[RFC][PATCH] Cogito support for simple subprojects

@@ -90,23 +90,13 @@ cg-*patch should be pre-1.0.)
 
 * cg-Xfetchprogress showing smooth progress for packfiles
 
+* Enhance subprojects notion
+	So far the subprojects support is trivial and prone to user error.
+	E.g. cg-add should check if it doesn't poke into a subproject,
+	cg-status should list subprojects, etc.
 
-Post 1.0:
-
-* Subprojects
-	Support a GIT project inside a GIT project:
 
-		x/.git
-		x/foo/bar/.git
-		x/foo/bar/baz/.git
-		x/quux/zot/.git
-
-	That means cg-update working recursively and cg-add'n'stuff
-	checking if there isn't another .git along the path of its
-	argument.
-
-	Needs more thought, especially wrt. fetching and merging
-	recursive semantics.
+Post 1.0:
 
 * Comfortable cg-log
 	Probably make it a real terminal application, not just less

@@ -197,6 +197,10 @@ list_untracked_files()
 		if [ -f "$EXCLUDEFILE" ]; then
 			EXCLUDE[${#EXCLUDE[@]}]="--exclude-from=$EXCLUDEFILE"
 		fi
+		EXCLUDEFILE="$_git/subprojects"
+		if [ -f "$EXCLUDEFILE" ]; then
+			EXCLUDE[${#EXCLUDE[@]}]="--exclude-from=$EXCLUDEFILE"
+		fi
 		# This is just for compatibility (2005-09-16).
 		# To be removed later.
 		EXCLUDEFILE="$_git/exclude"

@@ -209,6 +213,29 @@ list_untracked_files()
 	git-ls-files -z --others "${EXCLUDE[@]}"
 }
 
+# Usage: subprojects_recurse ACTIONNAME COMMAND...
+# Run command recursively on subprojects, displaying warning using the
+# ACTIONNAME string in case any of them failed.
+subprojects_recurse()
+{
+	[ -s "$_git/subprojects" ] || return 0
+	local failures=0 subprj= actionname="$1" s=
+	local Actionname="$(echo "$actionname" | perl -pe '$_=ucfirst')"
+	shift
+	while IFS= read -r subprj; do
+		echo "Running $actionname in $subprj..." >&2
+		if ( cd "$subprj" && "$@" ); then
+			echo "$Actionname in $subprj succeeded." >&2
+		else
+			echo "$Actionname in $subprj failed!" >&2
+			failures=$(($failures+1))
+		fi
+	done <"$_git/subprojects"
+	local s=; if [ $failures -gt 1 ]; then s=s; fi
+	[ $failures -gt 0 ] && echo "Warning: $failures subproject $actionname$s failed" >&2
+	return $failures
+}
+
 # Usage: showdate SECONDS TIMEZONE [FORMAT]
 # Display date nicely based on how GIT stores it.
 # Save the date to $_showdate

@@ -11,6 +11,15 @@
 # parameter is omitted, the basename of the source repository is used as the
 # destination.
 #
+# If you are cloning inside another working tree, you are automatically
+# establishing a subproject - that means that when you will update the
+# parent project, this project will be auto-updated as well, and in the
+# future, certain other operations may also recurse to subprojects. Use the
+# -P option to prevent this from becoming a subproject. Also please note
+# that the subprojects support is preliminary and subject to change. If you
+# remove the subproject later, you must also remove the corresponding entry
+# in '.git/subprojects' for now.
+#
 # OPTIONS
 # -------
 # -l::	Symlink the object database when cloning locally

@@ -24,20 +33,28 @@
 #	Note that you MUST NOT prune repository containing a symlink
 #	or being symlinked to.
 #
+# -P::	Prevent this from becoming a subproject
+#	If this option is passed, cg-clone will never create a subproject
+#	even if called inside working tree of another project.
+#
 # -s::	Clone into the current directory
 #	Clone in the current directory instead of creating a new one.
 #	Specifying both -s and a destination directory makes no sense.
+#	This also implies -P.
 
