Fix dumping of views that are just VALUES(...) but have column aliases.

The "simple" path for printing VALUES clauses doesn't work if we need
to attach nondefault column aliases, because there's noplace to do that
in the minimal VALUES() syntax.  So modify get_simple_values_rte() to
detect nondefault aliases and treat that as a non-simple case.  This
further exposes that the "non-simple" path never actually worked;
it didn't produce valid syntax.  Fix that too.  Per bug #12789 from
Curtis McEnroe, and analysis by Andrew Gierth.

Back-patch to all supported branches.  Before 9.3, this also requires
back-patching the part of commit 092d7ded29f36b0539046b23b81b9f0bf2d637f1
that created get_simple_values_rte() to begin with; inserting the extra
test into the old factorization of that logic would've been too messy.

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index c1d860ceffd14c623007b4d6243b73dcb83aad7b..2fa30be401f77be32fbc12e5d15dd63a985050d2 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -4498,10 +4498,7 @@ get_simple_values_rte(Query *query)
        /*
         * We want to return TRUE even if the Query also contains OLD or NEW rule
         * RTEs.  So the idea is to scan the rtable and see if there is only one
-        * inFromCl RTE that is a VALUES RTE.  We don't look at the targetlist at
-        * all.  This is okay because parser/analyze.c will never generate a
-        * "bare" VALUES RTE --- they only appear inside auto-generated
-        * sub-queries with very restricted structure.
+        * inFromCl RTE that is a VALUES RTE.
         */
        foreach(lc, query->rtable)
        {
@@ -4518,6 +4515,33 @@ get_simple_values_rte(Query *query)
                else
                        return NULL;            /* something else -> not simple VALUES */
        }
+
+       /*
+        * We don't need to check the targetlist in any great detail, because
+        * parser/analyze.c will never generate a "bare" VALUES RTE --- they only
+        * appear inside auto-generated sub-queries with very restricted
+        * structure.  However, DefineView might have modified the tlist by
+        * injecting new column aliases; so compare tlist resnames against the
+        * RTE's names to detect that.
+        */
+       if (result)
+       {
+               ListCell   *lcn;
+
+               if (list_length(query->targetList) != list_length(result->eref->colnames))
+                       return NULL;            /* this probably cannot happen */
+               forboth(lc, query->targetList, lcn, result->eref->colnames)
+               {
+                       TargetEntry *tle = (TargetEntry *) lfirst(lc);
+                       char       *cname = strVal(lfirst(lcn));
+
+                       if (tle->resjunk)
+                               return NULL;    /* this probably cannot happen */
+                       if (tle->resname == NULL || strcmp(tle->resname, cname) != 0)
+                               return NULL;    /* column name has been changed */
+               }
+       }
+
        return result;
 }
 
@@ -8517,7 +8541,9 @@ get_from_clause_item(Node *jtnode, Query *query, deparse_context *context)
                                break;
                        case RTE_VALUES:
                                /* Values list RTE */
+                               appendStringInfoChar(buf, '(');
                                get_values_def(rte->values_lists, context);
+                               appendStringInfoChar(buf, ')');
                                break;
                        case RTE_CTE:
                                appendStringInfoString(buf, quote_identifier(rte->ctename));
@@ -8559,6 +8585,11 @@ get_from_clause_item(Node *jtnode, Query *query, deparse_context *context)
                         */
                        printalias = true;
                }
+               else if (rte->rtekind == RTE_VALUES)
+               {
+                       /* Alias is syntactically required for VALUES */
+                       printalias = true;
+               }
                else if (rte->rtekind == RTE_CTE)
                {
                        /*

diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index d50b103f159cb52a89b158bc173a59c5078eeb8d..26c60e4153f9d719044e76de785f075240eb451f 100644 (file)
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2507,6 +2507,7 @@ select * from only t1_2;
  19
 (10 rows)
 
+reset constraint_exclusion;
 -- test various flavors of pg_get_viewdef()
 select pg_get_viewdef('shoe'::regclass) as unpretty;
                     unpretty                    
@@ -2678,3 +2679,56 @@ ALTER RULE "_RETURN" ON rule_v1 RENAME TO abc; -- ON SELECT rule cannot be renam
 ERROR:  renaming an ON SELECT rule is not allowed
 DROP VIEW rule_v1;
 DROP TABLE rule_t1;
+--
+-- check display of VALUES in view definitions
+--
+create view rule_v1 as values(1,2);
+\d+ rule_v1
+                 View "public.rule_v1"
+ Column  |  Type   | Modifiers | Storage | Description 
+---------+---------+-----------+---------+-------------
+ column1 | integer |           | plain   | 
+ column2 | integer |           | plain   | 
+View definition:
+ VALUES (1,2);
+
+drop view rule_v1;
+create view rule_v1(x) as values(1,2);
+\d+ rule_v1
+                 View "public.rule_v1"
+ Column  |  Type   | Modifiers | Storage | Description 
+---------+---------+-----------+---------+-------------
+ x       | integer |           | plain   | 
+ column2 | integer |           | plain   | 
+View definition:
+ SELECT "*VALUES*".column1 AS x,
+    "*VALUES*".column2
+   FROM (VALUES (1,2)) "*VALUES*";
+
+drop view rule_v1;
+create view rule_v1(x) as select * from (values(1,2)) v;
+\d+ rule_v1
+                 View "public.rule_v1"
+ Column  |  Type   | Modifiers | Storage | Description 
+---------+---------+-----------+---------+-------------
+ x       | integer |           | plain   | 
+ column2 | integer |           | plain   | 
+View definition:
+ SELECT v.column1 AS x,
+    v.column2
+   FROM ( VALUES (1,2)) v;
+
+drop view rule_v1;
+create view rule_v1(x) as select * from (values(1,2)) v(q,w);
+\d+ rule_v1
+                View "public.rule_v1"
+ Column |  Type   | Modifiers | Storage | Description 
+--------+---------+-----------+---------+-------------
+ x      | integer |           | plain   | 
+ w      | integer |           | plain   | 
+View definition:
+ SELECT v.q AS x,
+    v.w
+   FROM ( VALUES (1,2)) v(q, w);
+
+drop view rule_v1;

diff --git a/src/test/regress/sql/rules.sql b/src/test/regress/sql/rules.sql
index 1e15f84dc85606376de5d39e0927fdc344b89e39..c385e414578fae8fa54e155f0c337c4e2388b0b3 100644 (file)
--- a/src/test/regress/sql/rules.sql
+++ b/src/test/regress/sql/rules.sql
@@ -953,6 +953,8 @@ select * from only t1;
 select * from only t1_1;
 select * from only t1_2;
 
+reset constraint_exclusion;
+
 -- test various flavors of pg_get_viewdef()
 
 select pg_get_viewdef('shoe'::regclass) as unpretty;
@@ -1007,3 +1009,19 @@ ALTER RULE "_RETURN" ON rule_v1 RENAME TO abc; -- ON SELECT rule cannot be renam
 
 DROP VIEW rule_v1;
 DROP TABLE rule_t1;
+
+--
+-- check display of VALUES in view definitions
+--
+create view rule_v1 as values(1,2);
+\d+ rule_v1
+drop view rule_v1;
+create view rule_v1(x) as values(1,2);
+\d+ rule_v1
+drop view rule_v1;
+create view rule_v1(x) as select * from (values(1,2)) v;
+\d+ rule_v1
+drop view rule_v1;
+create view rule_v1(x) as select * from (values(1,2)) v(q,w);
+\d+ rule_v1
+drop view rule_v1;