[TOPGIT] implement linearize export method

This is a draft that seems to work for my test case.  The error handling
is to be improved though.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

diff --git a/tg-export.sh b/tg-export.sh
index dea24d9d6fa024ba3da1103a584991e7d9f4c7ec..748ca54f6c093480684d53982ba72e82daedb412 100644 (file)
--- 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)"
@@ -195,10 +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 "$output"  ||
@@ -247,6 +299,17 @@ if [ "$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