Re: [GSoC][PATCH v2 1/1] rebase -i: add --ignore-whitespace flag

[Phillip Wood <phillip.wood123@gmail.com>]

Hi Rohit,

It's good to see another patch reducing the differences between the
rebase back ends.

On 18/07/2019 19:55, Rohit Ashiwal wrote:
> There are two backends available for rebasing, viz, the am and the
> interactive. Naturally, there shall be some features that are
> implemented in one but not in the other. One such flag is
> --ignore-whitespace which indicates merge mechanism to treat lines
> with only whitespace changes as unchanged. Wire the interactive
> rebase to also understand the --ignore-whitespace flag by
> translating it to -Xignore-space-change.
> 
> Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
> ---
>  Documentation/git-rebase.txt            |  9 +++-
>  builtin/rebase.c                        | 26 ++++++++--
>  sequencer.h                             |  1 +
>  t/t3422-rebase-incompatible-options.sh  |  1 -
>  t/t3431-rebase-options-compatibility.sh | 66 +++++++++++++++++++++++++
>  5 files changed, 97 insertions(+), 6 deletions(-)
>  create mode 100755 t/t3431-rebase-options-compatibility.sh
> 
> diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
> index 5e4e927647..eda52ed824 100644
> --- a/Documentation/git-rebase.txt
> +++ b/Documentation/git-rebase.txt
> @@ -371,8 +371,13 @@ If either <upstream> or --root is given on the command line, then the
>  default is `--no-fork-point`, otherwise the default is `--fork-point`.
>  
>  --ignore-whitespace::
> +	This flag is either passed to the 'git apply' program
> +	(see linkgit:git-apply[1]), or to 'git merge' program
> +	(see linkgit:git-merge[1]) as `-Xignore-space-change`,
> +	depending on which backend is selected by other options.
> +
>  --whitespace=<option>::
> -	These flag are passed to the 'git apply' program
> +	This flag is passed to the 'git apply' program
>  	(see linkgit:git-apply[1]) that applies the patch.
>  +
>  See also INCOMPATIBLE OPTIONS below.
> @@ -520,7 +525,6 @@ The following options:
>   * --committer-date-is-author-date
>   * --ignore-date
>   * --whitespace
> - * --ignore-whitespace
>   * -C
>  
>  are incompatible with the following options:
> @@ -543,6 +547,7 @@ In addition, the following pairs of options are incompatible:
>   * --preserve-merges and --interactive
>   * --preserve-merges and --signoff
>   * --preserve-merges and --rebase-merges
> + * --rebase-merges and --ignore-whitespace
>   * --rebase-merges and --strategy
>   * --rebase-merges and --strategy-option
>  
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index db6ca9bd7d..afe376c3fe 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -79,6 +79,7 @@ struct rebase_options {
>  	int allow_rerere_autoupdate;
>  	int keep_empty;
>  	int autosquash;
> +	int ignore_whitespace;
>  	char *gpg_sign_opt;
>  	int autostash;
>  	char *cmd;
> @@ -376,6 +377,17 @@ static int run_rebase_interactive(struct rebase_options *opts,
>  	flags |= opts->rebase_cousins > 0 ? TODO_LIST_REBASE_COUSINS : 0;
>  	flags |= command == ACTION_SHORTEN_OIDS ? TODO_LIST_SHORTEN_IDS : 0;
>  
> +	if (opts->ignore_whitespace) {
> +		struct strbuf buf = STRBUF_INIT;
> +
> +		if (opts->strategy_opts)
> +			strbuf_addstr(&buf, opts->strategy_opts);
> +
> +		strbuf_addstr(&buf, " --ignore-space-change");
> +		free(opts->strategy_opts);
> +		opts->strategy_opts = strbuf_detach(&buf, NULL);
> +	}
> +

I think this would fit better in get_replay_opts()

>  	switch (command) {
>  	case ACTION_NONE: {
>  		if (!opts->onto && !opts->upstream)
> @@ -489,6 +501,8 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
>  		{ OPTION_STRING, 'S', "gpg-sign", &opts.gpg_sign_opt, N_("key-id"),
>  			N_("GPG-sign commits"),
>  			PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
> +		OPT_BOOL(0, "ignore-whitespace", &opts.ignore_whitespace,
> +			 N_("ignore changes in whitespace")),

As with the other patch is this actually going to be used by
rebase--preserve-merges.sh?

