fetch: protect branches checked out in all worktrees

Refuse to fetch into the currently checked out branch of any working
tree, not just the current one.

Fixes this previously reported bug:

https://lore.kernel.org/git/cb957174-5e9a-5603-ea9e-ac9b58a2eaad@mathema.de/

As a side effect of using find_shared_symref, we’ll also refuse the
fetch when we’re on a detached HEAD because we’re rebasing or bisecting
on the branch in question. This seems like a sensible change.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 16b98523ceeea0daa54d301c3d21448f7c897f32..e45185cf9cf5ec71fa0a294a5f250c2d79342119 100644 (file)
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -28,6 +28,7 @@
 #include "promisor-remote.h"
 #include "commit-graph.h"
 #include "shallow.h"
+#include "worktree.h"
 
 #define FORCED_UPDATES_DELAY_WARNING_IN_MS (10 * 1000)
 
@@ -848,13 +849,12 @@ static void format_display(struct strbuf *display, char code,
 
 static int update_local_ref(struct ref *ref,
                            struct ref_transaction *transaction,
-                           const char *remote,
-                           const struct ref *remote_ref,
-                           struct strbuf *display,
-                           int summary_width)
+                           const char *remote, const struct ref *remote_ref,
+                           struct strbuf *display, int summary_width,
+                           struct worktree **worktrees)
 {
        struct commit *current = NULL, *updated;
-       struct branch *current_branch = branch_get(NULL);
+       const struct worktree *wt;
        const char *pretty_ref = prettify_refname(ref->name);
        int fast_forward = 0;
 
@@ -868,16 +868,17 @@ static int update_local_ref(struct ref *ref,
                return 0;
        }
 
-       if (current_branch &&
-           !strcmp(ref->name, current_branch->name) &&
-           !(update_head_ok || is_bare_repository()) &&
-           !is_null_oid(&ref->old_oid)) {
+       if (!update_head_ok &&
+           (wt = find_shared_symref(worktrees, "HEAD", ref->name)) &&
+           !wt->is_bare && !is_null_oid(&ref->old_oid)) {
                /*
                 * If this is the head, and it's not okay to update
                 * the head, and the old value of the head isn't empty...
                 */
                format_display(display, '!', _("[rejected]"),
-                              _("can't fetch in current branch"),
+                              wt->is_current ?
+                                      _("can't fetch in current branch") :
+                                      _("checked out in another worktree"),
                               remote, pretty_ref, summary_width);
                return 1;
        }
@@ -1076,7 +1077,8 @@ N_("it took %.2f seconds to check forced updates; you can use\n"
    "to avoid this check\n");
 
 static int store_updated_refs(const char *raw_url, const char *remote_name,
-                             int connectivity_checked, struct ref *ref_map)
+                             int connectivity_checked, struct ref *ref_map,
+                             struct worktree **worktrees)
 {
        struct fetch_head fetch_head;
        int url_len, i, rc = 0;
@@ -1205,7 +1207,8 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
                        strbuf_reset(&note);
                        if (ref) {
                                rc |= update_local_ref(ref, transaction, what,
-                                                      rm, &note, summary_width);
+                                                      rm, &note, summary_width,
+                                                      worktrees);
                                free(ref);
                        } else if (write_fetch_head || dry_run) {
                                /*
@@ -1298,7 +1301,9 @@ static int check_exist_and_connected(struct ref *ref_map)
        return check_connected(iterate_ref_map, &rm, &opt);
 }
 
-static int fetch_and_consume_refs(struct transport *transport, struct ref *ref_map)
+static int fetch_and_consume_refs(struct transport *transport,
+                                 struct ref *ref_map,
+                                 struct worktree **worktrees)
 {
        int connectivity_checked = 1;
        int ret;
@@ -1319,10 +1324,8 @@ static int fetch_and_consume_refs(struct transport *transport, struct ref *ref_m
        }
 
        trace2_region_enter("fetch", "consume_refs", the_repository);
-       ret = store_updated_refs(transport->url,
-                                transport->remote->name,
-                                connectivity_checked,
-                                ref_map);
+       ret = store_updated_refs(transport->url, transport->remote->name,
+                                connectivity_checked, ref_map, worktrees);
        trace2_region_leave("fetch", "consume_refs", the_repository);
 
 out:
@@ -1385,19 +1388,18 @@ static int prune_refs(struct refspec *rs, struct ref *ref_map,
        return result;
 }
 