-USAGE="cg-clone [-l] [-s] LOCATION [DESTDIR]"
+USAGE="cg-clone [-l] [-P] [-s] LOCATION [DESTDIR]"
 _git_repo_unneeded=1
 
 . ${COGITO_LIB}cg-Xlib || exit 1
 
 same_dir=
 symlink=
+may_subproject=1
 while optparse; do
 	if optparse -l; then
 		symlink=1
+	elif optparse -P; then
+		may_subproject=
 	elif optparse -s; then
 		same_dir=1
 	else

@@ -65,7 +82,13 @@ else
 	location="$location"
 fi
 
+parentprj=
+parentpath=
 if [ ! "$same_dir" ]; then
+	if [ "$may_subproject" ]; then
+		parentprj="$(git-rev-parse --git-dir 2>/dev/null)"
+		parentpath="$(git-rev-parse --show-prefix 2>/dev/null)$dir"
+	fi
 	[ -e "$dir" ] && die "$dir/ already exists"
 	mkdir "$dir" || exit $?
 	cd "$dir" || exit $?

@@ -94,4 +117,14 @@ cp "$_git/refs/heads/origin" "$_git/refs
 	git-update-index --refresh ||
 	exit 1
 
+if [ "$parentprj" ]; then
+	cd ..
+	parentroot="${parentprj%.git}"
+	if [ -z "$parentroot" ]; then
+		parentroot="$(pwd)"
+	fi
+	echo "Registering as a subproject of $parentroot..."
+	echo "$parentpath" >>"$parentprj"/subprojects
+fi
+
 echo "Cloned to $dir/ (origin $location available as branch \"origin\")"

@@ -28,6 +28,10 @@
 # -f:: Force the complete fetch even if the heads are the same.
 #	Force the complete fetch even if the heads are the same.
 #
+# -R:: Do not recurse to subprojects
+#	Do not recursively fetch the subprojects (see the `cg-clone`
+#	documentation for more information).
+#
 # -v:: Enable verbosity
 #	Display more verbose output - most notably list all the files
 #	touched by the fetched changes.

@@ -53,7 +57,7 @@
 #	won't unpack the transferred pack.
 
 
-USAGE="cg-fetch [-f] [-v] [BRANCH_NAME]"
+USAGE="cg-fetch [-f] [-R] [-v] [BRANCH_NAME]"
 
 . ${COGITO_LIB}cg-Xlib || exit 1
 deprecated_alias cg-fetch cg-pull

@@ -234,12 +238,15 @@ fetch_tags()
 
 
 recovery=
+recurse=1
 verbose=
 while optparse; do
 	if optparse -f; then
 		# When forcing, let the fetch tools make more extensive
 		# walk over the dependency tree with --recover.
 		recovery=--recover
+	elif optparse -R; then
+		recurse=
 	elif optparse -v; then
 		verbose=1
 	else

@@ -248,9 +255,10 @@ while optparse; do
 done
 
 name="${ARGS[0]}"
-
 [ "$name" ] || { [ -s "$_git/branches/origin" ] && name=origin; }
+[ "$recurse" ] && subprojects_recurse "fetch" cg-fetch $recovery $verbose "$name"
 [ "$name" ] || die "where to fetch from?"
+
 uri=$(cat "$_git/branches/$name" 2>/dev/null) || die "unknown branch: $name"
 
 rembranch=

@@ -25,23 +25,30 @@
 # -f:: Force the complete fetch even if the heads are the same.
 #	Force the complete fetch even if the heads are the same.
 #
+# -R:: Do not recurse to subprojects
+#	Do not recursively update the subprojects (see the `cg-clone`
+#	documentation for more information).
+#
 # --squash:: Use "squash" merge to record pending commits as a single merge commit
 #	"Squash" merge - condense all the to-be-merged commits to a single
 #	merge commit. This is not to be used lightly; see the cg-merge
 #	documenation for further details.
 
