GSoC 2026 Week 3: Merging and Moving Forward
Look how fast time flies.
We are currently looking at
git repo info path.*'s foundation,
ready to be merged.
In this blog I wanna post the patches of the
final version that gets merged.
Since we discussed the technical details before,
I won't go into the nitty gritty again.
The Final Patches
Here are the patches:
View Patch 1/4: path: introduce append_formatted_path()
Subject: [GSoC Patch v4 1/4] path: introduce append_formatted_path() for
shared path formatting
The path-formatting logic in builtin/rev-parse.c is tightly coupled
to that command and writes directly to stdout, making it impossible
for other builtins to reuse.
Extract the core algorithm into append_formatted_path() in path.c
and expose a path_format enum in path.h so that any builtin can
format paths consistently without duplicating logic.
diff --git a/path.c b/path.c
index d7e17bf174..5e83e3e4f6 100644
--- a/path.c
+++ b/path.c
@@ -1579,6 +1579,76 @@ char *xdg_cache_home(const char *filename)
return NULL;
}
+void append_formatted_path(struct strbuf *dest, const char *path,
+ const char *prefix, enum path_format format)
+{
+ switch (format) {
+ case PATH_FORMAT_DEFAULT:
+ case PATH_FORMAT_UNMODIFIED:
+ strbuf_addstr(dest, path);
+ break;
+
+ case PATH_FORMAT_RELATIVE: {
+ struct strbuf relative_buf = STRBUF_INIT;
+ struct strbuf real_path = STRBUF_INIT;
+ struct strbuf real_prefix = STRBUF_INIT;
+ char *cwd = NULL;
+
+ if (!prefix)
+ prefix = cwd = xgetcwd();
+
+ if (!is_absolute_path(path)) {
+ strbuf_realpath_forgiving(&real_path, path, 1);
+ path = real_path.buf;
+ }
+ if (!is_absolute_path(prefix)) {
+ strbuf_realpath_forgiving(&real_prefix, prefix, 1);
+ prefix = real_prefix.buf;
+ }
+
+ strbuf_addstr(dest, relative_path(path, prefix, &relative_buf));
+
+ strbuf_release(&relative_buf);
+ strbuf_release(&real_path);
+ strbuf_release(&real_prefix);
+ free(cwd);
+ break;
+ }
+
+ case PATH_FORMAT_RELATIVE_IF_SHARED: {
+ struct strbuf relative_buf = STRBUF_INIT;
+
+ strbuf_addstr(dest, relative_path(path, prefix, &relative_buf));
+ strbuf_release(&relative_buf);
+ break;
+ }
+
+ case PATH_FORMAT_CANONICAL: {
+ struct strbuf canonical_buf = STRBUF_INIT;
+
+ strbuf_realpath_forgiving(&canonical_buf, path, 1);
+ strbuf_addbuf(dest, &canonical_buf);
+
+ strbuf_release(&canonical_buf);
+ break;
+ }
+
+ default:
+ BUG("unknown path_format value %d", format);
+ }
+}
+
REPO_GIT_PATH_FUNC(squash_msg, "SQUASH_MSG")
diff --git a/path.h b/path.h
index 0434ba5e07..6aca53b100 100644
--- a/path.h
+++ b/path.h
@@ -262,6 +262,42 @@ enum scld_error safe_create_leading_directories_no_share(char *path);
int safe_create_file_with_leading_directories(struct repository *repo,
const char *path);
+enum path_format {
+ PATH_FORMAT_DEFAULT,
+ PATH_FORMAT_UNMODIFIED,
+ PATH_FORMAT_RELATIVE,
+ PATH_FORMAT_RELATIVE_IF_SHARED,
+ PATH_FORMAT_CANONICAL
+};
+
+void append_formatted_path(struct strbuf *dest, const char *path,
+ const char *prefix, enum path_format format);
+
# ifdef USE_THE_REPOSITORY_VARIABLE
View Patch 2/4: rev-parse: use append_formatted_path()
Subject: [GSoC Patch v4 2/4] rev-parse: use append_formatted_path() for path
formatting
Replace the local format_type and default_type enums and the
hand-rolled formatting logic with a call to append_formatted_path().
