Add SPI_push/SPI_pop calls so that datatype input and output functions called

by plpgsql can themselves use SPI --- possibly indirectly, as in the case
of domain_in() invoking plpgsql functions in a domain check constraint.
Per bug #2945 from Sergiy Vyshnevetskiy.

Somewhat arbitrarily, I've chosen to back-patch this as far as 8.0.  Given
the lack of prior complaints, it doesn't seem critical for 7.x.

diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 67bcbf0..8a9c009 100644 (file)
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.185 2007/01/28 17:58:13 tgl Exp $
+ *       $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.186 2007/01/30 18:02:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4282,12 +4282,27 @@ make_tuple_from_row(PLpgSQL_execstate *estate,
 static char *
 convert_value_to_string(Datum value, Oid valtype)
 {
+       char       *str;
        Oid                     typoutput;
        bool            typIsVarlena;
 
        getTypeOutputInfo(valtype, &typoutput, &typIsVarlena);
 
-       return OidOutputFunctionCall(typoutput, value);
+       /*
+        * We do SPI_push to allow the datatype output function to use SPI.
+        * However we do not mess around with CommandCounterIncrement or advancing
+        * the snapshot, which means that a stable output function would not see
+        * updates made so far by our own function.  The use-case for such
+        * scenarios seems too narrow to justify the cycles that would be
+        * expended.
+        */
+       SPI_push();
+
+       str = OidOutputFunctionCall(typoutput, value);
+
+       SPI_pop();
+
+       return str;
 }
 
 /* ----------
@@ -4313,14 +4328,25 @@ exec_cast_value(Datum value, Oid valtype,
                        char       *extval;
 
                        extval = convert_value_to_string(value, valtype);
+
+                       /* Allow input function to use SPI ... see notes above */
+                       SPI_push();
+
                        value = InputFunctionCall(reqinput, extval,
                                                                          reqtypioparam, reqtypmod);
+
+                       SPI_pop();
+
                        pfree(extval);
                }
                else
                {
+                       SPI_push();
+
                        value = InputFunctionCall(reqinput, NULL,
                                                                          reqtypioparam, reqtypmod);
+
+                       SPI_pop();
                }
        }