code-extractor

code-extractor.sh

#!/bin/bash

# Also see https://github.com/juliancheal/code-extractor/blob/master/code_extractor.rb

SOURCE_URL=git@github.com:crystal-lang/crystal
SOURCE_REPO=crystal-lang/crystal
SOURCE_BRANCH=master
DEST_NAME=crystal-readline
DEST_DIR=$DEST_NAME

# List of all of the files and directories to extract, space-delimited
EXTRACTIONS="spec/std/readline_spec.cr src/readline.cr"

git clone -o upstream $SOURCE_URL $DEST_DIR

# Create branch for upstream deletion
cd $DEST_DIR
git checkout $SOURCE_BRANCH
git fetch upstream
git rebase upstream/$SOURCE_BRANCH
git checkout -b extract_$DEST_NAME
git rm -r $EXTRACTIONS
git commit -m "Extract $DEST_NAME"

# Cleanup
git remote rm upstream
for tag in $(git tag); do
	git tag -d $tag
done

# Filter down to the extractions
git filter-branch --index-filter "
	git read-tree --empty
	git reset \$GIT_COMMIT -- $EXTRACTIONS
" --msg-filter "
	cat -
	echo
	echo
	echo \"(transferred from $SOURCE_REPO@\$GIT_COMMIT)\"
" -- $SOURCE_BRANCH -- $EXTRACTIONS

git checkout $SOURCE_BRANCH