diff mbox series

[1/7] built-in add -p: prepare for patch modes other than "stage"

Message ID 8f6139f94debb9b3bfb9c9e8b8e18e3c2fb46a06.1576579264.git.gitgitgadget@gmail.com (mailing list archive)
State New, archived
Headers show
Series stash/reset/checkout -p: optionally use the add --patch backend written in pure C | expand

Commit Message

Johannes Schindelin via GitGitGadget Dec. 17, 2019, 10:40 a.m. UTC 
From: Johannes Schindelin <johannes.schindelin@gmx.de>

The Perl script backing `git add -p` is used not only for that command,
but also for `git stash -p`, `git reset -p` and `git checkout -p`.

In preparation for teaching the C version of `git add -p` to support
also the latter commands, let's abstract away what is "stage" specific
into a dedicated data structure describing the differences between the
patch modes.

Finally, please note that the Perl version tries to make sure that the
diffs are only generated for the modified files. This is not actually
necessary, as the calls to Git's diff machinery already perform that
work, and perform it well. This makes it unnecessary to port the
`FILTER` field of the `%patch_modes` struct, as well as the
`get_diff_reference()` function.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-interactive.c |  2 +-
 add-interactive.h |  8 ++++-
 add-patch.c       | 88 +++++++++++++++++++++++++++++++++--------------
 builtin/add.c     | 10 ++++--
 4 files changed, 79 insertions(+), 29 deletions(-)

Comments

Junio C Hamano Dec. 17, 2019, 7:37 p.m. UTC | #1 
"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> +
> +enum add_p_mode {
> +	ADD_P_STAGE,
> +};

Nice to see a trailing comma here ;-)

> +int run_add_p(struct repository *r, enum add_p_mode mode,
> +	      const char *revision, const struct pathspec *ps);

This makes readers wonder if "const struct object_id *" is more
appropriate; "const char *revision" that holds human-readable name
is better when the internal machinery uses it for reporting, so that
may be what is going on here (so is the new field in add_p_state
structure).

>  #endif
> diff --git a/add-patch.c b/add-patch.c
> index 2c46fe5b33..8a691f07da 100644
> --- a/add-patch.c
> +++ b/add-patch.c
> @@ -11,10 +11,33 @@ enum prompt_mode_type {
>  	PROMPT_MODE_CHANGE = 0, PROMPT_DELETION, PROMPT_HUNK
>  };
>  
> -static const char *prompt_mode[] = {
> -	N_("Stage mode change [y,n,a,q,d%s,?]? "),
> -	N_("Stage deletion [y,n,a,q,d%s,?]? "),
> -	N_("Stage this hunk [y,n,a,q,d%s,?]? ")
> +struct patch_mode {
> +	const char *diff[4], *apply[4], *apply_check[4];

Hardcoded "4" and not-quite descriptive names puzzle readers at the
first glance.  Let's read on to see if they need any further
improvement.

> +	unsigned is_reverse:1, apply_for_checkout:1;
> +	const char *prompt_mode[PROMPT_HUNK + 1];

This relies on the enum value assignment (or listing) order to
ensure that PROMPT_HUNK always comes at the end.  Perhaps that
deserves a comment before "enum prompt_mode_type", e.g.

	+/* Keep PROMPT_HUNK at the end */
	 enum prompt_mode_type {
	 	PROMPT_MODE_CHANGE = 0, ...
	 };

> +	const char *edit_hunk_hint, *help_patch_text;
> +};
> +
> +static struct patch_mode patch_mode_stage = {
> +	.diff = { "diff-files", NULL },

Nice to see designated initializers used ;-)

Mental note: the "diff" field is (probably) for "the command line
to be used to generate the patch"

> +	.apply = { "--cached", NULL },
> +	.apply_check = { "--cached", NULL },

Mental note: these "apply" and "apply_check" fields are (probably)
not for the command line; unlike the "diff" field, these only have
arguments.

