[PATCH v5 0/2] Add @ shortcut, again

[PATCH v5 0/2] Add @ shortcut, again

[Felipe Contreras]

Felipe Contreras (2):
  sha1-name: pass len argument to interpret_branch_name()
  Add new @ shortcut for HEAD

 Documentation/git-check-ref-format.txt |  2 ++
 Documentation/revisions.txt            |  3 +++
 cache.h                                |  2 +-
 refs.c                                 |  6 +++++-
 revision.c                             |  2 +-
 sha1_name.c                            | 36 ++++++++++++++++++++++++++++++----
 t/t1508-at-combinations.sh             |  4 ++++
 7 files changed, 48 insertions(+), 7 deletions(-)

-- 
1.8.4-338-gefd7fa6

[PATCH v5 1/2] sha1-name: pass len argument to interpret_branch_name()

[Felipe Contreras]

This is useful to make sure we don't step outside the boundaries of what
we are interpreting at the moment. For example while interpreting
foobar@{u}~1, the job of interpret_branch_name() ends right before ~1,
but there's no way to figure that out inside the function, unless the
len argument is passed.

So let's do that.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
---
 cache.h     |  2 +-
 refs.c      |  2 +-
 revision.c  |  2 +-
 sha1_name.c | 10 ++++++----
 4 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/cache.h b/cache.h
index 85b544f..9fbc5fa 100644
--- a/cache.h
+++ b/cache.h
@@ -893,7 +893,7 @@ extern char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, i
 
 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
 extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
-extern int interpret_branch_name(const char *str, struct strbuf *);
+extern int interpret_branch_name(const char *str, int len, struct strbuf *);
 extern int get_sha1_mb(const char *str, unsigned char *sha1);
 
 extern int refname_match(const char *abbrev_name, const char *full_name, const char **rules);
diff --git a/refs.c b/refs.c
index 7922261..8fd5faf 100644
--- a/refs.c
+++ b/refs.c
@@ -1951,7 +1951,7 @@ static int remove_empty_directories(const char *file)
 static char *substitute_branch_name(const char **string, int *len)
 {
 	struct strbuf buf = STRBUF_INIT;
-	int ret = interpret_branch_name(*string, &buf);
+	int ret = interpret_branch_name(*string, *len, &buf);
 
 	if (ret == *len) {
 		size_t size;
diff --git a/revision.c b/revision.c
index 84ccc05..3ef1384 100644
--- a/revision.c
+++ b/revision.c
@@ -200,7 +200,7 @@ static void add_pending_object_with_mode(struct rev_info *revs,
 		revs->no_walk = 0;
 	if (revs->reflog_info && obj->type == OBJ_COMMIT) {
 		struct strbuf buf = STRBUF_INIT;
-		int len = interpret_branch_name(name, &buf);
+		int len = interpret_branch_name(name, 0, &buf);
 		int st;
 
 		if (0 < len && name[len] && buf.len)
diff --git a/sha1_name.c b/sha1_name.c
index 65ad066..93197b9 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1012,7 +1012,7 @@ static int reinterpret(const char *name, int namelen, int len, struct strbuf *bu
 	int ret;
 
 	strbuf_add(buf, name + len, namelen - len);
-	ret = interpret_branch_name(buf->buf, &tmp);
+	ret = interpret_branch_name(buf->buf, buf->len, &tmp);
 	/* that data was not interpreted, remove our cruft */
 	if (ret < 0) {
 		strbuf_setlen(buf, used);
@@ -1046,14 +1046,16 @@ static int reinterpret(const char *name, int namelen, int len, struct strbuf *bu
  * If the input was ok but there are not N branch switches in the
  * reflog, it returns 0.
  */
-int interpret_branch_name(const char *name, struct strbuf *buf)
+int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
 {
 	char *cp;
 	struct branch *upstream;
-	int namelen = strlen(name);
 	int len = interpret_nth_prior_checkout(name, buf);
 	int tmp_len;
 
