Re: [PATCH 4/4] submodule: port submodule subcommand 'foreach' from shell to C

[Junio C Hamano]

Stefan Beller  writes:

> +static void runcommand_in_submodule_cb(const struct cache_entry *list_item,
> +void *cb_data)
> +{
> + struct cb_foreach *info = cb_data;
> + const char *path = list_item->name;
> + const struct object_id *ce_oid = _item->oid;
> +
> + const struct submodule *sub;
> + struct child_process cp = CHILD_PROCESS_INIT;
> + char *displaypath;
> +
> + displaypath = get_submodule_displaypath(path, info->prefix);
> +
> + sub = submodule_from_path(the_repository, _oid, path);
> +
> + if (!sub)
> + die(_("No url found for submodule path '%s' in .gitmodules"),
> + displaypath);
> +
> + if (!is_submodule_populated_gently(path, NULL))
> + goto cleanup;
> +
> + prepare_submodule_repo_env(_array);
> +
> + /*
> + * For the purpose of executing  in the submodule,
> + * separate shell is used for the purpose of running the
> + * child process.
> + */

Micronit: this multi-line comment is indented in a funny way.

> + cp.use_shell = 1;
> + cp.dir = path;
> +
> + /*
> + * NEEDSWORK: the command currently has access to the variables $name,
> + * $sm_path, $displaypath, $sha1 and $toplevel only when the command
> + * contains a single argument. This is done for maintaining a faithful
> + * translation from shell script.
> + */

Same micronit.

The scripted version does 'eval "$1"', so $1 could be something like 

for-each 'echo "$name:$sm_path:$displaypath:$sha1:$toplevel"'

and it can see any variable, not just these 5 (i.e. we could have
fed e.g. $wt_prefix and $mode to the above 'echo' and with the
scripted version the script would have learned their values; with
this version it no longer does, but only these 5 are part of the
documented API, so we choose not to consider it a regression).

> + if (info->argc == 1) {
> + char *toplevel = xgetcwd();
> + struct strbuf sb = STRBUF_INIT;
> +
> + argv_array_pushf(_array, "name=%s", sub->name);
> + argv_array_pushf(_array, "sm_path=%s", path);
> + argv_array_pushf(_array, "displaypath=%s", displaypath);
> + argv_array_pushf(_array, "sha1=%s",
> + oid_to_hex(ce_oid));
> + argv_array_pushf(_array, "toplevel=%s", toplevel);
> +
> + /*
> + * Since the path variable was accessible from the script
> + * before porting, it is also made available after porting.
> + * The environment variable "PATH" has a very special purpose
> + * on windows. And since environment variables are
> + * case-insensitive in windows, it interferes with the
> + * existing PATH variable. Hence, to avoid that, we expose
> + * path via the args argv_array and not via env_array.
> + */
> + sq_quote_buf(, path);
> + argv_array_pushf(, "path=%s; %s",
> +  sb.buf, info->argv[0]);

OK, so we do the equivalent of

name=... sm_path=... displaypath=... sha1=... toplevel=... \
sh -c 'path=...; echo "$name:$sm_path:..."'

when doing

for-each 'echo "$name:$sm_path:..."'

with parts denoted with ... correctly quoted as necessary.  I guess
it would be the best we could do.

I myself do not know if it is true that bash ported to Windows won't
get confused with the above "we use path (all lowercase) only as a
pure shell variable without exporting it ourselves"; I'd trust those
who are more familiar with the platform to raise objections and
suggest a better alternative if it is not the case.  

Thanks for the (malformatted;-) leading comment to highlight why the
'path' variable alone is treated differently from the others.

> + strbuf_release();
> + free(toplevel);
> + } else {
> + argv_array_pushv(, info->argv);
> + }
> +
> + if (!info->quiet)
> + printf(_("Entering '%s'\n"), displaypath);
> +
> + if (info->argv[0] && run_command())
> + die(_("run_command returned non-zero status for %s\n."),
> + displaypath);
> +
> + if (info->recursive) {
> + struct child_process cpr = CHILD_PROCESS_INIT;
> +
> + cpr.git_cmd = 1;
> + cpr.dir = path;
> + prepare_submodule_repo_env(_array);
> +
> + argv_array_pushl(, "--super-prefix", NULL);
> + argv_array_pushf(, "%s/", displaypath);
> + argv_array_pushl(, "submodule--helper", "foreach", 
> "--recursive",
> + NULL);
> +
> + if (info->quiet)
> + argv_array_push(, "--quiet");
> +
> + argv_array_pushv(, info->argv);
> +
> + if (run_command())
> + die(_("run_command returned non-zero status while"

[PATCH 4/4] submodule: port submodule subcommand 'foreach' from shell to C

[Stefan Beller]

From: Prathamesh Chavan 

This aims to make git-submodule foreach a builtin. 'foreach' is ported to
the submodule--helper, and submodule--helper is called from
git-submodule.sh.

