From c6a0aacd51a4f5d72b46a313eba1789aedfc883e Mon Sep 17 00:00:00 2001
From: Pedro Alves <pedro@palves.net>
Date: Tue, 27 May 2025 20:01:36 +0100
Subject: [PATCH 2/4] Testcase showing need for prompt anchor too

Let's add some interspersed lines meant to be consumed by -lbl, an
<LBL> tag for when the built-in -lbl match triggers, and add anchors
to the testcase's "prefix" matches.

With that, the prefix matches no longer each too much, but the
testcase now fails like so:

(gdb) command
prefix
meant-to-be-matched-by-lbl-1
prefix foo
prefix bar
meant-to-be-matched-by-lbl-2
prefix
prefix
meant-to-be-matched-by-lbl-3
(gdb) <COMMAND>
<PREFIX>
<PROMPT>
PASS: gdb.testsuite/gdb-test-multiple.exp: command
PASS: gdb.testsuite/gdb-test-multiple.exp: $saw_command == 1
PASS: gdb.testsuite/gdb-test-multiple.exp: $saw_prompt == 1
FAIL: gdb.testsuite/gdb-test-multiple.exp: $saw_prefix == 3
FAIL: gdb.testsuite/gdb-test-multiple.exp: $saw_prefix_foo == 1
FAIL: gdb.testsuite/gdb-test-multiple.exp: $saw_prefix_bar == 1
saw_prompt: 1
saw_prefix: 1
saw_prefix_foo: 0
saw_prefix_bar: 0

What happened was that expect managed to put all the output up to and
including the prompt in the expect buffer, and since the testcase's
prompt match does not have an ^\r\n anchor, the built-in prompt match
consumed all the output in the expected buffer (since the previous
<PREFIX> match).

Change-Id: Ib59084bad199f3fe945c14fbe1970e730104d3f4
---
 gdb/testsuite/gdb.testsuite/gdb-test-multiple.exp | 8 ++++----
 gdb/testsuite/gdb.testsuite/gdb.sh                | 7 ++++---
 gdb/testsuite/lib/gdb.exp                         | 1 +
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/gdb/testsuite/gdb.testsuite/gdb-test-multiple.exp b/gdb/testsuite/gdb.testsuite/gdb-test-multiple.exp
index a1c9d95a71c..d593d5dc81a 100644
--- a/gdb/testsuite/gdb.testsuite/gdb-test-multiple.exp
+++ b/gdb/testsuite/gdb.testsuite/gdb-test-multiple.exp
@@ -8,22 +8,22 @@ set saw_prefix_foo 0
 set saw_prefix_bar 0
 
 gdb_test_multiple "command" "" -lbl {
-    -re "command(?=\r\n)" {
+    -re "^command(?=\r\n)" {
 	verbose -log <COMMAND>
 	incr saw_command
 	exp_continue
     }
-    -re "\r\nprefix foo(?=\r\n)" {
+    -re "^\r\nprefix foo(?=\r\n)" {
 	verbose -log <PREFIX-FOO>
 	incr saw_prefix_foo
 	exp_continue
     }
-    -re "\r\nprefix bar(?=\r\n)" {
+    -re "^\r\nprefix bar(?=\r\n)" {
 	verbose -log <PREFIX-BAR>
 	incr saw_prefix_bar
 	exp_continue
     }
-    -re "\r\nprefix (?=\r\n)" {
+    -re "^\r\nprefix (?=\r\n)" {
 	verbose -log <PREFIX>
 	incr saw_prefix
 	exp_continue
diff --git a/gdb/testsuite/gdb.testsuite/gdb.sh b/gdb/testsuite/gdb.testsuite/gdb.sh
index 1e9ceee8e23..55bd6473bf8 100755
--- a/gdb/testsuite/gdb.testsuite/gdb.sh
+++ b/gdb/testsuite/gdb.testsuite/gdb.sh
@@ -39,11 +39,12 @@ while true; do
     esac
     if [ "$line" = "command" ]; then
 	echo "prefix "
+	echo "meant-to-be-matched-by-lbl-1"
 	echo "prefix foo"
 	echo "prefix bar"
+	echo "meant-to-be-matched-by-lbl-2"
 	echo "prefix "
-	for n in $(seq 1 1); do
-            echo "meant-to-be-matched-by-lbl-$n"
-	done
+	echo "prefix "
+	echo "meant-to-be-matched-by-lbl-3"
     fi
 done
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index c51cea86a9d..3515d88bae5 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -1431,6 +1431,7 @@ proc gdb_test_multiple { command message args } {
     if {$line_by_line} {
        append code {
            -re "\r\n\[^\r\n\]*(?=\r\n)" {
+	       verbose -log "<LBL>"
                exp_continue
            }
        }
-- 
2.49.0