Mental note: if the three field names become confusing, perhaps we
can clarify them by either (1) calling diff as diff_cmd[], or (2)
calling the other as apply_args[] and apply_check_args[], or (3)
rename both.

> +	.is_reverse = 0,

Wouldn't it be sufficient to apply the default initialization, just
like it is done for apply_for_checkout bitfield?

> @@ -1310,6 +1345,9 @@ int run_add_p(struct repository *r, const struct pathspec *ps)
>  
>  	init_add_i_state(&s.s, r);
>  
> +	s.mode = &patch_mode_stage;
> +	s.revision = revision;

The phrase "mode_stage" may become problematic, as other modes that
will be introduced, like "reset", "checkout" all will stage
different contents to the index.  The only mode the machinery knows
at this point in the series is how "add" stages contents to the
index, so "patch_mode_add" might turn out to be a better choice of
the phrase as we read the series along.  We'll see.

> +		if (!strcmp(patch_mode, "--patch"))
> +			mode = ADD_P_STAGE;

The same comment applies to this enum token.

Thanks.
Johannes Schindelin Dec. 21, 2019, 9:19 p.m. UTC | #2 
Hi Junio,

On Tue, 17 Dec 2019, Junio C Hamano wrote:

> "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
> writes:
>
> > +int run_add_p(struct repository *r, enum add_p_mode mode,
> > +	      const char *revision, const struct pathspec *ps);
>
> This makes readers wonder if "const struct object_id *" is more
> appropriate; "const char *revision" that holds human-readable name
> is better when the internal machinery uses it for reporting, so that
> may be what is going on here (so is the new field in add_p_state
> structure).

The main reason why this is a string instead of an object ID is to be able
to discern between the `HEAD` vs `non-HEAD` versions.

A secondary consideration was that we will want to keep the scripted
version of `add -p` as the default for now, and that needs the value as
the original string, not as the parsed object ID.

> >  #endif
> > diff --git a/add-patch.c b/add-patch.c
> > index 2c46fe5b33..8a691f07da 100644
> > --- a/add-patch.c
> > +++ b/add-patch.c
> > @@ -11,10 +11,33 @@ enum prompt_mode_type {
> >  	PROMPT_MODE_CHANGE = 0, PROMPT_DELETION, PROMPT_HUNK
> >  };
> >
> > -static const char *prompt_mode[] = {
> > -	N_("Stage mode change [y,n,a,q,d%s,?]? "),
> > -	N_("Stage deletion [y,n,a,q,d%s,?]? "),
> > -	N_("Stage this hunk [y,n,a,q,d%s,?]? ")
> > +struct patch_mode {
> > +	const char *diff[4], *apply[4], *apply_check[4];
>
> Hardcoded "4" and not-quite descriptive names puzzle readers at the
> first glance.  Let's read on to see if they need any further
> improvement.

Good point. I added a code comment.

> > +	unsigned is_reverse:1, apply_for_checkout:1;
> > +	const char *prompt_mode[PROMPT_HUNK + 1];
>
> This relies on the enum value assignment (or listing) order to
> ensure that PROMPT_HUNK always comes at the end.  Perhaps that
> deserves a comment before "enum prompt_mode_type", e.g.
>
> 	+/* Keep PROMPT_HUNK at the end */
> 	 enum prompt_mode_type {
> 	 	PROMPT_MODE_CHANGE = 0, ...
> 	 };

I agree, and introduced `PROMPT_MODE_MAX` for that purpose.

>
> > +	const char *edit_hunk_hint, *help_patch_text;
> > +};
> > +
> > +static struct patch_mode patch_mode_stage = {
> > +	.diff = { "diff-files", NULL },
>
> Nice to see designated initializers used ;-)
>
> Mental note: the "diff" field is (probably) for "the command line
> to be used to generate the patch"
>
> > +	.apply = { "--cached", NULL },
> > +	.apply_check = { "--cached", NULL },
>
> Mental note: these "apply" and "apply_check" fields are (probably)
> not for the command line; unlike the "diff" field, these only have
> arguments.
>
> Mental note: if the three field names become confusing, perhaps we
> can clarify them by either (1) calling diff as diff_cmd[], or (2)
> calling the other as apply_args[] and apply_check_args[], or (3)
> rename both.

