[PATCH] transplant: move a series of commits to a different parent

[Steffen Prohaska <prohaska@zib.de>]

git-transplant.sh <onto> <from> <to>

transplant starts with the contents of <onto> and puts on top of
it the contents of files if they are touched by the series of
commits <from>..<to>.  If a commit touches a file the content of
this file is taken as it is in the commit. No merging is
performed. Original authors, commiters, and commit messages are
preserved.

Warning: this is just a quick hack to solve _my_ problem.
- No error checking is performed.
- Removal of files is not handled.
- Whitespace in filename is not handled.
- The index is left in dirty state.
- No branch is created for the result.
- The script is not integrated with git's shell utilities.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
---
 git-transplant.sh |   60 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 60 insertions(+), 0 deletions(-)
 create mode 100755 git-transplant.sh

This script seems to solved the problem for me. I can place
the topic branch imported from cvs to the right place.

What do you think? Is this a sane way to handle the situation?

    Steffen

diff --git a/git-transplant.sh b/git-transplant.sh
new file mode 100755
index 0000000..3320071
--- /dev/null
+++ b/git-transplant.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+
+[[ $# == 3 ]] || { echo "$0 <onto> <from> <to>"; exit 1; }
+onto=$(git-rev-parse $1)
+from=$(git-rev-parse $2)
+to=$(git-rev-parse $3)
+
+# copied from git-filter-branch.sh 
+set_ident () {
+    lid="$(echo "$1" | tr "A-Z" "a-z")"
+    uid="$(echo "$1" | tr "a-z" "A-Z")"
+    pick_id_script='
+        /^'$lid' /{
+            s/'\''/'\''\\'\'\''/g
+            h
+            s/^'$lid' \([^<]*\) <[^>]*> .*$/\1/
+            s/'\''/'\''\'\'\''/g
+            s/.*/export GIT_'$uid'_NAME='\''&'\''/p
+
+            g
+            s/^'$lid' [^<]* <\([^>]*\)> .*$/\1/
+            s/'\''/'\''\'\'\''/g
+            s/.*/export GIT_'$uid'_EMAIL='\''&'\''/p
+
+            g
+            s/^'$lid' [^<]* <[^>]*> \(.*\)$/\1/
+            s/'\''/'\''\'\'\''/g
+            s/.*/export GIT_'$uid'_DATE='\''&'\''/p
+
+            q
+        }
+    '
+
+    LANG=C LC_ALL=C sed -ne "$pick_id_script"
+    # Ensure non-empty id name.
+    echo "[ -n \"\$GIT_${uid}_NAME\" ] || export GIT_${uid}_NAME=\"\${GIT_${uid}_EMAIL%%@*}\""
+}
+
+parent=$onto
+git-read-tree --reset $parent
+
+for commit in $(git-rev-list --reverse $from..$to)
+do
+    echo "rewriting commit $commit..."
+    git-diff-tree -r $commit | grep ^: | cut -b 9-15,57-97,100- |
+    while read mode sha path 
+    do
+        echo " $mode $sha $path"
+        git-update-index --add --cacheinfo $mode $sha $path
+    done
+
+    eval "$(git-cat-file commit $commit |set_ident AUTHOR)"
+    eval "$(git-cat-file commit $commit |set_ident COMMITTER)"
+
+    parent=$(git-cat-file commit $commit |  sed -e '1,/^$/d' | git-commit-tree $(git-write-tree) -p $parent)
+    echo "... new commit $parent"
+done
+
+echo ""
+echo "new head is $parent"
-- 
1.5.2.2.315.gc649a