Subject: Re: [PATCH v5 1/5] rebase -i: add --ignore-whitespace flag

From: Đoàn Trần Công Danh <[email-masked]>
Date: Mon, 29 Jun 2020 21:14:53 +0700

Hi Phillip,

On 2020-06-26 15:43:00+0100, Phillip Wood <[email-masked]> wrote:
> > > +	if (options.type == REBASE_APPLY) {
> > > +		if (ignore_whitespace)
> > > +			argv_array_push (&options.git_am_opts,
> > > +					 "--ignore-whitespace");
> > > +	} else if (ignore_whitespace) {
> > > +			string_list_append (&strategy_options,
> > > +					    "ignore-space-change");
> > > +	}
> > > +
> > 
> > Hm, I've just noticed this by now.
> > Would it's better if we rewrite it as:
> > 
> > 	if (ignore_whitespace) {
> > 		if (options.type == REBASE_APPLY)
> > 			argv_array_push(&options.git_am_opts,
> > 					"--ignore-whitespace");
> > 		else
> > 			string_list_append(&strategy_options,
> > 					   "ignore-space-change");
> > 	}
> > 
> > Ah, the incoming patches will add more conditions into the:
> > 
> > 	if (options.type == REBASE_APPLY)
> > 
> > I'm still not convinced, though.
> 
> I wanted to keep the subsequent patches as simple as possible. Having to
> rewrite the if statement in the next patch just clutters it up and makes the
> real changes introduced by that patch less obvious

I think the code suggested by Junio may be cleaner ;)
I may write as:

	if (ignore_whitespace) {
		if (options.type == REBASE_APPLY)
			argv_array_push(...)
		else
			string_list_append(...)
	}

	if (other_condition)
		do_something_else(...)

I don't know if it's cleaner or not.
I haven't tried applied it into real code.

> > Anyway, IIRC, --ignore-whitespace and --ignore-space-change has the
> > same meaning, I think it's better to use the same option for both
> > legs, no?
> > 
> > I can understand the decision to use --ignore-whitespace as keeping
> > the pass-through behavior of old code, but I think future maintenance
> > is more important than that.
> 
> I'm not sure how it affects future maintenance. The two different options
> are for two different commands so I'm not sure it is worth the effort

I vaguely remember I was thinking about same option text in both leg
would make the code easier for reasoning. And we can unify the
recommendation for both backend. We will never strip
--ignore-whitespace from git-apply, but it would be easier to always
answer: "--ignore-space-change should be used to ignore space" when
someone asks about it.

Typing this now makes me wonder if we should teach --ignore-space-change to
git-rebase?

Thanks,

-- Danh

> 
> Best Wishes
> 
> Phillip
> 
> > I've tried changing ignore-whitespace to ignore-space-change and run
> > make test
> > 
> > It looks good to me (aka nothing failed _in my machine_),
> > 4/5 and 5/5 is not applied, though.
> > 
> > >   	if (strategy_options.nr) {
> > >   		int i;
> > > diff --git a/t/t3422-rebase-incompatible-options.sh b/t/t3422-rebase-incompatible-options.sh
> > > index 50e7960702..55ca46786d 100755
> > > --- a/t/t3422-rebase-incompatible-options.sh
> > > +++ b/t/t3422-rebase-incompatible-options.sh
> > > @@ -61,7 +61,6 @@ test_rebase_am_only () {
> > >   }
> > >   test_rebase_am_only --whitespace=fix
> > > -test_rebase_am_only --ignore-whitespace
> > >   test_rebase_am_only --committer-date-is-author-date
> > >   test_rebase_am_only -C4
> > > diff --git a/t/t3436-rebase-more-options.sh b/t/t3436-rebase-more-options.sh
> > > new file mode 100755
> > > index 0000000000..4f8a6e51c9
> > > --- /dev/null
> > > +++ b/t/t3436-rebase-more-options.sh
> > > @@ -0,0 +1,60 @@
> > > +#!/bin/sh
> > > +#
> > > +# Copyright (c) 2019 Rohit Ashiwal
> > > +#
> > > +
> > > +test_description='tests to ensure compatibility between am and interactive backends'
> > > +
> > > +. ./test-lib.sh
> > > +
> > > +. "$TEST_DIRECTORY"/lib-rebase.sh
> > > +
> > > +# This is a special case in which both am and interactive backends
> > > +# provide the same output. It was done intentionally because
> > > +# both the backends fall short of optimal behaviour.
> > > +test_expect_success 'setup' '
> > > +	git checkout -b topic &&
> > > +	test_write_lines "line 1" "	line 2" "line 3" >file &&
> > > +	git add file &&
> > > +	git commit -m "add file" &&
> > > +
> > > +	test_write_lines "line 1" "new line 2" "line 3" >file &&
> > > +	git commit -am "update file" &&
> > > +	git tag side &&
> > > +
> > > +	git checkout --orphan master &&
> > > +	test_write_lines "line 1" "        line 2" "line 3" >file &&
> > > +	git commit -am "add file" &&
> > > +	git tag main
> > > +'
> > > +
> > > +test_expect_success '--ignore-whitespace works with apply backend' '
> > > +	test_must_fail git rebase --apply main side &&
> > > +	git rebase --abort &&
> > > +	git rebase --apply --ignore-whitespace main side &&
> > > +	git diff --exit-code side
> > > +'
> > > +
> > > +test_expect_success '--ignore-whitespace works with merge backend' '
> > > +	test_must_fail git rebase --merge main side &&
> > > +	git rebase --abort &&
> > > +	git rebase --merge --ignore-whitespace main side &&
> > > +	git diff --exit-code side
> > > +'
> > > +
> > > +test_expect_success '--ignore-whitespace is remembered when continuing' '
> > > +	(
> > > +		set_fake_editor &&
> > > +		FAKE_LINES="break 1" git rebase -i --ignore-whitespace \
> > > +			main side &&
> > > +		git rebase --continue
> > > +	) &&
> > > +	git diff --exit-code side
> > > +'
> > > +
> > > +# This must be the last test in this file
> > > +test_expect_success '$EDITOR and friends are unchanged' '
> > > +	test_editor_unchanged
> > > +'
> > > +
> > > +test_done
> > > -- 
> > > 2.27.0
> > > 
> > 

-- 
Danh