Add base_dir argument to more accurately fix absolute paths

README.md

@@ -72,6 +72,9 @@ at once, so `clang-tidy-review` will only attempt to post the first
   should be relative to `GITHUB_WORKSPACE` (the default place where your
   repository is cloned)
   - default: `'.'`
+- `base_dir`: Absolute path to initial working directory
+  `GITHUB_WORKSPACE`.
+  - default: `GITHUB_WORKSPACE`
 - `clang_tidy_version`: Version of clang-tidy to use; one of 6.0, 7, 8, 9, 10, 11
   - default: '11'
 - `clang_tidy_checks`: List of checks
@@ -86,7 +89,8 @@ at once, so `clang-tidy-review` will only attempt to post the first
 - `apt_packages`: Comma-separated list of apt packages to install
   - default: ''
 - `cmake_command`: A CMake command to configure your project and generate
-  `compile_commands.json` in `build_dir`
+  `compile_commands.json` in `build_dir`. You _almost certainly_ want
+  to include `-DCMAKE_EXPORT_COMPILE_COMMANDS=ON`!
   - default: ''
 - `max_comments`: Maximum number of comments to post at once
   - default: '25'
@@ -95,8 +99,97 @@ at once, so `clang-tidy-review` will only attempt to post the first
 
 - `total_comments`: Total number of warnings from clang-tidy
 
+## Generating `compile_commands.json` inside the container
+
+Very simple projects can get away without a `compile_commands.json`
+file, but for most projects `clang-tidy` needs this file in order to
+find include paths and macro definitions.
+
+If you use the GitHub `ubuntu-latest` image as your normal `runs-on`
+container, you only install packages from the system package manager,
+and don't need to build or install other tools yourself, then you can
+generate `compile_commands.json` as part of the `clang-tidy-review`
+action:
+
+```yaml
+name: clang-tidy-review
+on: [pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - uses: ZedThree/clang-tidy-review@v0.8.0
+      id: review
+      with:
+        # List of packages to install
+        apt_packages: liblapack-dev
+        # CMake command to run in order to generate compile_commands.json
+        cmake_command: cmake . -DCMAKE_EXPORT_COMPILE_COMMANDS=on
+```
+
+If you don't use CMake, this may still work for you if you can use a
+tool like [bear](https://github.com/rizsotto/Bear) for example.
+
+## Use in a non-default location
+
+If you're using the `container` argument in your GitHub workflow,
+downloading/building other tools manually, or not using CMake, you
+will need to generate `compile_commands.json` before the
+`clang-tidy-review` action. However, the Action is run inside another
+container, and due to the way GitHub Actions work, `clang-tidy-review`
+ends up running with a different absolute path.
+
+What this means is that if `compile_commands.json` contains absolute
+paths, `clang-tidy-review` needs to adjust them to where it is being
+run instead. By default, it replaces absolute paths that start with
+the value of [`${GITHUB_WORKSPACE}`][env_vars] with the new working
+directory.
+
+If you're running in a container other than a default GitHub
+container, then you may need to pass the working directory to
+`base_dir`. Unfortunately there's not an easy way for
+`clang-tidy-review` to auto-detect this, so in order to pass the
+current directory you will need to do something like the following:
+
+```yaml
+name: clang-tidy-review
+on: [pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    # Using another container changes the
+    # working directory from GITHUB_WORKSPACE
+    container:
+      image: my-container
+
+    steps:
+    - uses: actions/checkout@v2
+
+    # Get the current working directory and set it
+    # as an environment variable
+    - name: Set base_dir
+      run: echo "base_dir=$(pwd)" >> $GITHUB_ENV
+
+    - uses: ZedThree/clang-tidy-review@v0.8.0
+      id: review
+      with:
+        # Tell clang-tidy-review the base directory.
+        # This will get replaced by the new working
+        # directory inside the action
+        base_dir: ${{ env.base_dir }}
+```
+
 ## Real world project samples
 |Project|Workflow|
 |----------|-------|
 |[BOUT++](https://github.com/boutproject/BOUT-dev) |[CMake](https://github.com/boutproject/BOUT-dev/blob/master/.github/workflows/clang-tidy-review.yml) |
 |[Mudlet](https://github.com/Mudlet/Mudlet) |[CMake + Qt](https://github.com/Mudlet/Mudlet/blob/development/.github/workflows/clangtidy-diff-analysis.yml) |
+
+
+
+[env_vars]: https://docs.github.com/en/actions/learn-github-actions/environment-variables#default-environment-variables

