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

[Andrew Burgess <aburgess@redhat.com>]

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

---

commit eccf885d59a785cc3d9a76bd75184a9b9420f6b9
Author: Andrew Burgess <aburgess@redhat.com>
Date:   Sat Oct 8 16:58:00 2022 +0100

    gdb/testsuite: use 'end' and the end of python blocks
    
    Use the keyword 'end' to terminate blocks of Python code being sent to
    GDB, rather than sending \004.

diff --git a/gdb/testsuite/gdb.base/style.exp b/gdb/testsuite/gdb.base/style.exp
index c6ed996c280..146e2b6d757 100644
--- a/gdb/testsuite/gdb.base/style.exp
+++ b/gdb/testsuite/gdb.base/style.exp
@@ -444,7 +444,7 @@ proc test_disassembler_error_handling { } {
 		 "def replacement_colorize_disasm(content,gdbarch):" \
 		 "  return None" \
 		 "gdb.styling.colorize_disasm = replacement_colorize_disasm" \
-		 "\004"] \
+		 "end"] \
 	    "setup replacement colorize_disasm function" \
 	    true
 
diff --git a/gdb/testsuite/gdb.python/py-arch-reg-groups.exp b/gdb/testsuite/gdb.python/py-arch-reg-groups.exp
index 9503e6c10f5..f2cf8b0e6ec 100644
--- a/gdb/testsuite/gdb.python/py-arch-reg-groups.exp
+++ b/gdb/testsuite/gdb.python/py-arch-reg-groups.exp
@@ -102,5 +102,5 @@ gdb_py_test_silent_cmd \
 	 "    raise gdb.GdbError (\"miss-matched names\")" \
 	 "  if (r1 != r2):" \
 	 "    raise gdb.GdbError (\"miss-matched objects\")" \
-	 "\004" ] \
+	 "end" ] \
     "check names and objects match" 1
diff --git a/gdb/testsuite/gdb.python/py-arch-reg-names.exp b/gdb/testsuite/gdb.python/py-arch-reg-names.exp
index d3c600ffc0f..62c47e8200e 100644
--- a/gdb/testsuite/gdb.python/py-arch-reg-names.exp
+++ b/gdb/testsuite/gdb.python/py-arch-reg-names.exp
@@ -102,7 +102,7 @@ gdb_py_test_silent_cmd \
 	 "    raise gdb.GdbError (\"miss-matched names\")" \
 	 "  if (r1 != r2):" \
 	 "    raise gdb.GdbError (\"miss-matched objects\")" \
-	 "\004" ] \
+	 "end" ] \
     "check names and objects match" 1
 
 # Ensure that the '.find' method on the iterator returns the same