I renamed all three.

> > +	.is_reverse = 0,
>
> Wouldn't it be sufficient to apply the default initialization, just
> like it is done for apply_for_checkout bitfield?

Yep, I dropped those unnecessary initializations.

> > @@ -1310,6 +1345,9 @@ int run_add_p(struct repository *r, const struct pathspec *ps)
> >
> >  	init_add_i_state(&s.s, r);
> >
> > +	s.mode = &patch_mode_stage;
> > +	s.revision = revision;
>
> The phrase "mode_stage" may become problematic, as other modes that
> will be introduced, like "reset", "checkout" all will stage
> different contents to the index.  The only mode the machinery knows
> at this point in the series is how "add" stages contents to the
> index, so "patch_mode_add" might turn out to be a better choice of
> the phrase as we read the series along.  We'll see.
>
> > +		if (!strcmp(patch_mode, "--patch"))
> > +			mode = ADD_P_STAGE;
>
> The same comment applies to this enum token.

I renamed both to the `*_add` and `*_ADD` version, respectively.

Thanks,
Dscho
diff mbox series

Patch

diff --git a/add-interactive.c b/add-interactive.c
index 6a5048c83e..0e753d2acc 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -924,7 +924,7 @@  static int run_patch(struct add_i_state *s, const struct pathspec *ps,
 		parse_pathspec(&ps_selected,
 			       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
 			       PATHSPEC_LITERAL_PATH, "", args.argv);
-		res = run_add_p(s->r, &ps_selected);
+		res = run_add_p(s->r, ADD_P_STAGE, NULL, &ps_selected);
 		argv_array_clear(&args);
 		clear_pathspec(&ps_selected);
 	}
diff --git a/add-interactive.h b/add-interactive.h
index 062dc3646c..3defa2ff3d 100644
--- a/add-interactive.h
+++ b/add-interactive.h
@@ -22,6 +22,12 @@  void init_add_i_state(struct add_i_state *s, struct repository *r);
 struct repository;
 struct pathspec;
 int run_add_i(struct repository *r, const struct pathspec *ps);
-int run_add_p(struct repository *r, const struct pathspec *ps);
+
+enum add_p_mode {
+	ADD_P_STAGE,
+};
+
+int run_add_p(struct repository *r, enum add_p_mode mode,
+	      const char *revision, const struct pathspec *ps);
 
 #endif
diff --git a/add-patch.c b/add-patch.c
index 2c46fe5b33..8a691f07da 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -11,10 +11,33 @@  enum prompt_mode_type {
 	PROMPT_MODE_CHANGE = 0, PROMPT_DELETION, PROMPT_HUNK
 };
 
-static const char *prompt_mode[] = {
-	N_("Stage mode change [y,n,a,q,d%s,?]? "),
-	N_("Stage deletion [y,n,a,q,d%s,?]? "),
-	N_("Stage this hunk [y,n,a,q,d%s,?]? ")
+struct patch_mode {
+	const char *diff[4], *apply[4], *apply_check[4];
+	unsigned is_reverse:1, apply_for_checkout:1;
+	const char *prompt_mode[PROMPT_HUNK + 1];
+	const char *edit_hunk_hint, *help_patch_text;
+};
+
+static struct patch_mode patch_mode_stage = {
+	.diff = { "diff-files", NULL },
+	.apply = { "--cached", NULL },
+	.apply_check = { "--cached", NULL },
+	.is_reverse = 0,
+	.prompt_mode = {
+		N_("Stage mode change [y,n,q,a,d%s,?]? "),
+		N_("Stage deletion [y,n,q,a,d%s,?]? "),
+		N_("Stage this hunk [y,n,q,a,d%s,?]? ")
+	},
+	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
+			     "will immediately be marked for staging."),
+	.help_patch_text =
+		N_("y - stage this hunk\n"
+		   "n - do not stage this hunk\n"
+		   "q - quit; do not stage this hunk or any of the remaining "
+			"ones\n"
+		   "a - stage this hunk and all later hunks in the file\n"
+		   "d - do not stage this hunk or any of the later hunks in "
+			"the file\n")
 };
 
