From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Date: Tue, 3 Mar 2009 09:30:10 +0000 (+0100)
Subject: Merge branch 'upstream' of git.debian.org:/git/collab-maint/topgit
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=topgit.git;a=commitdiff_plain;h=2f7cb405238120a51ab113427d25488ef87ef14b;hp=d0fd65c3d26419ec9f21310c7aaea73610b058d8

Merge branch 'upstream' of git.debian.org:/git/collab-maint/topgit
---

diff --git a/README b/README
index 5796112..d2f095d 100644
--- a/README
+++ b/README
@@ -351,11 +351,12 @@ tg export
 	in the cleaned up history (corresponding basically exactly
 	to `tg patch` output for the topic branch).
 
-	The command has two possible outputs now - either a Git branch
-	with the collapsed history, or a quilt series in new directory.
+	The command has three possible outputs now - either a Git branch with
+	the collapsed history, a Git branch with a linearized history, or a
+	quilt series in new directory.
 
 	In case of producing collapsed history in new branch,
-	You can use this collapsed structure either for providing
+	you can use this collapsed structure either for providing
 	a pull source for upstream, or further linearization e.g.
 	for creation of a quilt series using git log:
 
@@ -378,6 +379,21 @@ tg export
 	             `- t/bar/good <,-------------------'/
 	             `- t/baz      ---------------------'
 
+	In case of using the linearize mode:
+
+	master$ tg export --linearize for-linus
+
+	you get a linear history respecting the dependencies of your patches in
+	a new branch for-linus.  The result should be more or less the same as
+	using quilt mode and reimporting it into a Git branch.  (More or less
+	because the topologic order can usually be extended in more than one
+	way into a complete ordering and the two methods may choose different
+	one's.)  The result might be more appropriate for merging upstream as
+	it contains fewer merges.
+
+	Note that you might get conflicts during linearization because the
+	patches are reordered to get a linear history.
+
 	In case of the quilt mode,
 
 	master$ tg export --quilt for-linus
@@ -418,14 +434,15 @@ tg export
 	names get a number as prefix to allow getting the order without
 	consulting the series file, which eases sending out the patches.
 
-	Usage: tg export ([--collapse] BRANCH | --quilt DIR)
+	Usage: tg export ([(--collapse | --linearize)] BRANCH | --quilt DIR)
 
 	TODO: Make stripping of non-essential headers configurable
 	TODO: Make stripping of [PATCH] and other prefixes configurable
 	TODO: --mbox option for other mode of operation
 	TODO: -a option to export all branches
-	TODO: For quilt exporting, use a temporary branch and remove it when
-	      done - this would allow producing conflict-less series
+	TODO: For quilt exporting, export the linearized history created in a
+	      temporary branch---this would allow producing conflict-less
+	      series
 
