[PATCH] git-submodule - allow a relative path as the subproject url

[PATCH] git-submodule - allow a relative path as the subproject url

[Mark Levedahl]

This allows a subproject's location to be specified and stored as relative
to the parent project's location (e.g., ./foo, or ../foo). This url is
stored in .gitmodules as given. It is resolved into an absolute url be
appending it to the parent project's url when the information is written
to .git/config (i.e., during submodule add for the originator, and
submodule init for a downstream recipient). This allows cloning of the
project to work "as expected" if the project is hosted on a different
server than when the subprojects were added.

Signed-off-by: Mark Levedahl <mdl123@verizon.net>
---
 Documentation/git-submodule.txt |    3 +++
 git-submodule.sh                |   34 ++++++++++++++++++++++++++++++----
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index 2c48936..d421677 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -21,6 +21,9 @@ add::
 	repository is cloned at the specified path, added to the
 	changeset and registered in .gitmodules.   If no path is
 	specified, the path is deduced from the repository specification.
+        If the repository url begins with ./ or ../, it is stored as
+        given but resolved as a relative path from the main project's
+        url when cloning.
 
 status::
 	Show the status of the submodules. This will print the SHA-1 of the
diff --git a/git-submodule.sh b/git-submodule.sh
index 3320998..c553e14 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -39,6 +39,19 @@ get_repo_base() {
 	) 2>/dev/null
 }
 
+# Get parent project's url
+get_parent_url ()
+{
+	# need to append this on parent project's url
+	branch="$(git branch --no-color | sed -ne 's/^\* //p')"
+	test -n "$branch" || die "I do not know what branch you are on: $branch"
+	upstream="$(git config branch.$branch.remote)"
+	test -n "$upstream" || die "Cannot find upstream repo for branch $branch"
+	uprepo="$(git config remote.$upstream.url)"
+	test -n "$upstream" || die "Cannot find url for repo $uprepo"
+	echo "$uprepo"
+}
+
 #
 # Map submodule path to submodule name
 #
@@ -105,9 +118,16 @@ module_add()
 
 	# Turn the source into an absolute path if
 	# it is local
-	if base=$(get_repo_base "$repo"); then
-		repo="$base"
-	fi
+	case $repo in
+	.*)
+		realrepo="$(get_parent_url)/$repo" ;;
+	*)
+		if base=$(get_repo_base "$repo"); then
+			repo="$base"
+			realrepo=$repo
+		fi
+		;;
+	esac
 
 	# Guess path from repo if not specified or strip trailing slashes
 	if test -z "$path"; then
@@ -122,7 +142,7 @@ module_add()
 	git ls-files --error-unmatch "$path" > /dev/null 2>&1 &&
 	die "'$path' already exists in the index"
 
-	module_clone "$path" "$repo" || exit
+	module_clone "$path" "$realrepo" || exit
 	(unset GIT_DIR && cd "$path" && git checkout -q ${branch:+-b "$branch" "origin/$branch"}) ||
 	die "Unable to checkout submodule '$path'"
 	git add "$path" ||
@@ -153,6 +173,12 @@ modules_init()
 		test -z "$url" &&
 		die "No url found for submodule path '$path' in .gitmodules"
 
+		# Possibly a url relative to parent
+		case $url in
+		.*)
+			url="$(get_parent_url)/$url";;
+		esac
+
 		git config submodule."$name".url "$url" ||
 		die "Failed to register url for submodule path '$path'"
 
-- 
1.5.3.1.36.gf01e8

Re: [PATCH] git-submodule - allow a relative path as the subproject url

[Michael Smith]

Mark Levedahl <mdl123 <at> verizon.net> writes:

> This allows a subproject's location to be specified and stored as relative
> to the parent project's location (e.g., ./foo, or ../foo). This url is
> stored in .gitmodules as given. 

> This allows cloning of the project to work "as expected" if the project
> is hosted on a different server than when the subprojects were added.