 struct hunk_header {
@@ -47,6 +70,10 @@  struct add_p_state {
 		unsigned deleted:1, mode_change:1,binary:1;
 	} *file_diff;
 	size_t file_diff_nr;
+
+	/* patch mode */
+	struct patch_mode *mode;
+	const char *revision;
 };
 
 static void err(struct add_p_state *s, const char *fmt, ...)
@@ -162,9 +189,18 @@  static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 	struct hunk *hunk = NULL;
 	int res;
 
+	argv_array_pushv(&args, s->mode->diff);
+	if (s->revision) {
+		struct object_id oid;
+		argv_array_push(&args,
+				/* could be on an unborn branch */
+				!strcmp("HEAD", s->revision) &&
+				get_oid("HEAD", &oid) ?
+				empty_tree_oid_hex() : s->revision);
+	}
+	color_arg_index = args.argc;
 	/* Use `--no-color` explicitly, just in case `diff.color = always`. */
-	argv_array_pushl(&args, "diff-files", "-p", "--no-color", "--", NULL);
-	color_arg_index = args.argc - 2;
+	argv_array_pushl(&args, "--no-color", "-p", "--", NULL);
 	for (i = 0; i < ps->nr; i++)
 		argv_array_push(&args, ps->items[i].original);
 
@@ -382,7 +418,10 @@  static void render_hunk(struct add_p_state *s, struct hunk *hunk,
 				- header->colored_extra_start;
 		}
 
-		new_offset += delta;
+		if (s->mode->is_reverse)
+			old_offset -= delta;
+		else
+			new_offset += delta;
 
 		strbuf_addf(out, "@@ -%lu,%lu +%lu,%lu @@",
 			    old_offset, header->old_count,
@@ -805,11 +844,10 @@  static int edit_hunk_manually(struct add_p_state *s, struct hunk *hunk)
 				"(context).\n"
 				"To remove '%c' lines, delete them.\n"
 				"Lines starting with %c will be removed.\n"),
-			      '-', '+', comment_line_char);
-	strbuf_commented_addf(&s->buf,
-			      _("If the patch applies cleanly, the edited hunk "
-				"will immediately be\n"
-				"marked for staging.\n"));
+			      s->mode->is_reverse ? '+' : '-',
+			      s->mode->is_reverse ? '-' : '+',
+			      comment_line_char);
+	strbuf_commented_addf(&s->buf, "%s", _(s->mode->edit_hunk_hint));
 	/*
 	 * TRANSLATORS: 'it' refers to the patch mentioned in the previous
 	 * messages.
@@ -890,7 +928,8 @@  static int run_apply_check(struct add_p_state *s,
 	reassemble_patch(s, file_diff, 1, &s->buf);
 
 	setup_child_process(s, &cp,
-			    "apply", "--cached", "--check", NULL);
+			    "apply", "--check", NULL);
+	argv_array_pushv(&cp.args, s->mode->apply_check);
 	if (pipe_command(&cp, s->buf.buf, s->buf.len, NULL, 0, NULL, 0))
 		return error(_("'git apply --cached' failed"));
 
@@ -1005,13 +1044,6 @@  static size_t display_hunks(struct add_p_state *s,
 	return end_index;
 }
 
