Hi Phillip,
sorry to be _so_ late in the game. (And sorry for sending this to you
twice, I managed to skip all the Cc:s due to the Reply-To: header the
first time round.)
On Wed, 27 May 2020, Phillip Wood wrote:
> From: Rohit Ashiwal <rohit.ashiwal265@xxxxxxxxx>
>
> Rebase is implemented with two different backends - 'apply' and 'merge'
> each of which support a different set of options. In particuar the apply
> backend supports a number of options implemented by 'git am' that are
> not available to the merge backend. As part of an on going effort to
As a non-native speaker, I am thrown off when reading "available to"
instead of the grammatically correct (I believe) "available in". Likewise,
"on going" instead of "ongoing" just disrupts my workflow.
Maybe these can be fixed?
> remove the apply backend this patch adds support for the
> --ignore-whitespace option to the merge backend. This option treats
> lines with only whitespace changes as unchanged and is implemented in
> the merge backend by translating it to -Xignore-space-change.
>
> Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@xxxxxxxxx>
> Signed-off-by: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
> ---
> Documentation/git-rebase.txt | 19 +++++-
> builtin/rebase.c | 19 ++++--
> t/t3422-rebase-incompatible-options.sh | 1 -
> t/t3436-rebase-more-options.sh | 86 ++++++++++++++++++++++++++
> 4 files changed, 118 insertions(+), 7 deletions(-)
> create mode 100755 t/t3436-rebase-more-options.sh
>
> diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
> index f7a6033607..b003784f01 100644
> --- a/Documentation/git-rebase.txt
> +++ b/Documentation/git-rebase.txt
> @@ -422,8 +422,23 @@ your branch contains commits which were dropped, this option can be used
> with `--keep-base` in order to drop those commits from your branch.
>
> --ignore-whitespace::
> + Ignore whitespace differences when trying to reconcile
> +differences. Currently, each backend implements an approximation of
> +this behavior:
> ++
> +apply backend: When applying a patch, ignore changes in whitespace in
> +context lines. Unfortunately, this means that if the "old" lines being
> +replaced by the patch differ only in whitespace from the existing
> +file, you will get a merge conflict instead of a successful patch
> +application.
> ++
> +merge backend: Treat lines with only whitespace changes as unchanged
> +when merging. Unfortunately, this means that any patch hunks that were
> +intended to modify whitespace and nothing else will be dropped, even
> +if the other side had no changes that conflicted.
> +
> --whitespace=<option>::
> - These flags 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.
> Implies --apply.
> +
> @@ -572,7 +587,6 @@ The following options:
> * --apply
> * --committer-date-is-author-date
> * --ignore-date
> - * --ignore-whitespace
> * --whitespace
> * -C
>
> @@ -598,6 +612,7 @@ In addition, the following pairs of options are incompatible:
> * --preserve-merges and --signoff
> * --preserve-merges and --rebase-merges
> * --preserve-merges and --empty=
> + * --preserve-merges and --ignore-whitespace
> * --keep-base and --onto
> * --keep-base and --root
>
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index 27a07d4e78..5d8e117276 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -86,6 +86,7 @@ struct rebase_options {
> int signoff;
> int allow_rerere_autoupdate;
> int autosquash;
> + int ignore_whitespace;
> char *gpg_sign_opt;
> int autostash;
> char *cmd;
> @@ -108,6 +109,7 @@ struct rebase_options {
>
> static struct replay_opts get_replay_opts(const struct rebase_options *opts)
> {
> + struct strbuf strategy_buf = STRBUF_INIT;
> struct replay_opts replay = REPLAY_OPTS_INIT;
>
> replay.action = REPLAY_INTERACTIVE_REBASE;
> @@ -126,14 +128,20 @@ static struct replay_opts get_replay_opts(const struct rebase_options *opts)
> replay.reschedule_failed_exec = opts->reschedule_failed_exec;
> replay.gpg_sign = xstrdup_or_null(opts->gpg_sign_opt);
> replay.strategy = opts->strategy;
> +
> if (opts->strategy_opts)
> - parse_strategy_opts(&replay, opts->strategy_opts);
> + strbuf_addstr(&strategy_buf, opts->strategy_opts);
> + if (opts->ignore_whitespace)
> + strbuf_addstr(&strategy_buf, " --ignore-space-change");
> + if (strategy_buf.len)
> + parse_strategy_opts(&replay, strategy_buf.buf);
Quite honestly, this is very, very ugly.