Hi Mark,

I have a use case where this would be very handy -- two teams geographically
separated. But in the end I think I disagree with it: it's not up to me, as the
person creating a superproject, to decide that anyone who forks or clones it
also has to clone all the submodules.

Instead they can decide themselves by editing .git/config between "git submodule
init" and "git submodule update", or by branching .gitmodules.

By the way:

> +# Get parent project's url
> +get_parent_url ()
> +{
> +	# need to append this on parent project's url
> +	branch="$(git branch --no-color | sed -ne 's/^\* //p')"
> +	test -n "$branch" || die "I do not know what branch you are on: $branch"
> +	upstream="$(git config branch.$branch.remote)"
> +	test -n "$upstream" || die "Cannot find upstream repo for branch $branch"
> +	uprepo="$(git config remote.$upstream.url)"
> +	test -n "$upstream" || die "Cannot find url for repo $uprepo"
> +	echo "$uprepo"
> +}
...
> +	case $repo in
> +	.*)
> +		realrepo="$(get_parent_url)/$repo" ;;

If you source git-parse-remote, you can use

                realrepo="$(get_remote_url "$(get_default_remote)")$repo"

Mike

Re: [PATCH] git-submodule - allow a relative path as the subproject url

[Mark Levedahl]

Michael Smith wrote:
> Hi Mark,
>
> I have a use case where this would be very handy -- two teams geographically
> separated. But in the end I think I disagree with it: it's not up to me, as the
> person creating a superproject, to decide that anyone who forks or clones it
> also has to clone all the submodules.
>
>   
With or without the patch, the cloner has to execute "submodule init" 
and "submodule update" to actually check things out. Absolutely nothing 
has changed there: it still requires the same explicit actions to get 
the submodules.

This patch does not alter any existing behavior: it provides an 
additional option, and one that is very useful in a world of mirrors. My 
particular use case is for a geographically distributed work flow 
involving several mirrors, all of which are behind firewalls and/or 
connected only to a LAN. There is no single server that is available to 
everyone, hence no single url for a submodule is usable across the 
group. By offering the *option* (and it is only an option) to make the 
urls relative to the super-project, the super-project can be usefully 
shared.
> Instead they can decide themselves by editing .git/config between "git submodule
> init" and "git submodule update", or by branching .gitmodules.
>   
Yes, a person can edit .gitmodules, or can edit .git/config, in order to 
tell git where things are. But why should they *have* to when relative 
urls will suffice and git can take care of this transparently.
> If you source git-parse-remote, you can use
>
>                 realrepo="$(get_remote_url "$(get_default_remote)")$repo"
>
> Mike
>   
Yes, the patch itself can be improved, am sending a revised one.

Mark

[PATCH] git-submodule - allow a relative path as the subproject url

[Mark Levedahl]

This allows a subproject's location to be specified and stored as relative
to the parent project's location (e.g., ./foo, or ../foo). This url is
stored in .gitmodules as given. It is resolved into an absolute url by
appending it to the parent project's url when the information is written
to .git/config (i.e., during submodule add for the originator, and
submodule init for a downstream recipient). This allows cloning of the
project to work "as expected" if the project is hosted on a different
server than when the subprojects were added.

Signed-off-by: Mark Levedahl <mdl123@verizon.net>
---
This patch is slightly improved as it removes embedded ./ and ../ sequences
from the url constructed from a base and relative part. It also avoids use
of git-branch in favor of git-symbolic-ref.