-static const char help_patch_text[] =
-N_("y - stage this hunk\n"
-   "n - do not stage this hunk\n"
-   "q - quit; do not stage this hunk or any of the remaining ones\n"
-   "a - stage this and all the remaining hunks\n"
-   "d - do not stage this hunk nor any of the remaining hunks\n");
-
 static const char help_patch_remainder[] =
 N_("j - leave this hunk undecided, see next undecided hunk\n"
    "J - leave this hunk undecided, see next hunk\n"
@@ -1097,7 +1129,8 @@  static int patch_update_file(struct add_p_state *s,
 			      (uintmax_t)hunk_index + 1,
 			      (uintmax_t)file_diff->hunk_nr);
 		color_fprintf(stdout, s->s.prompt_color,
-			      _(prompt_mode[prompt_mode_type]), s->buf.buf);
+			      _(s->mode->prompt_mode[prompt_mode_type]),
+			      s->buf.buf);
 		fflush(stdout);
 		if (strbuf_getline(&s->answer, stdin) == EOF)
 			break;
@@ -1254,7 +1287,7 @@  static int patch_update_file(struct add_p_state *s,
 			const char *p = _(help_patch_remainder), *eol = p;
 
 			color_fprintf(stdout, s->s.help_color, "%s",
-				      _(help_patch_text));
+				      _(s->mode->help_patch_text));
 
 			/*
 			 * Show only those lines of the remainder that are
@@ -1288,10 +1321,11 @@  static int patch_update_file(struct add_p_state *s,
 		reassemble_patch(s, file_diff, 0, &s->buf);
 
 		discard_index(s->s.r->index);
-		setup_child_process(s, &cp, "apply", "--cached", NULL);
+		setup_child_process(s, &cp, "apply", NULL);
+		argv_array_pushv(&cp.args, s->mode->apply);
 		if (pipe_command(&cp, s->buf.buf, s->buf.len,
 				 NULL, 0, NULL, 0))
-			error(_("'git apply --cached' failed"));
+			error(_("'git apply' failed"));
 		if (!repo_read_index(s->s.r))
 			repo_refresh_and_write_index(s->s.r, REFRESH_QUIET, 0,
 						     1, NULL, NULL, NULL);
@@ -1301,7 +1335,8 @@  static int patch_update_file(struct add_p_state *s,
 	return quit;
 }
 
-int run_add_p(struct repository *r, const struct pathspec *ps)
+int run_add_p(struct repository *r, enum add_p_mode mode,
+	      const char *revision, const struct pathspec *ps)
 {
 	struct add_p_state s = {
 		{ r }, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
@@ -1310,6 +1345,9 @@  int run_add_p(struct repository *r, const struct pathspec *ps)
 
 	init_add_i_state(&s.s, r);
 
+	s.mode = &patch_mode_stage;
+	s.revision = revision;
+
 	if (discard_index(r->index) < 0 || repo_read_index(r) < 0 ||
 	    repo_refresh_and_write_index(r, REFRESH_QUIET, 0, 1,
 					 NULL, NULL, NULL) < 0 ||
diff --git a/builtin/add.c b/builtin/add.c
index 1deb59a642..05b727a426 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -194,12 +194,18 @@  int run_add_interactive(const char *revision, const char *patch_mode,
 				    &use_builtin_add_i);
 
 	if (use_builtin_add_i == 1) {
+		enum add_p_mode mode;
+
 		if (!patch_mode)
 			return !!run_add_i(the_repository, pathspec);
-		if (strcmp(patch_mode, "--patch"))
+
+		if (!strcmp(patch_mode, "--patch"))
+			mode = ADD_P_STAGE;
+		else
 			die("'%s' not yet supported in the built-in add -p",
 			    patch_mode);
-		return !!run_add_p(the_repository, pathspec);
+
+		return !!run_add_p(the_repository, mode, revision, pathspec);
 	}
 
 	argv_array_push(&argv, "add--interactive");