Fix PL/Tcl's encoding conversion logic.

PL/Tcl appears to contain logic to convert strings between the database
encoding and UTF8, which is the only encoding modern Tcl will deal with.
However, that code has been disabled since commit 03489512, which
made it "#if defined(UNICODE_CONVERSION)" and neglected to provide any way
for that symbol to become defined.  That might have been all right back
in 2001, but these days we take a dim view of allowing strings with
incorrect encoding into the database.

Remove the conditional compilation, fix warnings about signed/unsigned char
conversions, clean up assorted places that didn't bother with conversions.
(Notably, there were lots of assumptions that database table and field
names didn't need conversion...)

Add a regression test based on plpython_unicode.  It's not terribly
thorough, but better than no test at all.

src/pl/tcl/Makefile

@@ -29,7 +29,7 @@ DATA = pltcl.control pltcl--1.0.sql pltcl--unpackaged--1.0.sql \
        pltclu.control pltclu--1.0.sql pltclu--unpackaged--1.0.sql
 
 REGRESS_OPTS = --dbname=$(PL_TESTDB) --load-extension=pltcl
-REGRESS = pltcl_setup pltcl_queries
+REGRESS = pltcl_setup pltcl_queries pltcl_unicode
 
 # Tcl on win32 ships with import libraries only for Microsoft Visual C++,
 # which are not compatible with mingw gcc. Therefore we need to build a

src/pl/tcl/expected/pltcl_unicode.out

+--
+-- Unicode handling
+--
+-- Note: this test case is known to fail if the database encoding is
+-- EUC_CN, EUC_JP, EUC_KR, or EUC_TW, for lack of any equivalent to
+-- U+00A0 (no-break space) in those encodings.  However, testing with
+-- plain ASCII data would be rather useless, so we must live with that.
+--
+SET client_encoding TO UTF8;
+CREATE TABLE unicode_test (
+    testvalue  text NOT NULL
+);
+CREATE FUNCTION unicode_return() RETURNS text AS $$
+  return "\xA0"
+$$ LANGUAGE pltcl;
+CREATE FUNCTION unicode_trigger() RETURNS trigger AS $$
+  set NEW(testvalue) "\xA0"
+  return [array get NEW]
+$$ LANGUAGE pltcl;
+CREATE TRIGGER unicode_test_bi BEFORE INSERT ON unicode_test
+  FOR EACH ROW EXECUTE PROCEDURE unicode_trigger();
+CREATE FUNCTION unicode_plan1() RETURNS text AS $$
+  set plan [ spi_prepare {SELECT $1 AS testvalue} [ list "text" ] ]
+  spi_execp $plan [ list "\xA0" ]
+  return $testvalue
+$$ LANGUAGE pltcl;
+SELECT unicode_return();
+ unicode_return 
+----------------
+  
+(1 row)
+
+INSERT INTO unicode_test (testvalue) VALUES ('test');
+SELECT * FROM unicode_test;
+ testvalue 
+-----------
+  
+(1 row)
+
+SELECT unicode_plan1();
+ unicode_plan1 
+---------------
+  
+(1 row)
+

src/pl/tcl/pltcl.c

@@ -21,6 +21,7 @@
 #include "commands/trigger.h"
 #include "executor/spi.h"
 #include "fmgr.h"
+#include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "parser/parse_type.h"
@@ -33,6 +34,8 @@
 #include "utils/typcache.h"
 
 
+PG_MODULE_MAGIC;
+
 #define HAVE_TCL_VERSION(maj,min) \
 	((TCL_MAJOR_VERSION > maj) || \
 	 (TCL_MAJOR_VERSION == maj && TCL_MINOR_VERSION >= min))
@@ -51,43 +54,44 @@
 #undef TEXTDOMAIN
 #define TEXTDOMAIN PG_TEXTDOMAIN("pltcl")
 
-#if defined(UNICODE_CONVERSION)
 
-#include "mb/pg_wchar.h"
+/*
+ * Support for converting between UTF8 (which is what all strings going into
+ * or out of Tcl should be) and the database encoding.
+ *
+ * If you just use utf_u2e() or utf_e2u() directly, they will leak some
+ * palloc'd space when doing a conversion.  This is not worth worrying about
+ * if it only happens, say, once per PL/Tcl function call.  If it does seem
+ * worth worrying about, use the wrapper macros.
+ */
 
-static unsigned char *
-utf_u2e(unsigned char *src)
+static inline char *
+utf_u2e(const char *src)
 {
-	return (unsigned char *) pg_any_to_server((char *) src,
-											  strlen(src),
-											  PG_UTF8);
+	return pg_any_to_server(src, strlen(src), PG_UTF8);
 }
 
