checkout: introduce --{,no-}overlay option

Currently 'git checkout' is defined as an overlay operation, which
means that if in 'git checkout <tree-ish> -- [<pathspec>]' we have an
entry in the index that matches <pathspec>, but that doesn't exist in
<tree-ish>, that entry will not be removed from the index or the
working tree.

Introduce a new --{,no-}overlay option, which allows using 'git
checkout' in non-overlay mode, thus removing files from the working
tree if they do not exist in <tree-ish> but match <pathspec>.

Note that 'git checkout -p <tree-ish> -- [<pathspec>]' already works
this way, so no changes are needed for the patch mode.  We disallow
'git checkout --overlay -p' to avoid confusing users who would expect
to be able to force overlay mode in 'git checkout -p' this way.

Untracked files are not affected by this change, so 'git checkout
--no-overlay HEAD -- untracked' will not remove untracked from the
working tree.  This is so e.g. 'git checkout --no-overlay HEAD -- dir/'
doesn't delete all untracked files in dir/, but rather just resets the
state of files that are known to git.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index 801de2f7645bf0b1fc506da58d469519abca8863..24e52b01e1897528780efed7ccb4490b897ec670 100644 (file)
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -260,6 +260,9 @@ the conflicted merge in the specified paths.
 This means that you can use `git checkout -p` to selectively discard
 edits from your current working tree. See the ``Interactive Mode''
 section of linkgit:git-add[1] to learn how to operate the `--patch` mode.
++
+Note that this option uses the no overlay mode by default (see also
+`--[no-]overlay`), and currently doesn't support overlay mode.
 
 --ignore-other-worktrees::
        `git checkout` refuses when the wanted ref is already checked
@@ -276,6 +279,13 @@ section of linkgit:git-add[1] to learn how to operate the `--patch` mode.
        Just like linkgit:git-submodule[1], this will detach the
        submodules HEAD.
 
+--[no-]overlay::
+       In the default overlay mode, `git checkout` never
+       removes files from the index or the working tree.  When
+       specifying `--no-overlay`, files that appear in the index and
+       working tree, but not in <tree-ish> are removed, to make them
+       match <tree-ish> exactly.
+
 <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 32c4b7f897f894bf73976e05a74b322a9a0ef192..0c5fe948ef58901870949532b1a4bfc2b1870452 100644 (file)
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -44,6 +44,7 @@ struct checkout_opts {
        int ignore_skipworktree;
        int ignore_other_worktrees;
        int show_progress;
+       int overlay_mode;
        /*
         * If new checkout options are added, skip_merge_working_tree
         * should be updated accordingly.
@@ -132,7 +133,8 @@ static int skip_same_name(const struct cache_entry *ce, int pos)
        return pos;
 }
 
-static int check_stage(int stage, const struct cache_entry *ce, int pos)
+static int check_stage(int stage, const struct cache_entry *ce, int pos,
+                      int overlay_mode)
 {
        while (pos < active_nr &&
               !strcmp(active_cache[pos]->name, ce->name)) {
@@ -140,6 +142,8 @@ static int check_stage(int stage, const struct cache_entry *ce, int pos)
                        return 0;
                pos++;
        }
+       if (!overlay_mode)
+               return 0;
        if (stage == 2)
                return error(_("path '%s' does not have our version"), ce->name);
        else
@@ -165,7 +169,7 @@ static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
 }
 
 static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
-                         const struct checkout *state)
+                         const struct checkout *state, int overlay_mode)
 {
        while (pos < active_nr &&
               !strcmp(active_cache[pos]->name, ce->name)) {
@@ -173,6 +177,10 @@ static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
                        return checkout_entry(active_cache[pos], state, NULL);
                pos++;
        }
+       if (!overlay_mode) {
+               unlink_entry(ce);
+               return 0;
+       }
        if (stage == 2)
                return error(_("path '%s' does not have our version"), ce->name);
        else
@@ -247,9 +255,9 @@ static int checkout_merged(int pos, const struct checkout *state)
        return status;
 }
 
-static void mark_ce_for_checkout(struct cache_entry *ce,
-                                char *ps_matched,
-                                const struct checkout_opts *opts)
+static void mark_ce_for_checkout_overlay(struct cache_entry *ce,
+                                        char *ps_matched,
+                                        const struct checkout_opts *opts)
 {
        ce->ce_flags &= ~CE_MATCHED;
        if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
@@ -281,6 +289,25 @@ static void mark_ce_for_checkout(struct cache_entry *ce,
                ce->ce_flags |= CE_MATCHED;
 }
 
+static void mark_ce_for_checkout_no_overlay(struct cache_entry *ce,
+                                           char *ps_matched,
+                                           const struct checkout_opts *opts)
+{
+       ce->ce_flags &= ~CE_MATCHED;
+       if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
+               return;
+       if (ce_path_match(&the_index, ce, &opts->pathspec, ps_matched)) {
+               ce->ce_flags |= CE_MATCHED;
+               if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
+                       /*
+                        * In overlay mode, but the path is not in
+                        * tree-ish, which means we should remove it
+                        * from the index and the working tree.
+                        */
+                       ce->ce_flags |= CE_REMOVE | CE_WT_REMOVE;
+       }
+}
+
 static int checkout_paths(const struct checkout_opts *opts,
                          const char *revision)
 {
@@ -332,7 +359,14 @@ static int checkout_paths(const struct checkout_opts *opts,
         * to be checked out.
         */
        for (pos = 0; pos < active_nr; pos++)
-               mark_ce_for_checkout(active_cache[pos], ps_matched, opts);
+               if (opts->overlay_mode)
+                       mark_ce_for_checkout_overlay(active_cache[pos],
+                                                    ps_matched,
+                                                    opts);
+               else
+                       mark_ce_for_checkout_no_overlay(active_cache[pos],
+                                                       ps_matched,
+                                                       opts);
 
