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Merge branch 'uk/checkout-ambiguous-ref'
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* uk/checkout-ambiguous-ref:
  Rename t2019 with typo "amiguous" that meant "ambiguous"
  checkout: rearrange update_refs_for_switch for clarity
  checkout: introduce --detach synonym for "git checkout foo^{commit}"
  checkout: split off a function to peel away branchname arg
  checkout: fix bug with ambiguous refs

Conflicts:
	builtin/checkout.c
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Junio C Hamano committed Feb 28, 2011
2 parents 28afcbf + 6c74ce8 commit c0791f3
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13 changes: 11 additions & 2 deletions Documentation/git-checkout.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@ SYNOPSIS
--------
[verse]
'git checkout' [-q] [-f] [-m] [<branch>]
'git checkout' [-q] [-f] [-m] [--detach] [<commit>]
'git checkout' [-q] [-f] [-m] [[-b|-B|--orphan] <new_branch>] [<start_point>]
'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <paths>...
'git checkout' --patch [<tree-ish>] [--] [<paths>...]
Expand All @@ -22,9 +23,10 @@ branch.

'git checkout' [<branch>]::
'git checkout' -b|-B <new_branch> [<start point>]::
'git checkout' [--detach] [<commit>]::

This form switches branches by updating the index, working
tree, and HEAD to reflect the specified branch.
tree, and HEAD to reflect the specified branch or commit.
+
If `-b` is given, a new branch is created as if linkgit:git-branch[1]
were called and then checked out; in this case you can
Expand Down Expand Up @@ -115,6 +117,13 @@ explicitly give a name with '-b' in such a case.
Create the new branch's reflog; see linkgit:git-branch[1] for
details.

--detach::
Rather than checking out a branch to work on it, check out a
commit for inspection and discardable experiments.
This is the default behavior of "git checkout <commit>" when
<commit> is not a branch name. See the "DETACHED HEAD" section
below for details.

--orphan::
Create a new 'orphan' branch, named <new_branch>, started from
<start_point> and switch to it. The first commit made on this
Expand Down Expand Up @@ -204,7 +213,7 @@ leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.



Detached HEAD
DETACHED HEAD
-------------

It is sometimes useful to be able to 'checkout' a commit that is
Expand Down
260 changes: 155 additions & 105 deletions builtin/checkout.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@ struct checkout_opts {
int quiet;
int merge;
int force;
int force_detach;
int writeout_stage;
int writeout_error;

Expand Down Expand Up @@ -541,7 +542,17 @@ static void update_refs_for_switch(struct checkout_opts *opts,
strbuf_addf(&msg, "checkout: moving from %s to %s",
old_desc ? old_desc : "(invalid)", new->name);

if (new->path) {
if (!strcmp(new->name, "HEAD") && !new->path && !opts->force_detach) {
/* Nothing to do. */
} else if (opts->force_detach || !new->path) { /* No longer on any branch. */
update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
REF_NODEREF, DIE_ON_ERR);
if (!opts->quiet) {
if (old->path && advice_detached_head)
detach_advice(old->path, new->name);
describe_detached_head("HEAD is now at", new->commit);
}
} else if (new->path) { /* Switch branches. */
create_symref("HEAD", new->path, msg.buf);
if (!opts->quiet) {
if (old->path && !strcmp(new->path, old->path))
Expand All @@ -563,18 +574,11 @@ static void update_refs_for_switch(struct checkout_opts *opts,
if (!file_exists(ref_file) && file_exists(log_file))
remove_path(log_file);
}
} else if (strcmp(new->name, "HEAD")) {
update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
REF_NODEREF, DIE_ON_ERR);
if (!opts->quiet) {
if (old->path && advice_detached_head)
detach_advice(old->path, new->name);
describe_detached_head("HEAD is now at", new->commit);
}
}
remove_branch_state();
strbuf_release(&msg);
if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
if (!opts->quiet &&
(new->path || (!opts->force_detach && !strcmp(new->name, "HEAD"))))
report_tracking(new);
}