-static unsigned char *
-utf_e2u(unsigned char *src)
+static inline char *
+utf_e2u(const char *src)
 {
-	return (unsigned char *) pg_server_to_any((char *) src,
-											  strlen(src),
-											  PG_UTF8);
+	return pg_server_to_any(src, strlen(src), PG_UTF8);
 }
 
-#define PLTCL_UTF
-#define UTF_BEGIN	 do { \
-					unsigned char *_pltcl_utf_src; \
-					unsigned char *_pltcl_utf_dst
-#define UTF_END		 if (_pltcl_utf_src!=_pltcl_utf_dst) \
-					pfree(_pltcl_utf_dst); } while (0)
-#define UTF_U2E(x)	 (_pltcl_utf_dst=utf_u2e(_pltcl_utf_src=(x)))
-#define UTF_E2U(x)	 (_pltcl_utf_dst=utf_e2u(_pltcl_utf_src=(x)))
-#else							/* !PLTCL_UTF */
-
-#define  UTF_BEGIN
-#define  UTF_END
-#define  UTF_U2E(x)  (x)
-#define  UTF_E2U(x)  (x)
-#endif   /* PLTCL_UTF */
+#define UTF_BEGIN \
+	do { \
+		const char *_pltcl_utf_src = NULL; \
+		char *_pltcl_utf_dst = NULL
 
-PG_MODULE_MAGIC;
+#define UTF_END \
+	if (_pltcl_utf_src != (const char *) _pltcl_utf_dst) \
+			pfree(_pltcl_utf_dst); \
+	} while (0)
+
+#define UTF_U2E(x) \
+	(_pltcl_utf_dst = utf_u2e(_pltcl_utf_src = (x)))
+
+#define UTF_E2U(x) \
+	(_pltcl_utf_dst = utf_e2u(_pltcl_utf_src = (x)))
 
 
 /**********************************************************************
@@ -572,14 +576,10 @@ pltcl_init_load_unknown(Tcl_Interp *interp)
 	SPI_freetuptable(SPI_tuptable);
 
 	if (tcl_rc != TCL_OK)
-	{
-		UTF_BEGIN;
 		ereport(ERROR,
 				(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
 				 errmsg("could not load module \"unknown\": %s",
-						UTF_U2E(Tcl_GetStringResult(interp)))));
-		UTF_END;
-	}
+						utf_u2e(Tcl_GetStringResult(interp)))));
 
 	relation_close(pmrel, AccessShareLock);
 }
@@ -804,14 +804,10 @@ pltcl_func_handler(PG_FUNCTION_ARGS, bool pltrusted)
 								   prodesc->result_typioparam,
 								   -1);
 	else
-	{
-		UTF_BEGIN;
 		retval = InputFunctionCall(&prodesc->result_in_func,
-							   UTF_U2E((char *) Tcl_GetStringResult(interp)),
+								   utf_u2e(Tcl_GetStringResult(interp)),
 								   prodesc->result_typioparam,
 								   -1);
-		UTF_END;
-	}
 
 	return retval;
 }
@@ -866,13 +862,13 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
 
 	PG_TRY();
 	{
-		/* The procedure name */
+		/* The procedure name (note this is all ASCII, so no utf_e2u) */
 		Tcl_ListObjAppendElement(NULL, tcl_cmd,
 							Tcl_NewStringObj(prodesc->internal_proname, -1));
 
 		/* The trigger name for argument TG_name */
 		Tcl_ListObjAppendElement(NULL, tcl_cmd,
-						 Tcl_NewStringObj(trigdata->tg_trigger->tgname, -1));
+				Tcl_NewStringObj(utf_e2u(trigdata->tg_trigger->tgname), -1));
 
 		/* The oid of the trigger relation for argument TG_relid */
 		/* Consider not converting to a string for more performance? */
@@ -885,13 +881,13 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
 		/* The name of the table the trigger is acting on: TG_table_name */
 		stroid = SPI_getrelname(trigdata->tg_relation);
 		Tcl_ListObjAppendElement(NULL, tcl_cmd,
-								 Tcl_NewStringObj(stroid, -1));
+								 Tcl_NewStringObj(utf_e2u(stroid), -1));
 		pfree(stroid);
 
 		/* The schema of the table the trigger is acting on: TG_table_schema */
 		stroid = SPI_getnspname(trigdata->tg_relation);
 		Tcl_ListObjAppendElement(NULL, tcl_cmd,
-								 Tcl_NewStringObj(stroid, -1));
+								 Tcl_NewStringObj(utf_e2u(stroid), -1));
 		pfree(stroid);
 
