update-ref: add support for 'symref-create' command

Add 'symref-create' command to the '--stdin' mode 'git-update-ref' to
allow creation of symbolic refs in a transaction. The 'symref-create'
command takes in a <new-target>, which the created <ref> will point to.

Also, support the 'core.prefersymlinkrefs' config, wherein if the config
is set and the filesystem supports symlinks, we create the symbolic ref
as a symlink. We fallback to creating a regular symref if creating the
symlink is unsuccessful.

Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-update-ref.txt b/Documentation/git-update-ref.txt
index 16e02f6979fdabf878b02e2c1b9b6c0bc24479ba..364ef78af14e232e89c4f7847ee0e31402975c63 100644 (file)
--- a/Documentation/git-update-ref.txt
+++ b/Documentation/git-update-ref.txt
@@ -65,6 +65,7 @@ performs all modifications together.  Specify commands of the form:
        create SP <ref> SP <new-oid> LF
        delete SP <ref> [SP <old-oid>] LF
        verify SP <ref> [SP <old-oid>] LF
+       symref-create SP <ref> SP <new-target> LF
        symref-delete SP <ref> [SP <old-target>] LF
        symref-verify SP <ref> [SP <old-target>] LF
        option SP <opt> LF
@@ -88,6 +89,7 @@ quoting:
        create SP <ref> NUL <new-oid> NUL
        delete SP <ref> NUL [<old-oid>] NUL
        verify SP <ref> NUL [<old-oid>] NUL
+       symref-create SP <ref> NUL <new-target> NUL
        symref-delete SP <ref> [NUL <old-target>] NUL
        symref-verify SP <ref> [NUL <old-target>] NUL
        option SP <opt> NUL
@@ -121,6 +123,10 @@ verify::
        Verify <ref> against <old-oid> but do not change it.  If
        <old-oid> is zero or missing, the ref must not exist.
 
+symref-create:
+       Create symbolic ref <ref> with <new-target> after verifying
+       it does not exist.
+
 symref-delete::
        Delete <ref> after verifying it exists with <old-target>, if given.
 

diff --git a/builtin/clone.c b/builtin/clone.c
index 74ec14542e811d10f0dc88c9bfe935fc41af1491..c0eed8e79504e31084d23bfd9d782c330952a9eb 100644 (file)
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -547,7 +547,7 @@ static void write_remote_refs(const struct ref *local_refs)
                if (!r->peer_ref)
                        continue;
                if (ref_transaction_create(t, r->peer_ref->name, &r->old_oid,
-                                          0, NULL, &err))
+                                          NULL, 0, NULL, &err))
                        die("%s", err.buf);
        }
 

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 833ebbdd42ed2773320334fc71c5a7729aeb8231..989c0ebc5f98ca1bf9227e7d3299ad47dfffcd3e 100644 (file)
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -257,7 +257,7 @@ static void parse_cmd_create(struct ref_transaction *transaction,
        if (*next != line_termination)
                die("create %s: extra input: %s", refname, next);
 
-       if (ref_transaction_create(transaction, refname, &new_oid,
+       if (ref_transaction_create(transaction, refname, &new_oid, NULL,
                                   update_flags | create_reflog_flag,
                                   msg, &err))
                die("%s", err.buf);
@@ -267,6 +267,35 @@ static void parse_cmd_create(struct ref_transaction *transaction,
        strbuf_release(&err);
 }
 
+
+static void parse_cmd_symref_create(struct ref_transaction *transaction,
+                                   const char *next, const char *end)
+{
+       struct strbuf err = STRBUF_INIT;
+       char *refname, *new_target;
+
+       refname = parse_refname(&next);
+       if (!refname)
+               die("symref-create: missing <ref>");
+
+       new_target = parse_next_refname(&next);
+       if (!new_target)
+               die("symref-create %s: missing <new-target>", refname);
+
+       if (*next != line_termination)
+               die("symref-create %s: extra input: %s", refname, next);
+
+       if (ref_transaction_create(transaction, refname, NULL, new_target,
+                                  update_flags | create_reflog_flag,
+                                  msg, &err))
+               die("%s", err.buf);
+
+       update_flags = default_flags;
+       free(refname);
+       free(new_target);
+       strbuf_release(&err);
+}
+
 static void parse_cmd_delete(struct ref_transaction *transaction,
                             const char *next, const char *end)
 {
@@ -473,6 +502,7 @@ static const struct parse_cmd {
        { "create",        parse_cmd_create,        2, UPDATE_REFS_OPEN },
        { "delete",        parse_cmd_delete,        2, UPDATE_REFS_OPEN },
        { "verify",        parse_cmd_verify,        2, UPDATE_REFS_OPEN },
+       { "symref-create", parse_cmd_symref_create, 2, UPDATE_REFS_OPEN },
        { "symref-delete", parse_cmd_symref_delete, 2, UPDATE_REFS_OPEN },
        { "symref-verify", parse_cmd_symref_verify, 2, UPDATE_REFS_OPEN },
        { "option",        parse_cmd_option,        1, UPDATE_REFS_OPEN },

