threads / discuss / 27307

Tags named '-'

Subject: Tags named '-'

## tl;dr

7 messages between May 9, 2011 and May 10, 2011.

replies: 6people: 4as markdown or json

Alex Vandiver· May 9, 2011, 15:21 UTC · lore

Heya,
  The functionality of `git checkout -` is very useful, and I am hopeful
that `git merge -` will eventually land, as it matches my workflow well
as well.  However, the porcelain is not entirely consistent about
forbidding '-' as a ref name:

        ~/tmp $ git init
        Initialized empty Git repository in /home/chmrr/tmp/.git/
        ~/tmp (master #) $ git commit --allow-empty -m 'First commit'
        [master (root-commit) b7402ef] First commit
        ~/tmp (master) $ git checkout -b other
        Switched to a new branch 'other'
        ~/tmp (other) $ git checkout -
        Switched to branch 'master'
        ~/tmp (master) $ git checkout -b -
        fatal: git checkout: we do not like '-' as a branch name.
        ~/tmp (master) $ git tag -
        ~/tmp (master) $ git tag -l
        -
        ~/tmp (master) $ git checkout -
        Switched to branch 'other'

The likely best fix is to disallow '-' as a tag name, as well, which
would be handy because the typo of leaving off the 'l' on '-l', for
example, which is not an uncommon mistake that I have seen.
 - Alex

Junio C Hamano· May 9, 2011, 18:01 UTC · re: Alex Vandiver · lore

Re: Tags named '-'

Alex Vandiver <alex@chmrr.net> writes:

> The likely best fix is to disallow '-' as a tag name, as well.

Sounds sane.  Patches welcome.

Michael Schubert· May 9, 2011, 22:56 UTC · re: Junio C Hamano · lore

[RFC/PATCH] tag: disallow '-' as tag name

Add strbuf_check_tag_ref() as helper to check a refname for a tag.

Signed-off-by: Michael Schubert <mschub@elegosoft.com>
---
 builtin/tag.c |   30 ++++++++++++++++++++++--------
 1 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/builtin/tag.c b/builtin/tag.c
index b66b34a..f087a7f 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -352,11 +352,26 @@ static int parse_msg_arg(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
+static int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
+{
+	if (name[0] == '-')
+		return CHECK_REF_FORMAT_ERROR;
+
+	strbuf_reset(sb);
+	strbuf_add(sb, "refs/tags/", 10);
+	strbuf_add(sb, name, strlen(name));
+
+	if (sb->len > PATH_MAX)
+		die(_("tag name too long: %.*s..."), 50, name);
+
+	return check_ref_format(sb->buf);
+}
+
 int cmd_tag(int argc, const char **argv, const char *prefix)
 {
 	struct strbuf buf = STRBUF_INIT;
+	struct strbuf ref = STRBUF_INIT;
 	unsigned char object[20], prev[20];
-	char ref[PATH_MAX];
 	const char *object_ref, *tag;
 	struct ref_lock *lock;
 
@@ -452,12 +467,10 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	if (get_sha1(object_ref, object))
 		die(_("Failed to resolve '%s' as a valid ref."), object_ref);
 
-	if (snprintf(ref, sizeof(ref), "refs/tags/%s", tag) > sizeof(ref) - 1)
-		die(_("tag name too long: %.*s..."), 50, tag);
-	if (check_ref_format(ref))
+	if (strbuf_check_tag_ref(&ref, tag))
 		die(_("'%s' is not a valid tag name."), tag);
 
-	if (!resolve_ref(ref, prev, 1, NULL))
+	if (!resolve_ref(ref.buf, prev, 1, NULL))
 		hashclr(prev);
 	else if (!force)
 		die(_("tag '%s' already exists"), tag);
@@ -466,14 +479,15 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		create_tag(object, tag, &buf, msg.given || msgfile,
 			   sign, prev, object);
 
-	lock = lock_any_ref_for_update(ref, prev, 0);
+	lock = lock_any_ref_for_update(ref.buf, prev, 0);
 	if (!lock)
-		die(_("%s: cannot lock the ref"), ref);
+		die(_("%s: cannot lock the ref"), ref.buf);
 	if (write_ref_sha1(lock, object, NULL) < 0)
-		die(_("%s: cannot update the ref"), ref);
+		die(_("%s: cannot update the ref"), ref.buf);
 	if (force && hashcmp(prev, object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));
 
 	strbuf_release(&buf);
+	strbuf_release(&ref);
 	return 0;
 }

-- 
1.7.5.1

Junio C Hamano· May 9, 2011, 23:08 UTC · re: Michael Schubert · lore

Re: [RFC/PATCH] tag: disallow '-' as tag name

Michael Schubert <mschub@elegosoft.com> writes:

> Add strbuf_check_tag_ref() as helper to check a refname for a tag.
>
> Signed-off-by: Michael Schubert <mschub@elegosoft.com>
> ---

That was quick ;-).