 		/* A list of attribute names for argument TG_relatts */
@@ -903,7 +899,7 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
 				Tcl_ListObjAppendElement(NULL, tcl_trigtup, Tcl_NewObj());
 			else
 				Tcl_ListObjAppendElement(NULL, tcl_trigtup,
-				  Tcl_NewStringObj(NameStr(tupdesc->attrs[i]->attname), -1));
+										 Tcl_NewStringObj(utf_e2u(NameStr(tupdesc->attrs[i]->attname)), -1));
 		}
 		Tcl_ListObjAppendElement(NULL, tcl_cmd, tcl_trigtup);
 
@@ -1001,7 +997,7 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
 		/* Finally append the arguments from CREATE TRIGGER */
 		for (i = 0; i < trigdata->tg_trigger->tgnargs; i++)
 			Tcl_ListObjAppendElement(NULL, tcl_cmd,
-					  Tcl_NewStringObj(trigdata->tg_trigger->tgargs[i], -1));
+			 Tcl_NewStringObj(utf_e2u(trigdata->tg_trigger->tgargs[i]), -1));
 
 	}
 	PG_CATCH();
@@ -1048,14 +1044,10 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
 	 ************************************************************/
 	if (Tcl_SplitList(interp, result,
 					  &ret_numvals, &ret_values) != TCL_OK)
-	{
-		UTF_BEGIN;
 		ereport(ERROR,
 				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
 				 errmsg("could not split return value from trigger: %s",
-						UTF_U2E(Tcl_GetStringResult(interp)))));
-		UTF_END;
-	}
+						utf_u2e(Tcl_GetStringResult(interp)))));
 
 	/* Use a TRY to ensure ret_values will get freed */
 	PG_TRY();
@@ -1078,8 +1070,8 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
 
 		for (i = 0; i < ret_numvals; i += 2)
 		{
-			const char *ret_name = ret_values[i];
-			const char *ret_value = ret_values[i + 1];
+			char	   *ret_name = utf_u2e(ret_values[i]);
+			char	   *ret_value = utf_u2e(ret_values[i + 1]);
 			int			attnum;
 			Oid			typinput;
 			Oid			typioparam;
@@ -1123,13 +1115,11 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
 			/************************************************************
 			 * Set the attribute to NOT NULL and convert the contents
 			 ************************************************************/
-			modnulls[attnum - 1] = ' ';
-			UTF_BEGIN;
 			modvalues[attnum - 1] = InputFunctionCall(&finfo,
-												 (char *) UTF_U2E(ret_value),
+													  ret_value,
 													  typioparam,
 									  tupdesc->attrs[attnum - 1]->atttypmod);
-			UTF_END;
+			modnulls[attnum - 1] = ' ';
 		}
 
 		rettup = SPI_modifytuple(trigdata->tg_relation, rettup, tupdesc->natts,
@@ -1183,9 +1173,9 @@ pltcl_event_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
 	Tcl_ListObjAppendElement(NULL, tcl_cmd,
 							 Tcl_NewStringObj(prodesc->internal_proname, -1));
 	Tcl_ListObjAppendElement(NULL, tcl_cmd,
-							 Tcl_NewStringObj(tdata->event, -1));
+							 Tcl_NewStringObj(utf_e2u(tdata->event), -1));
 	Tcl_ListObjAppendElement(NULL, tcl_cmd,
-							 Tcl_NewStringObj(tdata->tag, -1));
+							 Tcl_NewStringObj(utf_e2u(tdata->tag), -1));
 
 	tcl_rc = Tcl_EvalObjEx(interp, tcl_cmd, (TCL_EVAL_DIRECT | TCL_EVAL_GLOBAL));
 
@@ -1217,18 +1207,13 @@ throw_tcl_error(Tcl_Interp *interp, const char *proname)
 	char	   *emsg;
 	char	   *econtext;
 
-	UTF_BEGIN;
-	emsg = pstrdup(UTF_U2E(Tcl_GetStringResult(interp)));
-	UTF_END;
-	UTF_BEGIN;
-	econtext = UTF_U2E((char *) Tcl_GetVar(interp, "errorInfo",
-										   TCL_GLOBAL_ONLY));
+	emsg = pstrdup(utf_u2e(Tcl_GetStringResult(interp)));
+	econtext = utf_u2e(Tcl_GetVar(interp, "errorInfo", TCL_GLOBAL_ONLY));
 	ereport(ERROR,
 			(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
 			 errmsg("%s", emsg),
 			 errcontext("%s\nin PL/Tcl function \"%s\"",
 						econtext, proname)));
-	UTF_END;
 }
 
