P4 Harmonize for Git UnrealEngine

• A tool for mirroring a git commit to perforce.
• Purpose built for syncing UnrealEngine releases to a local p4 server.
• Based on p4harmonize which is a tool for mirroring p4-to-p4.

Usage

$ pip install -r requirements.txt

• Create a config.toml mapping the source git repo and destination p4 server.
• Set is_unreal to True to enable some Unreal-specific behavior:
  • Runs GitDependencies.exe and gathers additional source files from .uedependencies.
  • Provides default lists of files to ignore, like .gitattributes, Setup.bat, etc.

[source]
root = "D:/github/EpicGames/UnrealEngine"
is_unreal = true

[destination]
p4port = "perforce:1666"
p4user = "bsayre"
p4client = "bsayre_my-machine_UE5-harmonize"
stream = "//UE5/Main"
root = "D:/mystudio/p4/UE5-harmonize"

• Clone or checkout the desired source branch in the git repo.
• Run the run command, starting in the same directory as the config, or pass it via -c my/config.toml

$ python p4harmonize-git-ue.py run

• All differences between the git repo and p4 stream will be staged to a changelist.
• Review and submit!

Cleaning and Re-running

• The destination workspace and root dir shouldn't exist before running.
• Use the clean command to delete the workspace and root directory (make sure it's set correctly!).

$ python p4harmonize-git-ue.py clean

How it works

• Files are listed from source and destination using git ls-tree and p4 fstat, so untracked files are ignored.
• Additional UnrealEngine files are discovered from .uedependencies (stuff downloaded via Setup.bat)
• An initial difference is calculated manually:
  • Source or destination only files are easily marked for add/delete
  • Case mismatches are handled as p4 move (case-sensitive server) or p4 delete, which requires a second run
  • A quick file size check is done (for binary files only), and if file sizes roughly match (or it's text), a md5 digest is calculated and compared against p4's known digest.
• Any files that could possibly differ are copied from git repo -> p4 workspace and staged.
• Unchanged files are reverted with p4 revert -a, which handles any false-positives from the file size or digest checks.

Nothing is ever submitted automatically, review and submit after running the tool.

TODO

• Run git checkout to ensure the source repo has no local modifications.
• Add some p4 type hinting based on Epic's p4 type rules, or verify the p4 servers typemap, etc.