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.

Signed-off-by: Thomas Gummerer <t.gumme...@gmail.com>
---
 builtin/checkout.c             | 64 +++++++++++++++++++++++++++-------
 t/t2025-checkout-no-overlay.sh | 47 +++++++++++++++++++++++++
 t/t9902-completion.sh          |  1 +
 3 files changed, 99 insertions(+), 13 deletions(-)
 create mode 100755 t/t2025-checkout-no-overlay.sh

diff --git a/builtin/checkout.c b/builtin/checkout.c
index acdafc6e4c..0aef35bbc4 100644
--- 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
@@ -302,15 +310,29 @@ static int checkout_paths(const struct checkout_opts 
*opts,
                ce->ce_flags &= ~CE_MATCHED;
                if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
                        continue;
-               if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
-                       /*
-                        * "git checkout tree-ish -- path", but this entry
-                        * is in the original index; it will not be checked
-                        * out to the working tree and it does not matter
-                        * if pathspec matched this entry.  We will not do
-                        * anything to this entry at all.
-                        */
-                       continue;
+               if (opts->source_tree && !(ce->ce_flags & CE_UPDATE)) {
+                       if (!opts->overlay_mode &&
+                           ce_path_match(&the_index, ce, &opts->pathspec, 
ps_matched)) {
+                               /*
+                                * "git checkout --no-overlay <tree-ish> -- 
path",
+                                * and the path is not in tree-ish, but is in
+                                * the current index, which means that it 
should 
+                                * be removed.
+                                */
+                               ce->ce_flags |= CE_MATCHED | CE_REMOVE | 
CE_WT_REMOVE;
+                               continue;
+                       } else {
+                               /*
+                                * "git checkout tree-ish -- path", but this
+                                * entry is in the original index; it will not
+                                * be checked out to the working tree and it
+                                * does not matter if pathspec matched this
+                                * entry.  We will not do anything to this entry
+                                * at all.
+                                */
+                               continue;
+                       }
+               }
                /*
                 * Either this entry came from the tree-ish we are
                 * checking the paths out of, or we are checking out
@@ -348,7 +370,7 @@ 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 {
@@ -375,12 +397,14 @@ 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))
@@ -542,6 +566,11 @@ 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
@@ -1178,6 +1207,10 @@ 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");
@@ -1266,6 +1299,7 @@ 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")),
                OPT_END(),
        };
 
@@ -1274,6 +1308,7 @@ 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);
 
@@ -1297,6 +1332,9 @@ 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
index 0000000000..3575321382
--- /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>' '
+       >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 M/D 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 175f83d704..a3fd9a9630 100755
--- 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
 '
 
-- 
2.20.0.405.gbc1bbc6f85

Reply via email to