Merge branch 'jk/symbolic-ref'
authorJunio C Hamano <gitster@pobox.com>
Tue, 26 Jan 2016 23:40:30 +0000 (15:40 -0800)
committerJunio C Hamano <gitster@pobox.com>
Tue, 26 Jan 2016 23:40:30 +0000 (15:40 -0800)
The low-level code that is used to create symbolic references has
been updated to share more code with the code that deals with
normal references.

* jk/symbolic-ref:
lock_ref_sha1_basic: handle REF_NODEREF with invalid refs
lock_ref_sha1_basic: always fill old_oid while holding lock
checkout,clone: check return value of create_symref
create_symref: write reflog while holding lock
create_symref: use existing ref-lock code
create_symref: modernize variable names

builtin/checkout.c
builtin/clone.c
refs.h
refs/files-backend.c
t/t1401-symbolic-ref.sh
t/t2011-checkout-invalid-head.sh
index e8110a9243f648129ffbea0de2af039ad7791aa1..5af84a3118d20da437d3e08c1667f76dc2f57845 100644 (file)
@@ -661,7 +661,8 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
                        describe_detached_head(_("HEAD is now at"), new->commit);
                }
        } else if (new->path) { /* Switch branches. */
-               create_symref("HEAD", new->path, msg.buf);
+               if (create_symref("HEAD", new->path, msg.buf) < 0)
+                       die("unable to update HEAD");
                if (!opts->quiet) {
                        if (old->path && !strcmp(new->path, old->path)) {
                                if (opts->new_branch_force)
index a0b3cd9e5617b5a3a45dd01c8a2c7af0b2fd9668..a7c8def8cb7199e82acad9e94bb01d93ba4ef0fb 100644 (file)
@@ -636,9 +636,11 @@ static void update_remote_refs(const struct ref *refs,
                struct strbuf head_ref = STRBUF_INIT;
                strbuf_addstr(&head_ref, branch_top);
                strbuf_addstr(&head_ref, "HEAD");
-               create_symref(head_ref.buf,
-                             remote_head_points_at->peer_ref->name,
-                             msg);
+               if (create_symref(head_ref.buf,
+                                 remote_head_points_at->peer_ref->name,
+                                 msg) < 0)
+                       die("unable to update %s", head_ref.buf);
+               strbuf_release(&head_ref);
        }
 }
 
@@ -648,7 +650,8 @@ static void update_head(const struct ref *our, const struct ref *remote,
        const char *head;
        if (our && skip_prefix(our->name, "refs/heads/", &head)) {
                /* Local default branch link */
-               create_symref("HEAD", our->name, NULL);
+               if (create_symref("HEAD", our->name, NULL) < 0)
+                       die("unable to update HEAD");
                if (!option_bare) {
                        update_ref(msg, "HEAD", our->old_oid.hash, NULL, 0,
                                   UPDATE_REFS_DIE_ON_ERR);
diff --git a/refs.h b/refs.h
index 7a040774890637253847e82e3ea3a90ac081f757..3c3da29bf0064cd189a6b0c8dc1a7daeb953150e 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -292,7 +292,7 @@ extern char *shorten_unambiguous_ref(const char *refname, int strict);
 /** rename ref, return 0 on success **/
 extern int rename_ref(const char *oldref, const char *newref, const char *logmsg);
 
-extern int create_symref(const char *ref, const char *refs_heads_master, const char *logmsg);
+extern int create_symref(const char *refname, const char *target, const char *logmsg);
 