Helped-by: Brandon Williams 
Mentored-by: Christian Couder 
Mentored-by: Stefan Beller 
Signed-off-by: Prathamesh Chavan 
Signed-off-by: Stefan Beller 
---
 builtin/submodule--helper.c | 144 
 git-submodule.sh|  39 +-
 2 files changed, 145 insertions(+), 38 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index c2403a915ff..4b0b773c06b 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -439,6 +439,149 @@ static void for_each_listed_submodule(const struct 
module_list *list,
fn(list->entries[i], cb_data);
 }
 
+struct cb_foreach {
+   int argc;
+   const char **argv;
+   const char *prefix;
+   int quiet;
+   int recursive;
+};
+#define CB_FOREACH_INIT { 0 }
+
+static void runcommand_in_submodule_cb(const struct cache_entry *list_item,
+  void *cb_data)
+{
+   struct cb_foreach *info = cb_data;
+   const char *path = list_item->name;
+   const struct object_id *ce_oid = _item->oid;
+
+   const struct submodule *sub;
+   struct child_process cp = CHILD_PROCESS_INIT;
+   char *displaypath;
+
+   displaypath = get_submodule_displaypath(path, info->prefix);
+
+   sub = submodule_from_path(the_repository, _oid, path);
+
+   if (!sub)
+   die(_("No url found for submodule path '%s' in .gitmodules"),
+   displaypath);
+
+   if (!is_submodule_populated_gently(path, NULL))
+   goto cleanup;
+
+   prepare_submodule_repo_env(_array);
+
+   /*
+   * For the purpose of executing  in the submodule,
+   * separate shell is used for the purpose of running the
+   * child process.
+   */
+   cp.use_shell = 1;
+   cp.dir = path;
+
+   /*
+   * NEEDSWORK: the command currently has access to the variables $name,
+   * $sm_path, $displaypath, $sha1 and $toplevel only when the command
+   * contains a single argument. This is done for maintaining a faithful
+   * translation from shell script.
+   */
+   if (info->argc == 1) {
+   char *toplevel = xgetcwd();
+   struct strbuf sb = STRBUF_INIT;
+
+   argv_array_pushf(_array, "name=%s", sub->name);
+   argv_array_pushf(_array, "sm_path=%s", path);
+   argv_array_pushf(_array, "displaypath=%s", displaypath);
+   argv_array_pushf(_array, "sha1=%s",
+   oid_to_hex(ce_oid));
+   argv_array_pushf(_array, "toplevel=%s", toplevel);
+
+   /*
+   * Since the path variable was accessible from the script
+   * before porting, it is also made available after porting.
+   * The environment variable "PATH" has a very special purpose
+   * on windows. And since environment variables are
+   * case-insensitive in windows, it interferes with the
+   * existing PATH variable. Hence, to avoid that, we expose
+   * path via the args argv_array and not via env_array.
+   */
+   sq_quote_buf(, path);
+   argv_array_pushf(, "path=%s; %s",
+sb.buf, info->argv[0]);
+   strbuf_release();
+   free(toplevel);
+   } else {
+   argv_array_pushv(, info->argv);
+   }
+
+   if (!info->quiet)
+   printf(_("Entering '%s'\n"), displaypath);
+
+   if (info->argv[0] && run_command())
+   die(_("run_command returned non-zero status for %s\n."),
+   displaypath);
+
+   if (info->recursive) {
+   struct child_process cpr = CHILD_PROCESS_INIT;
+
+   cpr.git_cmd = 1;
+   cpr.dir = path;
+   prepare_submodule_repo_env(_array);
+
+   argv_array_pushl(, "--super-prefix", NULL);
+   argv_array_pushf(, "%s/", displaypath);
+   argv_array_pushl(, "submodule--helper", "foreach", 
"--recursive",
+   NULL);
+
+   if (info->quiet)
+   argv_array_push(, "--quiet");
+
+   argv_array_pushv(, info->argv);
+
+   if (run_command())
+   die(_("run_command returned non-zero status while"
+   "recursing in the nested submodules of %s\n."),
+   displaypath);
+   }
+
+cleanup:
+   free(displaypath);
+}
+
+static int module_foreach(int argc, const char **argv, const char *prefix)
+{
+   struct