Show 15 quoted lines

>  builtin/tag.c |   30 ++++++++++++++++++++++--------
>  1 files changed, 22 insertions(+), 8 deletions(-)
>
> diff --git a/builtin/tag.c b/builtin/tag.c
> index b66b34a..f087a7f 100644
> --- a/builtin/tag.c
> +++ b/builtin/tag.c
> @@ -352,11 +352,26 @@ static int parse_msg_arg(const struct option *opt, const char *arg, int unset)
>  	return 0;
>  }
>  
> +static int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
> +{
> +	if (name[0] == '-')
> +		return CHECK_REF_FORMAT_ERROR;

So contrary to what the title claims, it forbids a tag that begins with '-', e.g. '-foo', not just a single dash. That is fine by me (we do the same in strbuf-check-branch-ref) but it needs to be explained better.

> +	strbuf_reset(sb);
> +	strbuf_add(sb, "refs/tags/", 10);
> +	strbuf_add(sb, name, strlen(name));

strbuf_addf(sb, "refs/tags/%s", name)?

> +	if (sb->len > PATH_MAX)
> +		die(_("tag name too long: %.*s..."), 50, name);

I think that should be

	if (PATH_MAX <= sb->len)

but I do not see the point of checking against PATH_MAX if you are already using a strbuf...

Michael Schubert· May 9, 2011, 23:36 UTC · re: Junio C Hamano · lore

[RFC/PATCH v2] tag: disallow '-' as tag name

Disallow '-' as tag name just as any tag name starting with '-' to be consistent with "git checkout".

Add strbuf_check_tag_ref() as helper to check a refname for a tag.

Signed-off-by: Michael Schubert <mschub@elegosoft.com>
---
 builtin/tag.c |   26 ++++++++++++++++++--------
 1 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/builtin/tag.c b/builtin/tag.c
index b66b34a..ec926fc 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -352,11 +352,22 @@ static int parse_msg_arg(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
+static int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
+{
+	if (name[0] == '-')
+		return CHECK_REF_FORMAT_ERROR;
+
+	strbuf_reset(sb);
+	strbuf_addf(sb, "refs/tags/%s", name);
+
+	return check_ref_format(sb->buf);
+}
+
 int cmd_tag(int argc, const char **argv, const char *prefix)
 {
 	struct strbuf buf = STRBUF_INIT;
+	struct strbuf ref = STRBUF_INIT;
 	unsigned char object[20], prev[20];
-	char ref[PATH_MAX];
 	const char *object_ref, *tag;
 	struct ref_lock *lock;
 
@@ -452,12 +463,10 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	if (get_sha1(object_ref, object))
 		die(_("Failed to resolve '%s' as a valid ref."), object_ref);
 
-	if (snprintf(ref, sizeof(ref), "refs/tags/%s", tag) > sizeof(ref) - 1)
-		die(_("tag name too long: %.*s..."), 50, tag);
-	if (check_ref_format(ref))
+	if (strbuf_check_tag_ref(&ref, tag))
 		die(_("'%s' is not a valid tag name."), tag);
 
-	if (!resolve_ref(ref, prev, 1, NULL))
+	if (!resolve_ref(ref.buf, prev, 1, NULL))
 		hashclr(prev);
 	else if (!force)
 		die(_("tag '%s' already exists"), tag);
@@ -466,14 +475,15 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		create_tag(object, tag, &buf, msg.given || msgfile,
 			   sign, prev, object);
 