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 218b5f34d6..2dd35361f3 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -632,73 +632,16 @@ static void handle_ref_opt(const char *pattern, const char *prefix)
clear_ref_exclusions(&ref_excludes);
}
-enum format_type {
- FORMAT_RELATIVE,
- FORMAT_CANONICAL,
- FORMAT_DEFAULT,
-};
-
-enum default_type {
- DEFAULT_RELATIVE,
- DEFAULT_RELATIVE_IF_SHARED,
- DEFAULT_CANONICAL,
- DEFAULT_UNMODIFIED,
-};
-
-static void print_path(const char *path, const char *prefix, enum format_type format, enum default_type def)
+static void print_path(const char *path, const char *prefix,
+ enum path_format arg_path_format, enum path_format def_format)
{
- char *cwd = NULL;
- if (!prefix && (format != FORMAT_DEFAULT || def != DEFAULT_RELATIVE_IF_SHARED))
- prefix = cwd = xgetcwd();
- if (format == FORMAT_DEFAULT && def == DEFAULT_UNMODIFIED) {
- puts(path);
- } else if (format == FORMAT_RELATIVE ||
- (format == FORMAT_DEFAULT && def == DEFAULT_RELATIVE)) {
- struct strbuf buf = STRBUF_INIT, realbuf = STRBUF_INIT, prefixbuf = STRBUF_INIT;
- if (!is_absolute_path(path)) {
- strbuf_realpath_forgiving(&realbuf, path, 1);
- path = realbuf.buf;
- }
- if (!is_absolute_path(prefix)) {
- strbuf_realpath_forgiving(&prefixbuf, prefix, 1);
- prefix = prefixbuf.buf;
- }
- puts(relative_path(path, prefix, &buf));
- strbuf_release(&buf);
- strbuf_release(&realbuf);
- strbuf_release(&prefixbuf);
- } else if (format == FORMAT_DEFAULT && def == DEFAULT_RELATIVE_IF_SHARED) {
- struct strbuf buf = STRBUF_INIT;
- puts(relative_path(path, prefix, &buf));
- strbuf_release(&buf);
- } else {
- struct strbuf buf = STRBUF_INIT;
- strbuf_realpath_forgiving(&buf, path, 1);
- puts(buf.buf);
- strbuf_release(&buf);
- }
- free(cwd);
+ struct strbuf sb = STRBUF_INIT;
+ enum path_format fmt = (arg_path_format != PATH_FORMAT_DEFAULT) ? arg_path_format : def_format;
+
+ append_formatted_path(&sb, path, prefix, fmt);
+ puts(sb.buf);
+
+ strbuf_release(&sb);
}
@@ -717,7 +660,7 @@ int cmd_rev_parse(int argc,
const char *name = NULL;
struct strbuf buf = STRBUF_INIT;
int seen_end_of_options = 0;
- enum format_type format = FORMAT_DEFAULT;
+ enum path_format arg_path_format = PATH_FORMAT_DEFAULT;
View Patch 3/4: repo: add path.commondir keys
Subject: [GSoC Patch v4 3/4] repo: add path.commondir with absolute and
relative suffix formatting
Introduce path.commondir.absolute and path.commondir.relative keys.
diff --git a/Documentation/git-repo.adoc b/Documentation/git-repo.adoc
index 42262c1983..890c34051d 100644
--- a/Documentation/git-repo.adoc
+++ b/Documentation/git-repo.adoc
@@ -104,6 +104,15 @@ values that they return:
`object.format`::
The object format (hash algorithm) used in the repository.
+`path.commondir.absolute`::
+ The canonical absolute path to the Git repository's common
+ directory (the shared `.git` directory containing objects,
+ refs, and global configuration).
+
+`path.commondir.relative`::
+ The path to the Git repository's common directory relative to
+ the current working directory.
+
`references.format`::
diff --git a/builtin/repo.c b/builtin/repo.c
index 71a5c1c29c..c4cc3bf3fc 100644
--- a/builtin/repo.c
+++ b/builtin/repo.c
@@ -75,6 +77,28 @@ static int get_object_format(struct repository *repo, struct strbuf *buf)
return 0;
}
+static int get_path_commondir_absolute(struct repository *repo, struct strbuf *buf)
+{
+ const char *common_dir = repo_get_common_dir(repo);
+
+ if (!common_dir)
+ return error(_("unable to get common directory"));
+
+ append_formatted_path(buf, common_dir, startup_info->prefix, PATH_FORMAT_CANONICAL);
+ return 0;
+}
+
+static int get_path_commondir_relative(struct repository *repo, struct strbuf *buf)
+{
+ const char *common_dir = repo_get_common_dir(repo);
+
+ if (!common_dir)
+ return error(_("unable to get common directory"));
+
+ append_formatted_path(buf, common_dir, startup_info->prefix, PATH_FORMAT_RELATIVE);
+ return 0;
+}
+
static const struct repo_info_field repo_info_field[] = {
{ "layout.bare", get_layout_bare },
{ "layout.shallow", get_layout_shallow },
{ "object.format", get_object_format },
+ { "path.commondir.absolute", get_path_commondir_absolute },
+ { "path.commondir.relative", get_path_commondir_relative },
{ "references.format", get_references_format },
};
View Patch 4/4: repo: add path.gitdir keys
Subject: [GSoC Patch v4 4/4] repo: add path.gitdir with absolute and relative
suffix formatting
Introduce path.gitdir.absolute and path.gitdir.relative keys,
consistent with the path.commondir keys added in the previous patch.
diff --git a/Documentation/git-repo.adoc b/Documentation/git-repo.adoc
index 890c34051d..ed7d80c690 100644
--- a/Documentation/git-repo.adoc
+++ b/Documentation/git-repo.adoc
@@ -113,6 +113,12 @@ values that they return:
The path to the Git repository's common directory relative to
the current working directory.