 enum action_on_err {
        UPDATE_REFS_MSG_ON_ERR,
index c648b5e853c347f0978d835cb057a9a2831bf0dd..81c92b410eb76cd11dd56f6b82afec6668745dd1 100644 (file)
@@ -1840,12 +1840,17 @@ static int verify_lock(struct ref_lock *lock,
        if (read_ref_full(lock->ref_name,
                          mustexist ? RESOLVE_REF_READING : 0,
                          lock->old_oid.hash, NULL)) {
-               int save_errno = errno;
-               strbuf_addf(err, "can't verify ref %s", lock->ref_name);
-               errno = save_errno;
-               return -1;
+               if (old_sha1) {
+                       int save_errno = errno;
+                       strbuf_addf(err, "can't verify ref %s", lock->ref_name);
+                       errno = save_errno;
+                       return -1;
+               } else {
+                       hashclr(lock->old_oid.hash);
+                       return 0;
+               }
        }
-       if (hashcmp(lock->old_oid.hash, old_sha1)) {
+       if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
                strbuf_addf(err, "ref %s is at %s but expected %s",
                            lock->ref_name,
                            sha1_to_hex(lock->old_oid.hash),
@@ -1882,7 +1887,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
        const char *orig_refname = refname;
        struct ref_lock *lock;
        int last_errno = 0;
-       int type, lflags;
+       int type;
+       int lflags = 0;
        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
        int resolve_flags = 0;
        int attempts_remaining = 3;
@@ -1893,10 +1899,11 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 
        if (mustexist)
                resolve_flags |= RESOLVE_REF_READING;
-       if (flags & REF_DELETING) {
+       if (flags & REF_DELETING)
                resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
-               if (flags & REF_NODEREF)
-                       resolve_flags |= RESOLVE_REF_NO_RECURSE;
+       if (flags & REF_NODEREF) {
+               resolve_flags |= RESOLVE_REF_NO_RECURSE;
+               lflags |= LOCK_NO_DEREF;
        }
 
        refname = resolve_ref_unsafe(refname, resolve_flags,
@@ -1932,6 +1939,10 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 
                goto error_return;
        }
+
+       if (flags & REF_NODEREF)
+               refname = orig_refname;
+
        /*
         * If the ref did not exist and we are creating it, make sure
         * there is no existing packed ref whose name begins with our
@@ -1947,11 +1958,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 
        lock->lk = xcalloc(1, sizeof(struct lock_file));
 
-       lflags = 0;
-       if (flags & REF_NODEREF) {
-               refname = orig_refname;
-               lflags |= LOCK_NO_DEREF;
-       }
        lock->ref_name = xstrdup(refname);
        lock->orig_ref_name = xstrdup(orig_refname);
        strbuf_git_path(&ref_file, "%s", refname);
@@ -1985,7 +1991,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
                        goto error_return;
                }
        }
-       if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
+       if (verify_lock(lock, old_sha1, mustexist, err)) {
                last_errno = errno;
                goto error_return;
        }
@@ -2811,73 +2817,72 @@ static int commit_ref_update(struct ref_lock *lock,
        return 0;
 }
 
-int create_symref(const char *ref_target, const char *refs_heads_master,
-                 const char *logmsg)
+static int create_ref_symlink(struct ref_lock *lock, const char *target)
 {
-       char *lockpath = NULL;
-       char ref[1000];
-       int fd, len, written;
-       char *git_HEAD = git_pathdup("%s", ref_target);
-       unsigned char old_sha1[20], new_sha1[20];
-       struct strbuf err = STRBUF_INIT;
-
-       if (logmsg && read_ref(ref_target, old_sha1))
-               hashclr(old_sha1);
-
-       if (safe_create_leading_directories(git_HEAD) < 0)
-               return error("unable to create directory for %s", git_HEAD);
-
+       int ret = -1;
 #ifndef NO_SYMLINK_HEAD
-       if (prefer_symlink_refs) {
-               unlink(git_HEAD);
-               if (!symlink(refs_heads_master, git_HEAD))
-                       goto done;
+       char *ref_path = get_locked_file_path(lock->lk);
+       unlink(ref_path);
+       ret = symlink(target, ref_path);
+       free(ref_path);
+
+       if (ret)
                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
-       }
 #endif
+       return ret;
+}
 
-       len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
-       if (sizeof(ref) <= len) {
-               error("refname too long: %s", refs_heads_master);
-               goto error_free_return;
-       }
-       lockpath = mkpathdup("%s.lock", git_HEAD);
-       fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
-       if (fd < 0) {
-               error("Unable to open %s for writing", lockpath);
-               goto error_free_return;
-       }
-       written = write_in_full(fd, ref, len);
-       if (close(fd) != 0 || written != len) {
-               error("Unable to write to %s", lockpath);
-               goto error_unlink_return;
-       }
-       if (rename(lockpath, git_HEAD) < 0) {
-               error("Unable to create %s", git_HEAD);
-               goto error_unlink_return;
-       }
-       if (adjust_shared_perm(git_HEAD)) {
-               error("Unable to fix permissions on %s", lockpath);
-       error_unlink_return:
-               unlink_or_warn(lockpath);
-       error_free_return:
-               free(lockpath);
-               free(git_HEAD);
-               return -1;
+static void update_symref_reflog(struct ref_lock *lock, const char *refname,
+                                const char *target, const char *logmsg)
+{
+       struct strbuf err = STRBUF_INIT;
+       unsigned char new_sha1[20];
+       if (logmsg && !read_ref(target, new_sha1) &&
+           log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
+               error("%s", err.buf);
+               strbuf_release(&err);
        }
-       free(lockpath);
+}
 
