In order to track and build on top of a branch 'topic' you track from
your upstream repository, you often would end up doing this sequence:
git checkout -b mytopic origin/topic
git config --add branch.mytopic.remote origin
git config --add branch.mytopic.merge refs/heads/topic
This would first fork your own 'mytopic' branch from the 'topic'
branch you track from the 'origin' repository; then it would set up two
configuration variables so that 'git pull' without parameters does the
right thing while you are on your own 'mytopic' branch.
This commit adds a --track option to git-branch, so that "git
branch --track mytopic origin/topic" performs the latter two actions
when creating your 'mytopic' branch.
If the configuration variable remote.NAME.trackintolocalbranches is
set to true, you do not have to pass the --track option explicitly;
further patches in this series allow setting the variable with a "git
remote add" option. The configuration variable is off by default, and
there is a --no-track option to countermand it even if the variable is
set.
Signed-off-by: Paolo Bonzini <bonzini@xxxxxxx>
---
Documentation/git-branch.txt | 9 ++-
builtin-branch.c | 126 ++++++++++++++++++++++++++++++++++++++++---
cache.h | 1
trace.c | 14 ++--
4 files changed, 134 insertions(+), 16 deletions(-)
This version provides a variable-argument wrapper nfasprintf around
the git function nfvasprintf, and uses it instead of the GNU extension
asprintf.
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index 3ea3b80..bd65b98 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -10,7 +10,7 @@ SYNOPSIS
[verse]
'git-branch' [--color | --no-color] [-r | -a]
[-v [--abbrev=<length> | --no-abbrev]]
-'git-branch' [-l] [-f] <branchname> [<start-point>]
+'git-branch' [--track | --no-track] [-l] [-f] <branchname> [<start-point>]
'git-branch' (-m | -M) [<oldbranch>] <newbranch>
'git-branch' (-d | -D) [-r] <branchname>...
@@ -26,6 +26,13 @@ It will start out with a head equal to the one given as <start-point>.
If no <start-point> is given, the branch will be created with a head
equal to that of the currently checked out branch.
+When a local branch is started off a remote branch, git can setup the
+branch so that gitlink:git-pull[1] will appropriately merge from that
+remote branch. If this behavior is desired, it is possible to make it
+the default using the `trackintolocalbranches` option of the
+corresponding remote. Otherwise, it can be chosen per-branch using
+the `--track` and `--no-track` options.
+
With a '-m' or '-M' option, <oldbranch> will be renamed to <newbranch>.
If <oldbranch> had a corresponding reflog, it is renamed to match
<newbranch>, and a reflog entry is created to remember the branch
diff --git a/builtin-branch.c b/builtin-branch.c
index d371849..f39759b 100644
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -12,7 +12,7 @@
#include "builtin.h"
static const char builtin_branch_usage[] =
- "git-branch [-r] (-d | -D) <branchname> | [-l] [-f] <branchname> [<start-point>] | (-m | -M) [<oldbranch>] <newbranch> | [--color | --no-color] [-r | -a] [-v [--abbrev=<length> | --no-abbrev]]";
+ "git-branch [-r] (-d | -D) <branchname> | [--track | --no-track] [-l] [-f] <branchname> [<start-point>] | (-m | -M) [<oldbranch>] <newbranch> | [--color | --no-color] [-r | -a] [-v [--abbrev=<length> | --no-abbrev]]";
#define REF_UNKNOWN_TYPE 0x00
#define REF_LOCAL_BRANCH 0x01
@@ -308,14 +308,99 @@ static void print_ref_list(int kinds, int detached, int verbose, int abbrev)
free_ref_list(&ref_list);
}
+static int config_track;
+static char *config_repo;
+static const char *start_ref;
+static int start_len;
+static int remote_len;
+
+static void get_remote_branch_name(const char* value)
+{
+ int len_first = -1, len_second = -1;
+ if (*value == '+')
+ value++;
+
+ /* Try an exact match first. */
+ sscanf(value, "refs/%*[^:]:%n", &len_first);
+ if (len_first != -1
+ && !strcmp(value + len_first, start_ref)) {
+ /* Truncate the value before the colon. */
+ nfasprintf(&config_repo, "%.*s", len_first - 1, value);
+ return;
+ }
+
+ /* Try with a wildcard match now. */
+ sscanf(value, "refs/%*[^/]/*:%nrefs/remotes/%*[^/]/*%n",
+ &len_first, &len_second);
+ if (len_first != -1 && len_second != -1
+ && (len_second - 2) - len_first == remote_len + 13
+ && !strncmp(value + len_first, start_ref, remote_len + 13)) {
+ /* Replace the star with the remote branch name. */
+ nfasprintf(&config_repo, "%.*s%s",
+ len_first - 3, value,
+ start_ref + remote_len + 13);
+ }
+}
+
+static int get_remote_config(const char* key, const char* value)
+{
+ if (!prefixcmp(key, "remote.") &&
+ !strncmp(key + 7, start_ref + 13, remote_len)) {
+ if (config_track == -1
+ && !strcmp(key + 7 + remote_len, ".trackintolocalbranches"))
+ config_track = git_config_bool(key, value);
+
+ else if (!strcmp(key + 7 + remote_len, ".fetch"))
+ get_remote_branch_name(value);
+ }
+ return 0;
+}
+
+static void set_branch_defaults(const char *name, const char *real_ref, int track)