+	if (!namelen)
+		namelen = strlen(name);
+
 	if (!len) {
 		return len; /* syntax Ok, not enough switches */
 	} else if (len > 0) {
@@ -1100,7 +1102,7 @@ int interpret_branch_name(const char *name, struct strbuf *buf)
 int strbuf_branchname(struct strbuf *sb, const char *name)
 {
 	int len = strlen(name);
-	int used = interpret_branch_name(name, sb);
+	int used = interpret_branch_name(name, len, sb);
 
 	if (used == len)
 		return 0;
-- 
1.8.4-338-gefd7fa6

[PATCH v5 2/2] Add new @ shortcut for HEAD

[Felipe Contreras]

Typing 'HEAD' is tedious, especially when we can use '@' instead.

The reason for choosing '@' is that it follows naturally from the
ref@op syntax (e.g. HEAD@{u}), except we have no ref, and no
operation, and when we don't have those, it makes sens to assume
'HEAD'.

So now we can use 'git show @~1', and all that goody goodness.

Until now '@' was a valid name, but it conflicts with this idea, so
let's make it invalid. Probably very few people, if any, used this name.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/git-check-ref-format.txt |  2 ++
 Documentation/revisions.txt            |  3 +++
 refs.c                                 |  4 ++++
 sha1_name.c                            | 26 ++++++++++++++++++++++++++
 t/t1508-at-combinations.sh             |  4 ++++
 5 files changed, 39 insertions(+)

diff --git a/Documentation/git-check-ref-format.txt b/Documentation/git-check-ref-format.txt
index a49be1b..fc02959 100644
--- a/Documentation/git-check-ref-format.txt
+++ b/Documentation/git-check-ref-format.txt
@@ -54,6 +54,8 @@ Git imposes the following rules on how references are named:
 
 . They cannot contain a sequence `@{`.
 
+. They cannot be the single character `@`.
+
 . They cannot contain a `\`.
 
 These rules make it easy for shell script based tools to parse
diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index d477b3f..09896a3 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -58,6 +58,9 @@ the '$GIT_DIR/refs' directory or from the '$GIT_DIR/packed-refs' file.
 While the ref name encoding is unspecified, UTF-8 is preferred as
 some output processing may assume ref names in UTF-8.
 
+'@'::
+  '@' alone is a shortcut for 'HEAD'.
+
 '<refname>@\{<date>\}', e.g. 'master@\{yesterday\}', 'HEAD@\{5 minutes ago\}'::
   A ref followed by the suffix '@' with a date specification
   enclosed in a brace
diff --git a/refs.c b/refs.c
index 8fd5faf..bfe10e2 100644
--- a/refs.c
+++ b/refs.c
@@ -72,6 +72,10 @@ int check_refname_format(const char *refname, int flags)
 {
 	int component_len, component_count = 0;
 
+	if (!strcmp(refname, "@"))
+		/* Refname is a single character '@'. */
+		return -1;
+
 	while (1) {
 		/* We are at the start of a path component. */
 		component_len = check_refname_component(refname, flags);
diff --git a/sha1_name.c b/sha1_name.c
index 93197b9..b8ece6e 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1004,6 +1004,26 @@ int get_sha1_mb(const char *name, unsigned char *sha1)
 	return st;
 }
 