>  		OPT_STRING(0, "strategy", &opts.strategy, N_("strategy"),
>  			   N_("rebase strategy")),
>  		OPT_STRING(0, "strategy-opts", &opts.strategy_opts, N_("strategy-opts"),
> @@ -511,6 +525,8 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
>  	argc = parse_options(argc, argv, NULL, options,
>  			builtin_rebase_interactive_usage, PARSE_OPT_KEEP_ARGV0);
>  
> +	opts.strategy_opts = xstrdup_or_null(opts.strategy_opts);
> +
>  	if (!is_null_oid(&squash_onto))
>  		opts.squash_onto = &squash_onto;
>  
> @@ -954,6 +970,8 @@ static int run_am(struct rebase_options *opts)
>  	am.git_cmd = 1;
>  	argv_array_push(&am.args, "am");
>  
> +	if (opts->ignore_whitespace)
> +		argv_array_push(&am.args, "--ignore-whitespace");
>  	if (opts->action && !strcmp("continue", opts->action)) {
>  		argv_array_push(&am.args, "--resolved");
>  		argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
> @@ -1401,9 +1419,6 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
>  			PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
>  		OPT_BOOL(0, "signoff", &options.signoff,
>  			 N_("add a Signed-off-by: line to each commit")),
> -		OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &options.git_am_opts,
> -				  NULL, N_("passed to 'git am'"),
> -				  PARSE_OPT_NOARG),
>  		OPT_PASSTHRU_ARGV(0, "committer-date-is-author-date",
>  				  &options.git_am_opts, NULL,
>  				  N_("passed to 'git am'"), PARSE_OPT_NOARG),
> @@ -1411,6 +1426,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
>  				  N_("passed to 'git am'"), PARSE_OPT_NOARG),
>  		OPT_PASSTHRU_ARGV('C', NULL, &options.git_am_opts, N_("n"),
>  				  N_("passed to 'git apply'"), 0),
> +		OPT_BOOL(0, "ignore-whitespace", &options.ignore_whitespace,
> +			 N_("ignore changes in whitespace")),
>  		OPT_PASSTHRU_ARGV(0, "whitespace", &options.git_am_opts,
>  				  N_("action"), N_("passed to 'git apply'"), 0),
>  		OPT_BIT('f', "force-rebase", &options.flags,
> @@ -1821,6 +1838,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
>  	}
>  
>  	if (options.rebase_merges) {
> +		if (options.ignore_whitespace)
> +			die(_("cannot combine '--rebase-merges' with "
> +			      "'--ignore-whitespace'"));

I was going to ask why we cannot just pass -Xignore-space-change when
making the merge but the lines below seem to show we don't support merge
options yet.

>  		if (strategy_options.nr)
>  			die(_("cannot combine '--rebase-merges' with "
>  			      "'--strategy-option'"));
> diff --git a/sequencer.h b/sequencer.h
> index 0c494b83d4..303047a133 100644
> --- a/sequencer.h
> +++ b/sequencer.h
> @@ -43,6 +43,7 @@ struct replay_opts {
>  	int verbose;
>  	int quiet;
>  	int reschedule_failed_exec;
> +	int ignore_whitespace;

Is this new field used anywhere - we add -Xignore-space-change to
replay_opts.xopts so why do we need this as well?

Best Wishes

Phillip

>  
>  	int mainline;
>  
> diff --git a/t/t3422-rebase-incompatible-options.sh b/t/t3422-rebase-incompatible-options.sh
> index a5868ea152..4342f79eea 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/t3431-rebase-options-compatibility.sh b/t/t3431-rebase-options-compatibility.sh
> new file mode 100755
> index 0000000000..f38ae6f5fc
> --- /dev/null
> +++ b/t/t3431-rebase-options-compatibility.sh
> @@ -0,0 +1,66 @@
> +#!/bin/sh
> +#
> +# Copyright (c) 2019 Rohit Ashiwal
> +#
> +
> +test_description='tests to ensure compatibility between am and interactive backends'
> +
> +. ./test-lib.sh
> +
> +# This is a special case in which both am and interactive backends
> +# provide the same outputs. It was done intentionally because
> +# --ignore-whitespace both the backends fall short of optimal
> +# behaviour.
> +test_expect_success 'setup' '
> +	git checkout -b topic &&
> +	q_to_tab >file <<-EOF &&
> +	line 1
> +	Qline 2
> +	line 3
> +	EOF
> +	git add file &&
> +	git commit -m "add file" &&
> +	q_to_tab >file <<-EOF &&
> +	line 1
> +	new line 2
> +	line 3
> +	EOF
> +	git commit -am "update file" &&
> +	git tag side &&
> +
> +	git checkout --orphan master &&
> +	q_to_tab >file <<-EOF &&
> +	line 1
> +	        line 2
> +	line 3
> +	EOF
> +	git add file &&
> +	git commit -m "add file" &&
> +	git tag main
> +'
> +
> +test_expect_success '--ignore-whitespace works with am backend' '
> +	cat >expect <<-EOF &&
> +	line 1
> +	new line 2
> +	line 3
> +	EOF
> +	test_must_fail git rebase main side &&
> +	git rebase --abort &&
> +	git rebase --ignore-whitespace main side &&
> +	test_cmp expect file
> +'
> +
> +test_expect_success '--ignore-whitespace works with interactive backend' '
> +	cat >expect <<-EOF &&
> +	line 1
> +	new line 2
> +	line 3
> +	EOF
> +	test_must_fail git rebase --merge main side &&
> +	git rebase --abort &&
> +	git rebase --merge --ignore-whitespace main side &&
> +	test_cmp expect file
> +'
> +
> +test_done
>