action.yml

@@ -13,6 +13,10 @@ inputs:
     description: 'Directory containing the compile_commands.json file'
     default: '.'
     required: false
+  base_dir:
+    description: 'Absolute path to initial working directory. Useful if generating `compile_commands.json` outside of the Action'
+    default: ${{ github.workspace }}
+    require: false
   clang_tidy_version:
     description: 'Version of clang-tidy to use; one of 6.0, 7, 8, 9, 10, 11, 12'
     default: '12'
@@ -61,6 +65,7 @@ runs:
     - --repo=${{ inputs.repo }}
     - --pr=${{ inputs.pr }}
     - --build_dir=${{ inputs.build_dir }}
+    - --base_dir=${{ inputs.base_dir }}
     - --clang_tidy_checks=${{ inputs.clang_tidy_checks }}
     - --config_file=${{ inputs.config_file }}
     - --include='${{ inputs.include }}'

review.py

@@ -13,6 +13,7 @@
 import json
 import os
 from operator import itemgetter
+import pathlib
 import pprint
 import re
 import requests
@@ -81,7 +82,7 @@ def make_review(contents, lookup):
             try:
                 comments.append(
                     {
-                        "path": rel_path,
+                        "path": str(rel_path),
                         "body": comment_body,
                         "position": lookup[rel_path][int(source_line)],
                     }
@@ -323,6 +324,33 @@ def strip_enclosing_quotes(string: str) -> str:
     return stripped
 
 
+def fix_absolute_paths(build_compile_commands, base_dir):
+    """Update absolute paths in compile_commands.json to new location, if
+    compile_commands.json was created outside the Actions container
+    """
+
+    basedir = pathlib.Path(base_dir).resolve()
+    newbasedir = pathlib.Path(".").resolve()
+
+    if basedir == newbasedir:
+        return
+
+    print(f"Found '{build_compile_commands}', updating absolute paths")
+    # We might need to change some absolute paths if we're inside
+    # a docker container
+    with open(build_compile_commands, "r") as f:
+        compile_commands = json.load(f)
+
+    print(f"Replacing '{basedir}' with '{newbasedir}'", flush=True)
+
+    modified_compile_commands = json.dumps(compile_commands).replace(
+        str(basedir), str(newbasedir)
+    )
+
+    with open(build_compile_commands, "w") as f:
+        f.write(modified_compile_commands)
+
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(
         description="Create a review from clang-tidy warnings"
@@ -335,6 +363,11 @@ def strip_enclosing_quotes(string: str) -> str:
     parser.add_argument(
         "--build_dir", help="Directory with compile_commands.json", default="."
     )
+    parser.add_argument(
+        "--base_dir",
+        help="Absolute path of initial working directory if compile_commands.json generated outside of Action",
+        default=".",
+    )
     parser.add_argument(
         "--clang_tidy_checks",
         help="checks argument",
@@ -399,44 +432,16 @@ def strip_enclosing_quotes(string: str) -> str:
 
     build_compile_commands = f"{args.build_dir}/compile_commands.json"
 
+    cmake_command = strip_enclosing_quotes(args.cmake_command)
+
     # If we run CMake as part of the action, then we know the paths in
     # the compile_commands.json file are going to be correct
-    if args.cmake_command:
-        cmake_command = strip_enclosing_quotes(args.cmake_command)
+    if cmake_command:
         with message_group(f"Running cmake: {cmake_command}"):
             subprocess.run(cmake_command, shell=True, check=True)
 
     elif os.path.exists(build_compile_commands):
-        print(f"Found '{build_compile_commands}', updating absolute paths")
-        # We might need to change some absolute paths if we're inside
-        # a docker container
-        with open(build_compile_commands, "r") as f:
-            compile_commands = json.load(f)
-
-        original_directory = compile_commands[0]["directory"]
-
-        # directory should either end with the build directory,
-        # unless it's '.', in which case use original directory
-        if original_directory.endswith(args.build_dir):
-            build_dir_index = -(len(args.build_dir) + 1)
-            basedir = original_directory[:build_dir_index]
-        elif args.build_dir == ".":
-            basedir = original_directory
-        else:
-            raise RuntimeError(
-                f"compile_commands.json contains absolute paths that I don't know how to deal with: '{original_directory}'"
-            )
-
-        newbasedir = os.getcwd()
-
-        print(f"Replacing '{basedir}' with '{newbasedir}'", flush=True)
-
-        modified_compile_commands = json.dumps(compile_commands).replace(
-            basedir, newbasedir
-        )
-
-        with open(build_compile_commands, "w") as f:
-            f.write(modified_compile_commands)
+        fix_absolute_paths(build_compile_commands, args.base_dir)
 
     main(
         repo=args.repo,