Looks more or less right but invoke "ls-files -z" and reading the \0
delimited output would be easier; otherwise you would have to worry
about c-unquoting the pathname when the submodule is bound at a path
with funny character (like a double-quote) in it.
Also, returning the exact string of the path from the API function is
absolutely the right thing. I however have to wonder if rev-parse need
to do the c-quoting unless it is told to show pathnames in its output
without quoting (perhaps with "-z")? Or are paths from "rev-parse"
(like "--git-dir", "--show-toplevel", etc.) already excempt from the
usual quoting rules---if so, doing puts() and nothing else is fine to
be consistent with the existing practice (in the longer term, I am
sure we would need to revisit so that scripts can handle paths with
funny characters sensibly, but that would be a different topic if
existing ones like "--git-dir" are already unsafe).
Sorry for top-posting (I am not on a terminal right now).
On Tue, Mar 7, 2017 at 4:56 PM, Stefan Beller <sbeller@xxxxxxxxxx> wrote:
> In some situations it is useful to know if the given repository
> is a submodule of another repository.
>
> Add the flag --show-superproject-working-tree to git-rev-parse
> to make it easy to find out if there is a superproject.
>
> Signed-off-by: Stefan Beller <sbeller@xxxxxxxxxx>
> ---
>
> * not RFC anymore, but for real this time; including a test and docs :)
>
> * Following Junios advice: there is only one function
> (superproject_exists was dropped) using ls-files.
> (the test actually tests for a staged submodule)
>
> Thanks,
> Stefan
>
>
> Documentation/git-rev-parse.txt | 5 +++
> builtin/rev-parse.c | 7 ++++
> submodule.c | 83 +++++++++++++++++++++++++++++++++++++++++
> submodule.h | 8 ++++
> t/t1500-rev-parse.sh | 14 +++++++
> 5 files changed, 117 insertions(+)
>
> diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
> index 91c02b8c85..b841bad7c7 100644
> --- a/Documentation/git-rev-parse.txt
> +++ b/Documentation/git-rev-parse.txt
> @@ -261,6 +261,11 @@ print a message to stderr and exit with nonzero status.
> --show-toplevel::
> Show the absolute path of the top-level directory.
>
> +--show-superproject-working-tree
> + Show the absolute path of the top-level directory of
> + the superproject. A superproject is a repository that records
> + this repository as a submodule.
> +
> --shared-index-path::
> Show the path to the shared index file in split index mode, or
> empty if not in split-index mode.
> diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
> index e08677e559..2549643267 100644
> --- a/builtin/rev-parse.c
> +++ b/builtin/rev-parse.c
> @@ -12,6 +12,7 @@
> #include "diff.h"
> #include "revision.h"
> #include "split-index.h"
> +#include "submodule.h"
>
> #define DO_REVS 1
> #define DO_NOREV 2
> @@ -779,6 +780,12 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
> puts(work_tree);
> continue;
> }
> + if (!strcmp(arg, "--show-superproject-working-tree")) {
> + const char *superproject = get_superproject_working_tree();
> + if (superproject)
> + puts(superproject);
> + continue;
> + }
> if (!strcmp(arg, "--show-prefix")) {
> if (prefix)
> puts(prefix);
> diff --git a/submodule.c b/submodule.c
> index 3b98766a6b..06473d3646 100644
> --- a/submodule.c
> +++ b/submodule.c
> @@ -1514,3 +1514,86 @@ void absorb_git_dir_into_superproject(const char *prefix,
> strbuf_release(&sb);
> }
> }
> +
> +const char *get_superproject_working_tree(void)
> +{
> + struct child_process cp = CHILD_PROCESS_INIT;
> + struct strbuf sb = STRBUF_INIT;
> + const char *one_up = real_path_if_valid("../");
> + const char *cwd = xgetcwd();
> + const char *ret = NULL;
> + const char *subpath;
> + int code;
> + ssize_t len;
> +
> + if (!is_inside_work_tree())
> + /*
> + * FIXME:
> + * We might have a superproject, but it is harder
> + * to determine.
