From c6a7d3bab493e8d589f24d239db00ce5c2934178 Mon Sep 17 00:00:00 2001
From: Masahiko Sawada <msawada@postgresql.org>
Date: Mon, 22 Dec 2025 14:28:12 -0800
Subject: [PATCH] psql: Improve tab completion for COPY option lists.

Previously, only the first option in a parenthesized option list was
suggested by tab completion. This commit enhances tab completion for
both COPY TO and COPY FROM commands to suggest options after each
comma.

Also add completion for HEADER and FREEZE option value candidates.

Author: Yugo Nagata <nagata@sraoss.co.jp>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/20250605100835.b396f9d656df1018f65a4556@sraoss.co.jp
---
 src/bin/psql/tab-complete.in.c | 60 ++++++++++++++++++++++------------
 1 file changed, 40 insertions(+), 20 deletions(-)

diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index b1ff6f6cd94..ab2712216b5 100644
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -3378,30 +3378,50 @@ match_previous_words(int pattern_id,
 			 Matches("COPY|\\copy", MatchAny, "FROM", "PROGRAM", MatchAny))
 		COMPLETE_WITH("WITH (", "WHERE");
 
-	/* Complete COPY <sth> FROM [PROGRAM] filename WITH ( */
-	else if (Matches("COPY|\\copy", MatchAny, "FROM", MatchAnyExcept("PROGRAM"), "WITH", "(") ||
-			 Matches("COPY|\\copy", MatchAny, "FROM", "PROGRAM", MatchAny, "WITH", "("))
-		COMPLETE_WITH(Copy_from_options);
+	/* Complete COPY <sth> FROM|TO [PROGRAM] filename WITH ( */
+	else if (HeadMatches("COPY|\\copy", MatchAny, "FROM|TO", MatchAnyExcept("PROGRAM"), "WITH", "(*") ||
+			 HeadMatches("COPY|\\copy", MatchAny, "FROM|TO", "PROGRAM", MatchAny, "WITH", "(*"))
+	{
+		if (!HeadMatches("COPY|\\copy", MatchAny, "FROM|TO", MatchAnyExcept("PROGRAM"), "WITH", "(*)") &&
+			!HeadMatches("COPY|\\copy", MatchAny, "FROM|TO", "PROGRAM", 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 tests are correct.
+			 */
 
-	/* Complete COPY <sth> TO [PROGRAM] filename WITH ( */
-	else if (Matches("COPY|\\copy", MatchAny, "TO", MatchAnyExcept("PROGRAM"), "WITH", "(") ||
-			 Matches("COPY|\\copy", MatchAny, "TO", "PROGRAM", MatchAny, "WITH", "("))
-		COMPLETE_WITH(Copy_to_options);
+			if (ends_with(prev_wd, '(') || ends_with(prev_wd, ','))
+			{
+				if (HeadMatches("COPY|\\copy", MatchAny, "FROM"))
+					COMPLETE_WITH(Copy_from_options);
+				else
+					COMPLETE_WITH(Copy_to_options);
+			}
 
-	/* Complete COPY <sth> FROM|TO [PROGRAM] <sth> WITH (FORMAT */
-	else if (Matches("COPY|\\copy", MatchAny, "FROM|TO", MatchAnyExcept("PROGRAM"), "WITH", "(", "FORMAT") ||
-			 Matches("COPY|\\copy", MatchAny, "FROM|TO", "PROGRAM", MatchAny, "WITH", "(", "FORMAT"))
-		COMPLETE_WITH("binary", "csv", "text");
+			/* Complete COPY <sth> FROM|TO filename WITH (FORMAT */
+			else if (TailMatches("FORMAT"))
+				COMPLETE_WITH("binary", "csv", "text");
 
-	/* Complete COPY <sth> FROM [PROGRAM] filename WITH (ON_ERROR */
-	else if (Matches("COPY|\\copy", MatchAny, "FROM", MatchAnyExcept("PROGRAM"), "WITH", "(", "ON_ERROR") ||
-			 Matches("COPY|\\copy", MatchAny, "FROM", "PROGRAM", MatchAny, "WITH", "(", "ON_ERROR"))
-		COMPLETE_WITH("stop", "ignore");
+			/* Complete COPY <sth> FROM|TO filename WITH (FREEZE */
+			else if (TailMatches("FREEZE"))
+				COMPLETE_WITH("true", "false");
 
-	/* Complete COPY <sth> FROM [PROGRAM] filename WITH (LOG_VERBOSITY */
-	else if (Matches("COPY|\\copy", MatchAny, "FROM", MatchAnyExcept("PROGRAM"), "WITH", "(", "LOG_VERBOSITY") ||
-			 Matches("COPY|\\copy", MatchAny, "FROM", "PROGRAM", MatchAny, "WITH", "(", "LOG_VERBOSITY"))
-		COMPLETE_WITH("silent", "default", "verbose");
+			/* Complete COPY <sth> FROM|TO filename WITH (HEADER */
+			else if (TailMatches("HEADER"))
+				COMPLETE_WITH("true", "false", "MATCH");
+
+			/* Complete COPY <sth> FROM filename WITH (ON_ERROR */
+			else if (TailMatches("ON_ERROR"))
+				COMPLETE_WITH("stop", "ignore");
+
+			/* Complete COPY <sth> FROM filename WITH (LOG_VERBOSITY */
+			else if (TailMatches("LOG_VERBOSITY"))
+				COMPLETE_WITH("silent", "default", "verbose");
+		}
+
+		/* A completed parenthesized option list should be caught below */
+	}
 
 	/* Complete COPY <sth> FROM [PROGRAM] <sth> WITH (<options>) */
 	else if (Matches("COPY|\\copy", MatchAny, "FROM", MatchAnyExcept("PROGRAM"), "WITH", MatchAny) ||