Re: [PATCH] gdb/testsuite: fix failure in gdb.python/py-send-packet.exp

[Andrew Burgess <aburgess@redhat.com>]

Andrew Burgess <aburgess@redhat.com> writes:

> While working on another patch I noticed that, when run on an AArch64
> target, the test gdb.python/py-send-packet.exp was failing:
>
>   Traceback (most recent call last):
>     File "<string>", line 1, in <module>
>     File "/tmp/build/gdb/testsuite/outputs/gdb.python/py-send-packet/py-send-packet.py",
>   line 106, in run_auxv_send_packet_test
>       assert string == expected_result
>   AssertionError
>   Error while executing Python code.
>   (gdb) FAIL: gdb.python/py-send-packet.exp: call python run_auxv_send_packet_test function
>
> The test uses 'maint packet ...' to send a packet to gdbserver, and
> then captures the output in TCL.  This output is then passed through
> to a Python function, which performs some actions using the Python
> API, and compares the results from the Python API to the results
> captured in TCL from 'maint packet ...'.
>
> The problem is that the output captured in TCL contains lots of things
> like '\x000', when this is passed through to Python the '\x' causes
> this to be treated as an escape code, which isn't what we want - we
> want the actual string "\x000".
>
> So, in the TCL part of the test we were expanding '\x' to '\\x', this
> seemed to work fine for my testing on x86-64.
>
> However, on AArch64 what I see is that the results from 'maint packet
> ...' contain a literal '\' character followed by a literal 'x'
> character.  When GDB prints this in the 'maint packet' output, GDB
> escapes the '\' for us, thus we get '\\x' printed by 'maint packet'.
>
> However, now our TCL test script kicks in and tries to "fix" the '\x',
> this means we now have '\\\x', which isn't correct.
>
> The problem is that in the TCL script we are too restrictive, we
> expand '\x' to '\\x', but really, we should be expanding all '\'
> characters, regardless of what follows them.  This is what this patch
> does.
>
> After this the gdb.python/py-send-packet.exp test passes on AArch64
> for me.

I've gone ahead and merged this patch.

Thanks,
Andrew


> ---
>  gdb/testsuite/gdb.python/py-send-packet.exp | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/testsuite/gdb.python/py-send-packet.exp b/gdb/testsuite/gdb.python/py-send-packet.exp
> index 11f0043db9b..5cb2f5a656c 100644
> --- a/gdb/testsuite/gdb.python/py-send-packet.exp
> +++ b/gdb/testsuite/gdb.python/py-send-packet.exp
> @@ -80,9 +80,9 @@ if { ! $skip_auxv_test } {
>  	}
>      }
>  
> -    # Expand the '\x' in the output, so we can pass a string through
> -    # to Python.
> -    set reply_data [string map {\x \\x} $reply_data]
> +    # Escape any backslash characters in the output, so we can safely
> +    # pass a string through to Python.
> +    set reply_data [string map {\\ \\\\} $reply_data]
>      gdb_assert { ![string equal "$reply_data" ""] }
>  
>      # Run the test, fetches the auxv data in Python and confirm it
> -- 
> 2.25.4