Add tab completion for the WAIT FOR LSN MODE option

Update psql tab completion to support the optional MODE option in the
WAIT FOR LSN command.  After specifying an LSN value, completion now offers
both MODE and WITH keywords.  The MODE option specifies which LSN type to wait
for.  In particular, it controls whether the wait is evaluated from the
standby or primary perspective.

When MODE is specified, the completion suggests the valid mode values:
standby_replay, standby_write, standby_flush, and primary_flush.

Discussion: https://postgr.es/m/CABPTF7UiArgW-sXj9CNwRzUhYOQrevLzkYcgBydmX5oDes1sjg%40mail.gmail.com
Author: Xuneng Zhou <xunengzhou@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@kurilemu.de>

diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index d81f2fcdbe6860727efc26684472f6faaf9d1a4f..06edea98f0608e1b6e84e4303b296408f2e7ab20 100644 (file)
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -5355,8 +5355,11 @@ match_previous_words(int pattern_id,
 /*
  * WAIT FOR LSN '<lsn>' [ WITH ( option [, ...] ) ]
  * where option can be:
+ *   MODE '<mode>'
  *   TIMEOUT '<timeout>'
  *   NO_THROW
+ * and mode can be:
+ *   standby_replay | standby_write | standby_flush | primary_flush
  */
        else if (Matches("WAIT"))
                COMPLETE_WITH("FOR");
@@ -5369,21 +5372,24 @@ match_previous_words(int pattern_id,
                COMPLETE_WITH("WITH");
        else if (Matches("WAIT", "FOR", "LSN", MatchAny, "WITH"))
                COMPLETE_WITH("(");
+
+       /*
+        * Handle parenthesized option list.  This fires when we're in an
+        * unfinished parenthesized option list.  get_previous_words treats a
+        * completed parenthesized option list as one word, so the above test is
+        * correct.
+        *
+        * 'mode' takes a string value (one of the listed above), 'timeout' takes
+        * a string value, and 'no_throw' takes no value.  We do not offer
+        * completions for the *values* of 'timeout' or 'no_throw'.
+        */
        else if (HeadMatches("WAIT", "FOR", "LSN", MatchAny, "WITH", "(*") &&
                         !HeadMatches("WAIT", "FOR", "LSN", MatchAny, "WITH", "(*)"))
        {
-               /*
-                * This fires if we're in an unfinished parenthesized option list.
-                * get_previous_words treats a completed parenthesized option list as
-                * one word, so the above test is correct.
-                */
                if (ends_with(prev_wd, '(') || ends_with(prev_wd, ','))
-                       COMPLETE_WITH("timeout", "no_throw");
-
-               /*
-                * timeout takes a string value, no_throw takes no value. We don't
-                * offer completions for these values.
-                */
+                       COMPLETE_WITH("mode", "timeout", "no_throw");
+               else if (TailMatches("mode"))
+                       COMPLETE_WITH("'standby_replay'", "'standby_write'", "'standby_flush'", "'primary_flush'");
        }
 
 /* WITH [RECURSIVE] */