-USAGE="cg-update [-f] [--squash] [BRANCH_NAME]"
+USAGE="cg-update [-f] [-R] [--squash] [BRANCH_NAME]"
 _git_requires_root=1
 
 . ${COGITO_LIB}cg-Xlib || exit 1
 
 force=
 squash=
+recurse=1
 while optparse; do
 	if optparse -f; then
 		force=-f
 	elif optparse --squash; then
 		squash=--squash
+	elif optparse -R; then
+		recurse=
 	else
 		optfail
 	fi

@@ -49,13 +56,14 @@ done
 
 name="${ARGS[0]}"
 [ "$name" ] || { [ -s "$_git/branches/origin" ] && name=origin; }
+[ "$recurse" ] && subprojects_recurse "update" cg-update $force $squash "$name"
 [ "$name" ] || die "where to update from?"
 
 # cg-merge can do better decision about fast-forwarding if it sees this.
 [ -s "$_git/refs/heads/$name" ] && export _cg_orig_head="$(cat "$_git/refs/heads/$name")"
 
 if [ -s "$_git/branches/$name" ]; then
-	cg-fetch $force "$name" || exit 1
+	cg-fetch -R $force "$name" || exit 1
 else
 	echo "Updating from a local branch."
 fi

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) 2005 Petr Baudis
+#
+test_description="Tests recursive cg-update functionality
+
+Create a subproject and then try to cg-update."
+
+. ./test-lib.sh
+
+mkdir prj1
+echo file >prj1/file
+test_expect_success 'initialize project 1' \
+	"(cd prj1 && cg-init -I && cg-add file && cg-commit -C -m\"Initial commit\")"
+
+mkdir prj2
+echo file >prj2/FILE
+test_expect_success 'initialize project 2' \
+	"(cd prj2 && cg-init -I && cg-add FILE && cg-commit -C -m\"Initial commit\")"
+
+test_expect_success 'clone project 1' \
+	"cg-clone prj1 clone"
+test_expect_success 'clone project 2 as subproject of project 1' \
+	"(cd clone && cg-clone ../prj2)"
+
+test_expect_success 'commit to project 1' \
+	"(cd prj1 && echo foo >>file && cg-commit -m\"Commit in project 1\")"
+test_expect_success 'commit to project 2' \
+	"(cd prj2 && echo bar >>FILE && cg-commit -m\"Commit in project 2\")"
+
+test_expect_success 'non-recursive update' \
+	"(cd clone && cg-update -R)"
+test_expect_success 'check if the prj1 head was updated in clone' \
+	"(cmp prj1/.git/refs/heads/master clone/.git/refs/heads/master)"
+test_expect_success 'check if the prj1 working copy was updated in clone' \
+	"(cmp prj1/file clone/file)"
+test_expect_failure 'check if the prj2 head was not updated in clone' \
+	"(cmp prj2/.git/refs/heads/master clone/prj2/.git/refs/heads/origin)"
+
+test_expect_success 'commit to project 1' \
+	"(cd prj1 && echo baz >>file && cg-commit -m\"Commit in project 1\")"
+
+test_expect_success 'recursive update' \
+	"(cd clone && cg-update)"
+test_expect_success 'check if the prj1 head was updated in clone' \
+	"(cmp prj1/.git/refs/heads/master clone/.git/refs/heads/master)"
+test_expect_success 'check if the prj1 working copy was updated in clone' \
+	"(cmp prj1/file clone/file)"
+test_expect_success 'check if the prj2 head was updated in clone' \
+	"(cmp prj2/.git/refs/heads/master clone/prj2/.git/refs/heads/master)"
+test_expect_success 'check if the prj2 working copy was updated in clone' \
+	"(cmp prj2/FILE clone/prj2/FILE)"
+
+test_done