Fix some more boundary-case errors in psql variable substitution:

wasn't really right for case where :var is at the end of the line,
was definitely not right if var expanded to empty in that case,
and failed to recalculate thislen before jumping back to rescan.

src/bin/psql/mainloop.c

@@ -3,7 +3,7 @@
  *
  * Copyright 2000 by PostgreSQL Global Development Group
  *
- * $Header: /cvsroot/pgsql/src/bin/psql/mainloop.c,v 1.48 2002/06/15 19:37:48 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/bin/psql/mainloop.c,v 1.49 2002/07/03 16:47:46 tgl Exp $
  */
 #include "postgres_fe.h"
 #include "mainloop.h"
@@ -366,41 +366,46 @@ MainLoop(FILE *source)
 										 * temporarily overwritten */
 
 				in_length = strspn(&line[i + thislen], VALID_VARIABLE_CHARS);
+				/* mark off the possible variable name */
 				after = line[i + thislen + in_length];
 				line[i + thislen + in_length] = '\0';
 
-				/*
-				 * if the variable doesn't exist we'll leave the string as
-				 * is
-				 */
 				value = GetVariable(pset.vars, &line[i + thislen]);
+
+				/* restore overwritten character */
+				line[i + thislen + in_length] = after;
+
 				if (value)
 				{
+					/* It is a variable, perform substitution */
 					out_length = strlen(value);
 
-					/* Allow for 'after' character also 2002-05-27 */
-					new = malloc(len + out_length - (1 + in_length) + 1 + 1);
+					new = malloc(len + out_length - in_length + 1);
 					if (!new)
 					{
 						psql_error("out of memory\n");
 						exit(EXIT_FAILURE);
 					}
 
-					sprintf(new, "%.*s%s%c", i, line, value, after);
-					if (after)
-						strcat(new, line + i + 1 + in_length + 1);
+					sprintf(new, "%.*s%s%s", i, line, value,
+							&line[i + thislen + in_length]);
 
 					free(line);
 					line = new;
 					len = strlen(new);
 
+					if (i < len)
+					{
+						thislen = PQmblen(line+i, pset.encoding);
 						goto rescan;	/* reparse the just substituted */
 					}
+				}
 				else
 				{
-					/* restore overwritten character */
-					line[i + thislen + in_length] = after;
-					/* move on ... */
+					/*
+					 * if the variable doesn't exist we'll leave the string as
+					 * is ... move on ...
+					 */
 				}
 			}