-static void check_not_current_branch(struct ref *ref_map)
+static void check_not_current_branch(struct ref *ref_map,
+                                    struct worktree **worktrees)
 {
-       struct branch *current_branch = branch_get(NULL);
-
-       if (is_bare_repository() || !current_branch)
-               return;
-
+       const struct worktree *wt;
        for (; ref_map; ref_map = ref_map->next)
-               if (ref_map->peer_ref && !strcmp(current_branch->refname,
-                                       ref_map->peer_ref->name))
-                       die(_("refusing to fetch into current branch %s "
-                             "of non-bare repository"),
-                           current_branch->refname);
+               if (ref_map->peer_ref &&
+                   (wt = find_shared_symref(worktrees, "HEAD",
+                                            ref_map->peer_ref->name)) &&
+                   !wt->is_bare)
+                       die(_("refusing to fetch into branch '%s' "
+                             "checked out at '%s'"),
+                           ref_map->peer_ref->name, wt->path);
 }
 
 static int truncate_fetch_head(void)
@@ -1495,7 +1497,8 @@ static struct transport *prepare_transport(struct remote *remote, int deepen)
        return transport;
 }
 
-static void backfill_tags(struct transport *transport, struct ref *ref_map)
+static void backfill_tags(struct transport *transport, struct ref *ref_map,
+                         struct worktree **worktrees)
 {
        int cannot_reuse;
 
@@ -1516,7 +1519,7 @@ static void backfill_tags(struct transport *transport, struct ref *ref_map)
        transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, NULL);
        transport_set_option(transport, TRANS_OPT_DEPTH, "0");
        transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
-       fetch_and_consume_refs(transport, ref_map);
+       fetch_and_consume_refs(transport, ref_map, worktrees);
 
        if (gsecondary) {
                transport_disconnect(gsecondary);
@@ -1534,6 +1537,7 @@ static int do_fetch(struct transport *transport,
        struct transport_ls_refs_options transport_ls_refs_options =
                TRANSPORT_LS_REFS_OPTIONS_INIT;
        int must_list_refs = 1;
+       struct worktree **worktrees = get_worktrees();
 
        if (tags == TAGS_DEFAULT) {
                if (transport->remote->fetch_tags == 2)
@@ -1589,7 +1593,7 @@ static int do_fetch(struct transport *transport,
        ref_map = get_ref_map(transport->remote, remote_refs, rs,
                              tags, &autotags);
        if (!update_head_ok)
-               check_not_current_branch(ref_map);
+               check_not_current_branch(ref_map, worktrees);
 
        if (tags == TAGS_DEFAULT && autotags)
                transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, "1");
@@ -1607,7 +1611,7 @@ static int do_fetch(struct transport *transport,
                                   transport->url);
                }
        }
-       if (fetch_and_consume_refs(transport, ref_map)) {
+       if (fetch_and_consume_refs(transport, ref_map, worktrees)) {
                free_refs(ref_map);
                retcode = 1;
                goto cleanup;
@@ -1656,7 +1660,7 @@ static int do_fetch(struct transport *transport,
                                  "you need to specify exactly one branch with the --set-upstream option"));
                }
        }
- skip:
+skip:
        free_refs(ref_map);
 
        /* if neither --no-tags nor --tags was specified, do automated tag
@@ -1666,11 +1670,12 @@ static int do_fetch(struct transport *transport,
                ref_map = NULL;
                find_non_local_tags(remote_refs, &ref_map, &tail);
                if (ref_map)
-                       backfill_tags(transport, ref_map);
+                       backfill_tags(transport, ref_map, worktrees);
                free_refs(ref_map);
        }
 
- cleanup:
+cleanup:
+       free_worktrees(worktrees);
        return retcode;
 }
 

diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 8212ca56dc5b132edb552fba714657eed3579681..f07e32126fced4a3f26bc10f3910f862359cb9d2 100755 (executable)
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1771,4 +1771,22 @@ test_expect_success 'denyCurrentBranch and worktrees' '
        git -C cloned push origin HEAD:new-wt &&
        test_must_fail git -C cloned push --delete origin new-wt
 '
+
+test_expect_success 'refuse fetch to current branch of worktree' '
+       test_when_finished "git worktree remove --force wt && git branch -D wt" &&
+       git worktree add wt &&
+       test_commit apple &&
+       test_must_fail git fetch . HEAD:wt &&
+       git fetch -u . HEAD:wt
+'
+
+test_expect_success 'refuse fetch to current branch of bare repository worktree' '
+       test_when_finished "rm -fr bare.git" &&
+       git clone --bare . bare.git &&
+       git -C bare.git worktree add wt &&
+       test_commit banana &&
+       test_must_fail git -C bare.git fetch .. HEAD:wt &&
+       git -C bare.git fetch -u .. HEAD:wt
+'
+
 test_done