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[PATCH v5 5/6] Implement 'git checkout --patch'

From
Thomas Rast <trast@student.ethz.ch>
Date
Aug 13, 2009, 12:29 UTC
Message-ID
<b75f4adebf7f417b8c46746202933e8f7ff80331.1250164190.git.trast@student.ethz.ch>
In-Reply-To
<cover.1250164190.git.trast@student.ethz.ch>
This introduces a --patch mode for git-checkout.  In the index usage
  git checkout --patch -- [files...]

it lets the user discard edits from the <files> at the granularity of hunks (by selecting hunks from 'git diff' and then reverse applying them to the worktree).

We also accept a revision argument.  In the case
  git checkout --patch HEAD -- [files...]

we offer hunks from the difference between HEAD and the worktree, and reverse applies them to both index and worktree, allowing you to discard staged changes completely. In the non-HEAD usage

  git checkout --patch <revision> -- [files...]

it offers hunks from the difference between the worktree and <revision>. The chosen hunks are then applied to both index and worktree.

The application to worktree and index is done "atomically" in the sense that we first check if the patch applies to the index (it should always apply to the worktree). If it does not, we give the user a choice to either abort or apply to the worktree anyway.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
---
 Documentation/git-checkout.txt |   13 +++++-
 builtin-checkout.c             |   19 +++++++
 git-add--interactive.perl      |   61 +++++++++++++++++++++++
 t/t2015-checkout-patch.sh      |  107 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 199 insertions(+), 1 deletions(-)
 create mode 100755 t/t2015-checkout-patch.sh
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index ad4b31e..26a5447 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -11,6 +11,7 @@ SYNOPSIS
 'git checkout' [-q] [-f] [-m] [<branch>]
 'git checkout' [-q] [-f] [-m] [-b <new_branch>] [<start_point>]
 'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <paths>...
+'git checkout' --patch [<tree-ish>] [--] [<paths>...]
 
 DESCRIPTION
 -----------
@@ -25,7 +26,7 @@ use the --track or --no-track options, which will be passed to `git
 branch`.  As a convenience, --track without `-b` implies branch
 creation; see the description of --track below.
 
-When <paths> are given, this command does *not* switch
+When <paths> or --patch are given, this command does *not* switch
 branches.  It updates the named paths in the working tree from
 the index file, or from a named <tree-ish> (most often a commit).  In
 this case, the `-b` and `--track` options are meaningless and giving
@@ -113,6 +114,16 @@ the conflicted merge in the specified paths.
 	"merge" (default) and "diff3" (in addition to what is shown by
 	"merge" style, shows the original contents).
 
+-p::
+--patch::
+	Interactively select hunks in the difference between the
+	<tree-ish> (or the index, if unspecified) and the working
+	tree.  The chosen hunks are then applied in reverse to the
+	working tree (and if a <tree-ish> was specified, the index).
++
+This means that you can use `git checkout -p` to selectively discard
+edits from your current working tree.
+
 <branch>::
 	Branch to checkout; if it refers to a branch (i.e., a name that,
 	when prepended with "refs/heads/", is a valid ref), then that
diff --git a/builtin-checkout.c b/builtin-checkout.c
index 8a9a474..8b942ba 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -572,6 +572,13 @@ static int git_checkout_config(const char *var, const char *value, void *cb)
 	return git_xmerge_config(var, value, cb);
 }
 
+static int interactive_checkout(const char *revision, const char **pathspec,
+				struct checkout_opts *opts)
+{
+	return run_add_interactive(revision, "--patch=checkout", pathspec);
+}
+
+
 int cmd_checkout(int argc, const char **argv, const char *prefix)
 {
 	struct checkout_opts opts;
@@ -580,6 +587,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	struct branch_info new;
 	struct tree *source_tree = NULL;
 	char *conflict_style = NULL;
+	int patch_mode = 0;
 	struct option options[] = {
 		OPT__QUIET(&opts.quiet),
 		OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
@@ -594,6 +602,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		OPT_BOOLEAN('m', "merge", &opts.merge, "merge"),
 		OPT_STRING(0, "conflict", &conflict_style, "style",
 			   "conflict style (merge or diff3)"),
+		OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
 		OPT_END(),
 	};
 	int has_dash_dash;
@@ -608,6 +617,10 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, options, checkout_usage,
 			     PARSE_OPT_KEEP_DASHDASH);
 
+	if (patch_mode && (opts.track > 0 || opts.new_branch
+			   || opts.new_branch_log || opts.merge || opts.force))
+		die ("--patch is incompatible with all other options");
+
 	/* --track without -b should DWIM */
 	if (0 < opts.track && !opts.new_branch) {
 		const char *argv0 = argv[0];
@@ -714,6 +727,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		if (!pathspec)
 			die("invalid path specification");
 
