Don't cast between GinNullCategory and bool

The original idea was that we could use an isNull-style bool array
directly as a GinNullCategory array.  However, the existing code already
acknowledges that that doesn't really work, because of the possibility
that bool as currently defined can have arbitrary bit patterns for true
values.  So it has to loop through the nullFlags array to set each bool
value to an acceptable value.  But if we are looping through the whole
array anyway, we might as well build a proper GinNullCategory array
instead and abandon the type casting.  That makes the code much safer in
case bool is ever changed to something else.

Reviewed-by: Michael Paquier <michael.paquier@gmail.com>

1 files changed, 8 insertions, 11 deletions

diff --git a/src/backend/access/gin/ginscan.c b/src/backend/access/gin/ginscan.c
index 7ceea7a741..77c0c577b5 100644
--- a/src/backend/access/gin/ginscan.c
+++ b/src/backend/access/gin/ginscan.c
@@ -295,6 +295,7 @@ ginNewScanKey(IndexScanDesc scan)
 		bool	   *partial_matches = NULL;
 		Pointer    *extra_data = NULL;
 		bool	   *nullFlags = NULL;
+		GinNullCategory *categories;
 		int32		searchMode = GIN_SEARCH_MODE_DEFAULT;
 
 		/*
@@ -346,15 +347,12 @@ ginNewScanKey(IndexScanDesc scan)
 		}
 
 		/*
-		 * If the extractQueryFn didn't create a nullFlags array, create one,
-		 * assuming that everything's non-null.  Otherwise, run through the
-		 * array and make sure each value is exactly 0 or 1; this ensures
-		 * binary compatibility with the GinNullCategory representation. While
-		 * at it, detect whether any null keys are present.
+		 * Create GinNullCategory representation.  If the extractQueryFn
+		 * didn't create a nullFlags array, we assume everything is non-null.
+		 * While at it, detect whether any null keys are present.
 		 */
-		if (nullFlags == NULL)
-			nullFlags = (bool *) palloc0(nQueryValues * sizeof(bool));
-		else
+		categories = (GinNullCategory *) palloc0(nQueryValues * sizeof(GinNullCategory));
+		if (nullFlags)
 		{
 			int32		j;
 
@@ -362,17 +360,16 @@ ginNewScanKey(IndexScanDesc scan)
 			{
 				if (nullFlags[j])
 				{
-					nullFlags[j] = true;	/* not any other nonzero value */
+					categories[j] = GIN_CAT_NULL_KEY;
 					hasNullQuery = true;
 				}
 			}
 		}
-		/* now we can use the nullFlags as category codes */
 
 		ginFillScanKey(so, skey->sk_attno,
 					   skey->sk_strategy, searchMode,
 					   skey->sk_argument, nQueryValues,
-					   queryValues, (GinNullCategory *) nullFlags,
+					   queryValues, categories,
 					   partial_matches, extra_data);
 	}