[PATCH 7/7] gdb: startup commands to control Python extension language

[Andrew Burgess]

* Tom de Vries <tdevries@suse.de> [2021-04-29 10:32:05 +0200]:

> I ran into https://sourceware.org/bugzilla/show_bug.cgi?id=27788 due to
> having PYTHONDONTWRITEBYTECODE set in my environment.  My guess at this
> point is that this is a test-case issue.
> 
> I played around a bit with the options and did:
> ...
> $ echo $PYTHONDONTWRITEBYTECODE
> 1
> 
> $ gdb -q -batch \
>     -iex "set python ignore-environment on" \
>     -iex "show python dont-write-bytecode"
> Python's dont-write-bytecode setting is auto (currently off).
> 
> $ gdb -q -batch \
>     -iex "set python ignore-environment off" \
>     -iex "show python dont-write-bytecode"
> Python's dont-write-bytecode setting is auto (currently on).
> ...
> which shows that there is an interaction between the two commands.
> AFAICT, this is not evident from either the NEWS item, or the docs, and
> I just wonder whether it's a good idea to make this explicit.

Hi Tom,

Thanks for looking at this feature.

The docs for dont-write-bytecode say:

  <snip>

  By default this option is set to @samp{auto}, in this mode Python will
  check the environment variable @env{PYTHONDONTWRITEBYTECODE} to see
  if it should write out byte-code or not.

  <snip>

I guess you saw this, but it still didn't seem clear enough?

What if this was extended to something like:

  By default this option is set to @samp{auto}, in this mode Python will
  check the environment variable @env{PYTHONDONTWRITEBYTECODE} to see
  if it should write out byte-code or not.  When @command{set python
  ignore-environment on} has been used then Python will ignore
  the environment variable and write out the byte-code files.

I've included the patch below that would make this change.

Thanks,
Andrew

---

commit 1557998d9d8e9b0587500980bd8731bb55a1c299
Author: Andrew Burgess <andrew.burgess@embecosm.com>
Date:   Thu Apr 29 10:45:17 2021 +0100

    gdb/doc: improve description of set python dont-write-bytecode
    
    Extend the description of 'set python dont-write-bytecode' to make the
    interaction with 'set python ignore-environment' clearer.
    
    gdb/doc/ChangeLog:
    
            * python.texinfo (Python Commands): Extend description of 'set
            python dont-write-bytecode'.

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 20d65742964..26e1446f005 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -136,8 +136,10 @@
 (@pxref{Initialization Files}) to have the desired effect.
 
 By default this option is set to @samp{auto}, in this mode Python will
-check the environment variable @env{PYTHONDONTWRITEBYTECODE} to see
-if it should write out byte-code or not.
+check the environment variable @env{PYTHONDONTWRITEBYTECODE} to see if
+it should write out byte-code or not.  When @command{set python
+ignore-environment on} has been used then Python will ignore the
+environment variable and write out the byte-code files.
 
 This option is equivalent to passing @option{-B} to the real
 @command{python} executable.