+{
+ char key[1024], value[1024];
+ const char *remote_name = real_ref + 13;
+ const char *slash = strchr(remote_name, '/');
+
+ if (!slash)
+ return;
+
+ start_ref = real_ref;
+ start_len = strlen(real_ref);
+ remote_len = slash - remote_name;
+ config_track = track;
+ git_config(get_remote_config);
+
+ /* Change to != 0 to enable this feature by default. */
+ if (config_track == 1 && config_repo) {
+ if (snprintf(key, sizeof(key), "branch.%s.remote", name)
+ > sizeof(key))
+ die("what a long branch name you have!");
+ if (snprintf(value, sizeof(value), "%.*s", remote_len, remote_name)
+ > sizeof(value))
+ die("what a long branch name you have!");
+
+ git_config_set(key, value);
+
+ snprintf(key, sizeof(key), "branch.%s.merge", name);
+ git_config_set(key, config_repo);
+
+ printf("Branch %s set up to track remote branch %s.\n",
+ name, real_ref);
+ }
+
+ if (config_repo)
+ free(config_repo);
+}
+
static void create_branch(const char *name, const char *start_name,
unsigned char *start_sha1,
- int force, int reflog)
+ int force, int reflog, int track)
{
struct ref_lock *lock;
struct commit *commit;
unsigned char sha1[20];
- char ref[PATH_MAX], msg[PATH_MAX + 20];
+ char *real_ref, ref[PATH_MAX], msg[PATH_MAX + 20];
int forcing = 0;
snprintf(ref, sizeof ref, "refs/heads/%s", name);
@@ -333,7 +424,9 @@ static void create_branch(const char *name, const char *start_name,
if (start_sha1)
/* detached HEAD */
hashcpy(sha1, start_sha1);
- else if (get_sha1(start_name, sha1))
+ else if (dwim_ref(start_name, strlen(start_name), sha1, &real_ref) > 1)
+ die("Ambiguous object name: '%s'.", start_name);
+ else if (real_ref == NULL)
die("Not a valid object name: '%s'.", start_name);
if ((commit = lookup_commit_reference(sha1)) == NULL)
@@ -354,8 +447,17 @@ static void create_branch(const char *name, const char *start_name,
snprintf(msg, sizeof msg, "branch: Created from %s",
start_name);
+ /* When branching off a remote branch, set up so that git-pull
+ automatically merges from there. So far, this is only done for
+ branches registered using git-remote. */
+ if (real_ref && !prefixcmp(real_ref, "refs/remotes/"))
+ set_branch_defaults(name, real_ref, track);
+
if (write_ref_sha1(lock, sha1, msg) < 0)
die("Failed to write ref: %s.", strerror(errno));
+
+ if (real_ref)
+ free(real_ref);
}
static void rename_branch(const char *oldname, const char *newname, int force)
@@ -397,7 +499,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
int delete = 0, force_delete = 0, force_create = 0;
int rename = 0, force_rename = 0;
int verbose = 0, abbrev = DEFAULT_ABBREV, detached = 0;
- int reflog = 0;
+ int reflog = 0, track = -1;
int kinds = REF_LOCAL_BRANCH;
int i;
@@ -412,6 +514,14 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
i++;
break;
}
+ if (!strcmp(arg, "--track")) {
+ track = 1;
+ continue;
+ }
+ if (!strcmp(arg, "--no-track")) {
+ track = 0;
+ continue;
+ }
if (!strcmp(arg, "-d")) {
delete = 1;
continue;
@@ -498,9 +608,11 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
else if (rename && (i == argc - 2))
rename_branch(argv[i], argv[i + 1], force_rename);
else if (i == argc - 1)
- create_branch(argv[i], head, head_sha1, force_create, reflog);
+ create_branch(argv[i], head, head_sha1, force_create, reflog,
+ track);
else if (i == argc - 2)
- create_branch(argv[i], argv[i+1], NULL, force_create, reflog);
+ create_branch(argv[i], argv[i+1], NULL, force_create, reflog,
+ track);
else
usage(builtin_branch_usage);
diff --git a/cache.h b/cache.h
index 8018b2c..e1b8416 100644
--- a/cache.h
+++ b/cache.h
@@ -477,6 +477,7 @@ extern struct tag *alloc_tag_node(void);
extern void alloc_report(void);
/* trace.c */
+extern int nfasprintf(char **str, const char *fmt, ...);
extern int nfvasprintf(char **str, const char *fmt, va_list va);
extern void trace_printf(const char *format, ...);
extern void trace_argv_printf(const char **argv, int count, const char *format, ...);
diff --git a/trace.c b/trace.c
index 27fef86..ab177fa 100644
--- a/trace.c
+++ b/trace.c
@@ -26,14 +26,14 @@
#include "quote.h"
/* Stolen from "imap-send.c". */
-static int git_vasprintf(char **strp, const char *fmt, va_list ap)
+int nfvasprintf(char **strp, const char *fmt, va_list ap)
{
int len;
char tmp[1024];
if ((len = vsnprintf(tmp, sizeof(tmp), fmt, ap)) < 0 ||
!(*strp = xmalloc(len + 1)))
- return -1;
+ die("Fatal: Out of memory\n");
if (len >= (int)sizeof(tmp))
vsprintf(*strp, fmt, ap);
else
@@ -41,13 +41,11 @@ static int git_vasprintf(char **strp, const char *fmt, va_list ap)
return len;
}
-/* Stolen from "imap-send.c". */
-int nfvasprintf(char **str, const char *fmt, va_list va)
+int nfasprintf(char **str, const char *fmt, ...)
{
- int ret = git_vasprintf(str, fmt, va);
- if (ret < 0)
- die("Fatal: Out of memory\n");
- return ret;
+ va_list args;
+ va_start(args, fmt);
+ return nfvasprintf(str, fmt, args);
}
/* Get a trace file descriptor from GIT_TRACE env variable. */
-
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