[PATCH b4] Avoid type error when local mbox lacks specified message ID

[PATCH b4] Avoid type error when local mbox lacks specified message ID

[Kyle Meyer]

Calling b4-am with --use-local=MBOX is supposed to abort with "Could
not find MID in MBOX" if the mbox doesn't contain the specified
message ID.  As of 4950093c0 (Don't use mboxo for anything,
2021-05-18), a type error is signaled because get_strict_thread()
returns None when there are no matches, and get_msgs() feeds this
result to len().

Update get_msgs() to instead check whether the returned value
evaluates to false.

Signed-off-by: Kyle Meyer <kyle@kyleam.com>
---
 b4/mbox.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/b4/mbox.py b/b4/mbox.py
index a4b005f..bf1a586 100644
--- a/b4/mbox.py
+++ b/b4/mbox.py
@@ -572,7 +572,7 @@ def get_msgs(cmdargs) -> Tuple[Optional[str], Optional[list]]:
 
             if msgid:
                 msgs = b4.get_strict_thread(in_mbx, msgid)
-                if not len(msgs):
+                if not msgs:
                     logger.critical('Could not find %s in %s', msgid, cmdargs.localmbox)
                     sys.exit(1)
             else:

base-commit: 7ed8a3cafd5f3ba5b4e914b495bb3035428e2d45
-- 
2.31.1

Re: [PATCH b4] Avoid type error when local mbox lacks specified message ID

[Konstantin Ryabitsev]

On Sat, 22 May 2021 22:58:12 -0400, Kyle Meyer wrote:
> Calling b4-am with --use-local=MBOX is supposed to abort with "Could
> not find MID in MBOX" if the mbox doesn't contain the specified
> message ID.  As of 4950093c0 (Don't use mboxo for anything,
> 2021-05-18), a type error is signaled because get_strict_thread()
> returns None when there are no matches, and get_msgs() feeds this
> result to len().
> 
> [...]

Applied, thanks!

[1/1] Avoid type error when local mbox lacks specified message ID
      commit: 5d6e3d8e47af6c787ca2cc32e873478fb5c3ba55

I should really refactor that part of the code to properly throw exceptions
instead of returning None. My head is a bit of a mishmash of "Python best
practices from 2003," back when throwing exceptions was considered "too slow."
I'm getting better, though -- who knows, I may even finally add a test suite.
:)

Best regards,
-- 
Konstantin Ryabitsev <konstantin@linuxfoundation.org>