+/* parse @something syntax, when 'something' is not {.*} */
+static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
+{
+	const char *next;
+
+	if (len || name[1] == '{')
+		return -1;
+
+	/* make sure it's a single @, or @@{.*}, not @foo */
+	next = strchr(name + len + 1, '@');
+	if (!next)
+		next = name + namelen;
+	if (next != name + 1)
+		return -1;
+
+	strbuf_reset(buf);
+	strbuf_add(buf, "HEAD", 4);
+	return 1;
+}
+
 static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
 {
 	/* we have extra data, which might need further processing */
@@ -1068,9 +1088,15 @@ int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
 	cp = strchr(name, '@');
 	if (!cp)
 		return -1;
+
+	len = interpret_empty_at(name, namelen, cp - name, buf);
+	if (len > 0)
+		return reinterpret(name, namelen, len, buf);
+
 	tmp_len = upstream_mark(cp, namelen - (cp - name));
 	if (!tmp_len)
 		return -1;
+
 	len = cp + tmp_len - name;
 	cp = xstrndup(name, cp - name);
 	upstream = branch_get(*cp ? cp : NULL);
diff --git a/t/t1508-at-combinations.sh b/t/t1508-at-combinations.sh
index e5aea3b..3a52375 100755
--- a/t/t1508-at-combinations.sh
+++ b/t/t1508-at-combinations.sh
@@ -32,6 +32,7 @@ test_expect_success 'setup' '
 	git checkout -b upstream-branch &&
 	test_commit upstream-one &&
 	test_commit upstream-two &&
+	git checkout -b @at-test &&
 	git checkout -b old-branch &&
 	test_commit old-one &&
 	test_commit old-two &&
@@ -55,6 +56,9 @@ check "HEAD@{u}" ref refs/heads/upstream-branch
 check "@{u}@{1}" commit upstream-one
 check "@{-1}@{u}" ref refs/heads/master
 check "@{-1}@{u}@{1}" commit master-one
+check "@" commit new-two
+check "@@{u}" ref refs/heads/upstream-branch
+check "@at-test" ref refs/heads/@at-test
 nonsense "@{u}@{-1}"
 nonsense "@{0}@{0}"
 nonsense "@{1}@{u}"
-- 
1.8.4-338-gefd7fa6

Re: [PATCH v5 1/2] sha1-name: pass len argument to interpret_branch_name()

[Junio C Hamano]

Felipe Contreras <felipe.contreras@gmail.com> writes:

> This is useful to make sure we don't step outside the boundaries of what
> we are interpreting at the moment. For example while interpreting
> foobar@{u}~1, the job of interpret_branch_name() ends right before ~1,
> but there's no way to figure that out inside the function, unless the
> len argument is passed.
>
> So let's do that.
>
> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>

Makes sense to me.  Thanks.

> ---
>  cache.h     |  2 +-
>  refs.c      |  2 +-
>  revision.c  |  2 +-
>  sha1_name.c | 10 ++++++----
>  4 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/cache.h b/cache.h
> index 85b544f..9fbc5fa 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -893,7 +893,7 @@ extern char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, i
>  
>  extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
>  extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
> -extern int interpret_branch_name(const char *str, struct strbuf *);
> +extern int interpret_branch_name(const char *str, int len, struct strbuf *);
>  extern int get_sha1_mb(const char *str, unsigned char *sha1);
>  
>  extern int refname_match(const char *abbrev_name, const char *full_name, const char **rules);
> diff --git a/refs.c b/refs.c
> index 7922261..8fd5faf 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -1951,7 +1951,7 @@ static int remove_empty_directories(const char *file)
>  static char *substitute_branch_name(const char **string, int *len)
>  {
>  	struct strbuf buf = STRBUF_INIT;
> -	int ret = interpret_branch_name(*string, &buf);
> +	int ret = interpret_branch_name(*string, *len, &buf);
>  
>  	if (ret == *len) {
>  		size_t size;
> diff --git a/revision.c b/revision.c
> index 84ccc05..3ef1384 100644
> --- a/revision.c
> +++ b/revision.c
> @@ -200,7 +200,7 @@ static void add_pending_object_with_mode(struct rev_info *revs,
>  		revs->no_walk = 0;
>  	if (revs->reflog_info && obj->type == OBJ_COMMIT) {
>  		struct strbuf buf = STRBUF_INIT;
> -		int len = interpret_branch_name(name, &buf);
> +		int len = interpret_branch_name(name, 0, &buf);
>  		int st;
>  
>  		if (0 < len && name[len] && buf.len)
> diff --git a/sha1_name.c b/sha1_name.c
> index 65ad066..93197b9 100644
> --- a/sha1_name.c
> +++ b/sha1_name.c
> @@ -1012,7 +1012,7 @@ static int reinterpret(const char *name, int namelen, int len, struct strbuf *bu
>  	int ret;
>  
>  	strbuf_add(buf, name + len, namelen - len);
> -	ret = interpret_branch_name(buf->buf, &tmp);
> +	ret = interpret_branch_name(buf->buf, buf->len, &tmp);
>  	/* that data was not interpreted, remove our cruft */
>  	if (ret < 0) {
>  		strbuf_setlen(buf, used);
> @@ -1046,14 +1046,16 @@ static int reinterpret(const char *name, int namelen, int len, struct strbuf *bu
>   * If the input was ok but there are not N branch switches in the
>   * reflog, it returns 0.
>   */
> -int interpret_branch_name(const char *name, struct strbuf *buf)
> +int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
>  {
>  	char *cp;
>  	struct branch *upstream;
> -	int namelen = strlen(name);
>  	int len = interpret_nth_prior_checkout(name, buf);
>  	int tmp_len;
>  
> +	if (!namelen)
> +		namelen = strlen(name);
> +
>  	if (!len) {
>  		return len; /* syntax Ok, not enough switches */
>  	} else if (len > 0) {
> @@ -1100,7 +1102,7 @@ int interpret_branch_name(const char *name, struct strbuf *buf)
>  int strbuf_branchname(struct strbuf *sb, const char *name)
>  {
>  	int len = strlen(name);
> -	int used = interpret_branch_name(name, sb);
> +	int used = interpret_branch_name(name, len, sb);
>  
>  	if (used == len)
>  		return 0;

