Add diff output to meson format --check-only

[julianneswinoga]

Currently meson format --check-only exits without any output if it fails. This implements some simple diff output so the user knows why it failed 🙂

$ meson.py format --check-only
--- meson.build (original)
+++ meson.build (reformatted)
@@ -1,5 +1,4 @@
-project('my_project', 'c'
-  )
+project('my_project', 'c')

 a = declare_dependency(dependencies: dependency('threads'))
 b = declare_dependency(dependencies: a)

Pretty simple change but I think it makes a huge DevEx improvement.

[dcbaker]

This all looks good and correct.

I think the todo being fixed here asking for a verbose mode (or a quiet mode, I don't really care which) is a good one. So adding either a --verbose that shows the diff, or a --quiet the suppresses it would be good.

[julianneswinoga]

Good point, unfortunately -q is the short form of --check-only (for some reason) so I opted for -s/--silent

[dcbaker]

Thanks!

This looks good to me, it'll have to wait until we leave feature freeze for 1.8, but I've added it to the 1.9 milestone.

[eli-schwartz]

Overall I really like the idea of this feature. That being said...

[bruchar1]

Good point, unfortunately -q is the short form of --check-only (for some reason) so I opted for -s/--silent

This was to use the same syntax as muon format. I think the logic was that the --check-only mode is quiet as is does not output the formatted file.

Would it be better to add a '-d', '--check-diff' option, and to keep the -q option silent by default? I think I would prefer that.

[julianneswinoga]

Sure, makes sense. Updated 🙂

[bruchar1]

LGTM. You should add a release snippet (just create a md file in docs/markdown/snippets) and update Commands.md page in the manual.

[bruchar1]

Thank you!