dockerized clang-format error detection tool

doc/clang-format.md

@@ -64,3 +64,7 @@ When this is done, you are set up. How to use:
 
 6) Commit. It won't work if code is not properly formatted due to the
    pre-commit hook. Force committing with `git commit --no-verify`
+
+# Checking errors introduced by a branch
+
+Here is the script that can be used to detect any clang-format errors introduced by a branch [here](../tools/formatting/README.md)

tools/formatting/README.md

+# Overview
+
+Dockerized tool to list clang-format errors introduced in a branch.
+
+# Usage
+
+Checkout the branch you want to compare. This is necessary because if there are files added by the branch
+they need to be present for clang-format to analyze them.
+
+Then:
+
+```
+./tools/formatting/detect_clang_format_errors.sh
+```
+
+Or
+
+```
+docker compose up
+```
+
+Or (to avoid docker related lines in stdout)
+
+```
+docker compose run clang-formatter | tee output
+```

tools/formatting/detect_clang_format_errors.sh

+#!/bin/bash
+set -eo pipefail
+
+BASE_COMMIT=$(git merge-base HEAD origin/develop)
+git diff -U0 --no-color $BASE_COMMIT...HEAD | clang-format-diff -p1

tools/formatting/docker-compose.yaml

+services:
+  clang-formatter:
+    image: clang-formatter
+    build:
+      dockerfile_inline: |
+        FROM ubuntu:22.04
+        RUN DEBIAN_FRONTEND=noninteractive apt update && apt install -y git clang-format
+    volumes:
+      - ../../:/code/
+    command:
+      bash -c "git config --global --add safe.directory /code && cd /code/ && \
+        git config --global clangFormat.style file && \
+        ./tools/formatting/detect_clang_format_errors.sh"