+		if (patch_mode)
+			return interactive_checkout(new.name, pathspec, &opts);
+
 		/* Checkout paths */
 		if (opts.new_branch) {
 			if (argc == 1) {
@@ -729,6 +745,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		return checkout_paths(source_tree, pathspec, &opts);
 	}
 
+	if (patch_mode)
+		return interactive_checkout(new.name, NULL, &opts);
+
 	if (opts.new_branch) {
 		struct strbuf buf = STRBUF_INIT;
 		if (strbuf_check_branch_ref(&buf, opts.new_branch))
diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index f040249..9c202fc 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -75,6 +75,7 @@
 my $patch_mode_revision;
 
 sub apply_patch;
+sub apply_patch_for_checkout_commit;
 
 my %patch_modes = (
 	'stage' => {
@@ -104,6 +105,33 @@
 		PARTICIPLE => 'applying',
 		FILTER => 'index-only',
 	},
+	'checkout_index' => {
+		DIFF => 'diff-files -p',
+		APPLY => sub { apply_patch 'apply -R', @_; },
+		APPLY_CHECK => 'apply -R',
+		VERB => 'Discard',
+		TARGET => ' from worktree',
+		PARTICIPLE => 'discarding',
+		FILTER => 'file-only',
+	},
+	'checkout_head' => {
+		DIFF => 'diff-index -p',
+		APPLY => sub { apply_patch_for_checkout_commit '-R', @_ },
+		APPLY_CHECK => 'apply',
+		VERB => 'Discard',
+		TARGET => ' from index and worktree',
+		PARTICIPLE => 'discarding',
+		FILTER => undef,
+	},
+	'checkout_nothead' => {
+		DIFF => 'diff-index -R -p',
+		APPLY => sub { apply_patch_for_checkout_commit '', @_ },
+		APPLY_CHECK => 'apply',
+		VERB => 'Apply',
+		TARGET => ' to index and worktree',
+		PARTICIPLE => 'applying',
+		FILTER => undef,
+	},
 );
 
 my %patch_mode_flavour = %{$patch_modes{stage}};
@@ -1069,6 +1097,29 @@
 	return $ret;
 }
 
