       }
+                       continue;
+               case REV_CMD_RIGHT:
+                       if (rpos >= 0)
+                               usage(builtin_diff_usage);
+                       rpos = i;
+                       continue;       /* don't mark B */
+               case REV_CMD_PARENTS_ONLY:
+               case REV_CMD_REF:
+               case REV_CMD_REV:
+                       othercount++;
+                       continue;
+               }
+               if (map == NULL)
+                       map = bitmap_new();
+               bitmap_set(map, i);
+       }
+
+       /*
+        * Forbid any additional revs for both A...B and A..B.
+        */
+       if (lpos >= 0 && othercount > 0)
+               usage(builtin_diff_usage);
+
+       if (!is_symdiff) {
+               bitmap_free(map);
+               sym->warn = 0;
+               sym->skip = NULL;
+               return;
+       }
+
+       sym->left = rev->pending.objects[lpos].name;
+       sym->right = rev->pending.objects[rpos].name;
+       if (basecount == 0)
+               die(_("%s...%s: no merge base"), sym->left, sym->right);
+       sym->base = rev->pending.objects[basepos].name;
+       bitmap_unset(map, basepos);     /* unmark the base we want */
+       sym->warn = basecount > 1;
+       sym->skip = map;
+}
+
 int cmd_diff(int argc, const char **argv, const char *prefix)
 {
        int i;
@@ -263,19 +372,29 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
        struct object_array_entry *blob[2];
        int nongit = 0, no_index = 0;
        int result = 0;
+       struct symdiff sdiff;
 
        /*
         * We could get N tree-ish in the rev.pending_objects list.
-        * Also there could be M blobs there, and P pathspecs.
+        * Also there could be M blobs there, and P pathspecs. --cached may
+        * also be present.
         *
         * N=0, M=0:
-        *      cache vs files (diff-files)
+        *      cache vs files (diff-files)
+        *
+        * N=0, M=0, --cached:
+        *      HEAD vs cache (diff-index --cached)
+        *
         * N=0, M=2:
         *      compare two random blobs.  P must be zero.
+        *
         * N=0, M=1, P=1:
-        *      compare a blob with a working tree file.
+        *      compare a blob with a working tree file.
         *
         * N=1, M=0:
+        *      tree vs files (diff-index)
+        *
+        * N=1, M=0, --cached:
         *      tree vs cache (diff-index --cached)
         *
         * N=2, M=0:
@@ -382,6 +501,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
                }
        }
 
+       symdiff_prepare(&rev, &sdiff);
        for (i = 0; i < rev.pending.nr; i++) {
                struct object_array_entry *entry = &rev.pending.objects[i];
                struct object *obj = entry->item;
@@ -396,6 +516,8 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
                        obj = &get_commit_tree(((struct commit *)obj))->object;
 
                if (obj->type == OBJ_TREE) {
+                       if (sdiff.skip && bitmap_get(sdiff.skip, i))
+                               continue;
                        obj->flags |= flags;
                        add_object_array(obj, name, &ent);
                } else if (obj->type == OBJ_BLOB) {
@@ -437,21 +559,12 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
                usage(builtin_diff_usage);
        else if (ent.nr == 1)
                result = builtin_diff_index(&rev, argc, argv);
-       else if (ent.nr == 2)
+       else if (ent.nr == 2) {
+               if (sdiff.warn)
+                       warning(_("%s...%s: multiple merge bases, using %s"),
+                               sdiff.left, sdiff.right, sdiff.base);
                result = builtin_diff_tree(&rev, argc, argv,
                                           &ent.objects[0], &ent.objects[1]);
-       else if (ent.objects[0].item->flags & UNINTERESTING) {
-               /*
-                * diff A...B where there is at least one merge base
-                * between A and B.  We have ent.objects[0] ==
-                * merge-base, ent.objects[ents-2] == A, and
-                * ent.objects[ents-1] == B.  Show diff between the
-                * base and B.  Note that we pick one merge base at
-                * random if there are more than one.
-                */
-               result = builtin_diff_tree(&rev, argc, argv,
-                                          &ent.objects[0],
-                                          &ent.objects[ent.nr-1]);
        } else
                result = builtin_diff_combined(&rev, argc, argv,
                                               ent.objects, ent.nr);