> + */
> + return NULL;
> +
> + if (!one_up)
> + return NULL;
> +
> + subpath = relative_path(cwd, one_up, &sb);
> +
> + prepare_submodule_repo_env(&cp.env_array);
> + argv_array_pop(&cp.env_array);
> +
> + argv_array_pushl(&cp.args, "--literal-pathspecs", "-C", "..",
> + "ls-files", "--stage", "--full-name", "--", subpath, NULL);
> + strbuf_reset(&sb);
> +
> + cp.no_stdin = 1;
> + cp.no_stderr = 1;
> + cp.out = -1;
> + cp.git_cmd = 1;
> +
> + if (start_command(&cp))
> + die(_("could not start ls-files in .."));
> +
> + len = strbuf_read(&sb, cp.out, PATH_MAX);
> + close(cp.out);
> +
> + if (starts_with(sb.buf, "160000")) {
> + int super_sub_len;
> + int cwd_len = strlen(cwd);
> + char *super_sub, *super_wt;
> +
> + /*
> + * There is a superproject having this repo as a submodule.
> + * The format is <mode> SP <hash> SP <stage> TAB <full name> LF,
> + * First remove LF, then skip up to \t.
> + */
> + strbuf_rtrim(&sb);
> + super_sub = strchr(sb.buf, '\t') + 1;
> +
> + super_sub_len = sb.buf + sb.len - super_sub;
> + if (super_sub_len > cwd_len ||
> + strcmp(&cwd[cwd_len - super_sub_len], super_sub))
> + die (_("BUG: returned path string doesn't match cwd?"));
> +
> + super_wt = xstrdup(cwd);
> + super_wt[cwd_len - super_sub_len] = '\0';
> +
> + ret = real_path(super_wt);
> +
> + free(super_wt);
> + }
> + strbuf_release(&sb);
> +
> + code = finish_command(&cp);
> +
> + if (code == 128)
> + /* '../' is not a git repository */
> + return NULL;
> + if (code == 0 && len == 0)
> + /* There is an unrelated git repository at '../' */
> + return NULL;
> + if (code)
> + die(_("ls-tree returned unexpected return code %d"), code);
> +
> + return ret;
> +}
> diff --git a/submodule.h b/submodule.h
> index 05ab674f06..c8a0c9cb29 100644
> --- a/submodule.h
> +++ b/submodule.h
> @@ -93,4 +93,12 @@ extern void prepare_submodule_repo_env(struct argv_array *out);
> extern void absorb_git_dir_into_superproject(const char *prefix,
> const char *path,
> unsigned flags);
> +
> +/*
> + * Return the absolute path of the working tree of the superproject, which this
> + * project is a submodule of. If this repository is not a submodule of
> + * another repository, return NULL.
> + */
> +extern const char *get_superproject_working_tree(void);
> +
> #endif
> diff --git a/t/t1500-rev-parse.sh b/t/t1500-rev-parse.sh
> index 9ed8b8ccba..03d3c7f6d6 100755
> --- a/t/t1500-rev-parse.sh
> +++ b/t/t1500-rev-parse.sh
> @@ -116,4 +116,18 @@ test_expect_success 'git-path inside sub-dir' '
> test_cmp expect actual
> '
>
> +test_expect_success 'showing the superproject correctly' '
> + git rev-parse --show-superproject-working-tree >out &&
> + test_must_be_empty out &&
> +
> + test_create_repo super &&
> + test_commit -C super test_commit &&
> + test_create_repo sub &&
> + test_commit -C sub test_commit &&
> + git -C super submodule add ../sub dir/sub &&
> + echo $(pwd)/super >expect &&
> + git -C super/dir/sub rev-parse --show-superproject-working-tree >out &&
> + test_cmp expect out
> +'
> +
> test_done
> --
> 2.12.0.190.g6a12a61b77.dirty
>