+sub apply_patch_for_checkout_commit {
+	my $reverse = shift;
+	my $applies_index = run_git_apply 'apply '.$reverse.' --cached --recount --check', @_;
+	my $applies_worktree = run_git_apply 'apply '.$reverse.' --recount --check', @_;
+
+	if ($applies_worktree && $applies_index) {
+		run_git_apply 'apply '.$reverse.' --cached --recount', @_;
+		run_git_apply 'apply '.$reverse.' --recount', @_;
+		return 1;
+	} elsif (!$applies_index) {
+		print colored $error_color, "The selected hunks do not apply to the index!\n";
+		if (prompt_yesno "Apply them to the worktree anyway? ") {
+			return run_git_apply 'apply '.$reverse.' --recount', @_;
+		} else {
+			print colored $error_color, "Nothing was applied.\n";
+			return 0;
+		}
+	} else {
+		print STDERR @_;
+		return 0;
+	}
+}
+
 sub patch_update_cmd {
 	my @all_mods = list_modified($patch_mode_flavour{FILTER});
 	my @mods = grep { !($_->{BINARY}) } @all_mods;
@@ -1432,6 +1483,16 @@
 						       'reset_head' : 'reset_nothead');
 					$arg = shift @ARGV or die "missing --";
 				}
+			} elsif ($1 eq 'checkout') {
+				$arg = shift @ARGV or die "missing --";
+				if ($arg eq '--') {
+					$patch_mode = 'checkout_index';
+				} else {
+					$patch_mode_revision = $arg;
+					$patch_mode = ($arg eq 'HEAD' ?
+						       'checkout_head' : 'checkout_nothead');
+					$arg = shift @ARGV or die "missing --";
+				}
 			} elsif ($1 eq 'stage') {
 				$patch_mode = 'stage';
 				$arg = shift @ARGV or die "missing --";
diff --git a/t/t2015-checkout-patch.sh b/t/t2015-checkout-patch.sh
new file mode 100755
index 0000000..4d1c2e9
--- /dev/null
+++ b/t/t2015-checkout-patch.sh
@@ -0,0 +1,107 @@
+#!/bin/sh
+
+test_description='git checkout --patch'
+
+. ./lib-patch-mode.sh
+
+test_expect_success 'setup' '
+	mkdir dir &&
+	echo parent > dir/foo &&
+	echo dummy > bar &&
+	git add bar dir/foo &&
+	git commit -m initial &&
+	test_tick &&
+	test_commit second dir/foo head &&
+	set_and_save_state bar bar_work bar_index &&
+	save_head
+'
+
+# note: bar sorts before dir/foo, so the first 'n' is always to skip 'bar'
+
+test_expect_success 'saying "n" does nothing' '
+	set_and_save_state dir/foo work head &&
+	(echo n; echo n) | git checkout -p &&
+	verify_saved_state bar &&
+	verify_saved_state dir/foo
+'
+
+test_expect_success 'git checkout -p' '
+	(echo n; echo y) | git checkout -p &&
+	verify_saved_state bar &&
+	verify_state dir/foo head head
+'
+
+test_expect_success 'git checkout -p with staged changes' '
+	set_state dir/foo work index
+	(echo n; echo y) | git checkout -p &&
+	verify_saved_state bar &&
+	verify_state dir/foo index index
+'
+
+test_expect_success 'git checkout -p HEAD with NO staged changes: abort' '
+	set_and_save_state dir/foo work head &&
+	(echo n; echo y; echo n) | git checkout -p HEAD &&
+	verify_saved_state bar &&
+	verify_saved_state dir/foo
+'
+
+test_expect_success 'git checkout -p HEAD with NO staged changes: apply' '
+	(echo n; echo y; echo y) | git checkout -p HEAD &&
+	verify_saved_state bar &&
+	verify_state dir/foo head head
+'
+
+test_expect_success 'git checkout -p HEAD with change already staged' '
+	set_state dir/foo index index
+	# the third n is to get out in case it mistakenly does not apply
+	(echo n; echo y; echo n) | git checkout -p HEAD &&
+	verify_saved_state bar &&
+	verify_state dir/foo head head
+'
+
+test_expect_success 'git checkout -p HEAD^' '
+	# the third n is to get out in case it mistakenly does not apply
+	(echo n; echo y; echo n) | git checkout -p HEAD^ &&
+	verify_saved_state bar &&
+	verify_state dir/foo parent parent
+'
+
+# The idea in the rest is that bar sorts first, so we always say 'y'
+# first and if the path limiter fails it'll apply to bar instead of
+# dir/foo.  There's always an extra 'n' to reject edits to dir/foo in
+# the failure case (and thus get out of the loop).
+
+test_expect_success 'path limiting works: dir' '
+	set_state dir/foo work head &&
+	(echo y; echo n) | git checkout -p dir &&
+	verify_saved_state bar &&
+	verify_state dir/foo head head
+'
+
+test_expect_success 'path limiting works: -- dir' '
+	set_state dir/foo work head &&
+	(echo y; echo n) | git checkout -p -- dir &&
+	verify_saved_state bar &&
+	verify_state dir/foo head head
+'
+
+test_expect_success 'path limiting works: HEAD^ -- dir' '
+	# the third n is to get out in case it mistakenly does not apply
+	(echo y; echo n; echo n) | git checkout -p HEAD^ -- dir &&
+	verify_saved_state bar &&
+	verify_state dir/foo parent parent
+'
+
+test_expect_success 'path limiting works: foo inside dir' '
+	set_state dir/foo work head &&
+	# the third n is to get out in case it mistakenly does not apply
+	(echo y; echo n; echo n) | (cd dir && git checkout -p foo) &&
+	verify_saved_state bar &&
+	verify_state dir/foo head head
+'
+
+test_expect_success 'none of this moved HEAD' '
+	verify_saved_head
+'
+
+test_done