-	lock = lock_any_ref_for_update(ref, prev, 0);
+	lock = lock_any_ref_for_update(ref.buf, prev, 0);
 	if (!lock)
-		die(_("%s: cannot lock the ref"), ref);
+		die(_("%s: cannot lock the ref"), ref.buf);
 	if (write_ref_sha1(lock, object, NULL) < 0)
-		die(_("%s: cannot update the ref"), ref);
+		die(_("%s: cannot update the ref"), ref.buf);
 	if (force && hashcmp(prev, object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));
 
 	strbuf_release(&buf);
+	strbuf_release(&ref);
 	return 0;
 }

-- 
1.7.5.1

Sverre Rabbelier· May 9, 2011, 22:04 UTC · re: Alex Vandiver · lore

Re: Tags named '-'

Heya,

On Mon, May 9, 2011 at 17:21, Alex Vandiver <alex@chmrr.net> wrote:

>  The functionality of `git checkout -` is very useful, and I am hopeful
> that `git merge -` will eventually land, as it matches my workflow well
> as well.

Speaking of which, my cursory check of 'man git-checkout' did not give me any information on 'git checkout -'. ISTR it lets you check out the branch you were previously on, but I'm not sure. Is it undocumented, or am I missing it (entirely possible, searching for an option named '-' is somewhat difficult).

-- 
Cheers,

Sverre Rabbelier

Michael Schubert· May 10, 2011, 09:47 UTC · lore

Re: [RFC/PATCH v2] tag: disallow '-' as tag name

On 05/10/2011 09:07 AM, Sverre Rabbelier wrote:

Show 7 quoted lines

>> Disallow '-' as tag name just as any tag name starting with '-' to be
>> consistent with "git checkout".
> 
> This was hard for me to parse, how about::
> 
> Disallow '-' as tag name, as well as tag names starting with '-', to
> be consistent with "git checkout".

Thanks.

-- >8 --
Subject: [PATCH] tag: disallow '-' as tag name

Disallow '-' as tag name, as well as tag names starting with '-', to be consistent with "git checkout".

Add strbuf_check_tag_ref() as helper to check a refname for a tag.

Signed-off-by: Michael Schubert <mschub@elegosoft.com>
---
 builtin/tag.c |   26 ++++++++++++++++++--------
 1 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/builtin/tag.c b/builtin/tag.c
index b66b34a..ec926fc 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -352,11 +352,22 @@ static int parse_msg_arg(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
+static int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
+{
+	if (name[0] == '-')
+		return CHECK_REF_FORMAT_ERROR;
+
+	strbuf_reset(sb);
+	strbuf_addf(sb, "refs/tags/%s", name);
+
+	return check_ref_format(sb->buf);
+}
+
 int cmd_tag(int argc, const char **argv, const char *prefix)
 {
 	struct strbuf buf = STRBUF_INIT;
+	struct strbuf ref = STRBUF_INIT;
 	unsigned char object[20], prev[20];
-	char ref[PATH_MAX];
 	const char *object_ref, *tag;
 	struct ref_lock *lock;
 
@@ -452,12 +463,10 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	if (get_sha1(object_ref, object))
 		die(_("Failed to resolve '%s' as a valid ref."), object_ref);
 
-	if (snprintf(ref, sizeof(ref), "refs/tags/%s", tag) > sizeof(ref) - 1)
-		die(_("tag name too long: %.*s..."), 50, tag);
-	if (check_ref_format(ref))
+	if (strbuf_check_tag_ref(&ref, tag))
 		die(_("'%s' is not a valid tag name."), tag);
 
-	if (!resolve_ref(ref, prev, 1, NULL))
+	if (!resolve_ref(ref.buf, prev, 1, NULL))
 		hashclr(prev);
 	else if (!force)
 		die(_("tag '%s' already exists"), tag);
@@ -466,14 +475,15 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		create_tag(object, tag, &buf, msg.given || msgfile,
 			   sign, prev, object);
 
-	lock = lock_any_ref_for_update(ref, prev, 0);
+	lock = lock_any_ref_for_update(ref.buf, prev, 0);
 	if (!lock)
-		die(_("%s: cannot lock the ref"), ref);
+		die(_("%s: cannot lock the ref"), ref.buf);
 	if (write_ref_sha1(lock, object, NULL) < 0)
-		die(_("%s: cannot update the ref"), ref);
+		die(_("%s: cannot update the ref"), ref.buf);
 	if (force && hashcmp(prev, object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));
 
 	strbuf_release(&buf);
+	strbuf_release(&ref);
 	return 0;
 }

-- 
1.7.5.1