External diff support assumes --binary exists

o/

This breaks macos (ventura at least) because apple provides its own diff:

  bash-3.2$ diff --version
  Apple diff (based on FreeBSD diff)

... which doesn't support --binary ... sighs

Is there any known workaround ?
Breezy doesn't have an internal diff anymore ?

On Thu, Nov 03, 2022 at 03:44:29PM -0000, Vincent Ladeuil wrote:
> o/
>
> This breaks macos ventura because apple provides its own diff:
>
> bash-3.2$ diff --version
> Apple diff (based on FreeBSD diff)
>
> ... which doesn't support --binary ... sighs
>
> Is there any known workaround ?
> Breezy doesn't have an internal diff anymore ?
>

We haven't removed the internal diff, so that should still work. Does "bzr
diff" not default to the internal one?

Jelmer

Hmm, when used directly it does.

The failing use case is:

  brz diff --diff-options -u .

which triggers the external diff defaulting to the one in PATH.

For whatever reason I'm running into this from emacs vc handling on macos but not on ubuntu...

Well, on ubuntu, it'd be GNU diff, wouldn't it? :)

I've traditionally worked around this by specifying --using as well; if you tell it the diff program, it didn't pretend it knew to add any arguments other than those you specify.

In 3.2 releases and branch, it's further broken due to bug 1977988 breaking --diff-options more generally...

> Well, on ubuntu, it'd be GNU diff, wouldn't it? :)

/me facepalms

Yes of course, verified.

Epilog: emacs can be taught that -u is the breezy diff default format anyway so emacs "'diff-switches" should not default to "-u" but to nil.

So my side of the issue (a subset of this bug) has a workaround at least.

On Fri, Nov 04, 2022 at 10:20:35AM -0000, Vincent Ladeuil wrote:
> Epilog: emacs can be taught that -u is the breezy diff default format
> anyway so emacs "'diff-switches" should not default to "-u" but to nil.
>
> So my side of the issue (a subset of this bug) has a workaround at
> least.

Thanks for the update!