 tg import
 ~~~~~~~~~
diff --git a/tg-create.sh b/tg-create.sh
index 6e84907..2edd537 100644
--- a/tg-create.sh
+++ b/tg-create.sh
@@ -78,9 +78,9 @@ done
 rm -f "$git_dir/top-name" "$git_dir/top-deps" "$git_dir/top-merge"
 
 
-## Create base
+## Find starting commit to create the base
 
-if [ -n "$merge" ]; then
+if [ -n "$merge" -a -z "$restarted" ]; then
 	# Unshift the first item from the to-merge list
 	branch="${merge%% *}"
 	merge="${merge#* }"
diff --git a/tg-export.sh b/tg-export.sh
index 9e6940f..748ca54 100644
--- a/tg-export.sh
+++ b/tg-export.sh
@@ -27,8 +27,10 @@ while [ -n "$1" ]; do
 		driver=quilt;;
 	--collapse)
 		driver=collapse;;
+	--linearize)
+		driver=linearize;;
 	-*)
-		echo "Usage: tg [...] export ([--collapse] NEWBRANCH | [-b BRANCH1,BRANCH2...] --quilt DIRECTORY)" >&2
+		echo "Usage: tg [...] export ([--collapse] NEWBRANCH | [-b BRANCH1,BRANCH2...] --quilt DIRECTORY | --linearize NEWBRANCH)" >&2
 		exit 1;;
 	*)
 		[ -z "$output" ] || die "output already specified ($output)"
@@ -71,14 +73,11 @@ pretty_tree()
 	 git write-tree)
 }
 
-# collapsed_commit NAME
-# Produce a collapsed commit of branch NAME.
-collapsed_commit()
+create_tg_commit()
 {
 	name="$1"
-
-	rm -f "$playground/^pre" "$playground/^post"
-	>"$playground/^body"
+	tree="$2"
+	parent="$3"
 
 	# Get commit message and authorship information
 	git cat-file blob "$name:.topmsg" | git mailinfo "$playground/^msg" /dev/null > "$playground/^info"
@@ -92,6 +91,20 @@ collapsed_commit()
 	test -n "$GIT_AUTHOR_EMAIL" && export GIT_AUTHOR_EMAIL
 	test -n "$GIT_AUTHOR_DATE" && export GIT_AUTHOR_DATE
 
+	(printf '%s\n\n' "$SUBJECT"; cat "$playground/^msg") |
+	git stripspace |
+	git commit-tree "$tree" -p "$parent"
+}
+
+# collapsed_commit NAME
+# Produce a collapsed commit of branch NAME.
+collapsed_commit()
+{
+	name="$1"
+
+	rm -f "$playground/^pre" "$playground/^post"
+	>"$playground/^body"
+
 	# Determine parent
 	parent="$(cut -f 1 "$playground/$name^parents")"
 	if [ "$(cat "$playground/$name^parents" | wc -l)" -gt 1 ]; then
@@ -107,9 +120,7 @@ collapsed_commit()
 	if branch_empty "$name"; then
 		echo "$parent";
 	else
-		(printf '%s\n\n' "$SUBJECT"; cat "$playground/^msg") |
-		git stripspace |
-		git commit-tree "$(pretty_tree "$name")" -p "$parent"
+		create_tg_commit "$name" "$(pretty_tree $name)" "$parent"
 	fi;
 
 	echo "$name" >>"$playground/^ticker"
@@ -186,10 +197,60 @@ quilt()
 	fi
 }
 
+linearize()
+{
+	if test ! -f "$playground/^BASE"; then
+		head="$(git rev-parse --verify "$_dep")"
+		echo "$head" > "$playground/^BASE"
+		git checkout -q "$head"
+		return;
+	fi;
+
+	head=$(git rev-parse --verify HEAD)
+
+	if [ -z "$_dep_is_tgish" ]; then
+		# merge in $_dep unless already included
+		rev="$(git rev-parse --verify "$_dep")";
+		common="$(git merge-base --all HEAD "$_dep")";
+		if test "$rev" = "$common"; then
+			# already included, just skip
+			:;
+		else
+			git merge -s recursive "$_dep";
+			retmerge="$?";
+			if test "x$retmerge" != "x0"; then
+				echo fix up the merge, commit and then exit;
+				#todo error handling
+				sh -i
+			fi;
+		fi;
+	else
+		git merge-recursive "$(pretty_tree "refs/top-bases/$_dep")" -- HEAD "$(pretty_tree "refs/heads/$_dep")";
+		retmerge="$?";
+
+		if test "x$retmerge" != "x0"; then