Re: [PATCH v5 2/2] Add new @ shortcut for HEAD

[Junio C Hamano]

Felipe Contreras <felipe.contreras@gmail.com> writes:

> diff --git a/sha1_name.c b/sha1_name.c
> index 93197b9..b8ece6e 100644
> --- a/sha1_name.c
> +++ b/sha1_name.c
> @@ -1004,6 +1004,26 @@ int get_sha1_mb(const char *name, unsigned char *sha1)
>  	return st;
>  }
>  
> +/* parse @something syntax, when 'something' is not {.*} */
> +static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
> +{
> +	const char *next;
> +
> +	if (len || name[1] == '{')
> +		return -1;
> +
> +	/* make sure it's a single @, or @@{.*}, not @foo */
> +	next = strchr(name + len + 1, '@');
> +	if (!next)
> +		next = name + namelen;
> +	if (next != name + 1)
> +		return -1;
> +
> +	strbuf_reset(buf);
> +	strbuf_add(buf, "HEAD", 4);
> +	return 1;
> +}

Hmph, is the above sufficient?  I added a case that mimics Stefano's
original regression report (which is handled) and another that uses
doubled "@" for the same purpose of introducing a "funny" hierarchy,
and it appears that "checkout -b" chokes on it.

 t/t1508-at-combinations.sh | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/t/t1508-at-combinations.sh b/t/t1508-at-combinations.sh
index 3a52375..ceb8449 100755
--- a/t/t1508-at-combinations.sh
+++ b/t/t1508-at-combinations.sh
@@ -32,6 +32,8 @@ test_expect_success 'setup' '
 	git checkout -b upstream-branch &&
 	test_commit upstream-one &&
 	test_commit upstream-two &&
+	git checkout -b @/at-test &&
+	git checkout -b @@/at-test &&
 	git checkout -b @at-test &&
 	git checkout -b old-branch &&
 	test_commit old-one &&
@@ -58,6 +60,8 @@ check "@{-1}@{u}" ref refs/heads/master
 check "@{-1}@{u}@{1}" commit master-one
 check "@" commit new-two
 check "@@{u}" ref refs/heads/upstream-branch
+check "@@/at-test" ref refs/heads/@@/at-test
+check "@/at-test" ref refs/heads/@/at-test
 check "@at-test" ref refs/heads/@at-test
 nonsense "@{u}@{-1}"
 nonsense "@{0}@{0}"

Re: [PATCH v5 2/2] Add new @ shortcut for HEAD

[Felipe Contreras]