diff --git a/refs.c b/refs.c
index 8114bf65e0ada33ac3eadc74d1e655162426af6e..44ae37a4cbea2d6ef0269b8e6cea6b0910a9121a 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -1302,15 +1302,18 @@ int ref_transaction_update(struct ref_transaction *transaction,
 int ref_transaction_create(struct ref_transaction *transaction,
                           const char *refname,
                           const struct object_id *new_oid,
+                          const char *new_target,
                           unsigned int flags, const char *msg,
                           struct strbuf *err)
 {
-       if (!new_oid || is_null_oid(new_oid)) {
-               strbuf_addf(err, "'%s' has a null OID", refname);
+       if (new_oid && new_target)
+               BUG("create called with both new_oid and new_target set");
+       if ((!new_oid || is_null_oid(new_oid)) && !new_target) {
+               strbuf_addf(err, "'%s' has neither a valid OID nor a target", refname);
                return 1;
        }
        return ref_transaction_update(transaction, refname, new_oid,
-                                     null_oid(), NULL, NULL, flags,
+                                     null_oid(), new_target, NULL, flags,
                                      msg, err);
 }
 

diff --git a/refs.h b/refs.h
index 5b84958528620d9687062a862dc0c6d77829a1b4..bb30c58132b1f533becccfe9ae1773af9472d2a7 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -753,6 +753,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
 int ref_transaction_create(struct ref_transaction *transaction,
                           const char *refname,
                           const struct object_id *new_oid,
+                          const char *new_target,
                           unsigned int flags, const char *msg,
                           struct strbuf *err);
 

diff --git a/t/t0600-reffiles-backend.sh b/t/t0600-reffiles-backend.sh
index 64214340e75f9ecbb20380c4cfe8e6f5813a5495..b0933a11c527e41d217f2f9d660572917c446b26 100755 (executable)
--- a/t/t0600-reffiles-backend.sh
+++ b/t/t0600-reffiles-backend.sh
@@ -472,4 +472,36 @@ test_expect_success POSIXPERM 'git reflog expire honors core.sharedRepository' '
        esac
 '
 
+test_expect_success SYMLINKS 'symref transaction supports symlinks' '
+       test_when_finished "git symbolic-ref -d TEST_SYMREF_HEAD" &&
+       git update-ref refs/heads/new @ &&
+       test_config core.prefersymlinkrefs true &&
+       cat >stdin <<-EOF &&
+       start
+       symref-create TEST_SYMREF_HEAD refs/heads/new
+       prepare
+       commit
+       EOF
+       git update-ref --no-deref --stdin <stdin &&
+       test_path_is_symlink .git/TEST_SYMREF_HEAD &&
+       test "$(test_readlink .git/TEST_SYMREF_HEAD)" = refs/heads/new
+'
+
+test_expect_success 'symref transaction supports false symlink config' '
+       test_when_finished "git symbolic-ref -d TEST_SYMREF_HEAD" &&
+       git update-ref refs/heads/new @ &&
+       test_config core.prefersymlinkrefs false &&
+       cat >stdin <<-EOF &&
+       start
+       symref-create TEST_SYMREF_HEAD refs/heads/new
+       prepare
+       commit
+       EOF
+       git update-ref --no-deref --stdin <stdin &&
+       test_path_is_file .git/TEST_SYMREF_HEAD &&
+       git symbolic-ref TEST_SYMREF_HEAD >actual &&
+       echo refs/heads/new >expect &&
+       test_cmp expect actual
+'
+
 test_done

diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index 2ddc586d5d66a17833980eb43f27e7cb875afb76..79f029ad22a766ee58dfd4d762ae55d359a4dc00 100755 (executable)
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -1797,6 +1797,71 @@ do
                git update-ref --stdin $type --no-deref <stdin
        '
 
