Re: [PATCH 2/3] gdb: improve disassembler styling when Pygments raises an exception

[Simon Marchi <simark@simark.ca>]

On 2022-10-08 12:00, Andrew Burgess wrote:
> Simon Marchi <simark@simark.ca> writes:
> 
>>> +# Check that, if the user is using Python Pygments for disassembler
>>> +# styling, then the styling correctly switches off when an error is
>>> +# detected in the Python code.
>>> +proc test_disassembler_error_handling { } {
>>> +
>>> +    # This test requires the Python Pygments module to be installed
>>> +    # and used by GDB.
>>> +    if { !$::python_disassembly_styling } {
>>> +	return
>>> +    }
>>> +
>>> +    save_vars { env(TERM) } {
>>> +	# We need an ANSI-capable terminal to get the output.
>>> +	setenv TERM ansi
>>> +
>>> +	# Restart GDB with the correct TERM variable setting, this
>>> +	# means that GDB will enable styling.
>>> +	clean_restart_and_disable "restart 4" $::binfile
>>> +
>>> +	# Disable use of libopcodes for styling.  As this function is
>>> +	# only called when Python Pygments module is available, we
>>> +	# should now be using that module to style the disassembler
>>> +	# output.
>>> +	gdb_test_no_output "maint set libopcodes-styling enabled off"
>>> +
>>> +	# Disassemble a single instruction and ensure that the output
>>> +	# has styling markers in it.
>>> +	set insn_before [get_single_disassembled_insn]
>>> +	gdb_assert { [regexp "\033" $insn_before] } \
>>> +	    "have style markers when Pygments is working fine"
>>> +
>>> +	# Now replace the standard function that colorizes the
>>> +	# disassembler output, with a new function that always returns
>>> +	# None, this should cause GDB to stop using the Pygments
>>> +	# module for disassembler styling.
>>> +	gdb_py_test_silent_cmd \
>>> +	    [multi_line_input \
>>> +		 "python" \
>>> +		 "def replacement_colorize_disasm(content,gdbarch):" \
>>> +		 "  return None" \
>>> +		 "gdb.styling.colorize_disasm = replacement_colorize_disasm" \
>>> +		 "\004"] \
>>
>> Any reason you are using \004 here, instead of end?  I don't quite
>> understand why, but it seems to cause some random failures.  Running the
>> test under `taskset -c 2` makes it fail most of the time.  Running it
>> with check-read1 makes it fail consistently:
>>
>>   FAIL: gdb.base/style.exp: capture_command_output for x/1i *main
>>
>> When changing \004 for end, it passes.  I don't have an explanation why
>> though.
> 
> It'll be a copy&paste.  There's a couple of other places in the
> testsuite where this pattern is used.
> 
> The patch below changes all three to use 'end'.  How's this?
> 
> Thanks,
> Andrew

This is fine with me, but again, I didn't dig into it so I don't really
know what sending a \004 was causing,

Thanks!

Simon