Revise syntax-error reporting behavior to give pleasant results for

errors in internally-generated queries, such as those submitted by
plpgsql functions.  Per recent discussions with Fabien Coelho.

src/pl/plpgsql/src/pl_comp.c

@@ -3,7 +3,7 @@
  *			  procedural language
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.74 2004/03/19 18:58:07 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.75 2004/03/21 22:29:11 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -270,7 +270,6 @@ do_compile(FunctionCallInfo fcinfo,
 		elog(ERROR, "null prosrc");
 	proc_source = DatumGetCString(DirectFunctionCall1(textout, prosrcdatum));
 	plpgsql_scanner_init(proc_source, functype);
-	pfree(proc_source);
 
 	plpgsql_error_funcname = pstrdup(NameStr(procStruct->proname));
 	plpgsql_error_lineno = 0;
@@ -279,7 +278,7 @@ do_compile(FunctionCallInfo fcinfo,
 	 * Setup error traceback support for ereport()
 	 */
 	plerrcontext.callback = plpgsql_compile_error_callback;
-	plerrcontext.arg = NULL;
+	plerrcontext.arg = forValidator ? proc_source : (char *) NULL;
 	plerrcontext.previous = error_context_stack;
 	error_context_stack = &plerrcontext;
 
@@ -714,6 +713,7 @@ do_compile(FunctionCallInfo fcinfo,
 		elog(ERROR, "plpgsql parser returned %d", parse_rc);
 
 	plpgsql_scanner_finish();
+	pfree(proc_source);
 
 	/*
 	 * If that was successful, complete the functions info.
@@ -749,10 +749,26 @@ do_compile(FunctionCallInfo fcinfo,
 
 /*
  * error context callback to let us supply a call-stack traceback
+ *
+ * If we are validating, the function source is passed as argument.
  */
 static void
 plpgsql_compile_error_callback(void *arg)
 {
+	if (arg)
+	{
+		/*
+		 * Try to convert syntax error position to reference text of
+		 * original CREATE FUNCTION command.
+		 */
+		if (function_parse_error_transpose((const char *) arg))
+			return;
+		/*
+		 * Done if a syntax error position was reported; otherwise we
+		 * have to fall back to a "near line N" report.
+		 */
+	}
+
 	if (plpgsql_error_funcname)
 		errcontext("compile of PL/pgSQL function \"%s\" near line %d",
 				   plpgsql_error_funcname, plpgsql_error_lineno);

src/pl/plpgsql/src/scan.l

@@ -4,7 +4,7 @@
  *			  procedural language
  *
  * IDENTIFICATION
- *    $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.33 2004/03/19 18:58:07 tgl Exp $
+ *    $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.34 2004/03/21 22:29:11 tgl Exp $
  *
  *    This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -51,6 +51,8 @@
 static YY_BUFFER_STATE scanbufhandle;
 static char *scanbuf;
 
+static const char *scanstr;		/* original input string */
+
 static int	scanner_functype;
 static int	scanner_typereported;
 static int	pushback_token;
@@ -431,7 +433,8 @@ plpgsql_yyerror(const char *message)
 				(errcode(ERRCODE_SYNTAX_ERROR),
 				 /* translator: %s is typically "syntax error" */
 				 errmsg("%s at end of input", message),
-				 errposition(cursorpos)));
+				 internalerrposition(cursorpos),
+				 internalerrquery(scanstr)));
 	}
 	else
 	{
@@ -439,7 +442,8 @@ plpgsql_yyerror(const char *message)
 				(errcode(ERRCODE_SYNTAX_ERROR),
 				 /* translator: first %s is typically "syntax error" */
 				 errmsg("%s at or near \"%s\"", message, loc),
-				 errposition(cursorpos)));
+				 internalerrposition(cursorpos),
+				 internalerrquery(scanstr)));
 	}
 }
 
@@ -467,6 +471,10 @@ plpgsql_scanner_lineno(void)
 
 /*
  * Called before any actual parsing is done
+ *
+ * Note: the passed "str" must remain valid until plpgsql_scanner_finish().
+ * Although it is not fed directly to flex, we need the original string
+ * to cite in error messages.
  */
 void
 plpgsql_scanner_init(const char *str, int functype)
@@ -490,7 +498,9 @@ plpgsql_scanner_init(const char *str, int functype)
 	scanbufhandle = yy_scan_buffer(scanbuf, slen + 2);
 
 	/* Other setup */
-    scanner_functype     = functype;
+	scanstr = str;
+
+    scanner_functype = functype;
     scanner_typereported = 0;
 
 	have_pushback_token = false;