+       test_expect_success "stdin $type symref-create fails with too many arguments" '
+               format_command $type "symref-create refs/heads/symref" "$a" "$a" >stdin &&
+               test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
+               if test "$type" = "-z"
+               then
+                       grep "fatal: unknown command: $a" err
+               else
+                       grep "fatal: symref-create refs/heads/symref: extra input:  $a" err
+               fi
+       '
+
+       test_expect_success "stdin $type symref-create fails with no target" '
+               format_command $type "symref-create refs/heads/symref" >stdin &&
+               test_must_fail git update-ref --stdin $type --no-deref <stdin
+       '
+
+       test_expect_success "stdin $type symref-create fails with empty target" '
+               format_command $type "symref-create refs/heads/symref" "" >stdin &&
+               test_must_fail git update-ref --stdin $type --no-deref <stdin
+       '
+
+       test_expect_success "stdin $type symref-create works" '
+               test_when_finished "git symbolic-ref -d refs/heads/symref" &&
+               format_command $type "symref-create refs/heads/symref" "$a" >stdin &&
+               git update-ref --stdin $type --no-deref <stdin &&
+               git symbolic-ref refs/heads/symref >expect &&
+               echo $a >actual &&
+               test_cmp expect actual
+       '
+
+       test_expect_success "stdin $type symref-create works with --no-deref" '
+               test_when_finished "git symbolic-ref -d refs/heads/symref" &&
+               format_command $type "symref-create refs/heads/symref" "$a" &&
+               git update-ref --stdin $type <stdin 2>err
+       '
+
+       test_expect_success "stdin $type create dangling symref ref works" '
+               test_when_finished "git symbolic-ref -d refs/heads/symref" &&
+               format_command $type "symref-create refs/heads/symref" "refs/heads/unkown" >stdin &&
+               git update-ref --stdin $type --no-deref <stdin &&
+               git symbolic-ref refs/heads/symref >expect &&
+               echo refs/heads/unkown >actual &&
+               test_cmp expect actual
+       '
+
+       test_expect_success "stdin $type symref-create does not create reflogs by default" '
+               test_when_finished "git symbolic-ref -d refs/symref" &&
+               format_command $type "symref-create refs/symref" "$a" >stdin &&
+               git update-ref --stdin $type --no-deref <stdin &&
+               git symbolic-ref refs/symref >expect &&
+               echo $a >actual &&
+               test_cmp expect actual &&
+               test_must_fail git reflog exists refs/symref
+       '
+
+       test_expect_success "stdin $type symref-create reflogs with --create-reflog" '
+               test_when_finished "git symbolic-ref -d refs/heads/symref" &&
+               format_command $type "symref-create refs/heads/symref" "$a" >stdin &&
+               git update-ref --create-reflog --stdin $type --no-deref <stdin &&
+               git symbolic-ref refs/heads/symref >expect &&
+               echo $a >actual &&
+               test_cmp expect actual &&
+               git reflog exists refs/heads/symref
+       '
+
 done
 
 test_done

diff --git a/t/t1416-ref-transaction-hooks.sh b/t/t1416-ref-transaction-hooks.sh
index ccde1b944be6f0055e34d17195a1bc21f1e11e3b..ff77dcca6b424bee580324adb4fe86516f85ea08 100755 (executable)
--- a/t/t1416-ref-transaction-hooks.sh
+++ b/t/t1416-ref-transaction-hooks.sh
@@ -189,15 +189,18 @@ test_expect_success 'hook gets all queued symref updates' '
        prepared
        ref:refs/heads/main $ZERO_OID refs/heads/symref
        ref:refs/heads/main $ZERO_OID refs/heads/symrefd
+       $ZERO_OID ref:refs/heads/main refs/heads/symrefc
        committed
        ref:refs/heads/main $ZERO_OID refs/heads/symref
        ref:refs/heads/main $ZERO_OID refs/heads/symrefd
+       $ZERO_OID ref:refs/heads/main refs/heads/symrefc
        EOF
 
        git update-ref --no-deref --stdin <<-EOF &&
        start
        symref-verify refs/heads/symref refs/heads/main
        symref-delete refs/heads/symrefd refs/heads/main
+       symref-create refs/heads/symrefc refs/heads/main
        prepare
        commit
        EOF

diff --git a/t/t5605-clone-local.sh b/t/t5605-clone-local.sh
index a3055869bc7bc182e2e4af736b06785ee28bed85..339d8c786f66a2254fa79393ace54e2078823b38 100755 (executable)
--- a/t/t5605-clone-local.sh
+++ b/t/t5605-clone-local.sh
@@ -163,7 +163,7 @@ test_expect_success REFFILES 'local clone from repo with corrupt refs fails grac
        echo a >corrupt/.git/refs/heads/topic &&
 
        test_must_fail git clone corrupt working 2>err &&
-       grep "has a null OID" err
+       grep "has neither a valid OID nor a target" err
 '
 
 test_done