utils/release: Add merge-git.sh

[tstellar]

Summary

This script allows you to use git to backport a commit to a stable
branch while generating the exact same commit message (ignoring
whitespace) that you would get from using the merge.sh script with svn.

[hans]

Cool!

utils/release/merge-git.sh

3

"Test the ..." doesn't really apply, but I see we have it in the old script too :-/

63

$proj doesn't seem to be used below. Is this assuming the monorepo? Or that the user is in the repository of the project they want to merge to/from?

Maybe the comment on the top of the file could have a short info about the expectations, i.e. where the script expects to be run, how the git repository was set up, etc?

68

If this first invocation is only to rebuild the map, maybe don't store it into git_hash?

[tstellar]

Remove unused options and document how to use the script.

[hans]

lgtm, just some comments on the comments

utils/release/merge-git.sh

11

s/patch/script/ ?

15

The checkout must be in one of the per-project git repositories, or does this also work in the monorepo?

18

and 3) git-svn dcommit?

utils/release/merge-git.sh

+#!/bin/bash
+#===-- merge-git.sh - Merge commit to the stable branch --------------------===#
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License.
+#
+#===------------------------------------------------------------------------===#
+#
+# This patch will merge an svn revision to a git repo using git-svn while
+# preserving the svn commit message.
+#
+# In order to use this script, you must:
+# 1) checkout the stable branch you would like to merge the revision into.
+# 2) Correctly configure the branch as an svn-remote by adding the following to
+# your .git/config file for your git repo (replace xy with the major/minor
+# version of the release branch. e.g. release_50 or release_60):
+#
+#[svn-remote "release_xy"]
+#url = https://llvm.org/svn/llvm-project/llvm/branches/release_xy
+#fetch = :refs/remotes/origin/release_xy
+#
+#===------------------------------------------------------------------------===#
+
+
+usage() {
+    echo "usage: `basename $0` [OPTIONS]"
+    echo "  -rev NUM       The revision to merge into the project"
+}
+
+while [ $# -gt 0 ]; do
+    case $1 in
+        -rev | --rev | -r )
+            shift
+            rev=$1
+            ;;
+        -h | -help | --help )
+            usage
+            ;;
+        * )
+            echo "unknown option: $1"
+            echo ""
+            usage
+            exit 1
+            ;;
+    esac
+    shift
+done
+
+if [ -z "$rev" ]; then
+    echo "error: need to specify a revision"
+    echo
+    usage
+    exit 1
+fi
+
+# Rebuild revision map
+git svn find-rev r$rev origin/master &>/dev/null
+
+git_hash=`git svn find-rev r$rev origin/master`
+
+if [ -z "$git_hash" ]; then
+    echo "error: could not determine git commit for r$rev"
+    exit 1
+fi
+
+commit_msg=`svn log -r $rev https://llvm.org/svn/llvm-project/`
+ammend="--amend"
+
+git cherry-pick $git_hash
+if [ $? -ne 0 ]; then
+  echo ""
+  echo "** cherry-pick failed enter 'e' to exit or 'c' when you have finished resolving the conflicts:"
+  read option
+  case $option in
+    c)
+      ammend=""
+      ;;
+    *)
+      exit 1
+      ;;
+  esac
+fi
+         
+git commit $ammend -m "Merging r$rev:" -m "$commit_msg"