psql: fix variable existence tab completion

[Steve Chavez]

Hello hackers,

psql has the :{?name} syntax for testing a psql variable existence.

But currently doing \echo :{?VERB<Tab> doesn't trigger tab completion.

This patch fixes it. I've also included a TAP test.

Best regards,
Steve Chavez

From adb1f997b67d8ef603017ab34e1b9061e4e229ea Mon Sep 17 00:00:00 2001
From: steve-chavez <stevechavez...@gmail.com>
Date: Sat, 2 Mar 2024 19:06:13 -0500
Subject: [PATCH 1/1] psql: fix variable existence tab completion

---
 src/bin/psql/t/010_tab_completion.pl | 8 ++++++++
 src/bin/psql/tab-complete.c          | 4 +++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/bin/psql/t/010_tab_completion.pl b/src/bin/psql/t/010_tab_completion.pl
index b6575b075e..b45c39f0f5 100644
--- a/src/bin/psql/t/010_tab_completion.pl
+++ b/src/bin/psql/t/010_tab_completion.pl
@@ -413,6 +413,14 @@ check_completion(
 
 clear_query();
 
+# check completion for psql variable test
+check_completion(
+	"\\echo :{?VERB\t",
+	qr/:\{\?VERBOSITY} /,
+	"complete a psql variable test");
+
+clear_query();
+
 # check no-completions code path
 check_completion("blarg \t\t", qr//, "check completion failure path");
 
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index ada711d02f..a16dac9e73 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -76,7 +76,7 @@
 #endif
 
 /* word break characters */
-#define WORD_BREAKS		"\t\n@><=;|&{() "
+#define WORD_BREAKS		"\t\n@><=;|&() "
 
 /*
  * Since readline doesn't let us pass any state through to the tab completion
@@ -1785,6 +1785,8 @@ psql_completion(const char *text, int start, int end)
 			matches = complete_from_variables(text, ":'", "'", true);
 		else if (text[1] == '"')
 			matches = complete_from_variables(text, ":\"", "\"", true);
+		else if (text[1] == '{' && text[2] == '?')
+			matches = complete_from_variables(text, ":{?", "}", true);
 		else
 			matches = complete_from_variables(text, ":", "", true);
 	}
-- 
2.40.1