On Tue, Sep 3, 2013 at 1:50 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Felipe Contreras <felipe.contreras@gmail.com> writes:
>
>> diff --git a/sha1_name.c b/sha1_name.c
>> index 93197b9..b8ece6e 100644
>> --- a/sha1_name.c
>> +++ b/sha1_name.c
>> @@ -1004,6 +1004,26 @@ int get_sha1_mb(const char *name, unsigned char *sha1)
>>       return st;
>>  }
>>
>> +/* parse @something syntax, when 'something' is not {.*} */
>> +static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
>> +{
>> +     const char *next;
>> +
>> +     if (len || name[1] == '{')
>> +             return -1;
>> +
>> +     /* make sure it's a single @, or @@{.*}, not @foo */
>> +     next = strchr(name + len + 1, '@');
>> +     if (!next)
>> +             next = name + namelen;
>> +     if (next != name + 1)
>> +             return -1;
>> +
>> +     strbuf_reset(buf);
>> +     strbuf_add(buf, "HEAD", 4);
>> +     return 1;
>> +}
>
> Hmph, is the above sufficient?  I added a case that mimics Stefano's
> original regression report (which is handled) and another that uses
> doubled "@" for the same purpose of introducing a "funny" hierarchy,
> and it appears that "checkout -b" chokes on it.

This fixes it:

--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1014,6 +1014,8 @@ static int interpret_empty_at(const char *name,
int namelen, int len, struct str

        /* make sure it's a single @, or @@{.*}, not @foo */
        next = strchr(name + len + 1, '@');
+       if (next && next[1] != '{')
+               return -1;
        if (!next)
                next = name + namelen;
        if (next != name + 1)

-- 
Felipe Contreras

Re: [PATCH v5 2/2] Add new @ shortcut for HEAD

[Junio C Hamano]

Felipe Contreras <felipe.contreras@gmail.com> writes:

>> Hmph, is the above sufficient?  I added a case that mimics Stefano's
>> original regression report (which is handled) and another that uses
>> doubled "@" for the same purpose of introducing a "funny" hierarchy,
>> and it appears that "checkout -b" chokes on it.
>
> This fixes it:
>
> --- a/sha1_name.c
> +++ b/sha1_name.c
> @@ -1014,6 +1014,8 @@ static int interpret_empty_at(const char *name,
> int namelen, int len, struct str
>
>         /* make sure it's a single @, or @@{.*}, not @foo */
>         next = strchr(name + len + 1, '@');
> +       if (next && next[1] != '{')
> +               return -1;
>         if (!next)
>                 next = name + namelen;
>         if (next != name + 1)

I think this should be sufficient for all cases, as the sequence
"@{" cannot be a part of valid reference names.

Thanks.

I see v6 was posted yesterday after this message, but it does not
seem to have this fix, nor the additional test case I gave you in
the message upthread.  Sent a wrong version of patch by mistake?

Re: [PATCH v5 2/2] Add new @ shortcut for HEAD

[Junio C Hamano]

Junio C Hamano <gitster@pobox.com> writes:

> Felipe Contreras <felipe.contreras@gmail.com> writes:
>
>>> Hmph, is the above sufficient?  I added a case that mimics Stefano's
>>> original regression report (which is handled) and another that uses
>>> doubled "@" for the same purpose of introducing a "funny" hierarchy,
>>> and it appears that "checkout -b" chokes on it.
>>
>> This fixes it:
>>
>> --- a/sha1_name.c
>> +++ b/sha1_name.c
>> @@ -1014,6 +1014,8 @@ static int interpret_empty_at(const char *name,
>> int namelen, int len, struct str
>>
>>         /* make sure it's a single @, or @@{.*}, not @foo */
>>         next = strchr(name + len + 1, '@');
>> +       if (next && next[1] != '{')
>> +               return -1;
>>         if (!next)
>>                 next = name + namelen;
>>         if (next != name + 1)
>
> I think this should be sufficient for all cases, as the sequence
> "@{" cannot be a part of valid reference names.
>
> Thanks.
>
> I see v6 was posted yesterday after this message, but it does not
> seem to have this fix, nor the additional test case I gave you in
> the message upthread.  Sent a wrong version of patch by mistake?

Ping?

I could squash the fixup at the tip of on fc/at-head in if you want
me to, but v6 seems to be a mistake to me.