 
@@ -1315,7 +1300,7 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid,
 		/************************************************************
 		 * Build our internal proc name from the function's Oid.  Append
 		 * "_trigger" when appropriate to ensure the normal and trigger
-		 * cases are kept separate.
+		 * cases are kept separate.  Note name must be all-ASCII.
 		 ************************************************************/
 		if (!is_trigger && !is_event_trigger)
 			snprintf(internal_proname, sizeof(internal_proname),
@@ -1570,13 +1555,11 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid,
 			free(prodesc->user_proname);
 			free(prodesc->internal_proname);
 			free(prodesc);
-			UTF_BEGIN;
 			ereport(ERROR,
 					(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
 					 errmsg("could not create internal procedure \"%s\": %s",
 							internal_proname,
-							UTF_U2E(Tcl_GetStringResult(interp)))));
-			UTF_END;
+							utf_u2e(Tcl_GetStringResult(interp)))));
 		}
 
 		/************************************************************
@@ -2212,7 +2195,8 @@ pltcl_SPI_prepare(ClientData cdata, Tcl_Interp *interp,
 		 * Prepare the plan and check for errors
 		 ************************************************************/
 		UTF_BEGIN;
-		qdesc->plan = SPI_prepare(UTF_U2E(Tcl_GetString(objv[1])), nargs, qdesc->argtypes);
+		qdesc->plan = SPI_prepare(UTF_U2E(Tcl_GetString(objv[1])),
+								  nargs, qdesc->argtypes);
 		UTF_END;
 
 		if (qdesc->plan == NULL)
@@ -2434,7 +2418,7 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
 			{
 				UTF_BEGIN;
 				argvalues[j] = InputFunctionCall(&qdesc->arginfuncs[j],
-								(char *) UTF_U2E(Tcl_GetString(callObjv[j])),
+										 UTF_U2E(Tcl_GetString(callObjv[j])),
 												 qdesc->argtypioparams[j],
 												 -1);
 				UTF_END;
@@ -2483,6 +2467,8 @@ pltcl_SPI_lastoid(ClientData cdata, Tcl_Interp *interp,
 /**********************************************************************
  * pltcl_set_tuple_values() - Set variables for all attributes
  *				  of a given tuple
+ *
+ * Note: arrayname is presumed to be UTF8; it usually came from Tcl
  **********************************************************************/
 static void
 pltcl_set_tuple_values(Tcl_Interp *interp, const char *arrayname,
@@ -2524,7 +2510,9 @@ pltcl_set_tuple_values(Tcl_Interp *interp, const char *arrayname,
 		/************************************************************
 		 * Get the attribute name
 		 ************************************************************/
-		attname = NameStr(tupdesc->attrs[i]->attname);
+		UTF_BEGIN;
+		attname = pstrdup(UTF_E2U(NameStr(tupdesc->attrs[i]->attname)));
+		UTF_END;
 
 		/************************************************************
 		 * Get the attributes value
@@ -2552,6 +2540,8 @@ pltcl_set_tuple_values(Tcl_Interp *interp, const char *arrayname,
 		}
 		else
 			Tcl_UnsetVar2(interp, *arrptr, *nameptr, 0);
+
+		pfree((char *) attname);
 	}
 }
 

src/pl/tcl/sql/pltcl_unicode.sql

+--
+-- Unicode handling
+--
+-- Note: this test case is known to fail if the database encoding is
+-- EUC_CN, EUC_JP, EUC_KR, or EUC_TW, for lack of any equivalent to
+-- U+00A0 (no-break space) in those encodings.  However, testing with
+-- plain ASCII data would be rather useless, so we must live with that.
+--
+
+SET client_encoding TO UTF8;
+
+CREATE TABLE unicode_test (
+    testvalue  text NOT NULL
+);
+
+CREATE FUNCTION unicode_return() RETURNS text AS $$
+  return "\xA0"
+$$ LANGUAGE pltcl;
+
+CREATE FUNCTION unicode_trigger() RETURNS trigger AS $$
+  set NEW(testvalue) "\xA0"
+  return [array get NEW]
+$$ LANGUAGE pltcl;
+
+CREATE TRIGGER unicode_test_bi BEFORE INSERT ON unicode_test
+  FOR EACH ROW EXECUTE PROCEDURE unicode_trigger();
+
+CREATE FUNCTION unicode_plan1() RETURNS text AS $$
+  set plan [ spi_prepare {SELECT $1 AS testvalue} [ list "text" ] ]
+  spi_execp $plan [ list "\xA0" ]
+  return $testvalue
+$$ LANGUAGE pltcl;
+
+
+SELECT unicode_return();
+INSERT INTO unicode_test (testvalue) VALUES ('test');
+SELECT * FROM unicode_test;
+SELECT unicode_plan1();