Make plpython cope with funny characters in function names.

A function name that's double-quoted in SQL can contain almost any
characters, but we were using that name directly as part of the name
generated for the Python-level function, and Python doesn't like
anything that isn't pretty much a standard identifier.  To fix,
replace anything that isn't an ASCII letter or digit with an underscore
in the generated name.  This doesn't create any risk of duplicate Python
function names because we were already appending the function OID to
the generated name to ensure uniqueness.  Per bug #13960 from Jim Nasby.

Patch by Jim Nasby, modified a bit by me.  Back-patch to all
supported branches.

src/pl/plpython/expected/plpython_test.out

@@ -16,8 +16,8 @@ select stupidn();
  zarkon
 (1 row)
 
--- test multiple arguments
-CREATE FUNCTION argument_test_one(u users, a1 text, a2 text) RETURNS text
+-- test multiple arguments and odd characters in function name
+CREATE FUNCTION "Argument test #1"(u users, a1 text, a2 text) RETURNS text
 	AS
 'keys = list(u.keys())
 keys.sort()
@@ -27,8 +27,8 @@ for key in keys:
 words = a1 + " " + a2 + " => {" + ", ".join(out) + "}"
 return words'
 	LANGUAGE plpythonu;
-select argument_test_one(users, fname, lname) from users where lname = 'doe' order by 1;
-                           argument_test_one                           
+select "Argument test #1"(users, fname, lname) from users where lname = 'doe' order by 1;
+                           Argument test #1                            
 -----------------------------------------------------------------------
  jane doe => {fname: jane, lname: doe, userid: 1, username: j_doe}
  john doe => {fname: john, lname: doe, userid: 2, username: johnd}

src/pl/plpython/plpy_procedure.c

@@ -146,6 +146,7 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
 	MemoryContext cxt;
 	MemoryContext oldcxt;
 	int			rv;
+	char	   *ptr;
 
 	procStruct = (Form_pg_proc) GETSTRUCT(procTup);
 	rv = snprintf(procName, sizeof(procName),
@@ -155,6 +156,15 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
 	if (rv >= sizeof(procName) || rv < 0)
 		elog(ERROR, "procedure name would overrun buffer");
 
+	/* Replace any not-legal-in-Python-names characters with '_' */
+	for (ptr = procName; *ptr; ptr++)
+	{
+		if (!((*ptr >= 'A' && *ptr <= 'Z') ||
+			  (*ptr >= 'a' && *ptr <= 'z') ||
+			  (*ptr >= '0' && *ptr <= '9')))
+			*ptr = '_';
+	}
+
 	cxt = AllocSetContextCreate(TopMemoryContext,
 								procName,
 								ALLOCSET_DEFAULT_MINSIZE,

src/pl/plpython/sql/plpython_test.sql

@@ -11,8 +11,8 @@ CREATE FUNCTION stupidn() RETURNS text AS 'return "zarkon"' LANGUAGE plpython2u;
 
 select stupidn();
 
--- test multiple arguments
-CREATE FUNCTION argument_test_one(u users, a1 text, a2 text) RETURNS text
+-- test multiple arguments and odd characters in function name
+CREATE FUNCTION "Argument test #1"(u users, a1 text, a2 text) RETURNS text
 	AS
 'keys = list(u.keys())
 keys.sort()
@@ -23,7 +23,7 @@ words = a1 + " " + a2 + " => {" + ", ".join(out) + "}"
 return words'
 	LANGUAGE plpythonu;
 
-select argument_test_one(users, fname, lname) from users where lname = 'doe' order by 1;
+select "Argument test #1"(users, fname, lname) from users where lname = 'doe' order by 1;
 
 
 -- check module contents