Expand Down Expand Up @@ -675,11 +679,123 @@ static const char *unique_tracking_name(const char *name)
return NULL;
}

static int parse_branchname_arg(int argc, const char **argv,
int dwim_new_local_branch_ok,
struct branch_info *new,
struct tree **source_tree,
unsigned char rev[20],
const char **new_branch)
{
int argcount = 0;
unsigned char branch_rev[20];
const char *arg;
int has_dash_dash;

/*
* case 1: git checkout <ref> -- [<paths>]
*
* <ref> must be a valid tree, everything after the '--' must be
* a path.
*
* case 2: git checkout -- [<paths>]
*
* everything after the '--' must be paths.
*
* case 3: git checkout <something> [<paths>]
*
* With no paths, if <something> is a commit, that is to
* switch to the branch or detach HEAD at it. As a special case,
* if <something> is A...B (missing A or B means HEAD but you can
* omit at most one side), and if there is a unique merge base
* between A and B, A...B names that merge base.
*
* With no paths, if <something> is _not_ a commit, no -t nor -b
* was given, and there is a tracking branch whose name is
* <something> in one and only one remote, then this is a short-hand
* to fork local <something> from that remote-tracking branch.
*
* Otherwise <something> shall not be ambiguous.
* - If it's *only* a reference, treat it like case (1).
* - If it's only a path, treat it like case (2).
* - else: fail.
*
*/
if (!argc)
return 0;

if (!strcmp(argv[0], "--")) /* case (2) */
return 1;

arg = argv[0];
has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");

if (!strcmp(arg, "-"))
arg = "@{-1}";

if (get_sha1_mb(arg, rev)) {
if (has_dash_dash) /* case (1) */
die("invalid reference: %s", arg);
if (dwim_new_local_branch_ok &&
!check_filename(NULL, arg) &&
argc == 1) {
const char *remote = unique_tracking_name(arg);
if (!remote || get_sha1(remote, rev))
return argcount;
*new_branch = arg;
arg = remote;
/* DWIMmed to create local branch */
} else {
return argcount;
}
}

/* we can't end up being in (2) anymore, eat the argument */
argcount++;
argv++;
argc--;

new->name = arg;
setup_branch_path(new);

if (check_ref_format(new->path) == CHECK_REF_FORMAT_OK &&
resolve_ref(new->path, branch_rev, 1, NULL))
hashcpy(rev, branch_rev);
else
new->path = NULL; /* not an existing branch */

new->commit = lookup_commit_reference_gently(rev, 1);
if (!new->commit) {
/* not a commit */
*source_tree = parse_tree_indirect(rev);
} else {
parse_commit(new->commit);
*source_tree = new->commit->tree;
}

if (!*source_tree) /* case (1): want a tree */
die("reference is not a tree: %s", arg);
if (!has_dash_dash) {/* case (3 -> 1) */
/*
* Do not complain the most common case
* git checkout branch
* even if there happen to be a file called 'branch';
* it would be extremely annoying.
*/
if (argc)
verify_non_filename(NULL, arg);
} else {
argcount++;
argv++;
argc--;
}

return argcount;
}

int cmd_checkout(int argc, const char **argv, const char *prefix)
{
struct checkout_opts opts;
unsigned char rev[20];
const char *arg;
struct branch_info new;
struct tree *source_tree = NULL;
char *conflict_style = NULL;
Expand All @@ -692,6 +808,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
OPT_STRING('B', NULL, &opts.new_branch_force, "branch",
"create/reset and checkout a branch"),
OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "create reflog for new branch"),
OPT_BOOLEAN(0, "detach", &opts.force_detach, "detach the HEAD at named commit"),
OPT_SET_INT('t', "track", &opts.track, "set upstream info for new branch",
BRANCH_TRACK_EXPLICIT),
OPT_STRING(0, "orphan", &opts.new_orphan_branch, "new branch", "new unparented branch"),
Expand All @@ -709,7 +826,6 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
OPT_END(),
};
int has_dash_dash;

memset(&opts, 0, sizeof(opts));
memset(&new, 0, sizeof(new));
Expand All @@ -731,9 +847,15 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
opts.new_branch = opts.new_branch_force;

if (patch_mode && (opts.track > 0 || opts.new_branch
|| opts.new_branch_log || opts.merge || opts.force))
|| opts.new_branch_log || opts.merge || opts.force
|| opts.force_detach))
die ("--patch is incompatible with all other options");

if (opts.force_detach && (opts.new_branch || opts.new_orphan_branch))
die("--detach cannot be used with -b/-B/--orphan");
if (opts.force_detach && 0 < opts.track)
die("--detach cannot be used with -t");

