From: Wouter van Oortmerssen <wvo@google.com>
Date: Thu, 21 Aug 2014 22:02:15 +0000 (-0700)
Subject: Checking for clashes between field names and generated field names.
X-Git-Tag: v1.0.2~12
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=541b06759f72dcff9008478da797957e6fbabb45;p=platform%2Fupstream%2Fflatbuffers.git

Checking for clashes between field names and generated field names.

This happens when the schema is parsed, to avoid compile time errors
later, which would be harder to understand.

Bug: 16325216
Change-Id: I24cabf1adaf1700796b91e3a9641bca43a68bfbd
Tested: on OS X.
---

diff --git a/src/idl_parser.cpp b/src/idl_parser.cpp
index d3b9519..8b7f78e 100644
--- a/src/idl_parser.cpp
+++ b/src/idl_parser.cpp
@@ -800,6 +800,31 @@ void Parser::ParseDecl() {
       }
     }
   }
+  // Check that no identifiers clash with auto generated fields.
+  // This is not an ideal situation, but should occur very infrequently,
+  // and allows us to keep using very readable names for type & length fields
+  // without inducing compile errors.
+  auto CheckClash = [&fields, &struct_def](const char *suffix,
+                                           BaseType basetype) {
+    auto len = strlen(suffix);
+    for (auto it = fields.begin(); it != fields.end(); ++it) {
+      auto &name = (*it)->name;
+      if (name.length() > len &&
+          name.compare(name.length() - len, len, suffix) == 0 &&
+          (*it)->value.type.base_type != BASE_TYPE_UTYPE) {
+        auto field = struct_def.fields.Lookup(
+                       name.substr(0, name.length() - len));
+        if (field && field->value.type.base_type == basetype)
+          Error("Field " + name +
+                " would clash with generated functions for field " +
+                field->name);
+      }
+    }
+  };
+  CheckClash("_type", BASE_TYPE_UNION);
+  CheckClash("Type", BASE_TYPE_UNION);
+  CheckClash("_length", BASE_TYPE_VECTOR);
+  CheckClash("Length", BASE_TYPE_VECTOR);
   Expect('}');
 }
 
diff --git a/tests/test.cpp b/tests/test.cpp
index 07545a0..edb971a 100644
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -488,6 +488,7 @@ void ErrorTest() {
   TestError("struct X { Y:int; } root_type X;", "a table");
   TestError("union X { Y }", "referenced");
   TestError("union Z { X } struct X { Y:int; }", "only tables");
+  TestError("table X { Y:[int]; YLength:int; }", "clash");
 }
 
 // Additional parser testing not covered elsewhere.