From: Pedro Alves <pedro@palves.net>
Date: Thu, 17 Apr 2025 21:55:25 +0000 (+0100)
Subject: gdb_test_multiple: Anchor prompt match if -lbl
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1d3289dc29b38e53b8ab497b209fc09bcb689449;p=thirdparty%2Fbinutils-gdb.git

gdb_test_multiple: Anchor prompt match if -lbl

I wrote a test like this:

    gdb_test_multiple "command" "" -lbl {
       -re "^\r\nprefix foo(?=\r\n)" {
           exp_continue
       }
       -re "^\r\nprefix bar(?=\r\n)" {
           exp_continue
       }
       -re "^\r\prefix (?=\r\n)" {
           exp_continue
       }
       -re "^\r\n$::gdb_prompt $" {
       	   pass $gdb_test_name
       }
    }

Anchors are needed in my case to avoid too-eager matching due to the
common prefix.

The intent is for the prompt match above to override the built-in
prompt match.  However, it doesn't and the test fails with output like
this:

  (gdb) command
  prefix foo
  prefix bar
  meant-to-be-matched-by-lbl
  (gdb)

That's because the built-in match for the prompt matches before the
-lbl pattern for this expect buffer:

  \r\nmeant-to-be-matched-by-lbl\r\n(gdb)

This this by anchoring the built-in prompt match if -lbl was
requested.

Change-Id: Ic2571ec793d856a89ee0d533ec363e2ac6036ea2
---

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index c51cea86a9d..6d64344bc0a 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -1124,6 +1124,7 @@ proc gdb_test_multiple { command message args } {
     global any_spawn_id
 
     set line_by_line 0
+    set lbl_anchor_re ""
     set prompt_regexp ""
     set prompt_anchor 1
     for {set i 0} {$i < [llength $args]} {incr i} {
@@ -1133,6 +1134,7 @@ proc gdb_test_multiple { command message args } {
 	    set prompt_regexp [lindex $args $i]
 	} elseif { $arg == "-lbl" } {
 	    set line_by_line 1
+	    set lbl_anchor_re "^"
 	} elseif { $arg == "-no-prompt-anchor" } {
 	    set prompt_anchor 0
 	} else {
@@ -1391,7 +1393,7 @@ proc gdb_test_multiple { command message args } {
 	    fail "$errmsg"
 	    set result -1
 	}
-	-re "\r\n$prompt_regexp" {
+	-re "${lbl_anchor_re}\r\n$prompt_regexp" {
 	    if {![string match "" $message]} {
 		fail "$message"
 	    }