/* --track without -b should DWIM */
if (0 < opts.track && !opts.new_branch) {
const char *argv0 = argv[0];
Expand Down Expand Up @@ -766,105 +888,30 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
die("git checkout: -f and -m are incompatible");

/*
* case 1: git checkout <ref> -- [<paths>]
*
* <ref> must be a valid tree, everything after the '--' must be
* a path.
*
* case 2: git checkout -- [<paths>]
*
* everything after the '--' must be paths.
*
* case 3: git checkout <something> [<paths>]
*
* With no paths, if <something> is a commit, that is to
* switch to the branch or detach HEAD at it. As a special case,
* if <something> is A...B (missing A or B means HEAD but you can
* omit at most one side), and if there is a unique merge base
* between A and B, A...B names that merge base.
* Extract branch name from command line arguments, so
* all that is left is pathspecs.
*
* With no paths, if <something> is _not_ a commit, no -t nor -b
* was given, and there is a remote-tracking branch whose name is
* <something> in one and only one remote, then this is a short-hand
* to fork local <something> from that remote-tracking branch.
* Handle
*
* Otherwise <something> shall not be ambiguous.
* - If it's *only* a reference, treat it like case (1).
* - If it's only a path, treat it like case (2).
* - else: fail.
* 1) git checkout <tree> -- [<paths>]
* 2) git checkout -- [<paths>]
* 3) git checkout <something> [<paths>]
*
* including "last branch" syntax and DWIM-ery for names of
* remote branches, erroring out for invalid or ambiguous cases.
*/
if (argc) {
if (!strcmp(argv[0], "--")) { /* case (2) */
argv++;
argc--;
goto no_reference;
}

arg = argv[0];
has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");

if (!strcmp(arg, "-"))
arg = "@{-1}";

if (get_sha1_mb(arg, rev)) {
if (has_dash_dash) /* case (1) */
die("invalid reference: %s", arg);
if (!patch_mode &&
dwim_new_local_branch &&
opts.track == BRANCH_TRACK_UNSPECIFIED &&
!opts.new_branch &&
!check_filename(NULL, arg) &&
argc == 1) {
const char *remote = unique_tracking_name(arg);
if (!remote || get_sha1(remote, rev))
goto no_reference;
opts.new_branch = arg;
arg = remote;
/* DWIMmed to create local branch */
}
else
goto no_reference;
}

/* we can't end up being in (2) anymore, eat the argument */
argv++;
argc--;

new.name = arg;
if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
setup_branch_path(&new);

if ((check_ref_format(new.path) == CHECK_REF_FORMAT_OK) &&
resolve_ref(new.path, rev, 1, NULL))
;
else
new.path = NULL;
parse_commit(new.commit);
source_tree = new.commit->tree;
} else
source_tree = parse_tree_indirect(rev);

if (!source_tree) /* case (1): want a tree */
die("reference is not a tree: %s", arg);
if (!has_dash_dash) {/* case (3 -> 1) */
/*
* Do not complain the most common case
* git checkout branch
* even if there happen to be a file called 'branch';
* it would be extremely annoying.
*/
if (argc)
verify_non_filename(NULL, arg);
}
else {
argv++;
argc--;
}
int dwim_ok =
!patch_mode &&
dwim_new_local_branch &&
opts.track == BRANCH_TRACK_UNSPECIFIED &&
!opts.new_branch;
int n = parse_branchname_arg(argc, argv, dwim_ok,
&new, &source_tree, rev, &opts.new_branch);
argv += n;
argc -= n;
}

no_reference:

if (opts.track == BRANCH_TRACK_UNSPECIFIED)
opts.track = git_branch_track;

Expand All @@ -886,6 +933,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
}
}

if (opts.force_detach)
die("git checkout: --detach does not take a path argument");

if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
die("git checkout: --ours/--theirs, --force and --merge are incompatible when\nchecking out of the index.");

Expand Down
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