[PATCH][gdb/testsuite] Handle PS1 quirk in gdb.base/multi-line-starts-subshell.exp

[PATCH][gdb/testsuite] Handle PS1 quirk in gdb.base/multi-line-starts-subshell.exp

[Tom de Vries]

Hi,

On SLE-11, I run into:
...
(gdb) if 1^M
 >shell HOME=/dev/null PS1="gdb-subshell$ " /bin/sh^M
 >end^M
hostname:/dir> FAIL: gdb.base/multi-line-starts-subshell.exp: \
  spawn subshell from multi-line (timeout)
...

The problem is that the PS1 setting has no effect.

Fix this by setting PS1 after spawning the subshell.

Tested on x86_64-linux.

Any comments?

Thanks,
- Tom

[gdb/testsuite] Handle PS1 quirk in gdb.base/multi-line-starts-subshell.exp

2020-12-14  Tom de Vries  <tdevries@suse.de>

	PR testsuite/26952
	* gdb.base/multi-line-starts-subshell.exp: Set PS1 after spawning
	shell.

---
 gdb/testsuite/gdb.base/multi-line-starts-subshell.exp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/gdb/testsuite/gdb.base/multi-line-starts-subshell.exp b/gdb/testsuite/gdb.base/multi-line-starts-subshell.exp
index 710c3916c6..dc6d70582a 100644
--- a/gdb/testsuite/gdb.base/multi-line-starts-subshell.exp
+++ b/gdb/testsuite/gdb.base/multi-line-starts-subshell.exp
@@ -27,11 +27,11 @@ set shell_prompt_re [string_to_regexp $shell_prompt]
 
 # Point HOME nowhere to avoid the shell sourcing the user's init
 # scripts.
-set shell_cmd "HOME=/dev/null PS1=\"$shell_prompt\" /bin/sh"
+set shell_cmd "HOME=/dev/null /bin/sh"
 
 set test "spawn subshell from multi-line"
-gdb_test_multiple "if 1\nshell ${shell_cmd}\nend" $test {
-    -re "$shell_prompt_re$" {
+gdb_test_multiple "if 1\nshell ${shell_cmd}\nend\nPS1=\"$shell_prompt\"" $test {
+    -re "PS1=\[^\r\n\]*\r\n$shell_prompt_re$" {
 	pass $test
 
 	# Now check that shell input works and that echo is enabled.

Re: [PATCH][gdb/testsuite] Handle PS1 quirk in gdb.base/multi-line-starts-subshell.exp

[Tom Tromey]

>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:

Tom> The problem is that the PS1 setting has no effect.

Why is that?

Tom> Fix this by setting PS1 after spawning the subshell.

Tom> Tested on x86_64-linux.

Tom> Any comments?

It seems fine but it may be good to understand why it is needed and
perhaps add a comment explaining it.

Tom

Re: [PATCH][gdb/testsuite] Handle PS1 quirk in gdb.base/multi-line-starts-subshell.exp

[Tom de Vries]

On 12/14/20 4:47 PM, Tom Tromey wrote:
>>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:
> 
> Tom> The problem is that the PS1 setting has no effect.
> 
> Why is that?
> 

The mechanism is as follows:
- /etc/profile sets ENV=/etc/bash.bashrc
- /bin/sh is started
- /bin/sh executes ENV, in other words /etc/bash.bashrc
- during the execution of /etc/bash.bashrc, PS1 is set unconditionally

AFAIU, this is caused by this PR (
https://bugzilla.opensuse.org/show_bug.cgi?id=611966 ) which lurks in
older version of openSUSE/SUSE.

> Tom> Fix this by setting PS1 after spawning the subshell.
> 
> Tom> Tested on x86_64-linux.
> 
> Tom> Any comments?
> 
> It seems fine but it may be good to understand why it is needed and
> perhaps add a comment explaining it.

Ack, will do.

Thanks,
- Tom