-- 
1.6.4.262.gbda8
Previous: Thomas RastNext: Thomas Rast
Message 51 of 76 in “git-add -p: be able to undo a given hunk”
  1. git-add -p: be able to undo a given hunkPierre Habouzit, Jul 23, 2009
  2. Thomas RastJul 23, 2009
  3. Pierre HabouzitJul 23, 2009
  4. Implement unstage and reset modes for git-add--interactiveThomas Rast, Jul 24, 2009
  5. 1/3 Introduce git-unstageThomas Rast, Jul 24, 2009
  6. Bert WesargJul 24, 2009
  7. Bert WesargJul 24, 2009
  8. Elijah NewrenJul 24, 2009
  9. 2/3 Introduce git-discardThomas Rast, Jul 24, 2009
  10. Elijah NewrenJul 24, 2009
  11. Bert WesargJul 24, 2009
  12. Elijah NewrenJul 24, 2009
  13. Pierre HabouzitJul 25, 2009
  14. 3/3 Implement unstage --patch and discard --patchThomas Rast, Jul 24, 2009
  15. Matthias KestenholzJul 24, 2009
  16. Bert WesargJul 24, 2009
  17. Junio C HamanoJul 24, 2009
  18. Nanako ShiraishiJul 24, 2009
  19. Thomas RastJul 24, 2009
  20. Junio C HamanoJul 24, 2009
  21. 0/5 {checkout,reset,stash} --patchThomas Rast, Jul 25, 2009
  22. 1/5 git-apply--interactive: Refactor patch mode codeThomas Rast, Jul 25, 2009
  23. 2/5 builtin-add: refactor the meat of interactive_add()Thomas Rast, Jul 25, 2009
  24. 3/5 Implement 'git reset --patch'Thomas Rast, Jul 25, 2009
  25. 4/5 Implement 'git checkout --patch'Thomas Rast, Jul 25, 2009
  26. 5/5 Implement 'git stash save --patch'Thomas Rast, Jul 25, 2009
  27. Sverre RabbelierJul 26, 2009
  28. Thomas RastJul 26, 2009
  29. Thomas RastJul 27, 2009
  30. 0/5 {checkout,reset,stash} --patchThomas Rast, Jul 28, 2009
  31. 1/5 git-apply--interactive: Refactor patch mode codeThomas Rast, Jul 28, 2009
  32. 2/5 builtin-add: refactor the meat of interactive_add()Thomas Rast, Jul 28, 2009
  33. 3/5 Implement 'git reset --patch'Thomas Rast, Jul 28, 2009
  34. 4/5 Implement 'git checkout --patch'Thomas Rast, Jul 28, 2009
  35. 5/5 Implement 'git stash save --patch'Thomas Rast, Jul 28, 2009
  36. 6/5 DWIM 'git stash save -p' for 'git stash -p'Thomas Rast, Jul 28, 2009
  37. Jeff KingAug 9, 2009
  38. Thomas RastAug 9, 2009
  39. 0/5 Re: {checkout,reset,stash} --patchNicolas Sebrecht, Aug 9, 2009
  40. Thomas RastAug 9, 2009
  41. 0/5 Re: {checkout,reset,stash} --patchNicolas Sebrecht, Aug 9, 2009
  42. Thomas RastAug 9, 2009
  43. 0/5 Re: {checkout,reset,stash} --patchNicolas Sebrecht, Aug 9, 2009
  44. Thomas RastAug 10, 2009
  45. 0/6 {checkout,reset,stash} --patchThomas Rast, Aug 13, 2009
  46. 1/6 git-apply--interactive: Refactor patch mode codeThomas Rast, Aug 13, 2009
  47. 2/6 Add a small patch-mode testing libraryThomas Rast, Aug 13, 2009
  48. 3/6 builtin-add: refactor the meat of interactive_add()Thomas Rast, Aug 13, 2009
  49. 4/6 Implement 'git reset --patch'Thomas Rast, Aug 13, 2009
  50. 4/6 Implement 'git reset --patch'Thomas Rast, Aug 15, 2009
  51. 5/6 Implement 'git checkout --patch'Thomas Rast, Aug 13, 2009
  52. 5/6 Implement 'git checkout --patch'Thomas Rast, Aug 15, 2009
  53. 6/6 Implement 'git stash save --patch'Thomas Rast, Aug 13, 2009
  54. 7/6 DWIM 'git stash save -p' for 'git stash -p'Thomas Rast, Aug 13, 2009
  55. 0/6 Re: {checkout,reset,stash} --patchNicolas Sebrecht, Aug 14, 2009
  56. Jeff KingAug 15, 2009
  57. Junio C HamanoAug 15, 2009
  58. Thomas RastAug 15, 2009
  59. Thomas RastAug 15, 2009
  60. Jeff KingAug 18, 2009
  61. Thomas RastAug 19, 2009
  62. Jeff KingAug 19, 2009
  63. Junio C HamanoJul 23, 2009
  64. Nanako ShiraishiJul 24, 2009
  65. Junio C HamanoJul 24, 2009
  66. Jeff KingJul 24, 2009
  67. Junio C HamanoJul 25, 2009
  68. Thomas RastJul 25, 2009
  69. Pierre HabouzitJul 25, 2009
  70. Pierre HabouzitJul 25, 2009
  71. Jeff KingJul 26, 2009
  72. Pierre HabouzitJul 27, 2009
  73. Jeff KingJul 27, 2009
  74. Thomas RastJul 27, 2009
  75. Jeff KingJul 27, 2009
  76. Pierre HabouzitJul 24, 2009

Read the whole thread, see it on lore, or plain text.

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