A tool for backporting changes of C files.

This tool follows the standard procedure of backporting by invoking the diff and patch utilities but in addition to it the tool also supports logging of the processed and rejected hunks in JSON format. The detailed description of the algorithm follows:

1. A temporary directory is created
2. diff is launched with begin and after files and the output is written into diff.patch file in the temporary directory.
3. patch is launched to merge diff.patch into target configured to write potential conflicts into reject file in the temporary directory.
4. If --log option is provided, the files are parsed and combined to indicate the hunks that have been merged and the ones that have been rejected

The tool can be launched as a python file on Linux or as a docker container on any platform supporting docker runtime.

To launch the tool on Linux:

1. Download the backport.py and formats.py and put them next to one another
2. Make sure that you have the diff and patch utilities installed. This can be checked by invoking the which diff and which patch commands. If the commands don't produce any output, you have to install them. On Ubuntu/Debian this can be done via apt install like following:

apt update
apt install rcs
apt install patch

3. Make sure that you have python3 installed
4. cd to the directory where you have stored the backport.py and formats.py.
5. Launch the python3 ./backport.py <path-to-before> <path-to-after> <path-to-target> --log <path-to-json-log>
6. Open the log file to examine the processed hunks

To launch the docker image containing the most recent version of the tool:

1. Make sure that you have docker installed on your system
2. Run the following command: docker run --rm -v <path-to-files>:/data ventice/backporter /data/<before> /data/<after> /data/<target> --log /data/history.json where <path-to-files> is the path to the local directory where all the three files can be found and <before>, <after> and <target> are the paths relative to the <path-to-files>. Slashes in <path-to-files> are to be specified in platform-specific manner, and in <before>, <after> and <target> in the Linux way
3. The command will download the docker image, mount the specified directory as a volume into the container, run the command and delete the container leaving the patched file and the log on the host system.

The unit tests are located in the tests directory. To launch them make sure you have pytest installed and simply invoke the pytest command in the project root directory.

All the pushes to the main branch are automatically built into a docker image and pushed to the ventice/backporter image.