psql: treat "--" comments between queries as separate history entries.

tglsfdc · tglsfdc · commit c2f654930e9f · 2021-12-01T12:18:25.000-05:00
If we've not yet collected any non-whitespace, non-comment token for a new query, flush the current input line to history before reading another line. This aligns psql's history behavior with the observation that lines containing only comments are generally not thought of as being part of the next query. psql's prompting behavior is consistent with that view, too, since it won't change the prompt until you enter something that's neither whitespace nor a "--" comment. Greg Nancarrow, simplified a bit by me Discussion: https://postgr.es/m/CAJcOf-cAdMVr7azeYR7nWKsNp7qhORzc84rV6d7m7knG5Hrtsw@mail.gmail.com
diff --git a/src/bin/psql/mainloop.c b/src/bin/psql/mainloop.c
@@ -564,9 +564,20 @@ MainLoop(FILE *source)
 				break;
 		}
 
-		/* Add line to pending history if we didn't execute anything yet */
-		if (pset.cur_cmd_interactive && !line_saved_in_history)
-			pg_append_history(line, history_buf);
+		/*
+		 * Add line to pending history if we didn't do so already.  Then, if
+		 * the query buffer is still empty, flush out any unsent history
+		 * entry.  This means that empty lines (containing only whitespace and
+		 * perhaps a dash-dash comment) that precede a query will be recorded
+		 * as separate history entries, not as part of that query.
+		 */
+		if (pset.cur_cmd_interactive)
+		{
+			if (!line_saved_in_history)
+				pg_append_history(line, history_buf);
+			if (query_buf->len == 0)
+				pg_send_history(history_buf);
+		}
 
 		psql_scan_finish(scan_state);
 		free(line);