-#ifndef NO_SYMLINK_HEAD
-       done:
-#endif
-       if (logmsg && !read_ref(refs_heads_master, new_sha1) &&
-               log_ref_write(ref_target, old_sha1, new_sha1, logmsg, 0, &err)) {
+static int create_symref_locked(struct ref_lock *lock, const char *refname,
+                               const char *target, const char *logmsg)
+{
+       if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
+               update_symref_reflog(lock, refname, target, logmsg);
+               return 0;
+       }
+
+       if (!fdopen_lock_file(lock->lk, "w"))
+               return error("unable to fdopen %s: %s",
+                            lock->lk->tempfile.filename.buf, strerror(errno));
+
+       update_symref_reflog(lock, refname, target, logmsg);
+
+       /* no error check; commit_ref will check ferror */
+       fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
+       if (commit_ref(lock) < 0)
+               return error("unable to write symref for %s: %s", refname,
+                            strerror(errno));
+       return 0;
+}
+
+int create_symref(const char *refname, const char *target, const char *logmsg)
+{
+       struct strbuf err = STRBUF_INIT;
+       struct ref_lock *lock;
+       int ret;
+
+       lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,
+                                  &err);
+       if (!lock) {
                error("%s", err.buf);
                strbuf_release(&err);
+               return -1;
        }
 
-       free(git_HEAD);
-       return 0;
+       ret = create_symref_locked(lock, refname, target, logmsg);
+       unlock_ref(lock);
+       return ret;
 }
 
 int reflog_exists(const char *refname)
index ce8b4f4d0f375fb49afdb80d002559464a5b2812..417eecc3af2a30c3544ddd2f83b7ccecc540eaf1 100755 (executable)
@@ -114,4 +114,19 @@ test_expect_success 'symbolic-ref writes reflog entry' '
        test_cmp expect actual
 '
 
+test_expect_success 'symbolic-ref does not create ref d/f conflicts' '
+       git checkout -b df &&
+       test_commit df &&
+       test_must_fail git symbolic-ref refs/heads/df/conflict refs/heads/df &&
+       git pack-refs --all --prune &&
+       test_must_fail git symbolic-ref refs/heads/df/conflict refs/heads/df
+'
+
+test_expect_success 'symbolic-ref handles existing pointer to invalid name' '
+       head=$(git rev-parse HEAD) &&
+       git symbolic-ref HEAD refs/heads/outer &&
+       git update-ref refs/heads/outer/inner $head &&
+       git symbolic-ref HEAD refs/heads/unrelated
+'
+
 test_done
index 300f8bf25c34cf4ea4e011d1daa525285ca94c5a..c5501b008c8f56ac0712d9f475ebc460a0d4eea4 100755 (executable)
@@ -19,4 +19,43 @@ test_expect_success 'checkout master from invalid HEAD' '
        git checkout master --
 '
 
+test_expect_success 'checkout notices failure to lock HEAD' '
+       test_when_finished "rm -f .git/HEAD.lock" &&
+       >.git/HEAD.lock &&
+       test_must_fail git checkout -b other
+'
+
+test_expect_success 'create ref directory/file conflict scenario' '
+       git update-ref refs/heads/outer/inner master &&
+
+       # do not rely on symbolic-ref to get a known state,
+       # as it may use the same code we are testing
+       reset_to_df () {
+               echo "ref: refs/heads/outer" >.git/HEAD
+       }
+'
+
+test_expect_success 'checkout away from d/f HEAD (unpacked, to branch)' '
+       reset_to_df &&
+       git checkout master
+'
+
+test_expect_success 'checkout away from d/f HEAD (unpacked, to detached)' '
+       reset_to_df &&
+       git checkout --detach master
+'
+
+test_expect_success 'pack refs' '
+       git pack-refs --all --prune
+'
+
+test_expect_success 'checkout away from d/f HEAD (packed, to branch)' '
+       reset_to_df &&
+       git checkout master
+'
+
+test_expect_success 'checkout away from d/f HEAD (packed, to detached)' '
+       reset_to_df &&
+       git checkout --detach master
+'
 test_done