Runs "git log" against two branches to help find out, which one introduced a code change

README.md

Resolving Merge Conflicts

The inspect-conflict.sh script compares a single file on two branches to find out which branch introduced a specific code changes. This documentation explains, how the log inside the script evolved and what it does.

Rules

1. Resolve one file at a time
2. First, apply the upstream version
3. Unstage all changes of that file
4. RESOLVE: Review each change one-by-one and either stage or discard

Reason for accepting the upstream version:
This step turns the 3-way-merge into a more digestible 2-way changeset

Stage or Discard?

When code exists in the working branch but not in upstream, we need to find out what happened:

• A) It was removed from upstream → discard it
• B) it was added in the working branch → keep it

But how to find out which strategy is the correct one?

Investigation Steps

1. Check Upstream History

git log main -S"method_name" -- path/to/file

• Shows commits → Go to step 3
• No results → Likely option B, verify with step 2

2. Check Feature Branch History

git log feature-branch -S"method_name" -- path/to/file

• Shows commit → Option B (keep it)
• No results → Check merge base

3. Verify Current State

# Confirm presence in each branch
git show main:path/to/file | grep -A5 "method_name"
git show feture-branch:path/to/file | grep -A5 "method_name"

4. Inspect Addition Context (if keeping)

# See why it was added
git show $(git log feature-branch -S"method_name" --format=%H -1)

# Find usage
git grep "method_name" feature-branch

Example

# Check upstream (no results = not in upstream)
git log develop -S"api.subscription_mode" -- modules/ppcp-api-client/services.php

# Control: verify search works
git log develop -S"api.helpers.paymentLevelHelper" -- modules/ppcp-api-client/services.php
# Returns 1 commit ✓

# Check current branch (found it)
git log remove-legacy-ui -S"api.subscription_mode" -- modules/ppcp-api-client/services.php
# Returns 1 commit → Option B: Keep the service

Result: Service added in current branch, keep it in merge resolution.

inspect-conflict.sh

#!/usr/bin/env bash

# Helps me determine whether a code snippet was added in the feature branch
# or removed from upstream — so you can decide: keep or discard?

prompt_if_empty() {
  local var_name="$1"
  local label="$2"

  if [[ -z "${!var_name}" ]]; then
    read -rp "${label} " input
    printf -v "$var_name" '%s' "$input"
  else
    echo "$label ${!var_name}"
  fi
}

function show_usage() {
  echo "Usage: $(basename "$0") [-f <file>] [-s <search>] [-u <upstream>]"
  echo ""
  echo "  -f, --file        Path to the file"
  echo "  -s, --search      Search term (method name, variable, etc.)"
  echo "  -u, --upstream    Upstream branch name"
}

while [[ $# -gt 0 ]]; do
  case "$1" in
    -f|--file)      FILE_PATH="$2";        shift 2 ;;
    -s|--search)    SEARCH_TERM="$2";      shift 2 ;;
    -u|--upstream)  UPSTREAM_BRANCH="$2";  shift 2 ;;
    -h|--help)      show_usage;            exit 0 ;;
    *) echo "Unknown option: $1"; show_usage; exit 1 ;;
  esac
done

CURRENT_BRANCH=$(git branch --show-current)

prompt_if_empty FILE_PATH       "File path:      "
prompt_if_empty SEARCH_TERM     "Search term:    "
echo "Current branch:  $CURRENT_BRANCH"
prompt_if_empty UPSTREAM_BRANCH "Upstream branch:"

echo ""
echo "--- Upstream ($UPSTREAM_BRANCH) ---"
UPSTREAM_RESULTS=$(git log "$UPSTREAM_BRANCH" -S"$SEARCH_TERM" --oneline -- "$FILE_PATH")
echo "${UPSTREAM_RESULTS:-No commits found}"

echo ""
echo "--- Feature branch ($CURRENT_BRANCH) ---"
FEATURE_RESULTS=$(git log "$CURRENT_BRANCH" -S"$SEARCH_TERM" --oneline -- "$FILE_PATH")
echo "${FEATURE_RESULTS:-No commits found}"

echo ""
echo "--- Verdict ---"
if [[ -z "$UPSTREAM_RESULTS" && -n "$FEATURE_RESULTS" ]]; then
  echo "KEEP — added in this branch, not present upstream"
elif [[ -n "$UPSTREAM_RESULTS" && -z "$FEATURE_RESULTS" ]]; then
  echo "DISCARD — removed from upstream, not introduced here"
elif [[ -n "$UPSTREAM_RESULTS" && -n "$FEATURE_RESULTS" ]]; then
  echo "REVIEW — found in both branches, likely modified"
else
  echo "INCONCLUSIVE — no commits found in either branch"
fi