Fix failure to handle conflicts in non-arbiter exclusion constraints.

ExecInsertIndexTuples treated an exclusion constraint as subject to
noDupErr processing even when it was not listed in arbiterIndexes, and
would therefore not error out for a conflict in such a constraint, instead
returning it as an arbiter-index failure.  That led to an infinite loop in
ExecInsert, since ExecCheckIndexConstraints ignored the index as-intended
and therefore didn't throw the expected error.  To fix, make the exclusion
constraint code path use the same condition as the index_insert call does
to decide whether no-error-for-duplicates behavior is appropriate.  While
at it, refactor a little bit to avoid unnecessary list_member_oid calls.
(That surely wouldn't save anything worth noticing, but I find the code
a bit clearer this way.)

Per bug report from Heikki Rauhala.  Back-patch to 9.5 where ON CONFLICT
was introduced.

Report: <4C976D6B-76B4-434C-8052-D009F7B7AEDA@reaktor.fi>

2 files changed, 37 insertions, 0 deletions

diff --git a/src/test/regress/expected/insert_conflict.out b/src/test/regress/expected/insert_conflict.out
index 6f4ec867d9f..155774ecfab 100644
--- a/src/test/regress/expected/insert_conflict.out
+++ b/src/test/regress/expected/insert_conflict.out
@@ -704,3 +704,26 @@ insert into dropcol(key, keep1, keep2) values(1, '5', 5) on conflict(key)
 
 ;
 DROP TABLE dropcol;
+-- check handling of regular btree constraint along with gist constraint
+create table twoconstraints (f1 int unique, f2 box,
+                             exclude using gist(f2 with &&));
+insert into twoconstraints values(1, '((0,0),(1,1))');
+insert into twoconstraints values(1, '((2,2),(3,3))');  -- fail on f1
+ERROR:  duplicate key value violates unique constraint "twoconstraints_f1_key"
+DETAIL:  Key (f1)=(1) already exists.
+insert into twoconstraints values(2, '((0,0),(1,2))');  -- fail on f2
+ERROR:  conflicting key value violates exclusion constraint "twoconstraints_f2_excl"
+DETAIL:  Key (f2)=((1,2),(0,0)) conflicts with existing key (f2)=((1,1),(0,0)).
+insert into twoconstraints values(2, '((0,0),(1,2))')
+  on conflict on constraint twoconstraints_f1_key do nothing;  -- fail on f2
+ERROR:  conflicting key value violates exclusion constraint "twoconstraints_f2_excl"
+DETAIL:  Key (f2)=((1,2),(0,0)) conflicts with existing key (f2)=((1,1),(0,0)).
+insert into twoconstraints values(2, '((0,0),(1,2))')
+  on conflict on constraint twoconstraints_f2_excl do nothing;  -- do nothing
+select * from twoconstraints;
+ f1 |     f2      
+----+-------------
+  1 | (1,1),(0,0)
+(1 row)
+
+drop table twoconstraints;
diff --git a/src/test/regress/sql/insert_conflict.sql b/src/test/regress/sql/insert_conflict.sql
index 94b1b0aadee..190c6055623 100644
--- a/src/test/regress/sql/insert_conflict.sql
+++ b/src/test/regress/sql/insert_conflict.sql
@@ -407,3 +407,17 @@ insert into dropcol(key, keep1, keep2) values(1, '5', 5) on conflict(key)
 ;
 
 DROP TABLE dropcol;
+
+-- check handling of regular btree constraint along with gist constraint
+
+create table twoconstraints (f1 int unique, f2 box,
+                             exclude using gist(f2 with &&));
+insert into twoconstraints values(1, '((0,0),(1,1))');
+insert into twoconstraints values(1, '((2,2),(3,3))');  -- fail on f1
+insert into twoconstraints values(2, '((0,0),(1,2))');  -- fail on f2
+insert into twoconstraints values(2, '((0,0),(1,2))')
+  on conflict on constraint twoconstraints_f1_key do nothing;  -- fail on f2
+insert into twoconstraints values(2, '((0,0),(1,2))')
+  on conflict on constraint twoconstraints_f2_excl do nothing;  -- do nothing
+select * from twoconstraints;
+drop table twoconstraints;