postgres.git / summary / log / commit / refs

commit    dc391dacf170593dceef07fc7ea287cb02d09d5d
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Tue Aug 07 17:13:42 2018 +0000

    Ensure pg_dump_sort.c sorts null vs non-null namespace consistently.
    
    The original coding here (which is, I believe, my fault) supposed that
    it didn't need to concern itself with the possibility that one object
    of a given type-priority has a namespace while another doesn't.  But
    that's not reliably true anymore, if it ever was; and if it does happen
    then it's possible that DOTypeNameCompare returns self-inconsistent
    comparison results.  That leads to unspecified behavior in qsort()
    and a resultant weird output order from pg_dump.
    
    This should end up being only a cosmetic problem, because any ordering
    constraints that actually matter should be enforced by the later
    dependency-based sort.  Still, it's a bug, so back-patch.
    
    Report and fix by Jacob Champion, though I editorialized on his
    patch to the extent of making NULL sort after non-NULL, for consistency
    with our usual sorting definitions.
    
    Discussion: https://postgr.es/m/CABAq_6Hw+V-Kj7PNfD5tgOaWT_-qaYkc+SRmJkPLeUjYXLdxwQ@mail.gmail.com


 src/bin/pg_dump/pg_dump_sort.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump_sort.c b/src/bin/pg_dump/pg_dump_sort.c
index 5044a767873..57acc1932f3 100644
--- a/src/bin/pg_dump/pg_dump_sort.c
+++ b/src/bin/pg_dump/pg_dump_sort.c
@@ -218,7 +218,7 @@ DOTypeNameCompare(const void *p1, const void *p2)
 	DumpableObject *obj2 = *(DumpableObject *const *) p2;
 	int			cmpval;
 
-	/* Sort by type */
+	/* Sort by type's priority */
 	cmpval = dbObjectTypePriority[obj1->objType] -
 		dbObjectTypePriority[obj2->objType];
 
@@ -226,17 +226,24 @@ DOTypeNameCompare(const void *p1, const void *p2)
 		return cmpval;
 
 	/*
-	 * Sort by namespace.  Note that all objects of the same type should
-	 * either have or not have a namespace link, so we needn't be fancy about
-	 * cases where one link is null and the other not.
+	 * Sort by namespace.  Typically, all objects of the same priority would
+	 * either have or not have a namespace link, but there are exceptions.
+	 * Sort NULL namespace after non-NULL in such cases.
 	 */
-	if (obj1->namespace && obj2->namespace)
+	if (obj1->namespace)
 	{
-		cmpval = strcmp(obj1->namespace->dobj.name,
-						obj2->namespace->dobj.name);
-		if (cmpval != 0)
-			return cmpval;
+		if (obj2->namespace)
+		{
+			cmpval = strcmp(obj1->namespace->dobj.name,
+							obj2->namespace->dobj.name);
+			if (cmpval != 0)
+				return cmpval;
+		}
+		else
+			return -1;
 	}
+	else if (obj2->namespace)
+		return 1;
 
 	/* Sort by name */
 	cmpval = strcmp(obj1->name, obj2->name);


[parent: 4191e37a9a1f]