 Documentation/git-submodule.txt |    3 ++
 git-submodule.sh                |   53 ++++++++++++++++++++++++++++++++++----
 2 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index 2c48936..d421677 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -21,6 +21,9 @@ add::
 	repository is cloned at the specified path, added to the
 	changeset and registered in .gitmodules.   If no path is
 	specified, the path is deduced from the repository specification.
+        If the repository url begins with ./ or ../, it is stored as
+        given but resolved as a relative path from the main project's
+        url when cloning.

 status::
 	Show the status of the submodules. This will print the SHA-1 of the
diff --git a/git-submodule.sh b/git-submodule.sh
index 3320998..5bf4551 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -39,6 +39,32 @@ get_repo_base() {
 	) 2>/dev/null
 }

+# Resolve relative url by appending to parent's url
+resolve_relative_url ()
+{
+	branch="$(git symbolic-ref HEAD 2>/dev/null)"
+	remote="$(git config branch.${branch#refs/heads/}.remote)"
+	remote="${remote:-origin}"
+	remoteurl="$(git config remote.$remote.url)" ||
+		die "remote ($remote) does not have a url in .git/config"
+	url="$1"
+	while test -n "$url"
+	do
+		case "$url" in
+		../*)
+			url="${url#../}"
+			remoteurl="${remoteurl%/*}"
+			;;
+		./*)
+			url="${url#./}"
+			;;
+		*)
+			break;;
+		esac
+	done
+	echo "$remoteurl/$url"
+}
+
 #
 # Map submodule path to submodule name
 #
@@ -103,11 +129,19 @@ module_add()
 		usage
 	fi

-	# Turn the source into an absolute path if
-	# it is local
-	if base=$(get_repo_base "$repo"); then
-		repo="$base"
-	fi
+	case $repo in
+	./*|../*)
+		# dereference source url relative to parent's url
+		realrepo="$(resolve_relative_url $repo)" ;;
+	*)
+		# Turn the source into an absolute path if
+		# it is local
+		if base=$(get_repo_base "$repo"); then
+			repo="$base"
+			realrepo=$repo
+		fi
+		;;
+	esac

 	# Guess path from repo if not specified or strip trailing slashes
 	if test -z "$path"; then
@@ -122,7 +156,7 @@ module_add()
 	git ls-files --error-unmatch "$path" > /dev/null 2>&1 &&
 	die "'$path' already exists in the index"

-	module_clone "$path" "$repo" || exit
+	module_clone "$path" "$realrepo" || exit
 	(unset GIT_DIR && cd "$path" && git checkout -q ${branch:+-b "$branch" "origin/$branch"}) ||
 	die "Unable to checkout submodule '$path'"
 	git add "$path" ||
@@ -153,6 +187,13 @@ modules_init()
 		test -z "$url" &&
 		die "No url found for submodule path '$path' in .gitmodules"

+		# Possibly a url relative to parent
+		case $url in
+		./*|../*)
+			url="$(resolve_relative_url $url)"
+			;;
+		esac
+
 		git config submodule."$name".url "$url" ||
 		die "Failed to register url for submodule path '$path'"

--
1.5.3.2.9.g69b29

Re: [PATCH] git-submodule - allow a relative path as the subproject url

[Junio C Hamano]

Mark Levedahl <mdl123@verizon.net> writes:

> This allows a subproject's location to be specified and stored as relative
> to the parent project's location (e.g., ./foo, or ../foo). This url is
> stored in .gitmodules as given. It is resolved into an absolute url by
> appending it to the parent project's url when the information is written
> to .git/config (i.e., during submodule add for the originator, and
> submodule init for a downstream recipient). This allows cloning of the
> project to work "as expected" if the project is hosted on a different
> server than when the subprojects were added.
>
> Signed-off-by: Mark Levedahl <mdl123@verizon.net>

I like the idea here.  If you maintain and serve a set related
projects you need to give the users a single URL (per where the
user is and how to reach the server).

> diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
> index 2c48936..d421677 100644
> --- a/Documentation/git-submodule.txt
> +++ b/Documentation/git-submodule.txt
> @@ -21,6 +21,9 @@ add::
>  	repository is cloned at the specified path, added to the
>  	changeset and registered in .gitmodules.   If no path is
>  	specified, the path is deduced from the repository specification.
> +        If the repository url begins with ./ or ../, it is stored as
> +        given but resolved as a relative path from the main project's
> +        url when cloning.

Tabs vs spaces?  Will fix up while applying.

Thanks.