+			echo "fix up the merge and update the index.  Don't commit!"
+			#todo error handling
+			sh -i
+		fi
+
+		result_tree=$(git write-tree)
+		# testing branch_empty might not always give the right answer.
+		# It can happen that the patch is non-empty but still after
+		# linearizing there is no change.  So compare the trees.
+		if test "x$result_tree" = "x$(git rev-parse $head^{tree})"; then
+			echo "skip empty commit $_dep";
+		else
+			newcommit=$(create_tg_commit "$_dep" "$result_tree" HEAD)
+			git update-ref HEAD $newcommit $head
+			echo "exported commit $_dep";
+		fi
+	fi
+}
 
 ## Machinery
 
-if [ "$driver" = "collapse" ]; then
+if [ "$driver" = "collapse" ] || [ "$driver" = "linearize" ]; then
 	[ -n "$output" ] ||
 		die "no target branch specified"
 	! ref_exists "$output"  ||
@@ -238,6 +299,17 @@ if [ "$driver" = "collapse" ]; then
 elif [ "$driver" = "quilt" ]; then
 	depcount="$(cat "$output/series" | wc -l)"
 	echo "Exported topic branch $name (total $depcount topics) to directory $output"
+
+elif [ "$driver" = "linearize" ]; then
+	git checkout -q -b $output
+
+	echo $name
+	if test $(git rev-parse "$(pretty_tree $name)^{tree}") != $(git rev-parse "HEAD^{tree}"); then
+		echo "Warning: Exported result doesn't match";
+		echo "tg-head=$(git rev-parse "$name"), exported=$(git rev-parse "HEAD")";
+		#git diff $head HEAD;
+	fi;
+
 fi
 
 # vim:noet
diff --git a/tg-summary.sh b/tg-summary.sh
index 842d95a..50ee883 100644
--- a/tg-summary.sh
+++ b/tg-summary.sh
@@ -53,13 +53,22 @@ fi
 git for-each-ref refs/top-bases |
 	while read rev type ref; do
 		name="${ref#refs/top-bases/}"
+		if branch_annihilated "$name"; then
+			continue;
+		fi;
+
 		if [ -n "$terse" ]; then
 			echo "$name"
 			continue
 		fi
 		if [ -n "$graphviz" ]; then
 			git cat-file blob "$name:.topdeps" | while read dep; do
-				echo "\"$name\" -> \"$dep\";"
+				dep_is_tgish=true
+				ref_exists "refs/top-bases/$dep"  ||
+					dep_is_tgish=false
+				if ! "$dep_is_tgish" || ! branch_annihilated $dep; then
+					echo "\"$name\" -> \"$dep\";"
+				fi
 			done
 			continue
 		fi
diff --git a/tg.sh b/tg.sh
index 7c6c09f..f0496f1 100644
--- a/tg.sh
+++ b/tg.sh
@@ -99,7 +99,7 @@ measure_branch()
 # Whether B1 is a superset of B2.
 branch_contains()
 {
-	[ -z "$(git rev-list ^"$1" "$2" --)" ]
+	[ -z "$(git rev-list --max-count=1 ^"$1" "$2" --)" ]
 }
 
 # ref_exists REF
@@ -116,6 +116,16 @@ has_remote()
 	[ -n "$base_remote" ] && ref_exists "remotes/$base_remote/$1"
 }
 
+branch_annihilated()
+{
+	_name="$1";
+
+	# use the merge base in case the base is ahead.
+	mb="$(git merge-base "refs/top-bases/$_name" "$_name")";
+
+	test "$(git rev-parse "$mb^{tree}")" = "$(git rev-parse "$_name^{tree}")";
+}
+
 # recurse_deps CMD NAME [BRANCHPATH...]
 # Recursively eval CMD on all dependencies of NAME.
 # CMD can refer to $_name for queried branch name,
@@ -138,7 +148,12 @@ recurse_deps()
 	if has_remote "top-bases/$_name"; then
 		echo "refs/remotes/$base_remote/top-bases/$_name" >>"$_depsfile"
 	fi
-	git cat-file blob "$_name:.topdeps" >>"$_depsfile"
+
+	# if the branch was annihilated, there exists no .topdeps file
+	if ! branch_annihilated "$_name"; then
+		#TODO: handle nonexisting .topdeps?
+		git cat-file blob "$_name:.topdeps" >>"$_depsfile";
+	fi;
 
 	_ret=0
 	while read _dep; do