Change various Gin*Is* macros to return 0/1.

Returning the direct result of bit arithmetic, in a macro intended to be
used in a boolean manner, can be problematic if the return value is
stored in a variable of type 'bool'. If bool is implemented using C99's
_Bool, that can lead to comparison failures if the variable is then
compared again with the expression (see ginStepRight() for an example
that fails), as _Bool forces the result to be 0/1. That happens in some
configurations of newer MSVC compilers.  It's also problematic when
storing the result of such an expression in a narrower type.

Several gin macros have been declared in that style since gin's initial
commit in 8a3631f8d86.

There's a lot more macros like this, but this is the only one causing
regression test failures; and I don't want to commit and backpatch a
larger patch with lots of conflicts just before the next set of minor
releases.

Discussion: 20150811154237.GD17575@awork2.anarazel.de
Backpatch: All supported branches

diff --git a/src/include/access/gin_private.h b/src/include/access/gin_private.h
index 665ca886f8e19935173919d2a1d4919d6ed55211..9537ae78cd8873e5eb72cf2b544154fa9f09d876 100644 (file)
--- a/src/include/access/gin_private.h
+++ b/src/include/access/gin_private.h
@@ -101,17 +101,17 @@ typedef struct GinMetaPageData
  */
 #define GinPageGetOpaque(page) ( (GinPageOpaque) PageGetSpecialPointer(page) )
 
-#define GinPageIsLeaf(page)    ( GinPageGetOpaque(page)->flags & GIN_LEAF )
+#define GinPageIsLeaf(page)    ( (GinPageGetOpaque(page)->flags & GIN_LEAF) != 0 )
 #define GinPageSetLeaf(page)   ( GinPageGetOpaque(page)->flags |= GIN_LEAF )
 #define GinPageSetNonLeaf(page)    ( GinPageGetOpaque(page)->flags &= ~GIN_LEAF )
-#define GinPageIsData(page)    ( GinPageGetOpaque(page)->flags & GIN_DATA )
+#define GinPageIsData(page)    ( (GinPageGetOpaque(page)->flags & GIN_DATA) != 0 )
 #define GinPageSetData(page)   ( GinPageGetOpaque(page)->flags |= GIN_DATA )
-#define GinPageIsList(page)    ( GinPageGetOpaque(page)->flags & GIN_LIST )
+#define GinPageIsList(page)    ( (GinPageGetOpaque(page)->flags & GIN_LIST) != 0 )
 #define GinPageSetList(page)   ( GinPageGetOpaque(page)->flags |= GIN_LIST )
-#define GinPageHasFullRow(page)    ( GinPageGetOpaque(page)->flags & GIN_LIST_FULLROW )
+#define GinPageHasFullRow(page)    ( (GinPageGetOpaque(page)->flags & GIN_LIST_FULLROW) != 0 )
 #define GinPageSetFullRow(page)   ( GinPageGetOpaque(page)->flags |= GIN_LIST_FULLROW )
 
-#define GinPageIsDeleted(page) ( GinPageGetOpaque(page)->flags & GIN_DELETED)
+#define GinPageIsDeleted(page) ( (GinPageGetOpaque(page)->flags & GIN_DELETED) != 0 )
 #define GinPageSetDeleted(page)    ( GinPageGetOpaque(page)->flags |= GIN_DELETED)
 #define GinPageSetNonDeleted(page) ( GinPageGetOpaque(page)->flags &= ~GIN_DELETED)