        if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
                free(ps_matched);
@@ -353,7 +387,7 @@ static int checkout_paths(const struct checkout_opts *opts,
                        if (opts->force) {
                                warning(_("path '%s' is unmerged"), ce->name);
                        } else if (opts->writeout_stage) {
-                               errs |= check_stage(opts->writeout_stage, ce, pos);
+                               errs |= check_stage(opts->writeout_stage, ce, pos, opts->overlay_mode);
                        } else if (opts->merge) {
                                errs |= check_stages((1<<2) | (1<<3), ce, pos);
                        } else {
@@ -380,12 +414,14 @@ static int checkout_paths(const struct checkout_opts *opts,
                                continue;
                        }
                        if (opts->writeout_stage)
-                               errs |= checkout_stage(opts->writeout_stage, ce, pos, &state);
+                               errs |= checkout_stage(opts->writeout_stage, ce, pos, &state, opts->overlay_mode);
                        else if (opts->merge)
                                errs |= checkout_merged(pos, &state);
                        pos = skip_same_name(ce, pos) - 1;
                }
        }
+       remove_marked_cache_entries(&the_index, 1);
+       remove_scheduled_dirs();
        errs |= finish_delayed_checkout(&state);
 
        if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
@@ -547,6 +583,11 @@ static int skip_merge_working_tree(const struct checkout_opts *opts,
         * opts->show_progress only impacts output so doesn't require a merge
         */
 
+       /*
+        * opts->overlay_mode cannot be used with switching branches so is
+        * not tested here
+        */
+
        /*
         * If we aren't creating a new branch any changes or updates will
         * happen in the existing branch.  Since that could only be updating
@@ -1183,6 +1224,10 @@ static int checkout_branch(struct checkout_opts *opts,
                die(_("'%s' cannot be used with switching branches"),
                    "--patch");
 
+       if (!opts->overlay_mode)
+               die(_("'%s' cannot be used with switching branches"),
+                   "--no-overlay");
+
        if (opts->writeout_stage)
                die(_("'%s' cannot be used with switching branches"),
                    "--ours/--theirs");
@@ -1271,6 +1316,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                            "checkout", "control recursive updating of submodules",
                            PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
                OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
+               OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode (default)")),
                OPT_END(),
        };
 
@@ -1279,6 +1325,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
        opts.overwrite_ignore = 1;
        opts.prefix = prefix;
        opts.show_progress = -1;
+       opts.overlay_mode = -1;
 
        git_config(git_checkout_config, &opts);
 
@@ -1302,6 +1349,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
        if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
                die(_("-b, -B and --orphan are mutually exclusive"));
 
+       if (opts.overlay_mode == 1 && opts.patch_mode)
+               die(_("-p and --overlay are mutually exclusive"));
+
        /*
         * From here on, new_branch will contain the branch to be checked out,
         * and new_branch_force and new_orphan_branch will tell us which one of

diff --git a/t/t2025-checkout-no-overlay.sh b/t/t2025-checkout-no-overlay.sh
new file mode 100755 (executable)
index 0000000..76330cb
--- /dev/null
+++ b/t/t2025-checkout-no-overlay.sh
@@ -0,0 +1,47 @@
+#!/bin/sh
+
+test_description='checkout --no-overlay <tree-ish> -- <pathspec>'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+       git commit --allow-empty -m "initial"
+'
+
+test_expect_success 'checkout --no-overlay deletes files not in <tree-ish>' '
+       >file &&
+       mkdir dir &&
+       >dir/file1 &&
+       git add file dir/file1 &&
+       git checkout --no-overlay HEAD -- file &&
+       test_path_is_missing file &&
+       test_path_is_file dir/file1
+'
+
+test_expect_success 'checkout --no-overlay removing last file from directory' '
+       git checkout --no-overlay HEAD -- dir/file1 &&
+       test_path_is_missing dir
+'
+
+test_expect_success 'checkout -p --overlay is disallowed' '
+       test_must_fail git checkout -p --overlay HEAD 2>actual &&
+       test_i18ngrep "fatal: -p and --overlay are mutually exclusive" actual
+'
+
+test_expect_success '--no-overlay --theirs with D/F conflict deletes file' '
+       test_commit file1 file1 &&
+       test_commit file2 file2 &&
+       git rm --cached file1 &&
+       echo 1234 >file1 &&
+       F1=$(git rev-parse HEAD:file1) &&
+       F2=$(git rev-parse HEAD:file2) &&
+       {
+               echo "100644 $F1 1      file1" &&
+               echo "100644 $F2 2      file1"
+       } | git update-index --index-info &&
+       test_path_is_file file1 &&
+       git checkout --theirs --no-overlay -- file1 &&
+       test_path_is_missing file1
+'
+
+test_done

diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index d01ad8eb2587ba32637d7ec8161811696a0aec34..5758fffa0dd19cf1a8095060d3dacb5b80b34216 100755 (executable)
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -1436,6 +1436,7 @@ test_expect_success 'double dash "git checkout"' '
        --progress Z
        --no-quiet Z
        --no-... Z
+       --overlay Z
        EOF
 '