From 2140880ff7d57563d057d744985027575260c0b8 Mon Sep 17 00:00:00 2001
From: Petr Baudis <pasky@suse.cz>
Date: Wed, 10 Sep 2008 00:29:24 +0200
Subject: [PATCH] tg create -r BRANCH: Create branch based on a remote one

---
 README       | 11 +++++++++++
 tg-create.sh | 19 ++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/README b/README
index fd88504..6d8253a 100644
--- a/README
+++ b/README
@@ -233,6 +233,10 @@ tg create
 	it will detect that you are on a topic branch base ref and
 	resume the topic branch creation operation.
 
+	In an alternative use case, if '-r BRANCH' is given instead
+	of dependency list, the topic branch is created based on
+	the given remote branch.
+
 tg delete
 ~~~~~~~~~
 	Remove a TopGit-controlled topic branch of given name
@@ -382,6 +386,13 @@ tg update
 	In case your dependencies are not up-to-date, tg update
 	will first recurse into them and update these.
 
+	If a remote branch update brings dependencies on branches
+	not yet instantiated locally, you can either bring in all
+	the new branches from the remote using 'tg remote --populate'
+	or only pick out the missing ones using 'tg create -r'
+	('tg summary' will point out branches with incomplete
+	dependencies by showing an '!' near to them).
+
 	TODO: tg update -a for updating all topic branches
 
 TODO: Some infrastructure for sharing topic branches between
diff --git a/tg-create.sh b/tg-create.sh
index fee7dff..6ee3f02 100644
--- a/tg-create.sh
+++ b/tg-create.sh
@@ -7,6 +7,7 @@ deps= # List of dependent branches
 restarted= # Set to 1 if we are picking up in the middle of base setup
 merge= # List of branches to be merged; subset of $deps
 name=
+rname= # Remote branch to base this one on
 
 
 ## Parse options
@@ -14,8 +15,10 @@ name=
 while [ -n "$1" ]; do
 	arg="$1"; shift
 	case "$arg" in
+	-r)
+		rname="$1"; shift;;
 	-*)
-		echo "Usage: tg [...] create NAME [DEPS...]" >&2
+		echo "Usage: tg [...] create NAME [DEPS...|-r RNAME]" >&2
 		exit 1;;
 	*)
 		if [ -z "$name" ]; then
@@ -27,6 +30,20 @@ while [ -n "$1" ]; do
 done
 
 
+## Fast-track creating branches based on remote ones
+
+if [ -n "$rname" ]; then
+	[ -n "$name" ] || die "no branch name given"
+	! ref_exists "$name" || die "branch '$name' already exists"
+	has_remote "$rname" || die "no branch $rname in remote $base_remote"
+
+	git update-ref "refs/top-bases/$name" "refs/remotes/$base_remote/top-bases/$rname"
+	git update-ref "refs/heads/$name" "refs/remotes/$base_remote/$rname"
+	info "Topic branch $name based on $base_remote : $rname set up."
+	exit 0
+fi
+
+
 ## Auto-guess dependencies
 
 deps="${deps# }"
-- 
2.30.2