I would have expected this at a way earlier layer, namely in
`cmd__rebase()`. Something along these lines:
-- snip --
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 37ba76ac3d26..748e08aee2f2 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -1289,6 +1289,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
struct strbuf revisions = STRBUF_INIT;
struct strbuf buf = STRBUF_INIT;
struct object_id merge_base;
+ int ignore_whitespace = 0;
enum action action = ACTION_NONE;
const char *gpg_sign = NULL;
struct string_list exec = STRING_LIST_INIT_NODUP;
@@ -1318,9 +1319,8 @@ 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_BOOL(0, "ignore-whitespace", &ignore_whitespace,
+ N_("passed to 'git am'")),
OPT_PASSTHRU_ARGV(0, "committer-date-is-author-date",
&options.git_am_opts, NULL,
N_("passed to 'git am'"), PARSE_OPT_NOARG),
@@ -1682,6 +1682,15 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
imply_merge(&options, "--rebase-merges");
}
+ if (ignore_whitespace) {
+ if (options.type == REBASE_APPLY)
+ argv_array_push(&options.git_am_opts,
+ "--ignore-whitespace");
+ else
+ string_list_append(&stragey_options,
+ "--ignore-space-change");
+ }
+
if (strategy_options.nr) {
int i;
-- snap --
>
> if (opts->squash_onto) {
> oidcpy(&replay.squash_onto, opts->squash_onto);
> replay.have_squash_onto = 1;
> }
>
> + strbuf_release(&strategy_buf);
> return replay;
> }
>
> @@ -539,6 +547,8 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
> argc = parse_options(argc, argv, prefix, options,
> builtin_rebase_interactive_usage, PARSE_OPT_KEEP_ARGV0);
>
> + opts.strategy_opts = xstrdup_or_null(opts.strategy_opts);
I am not sure what this is about: `opts.strategy_opts` is of type `char
*`, i.e. it is supposed to be already allocated.
Not that `cmd_rebase__interactive()` matters _all_ that much anymore, of
course: it is only used by the --preserve-merges backend, which will
hopefully be retired soon.
> +
> if (!is_null_oid(&squash_onto))
> opts.squash_onto = &squash_onto;
>
> @@ -991,6 +1001,8 @@ 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);
> @@ -1495,16 +1507,15 @@ 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),
> OPT_PASSTHRU_ARGV(0, "ignore-date", &options.git_am_opts, NULL,
> 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,
> 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..fb5e747e86
> --- /dev/null
> +++ b/t/t3436-rebase-more-options.sh
> @@ -0,0 +1,86 @@
> +#!/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 &&
> + q_to_tab >file <<-\EOF &&
> + line 1
> + Qline 2
> + line 3
> + EOF
> + git add file &&
> + git commit -m "add file" &&
> + cat >file <<-\EOF &&
> + line 1
> + new line 2
> + line 3
> + EOF
> + git commit -am "update file" &&
> + git tag side &&
> +
> + git checkout --orphan master &&
> + sed -e "s/^|//" >file <<-\EOF &&
> + |line 1
> + | line 2
> + |line 3
> + EOF
> + git add file &&
> + git commit -m "add file" &&
> + git tag main
> +'
The file contents are repeated in an awfully repetitive manner. That not
only makes things a bit hard to read, it also makes it all too easy to
slip in bugs by mistake. How about something like this instead?
test_commit file &&
test_write_lines line1 Qline2 line3 >templ &&
q_to_tab <templ >file.t &&
git commit -m tab file.t &&
sed "s/Q/new /" <templ >file.t &&
git commit -m new file.t &&
git tag side &&
git checkout file -- &&
sed "s/Q/ /" <templ >file.t &&
git commit -m spaces file.t
... and then...
> +
> +test_expect_success '--ignore-whitespace works with apply backend' '
> + cat >expect <<-\EOF &&
> + line 1
> + new line 2
> + line 3
> + EOF
sed "s/Q/new /" <templ >expect
> + test_must_fail git rebase --apply main side &&
> + git rebase --abort &&
> + git rebase --apply --ignore-whitespace main side &&
> + test_cmp expect file
Personally, I prefer to read the contents of `expect` directly before the
`test_cmp expect file.t`
> +'
> +
> +test_expect_success '--ignore-whitespace works with merge backend' '
> + cat >expect <<-\EOF &&
> + line 1
> + new line 2
> + line 3
> + EOF
Isn't this totally identical to the `expect` constructed earlier? And in
any case, isn't this identical to `git show main:file.t`, which is what we
_actually_ expect: for the file contents to be identical to the tagged
`main`? I.e.
git diff --exit-code main
> + test_must_fail git rebase --merge main side &&
> + git rebase --abort &&
> + git rebase --merge --ignore-whitespace main side &&
> + test_cmp expect file
> +'
> +
> +test_expect_success '--ignore-whitespace is remembered when continuing' '
> + cat >expect <<-\EOF &&
> + line 1
> + new line 2
> + line 3
> + EOF
> + (
> + set_fake_editor &&
> + FAKE_LINES="break 1" git rebase -i --ignore-whitespace main side
> + ) &&
> + git rebase --continue &&
> + test_cmp expect file
It is a bit funny to see these two invocations _specifically_ pulled out
from the subshell, that's not how we do things in other test scripts:
instead, we run all the Git commands _inside_ the subshell, and all the
verifications after the subshell.
I believe that with my suggestions, this test script will be a ton easier
to read and to maintain. At least it will be a lot DRYer.
Ciao,
Dscho
> +'
> +
> +# This must be the last test in this file
> +test_expect_success '$EDITOR and friends are unchanged' '
> + test_editor_unchanged
> +'
> +
> +test_done
> --
> 2.26.2
>
>
