Fix another bug in merging of inherited CHECK constraints.

It's not good for an inherited child constraint to be marked connoinherit;
that would result in the constraint not propagating to grandchild tables,
if any are created later.  The code mostly prevented this from happening
but there was one case that was missed.

This is somewhat related to commit e55a946a8, which also tightened checks
on constraint merging.  Hence, back-patch to 9.2 like that one.  This isn't
so much because there's a concrete feature-related reason to stop there,
as to avoid having more distinct behaviors than we have to in this area.

Amit Langote

Discussion: <b28ee774-7009-313d-dd55-5bdd81242c41@lab.ntt.co.jp>

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 9102b050e8128b38c6601ccce13517a42f50f9c9..03c1695e45bf4fd38c6f569e22d7462e0c47e4e6 100644 (file)
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2423,6 +2423,17 @@ MergeWithExistingConstraint(Relation rel, char *ccname, Node *expr,
                         errmsg("constraint \"%s\" conflicts with non-inherited constraint on relation \"%s\"",
                                ccname, RelationGetRelationName(rel))));
 
+           /*
+            * Must not change an existing inherited constraint to "no
+            * inherit" status.  That's because inherited constraints should
+            * be able to propagate to lower-level children.
+            */
+           if (con->coninhcount > 0 && is_no_inherit)
+               ereport(ERROR,
+                       (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+                        errmsg("constraint \"%s\" conflicts with inherited constraint on relation \"%s\"",
+                               ccname, RelationGetRelationName(rel))));
+
            /*
             * If the child constraint is "not valid" then cannot merge with a
             * valid parent constraint

diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index a274813bff2952a43a99539c601bce6745512059..6a6b840217f7a6d4d679ba74725758cb0f4d1733 100644 (file)
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -645,6 +645,9 @@ Check constraints:
     "p2chk" CHECK (ff1 > 10)
 Inherits: p1
 
+-- Test that child does not override inheritable constraints of the parent
+create table c2 (constraint p2chk check (ff1 > 10) no inherit) inherits (p1);  --fails
+ERROR:  constraint "p2chk" conflicts with inherited constraint on relation "c2"
 drop table p1 cascade;
 NOTICE:  drop cascades to table c1
 -- Tests for casting between the rowtypes of parent and child

diff --git a/src/test/regress/sql/inherit.sql b/src/test/regress/sql/inherit.sql
index a5e6ecdb868287a2700db43af069cef8484682ba..d65839899c1f3d26797e0d0e99609eaa183efc50 100644 (file)
--- a/src/test/regress/sql/inherit.sql
+++ b/src/test/regress/sql/inherit.sql
@@ -157,6 +157,9 @@ create table c1 () inherits (p1);
 \d p1
 \d c1
 
+-- Test that child does not override inheritable constraints of the parent
+create table c2 (constraint p2chk check (ff1 > 10) no inherit) inherits (p1);  --fails
+
 drop table p1 cascade;
 
 -- Tests for casting between the rowtypes of parent and child