New and improved cherry-pick support

README.md

@@ -129,5 +129,14 @@ Eg. you can run the gradle build like this - ./gradlew clean -Pddprof.jar=file:/
 ## Working with upstream
 
 Although this project still shares the git history with the upstream the code structure is different. This makes it dificult to reliably
-cherry-pick the upstream changes. To make this easier we have a script that will prepare a filtered version of the upstream repository
-and add it as 'cherry' remote to this repository. This way you can cherry-pick the changes from the upstream repository with (relative) ease.
+cherry-pick the upstream changes. To make this easier we have a script that will prepare the upstream repository
+and add it as 'cherry' remote to this repository.
+This way you can cherry-pick the changes from the upstream repository with (relative) ease.
+
+```bash
+./utils/init_cherrypick_repo.sh # you need to run this only once
+
+./utils/cherry.sh <commit>
+# ... resolve conflicts, if any
+./utils/cherry.sh --continue # to commit the resolved conflicts
+```

utils/cherry.sh

@@ -0,0 +1,140 @@
+#!/bin/bash
+set -euo pipefail
+
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+if [ $# -ne 1 ]; then
+  echo "Usage: $0 [<upstream-commit-hash> | --continue | --abort]"
+  exit 1
+fi
+
+CMD=$1
+
+if [[ "$CMD" == "--continue" ]] || [[ "$CMD" == "--abort" ]]; then
+  GIT_DIR="$HERE/../.git"
+  if [ -f "$GIT_DIR/CHERRY_PICK_HEAD" ] && [ -f "$GIT_DIR/CHERRY_COMMIT_EDITMSG" ]; then
+    if [[ "$CMD" == "--continue" ]]; then
+      git commit -F "$GIT_DIR/CHERRY_COMMIT_EDITMSG" --author "$(cat $GIT_DIR/COMMIT_AUTHOR_NAME) <$(cat $GIT_DIR/COMMIT_AUTHOR_EMAIL)>)" --date "$(cat $GIT_DIR/COMMIT_AUTHOR_DATE)"
+    else
+      git reset --hard HEAD
+    fi
+    rm -f $GIT_DIR/CHERRY_PICK_HEAD $GIT_DIR/CHERY_COMMIT_EDITMSG $GIT_DIR/COMMIT_AUTHOR_NAME $GIT_DIR/COMMIT_AUTHOR_EMAIL $GIT_DIR/COMMIT_AUTHOR_DATE
+    exit 0
+  else
+    echo "No cherry-pick in progress."
+    exit 1
+  fi
+fi
+
+UPSTREAM_COMMIT=$1
+
+PATCH_FILE=$(mktemp)
+TMP_REWRITTEN=$(mktemp)
+
+cleanup() {
+  rm -f "$PATCH_FILE" "$TMP_REWRITTEN"
+}
+trap cleanup EXIT
+
+# Step 1: Generate patch from upstream commit (only src/)
+git diff-tree -p "$UPSTREAM_COMMIT" -- src/ > "$PATCH_FILE"
+
+# Step 2: Rewrite and filter paths
+awk '
+  function is_cpp_or_header(path) {
+    return path ~ /\.(cpp|cc|cxx|h|hpp)$/
+  }
+  function is_api_java(path) {
+    return path ~ /^src\/api\/.*\.java$/
+  }
+  function translate_path(path) {
+    if (is_cpp_or_header(path)) {
+      sub(/^src\//, "ddprof-lib/src/main/cpp/", path)
+      return path
+    } else if (is_api_java(path)) {
+      sub(/^src\/api\//, "ddprof-lib/src/main/java/", path)
+      return path
+    }
+    return ""
+  }
+
+  BEGIN {
+    skip = 0
+  }
+
+  /^diff --git a\// {
+    a = substr($3, 3)
+    b = substr($4, 3)
+    a_new = translate_path(a)
+    b_new = translate_path(b)
+    if (a_new == "" || b_new == "") {
+      skip = 1
+      next
+    }
+    print "diff --git a/" a_new " b/" b_new
+    skip = 0
+    next
+  }
+
+  /^--- a\// {
+    if (skip) next
+    path = substr($0, 7)
+    newpath = translate_path(path)
+    if (newpath == "") { skip = 1; next }
+    print "--- a/" newpath
+    next
+  }
+
+  /^\+\+\+ b\// {
+    if (skip) next
+    path = substr($0, 7)
+    newpath = translate_path(path)
+    if (newpath == "") { skip = 1; next }
+    print "+++ b/" newpath
+    next
+  }
+
+  {
+    if (!skip) print
+  }
+' "$PATCH_FILE" > "$TMP_REWRITTEN"
+
+# Step 3: Apply the rewritten patch if it's not empty
+if ! grep -q '^diff --git' "$TMP_REWRITTEN"; then
+  echo "No applicable changes after path filtering. Skipping commit $UPSTREAM_COMMIT"
+  exit 0
+fi
+
+# Step 4: Commit using original metadata
+tree=$(git write-tree)
+parent=$(git rev-parse HEAD)
+author_name=$(git show -s --format='%an' "$UPSTREAM_COMMIT")
+author_email=$(git show -s --format='%ae' "$UPSTREAM_COMMIT")
+author_date=$(git show -s --format='%aI' "$UPSTREAM_COMMIT")
+commit_message=$(git show -s --format='%s%n%n%b' "$UPSTREAM_COMMIT")
+
+if ! grep -q "$UPSTREAM_COMMIT" <<< "$commit_message"; then
+  commit_message="$commit_message
+
+(cherry picked from commit $UPSTREAM_COMMIT)"
+fi
+
+if ! git apply --3way "$TMP_REWRITTEN"; then
+  echo "Patch had conflicts. Please resolve manually, then run:"
+  echo "./utils/cherry.sh --continue"
+  echo "  or "
+  echo "  git add <resolved files>"
+  echo "  git commit --author=\"$author_name <$author_email>\" --date=\"$author_date\" -m \"$commit_message\""
+  echo
+  echo "$author_date" > .git/COMMIT_AUTHOR_DATE
+  echo "$author_email" > .git/COMMIT_AUTHOR_EMAIL
+  echo "$author_name" > .git/COMMIT_AUTHOR_NAME
+  echo "$UPSTREAM_COMMIT" > .git/CHERRY_PICK_HEAD
+  echo "$commit_message" > .git/CHERRY_COMMIT_EDITMSG
+  exit 1
+fi
+
+GIT_AUTHOR_NAME="$author_name" \
+GIT_AUTHOR_EMAIL="$author_email" \
+GIT_AUTHOR_DATE="$author_date" \
+git commit-tree "$tree" -p "$parent" -m "$commit_message" | xargs git reset --hard

utils/init_cherypick_repo.sh

@@ -16,10 +16,6 @@ if [ ! -d "$PATH_REPO" ]; then
   git clone https://github.com/async-profiler/async-profiler.git $PATH_REPO
 
   cd "$PATH_REPO" || exit 1
-  git filter-repo --path-rename src/:ddprof-lib/src/main/cpp/
-
-  # filter-repo will remove the remote origin, so we need to add it back but as 'upstream' to avoid
-  #  accidental pushes to the original repo
 
   git remote add upstream https://github.com/async-profiler/async-profiler.git
 fi