+`path.gitdir.absolute`::
+ The canonical absolute path to the Git repository directory (the `.git` directory).
+
+`path.gitdir.relative`::
+ The path to the Git repository directory relative to the current working directory.
+
`references.format`::
diff --git a/builtin/repo.c b/builtin/repo.c
index c4cc3bf3fc..9a312d127a 100644
--- a/builtin/repo.c
+++ b/builtin/repo.c
@@ -99,6 +99,28 @@ static int get_path_commondir_relative(struct repository *repo, struct strbuf *b
return 0;
}
+static int get_path_gitdir_absolute(struct repository *repo, struct strbuf *buf)
+{
+ const char *git_dir = repo_get_git_dir(repo);
+
+ if (!git_dir)
+ return error(_("unable to get git directory"));
+
+ append_formatted_path(buf, git_dir, startup_info->prefix, PATH_FORMAT_CANONICAL);
+ return 0;
+}
+
+static int get_path_gitdir_relative(struct repository *repo, struct strbuf *buf)
+{
+ const char *git_dir = repo_get_git_dir(repo);
+
+ if (!git_dir)
+ return error(_("unable to get git directory"));
+
+ append_formatted_path(buf, git_dir, startup_info->prefix, PATH_FORMAT_RELATIVE);
+ return 0;
+}
+
static const struct repo_info_field repo_info_field[] = {
{ "object.format", get_object_format },
{ "path.commondir.absolute", get_path_commondir_absolute },
{ "path.commondir.relative", get_path_commondir_relative },
+ { "path.gitdir.absolute", get_path_gitdir_absolute },
+ { "path.gitdir.relative", get_path_gitdir_relative },
{ "references.format", get_references_format },
};
What I Learned This Week
Something else I learned this week is range diffs. learnt about range diffs.Range diffs are underrated.
They practically give you a "diff" between your
v1 and v2 patch series.
I also learned how to use range-diffs directly
in the format-patch command.
Wanna see how the range diff turned out from v3 to v4 of my patches?
View Range-diff: v3 → v4
1: d276ac145e = 1: a396b4f8e6 path: introduce append_formatted_path() for shared path formatting
2: 5dba41bcb3 = 2: 16198f96d1 rev-parse: use append_formatted_path() for path formatting
3: b21c97f5d9 ! 3: b45c6f0d12 repo: add path.commondir with absolute and relative suffix formatting
@@ t/t1900-repo-info.sh
+ test_expect_success "absolute: $label" '
+ (
+ cd "$absolute_root/sub" &&
-+ ROOT="$(test-tool path-utils real_path "..")" && export ROOT &&
++ ROOT="$(test-tool path-utils real_path ..)" && export ROOT &&
+ eval "$init_command" &&
+ expect_path="$ROOT${expect_absolute_suffix:+/$expect_absolute_suffix}" &&
+ echo "path.$field_name.absolute=$expect_path" >expect &&
+ git repo info "path.$field_name.absolute" >actual &&
+ test_cmp expect actual
+ )
+ '
+
+ test_expect_success "relative: $label" '
+ (
+ cd "$relative_root/sub" &&
-+ ROOT="$(test-tool path-utils real_path "..")" && export ROOT &&
++ ROOT="$(test-tool path-utils real_path ..)" && export ROOT &&
+ eval "$init_command" &&
+ echo "path.$field_name.relative=$expect_relative" >expect &&
+ git repo info "path.$field_name.relative" >actual &&
+ test_cmp expect actual
+ )
+ '
4: fd7a899788 = 4: b5234ffe3e repo: add path.gitdir with absolute and relative suffix formatting
Patches 1, 2, and 4 were identical between v3
and v4, a clean =.
Only Patch 3 changed, and the only difference
was removing the quotes around ..
in the test helper.
That's the beauty of range diffs, a whole patch series summarised into a single glance.
Looking Back
When I look back at my older patches and my current ones, I can see how much I've grown.
Back when I was new to Git, somewhere around
February 2025, I had to send a v3 or v4.
I used git rebase -i and changed a
commit, but then instead of running
git rebase --continue, I ran
format-patch on the rebase itself.
Without verifying the patches, I sent them to
the mailing list.
To this day I cringe looking at those patches.
But I think everyone has their mishaps when
they're new to a community.
Nobody's perfect when you think about it.
Phase 2: What's Next
I also wanted to share my Phase 2 plan.
I'm going to implement more
path.* keys and also a querying
system.
The querying system groups keys in one call.
If you say:
git repo info pathAll the path.* keys get printed.
Sounds good right?
Currently git repo info only does
--all keys, or individual keys
where you have to literally type out every
path.* key one by one if you just
want those.
Instead of that, I am building a querying
system which searches for the first item
matching path.<something> and
goes on till the end.
While doing that, I am also planning to add
more path.* keys in parallel.
I expect this to go much faster than the
current foundation, because these are just
keys.
The foundation takes time, but the keys
themselves are just function calls that we
have to write.
That's my Week 3!