Git

Configure Git for a development environment with git.config:

{
  git.config = {
    merge.conflictStyle = "diff3";
    merge.tool = "vimdiff";
    diff.algorithm = "histogram";
  };
}

Sections and subsections use nested attribute sets. Values may be strings, booleans, numbers, or lists for repeated keys. These settings apply to Git commands inside the devenv environment. Git still reads your existing configuration, but these settings take precedence over configuration files, including repository configuration. Explicit git -c key=value options take precedence over devenv.

The implementation uses GIT_CONFIG_COUNT, GIT_CONFIG_KEY_0, and GIT_CONFIG_VALUE_0 to include a generated configuration file. Do not configure those environment variables separately. Generated files are stored in the Nix store, so configuration must not contain secrets.

Use git.attributes to select merge drivers, diff drivers, and other file-specific behavior. For example, this configuration registers a custom merge driver and selects it for generated text files:

{
  git.config.merge.keepCurrent = {
    name = "Keep the current version";
    driver = "true";
  };
  git.attributes = [
    "generated/*.txt merge=keepCurrent"
    "*.png binary"
  ];
}

Attribute rules are written to a generated file selected by core.attributesFile. When configured, this replaces your global attributes file for the environment. Repository .gitattributes files and .git/info/attributes retain their higher precedence. Devenv does not modify those files or your Git configuration files.

The defaults are empty and leave Git’s configuration and attributes unchanged. Install any tools referenced by your settings through packages.

Mergiraf

Enable Mergiraf to use syntax-aware merging during Git merges, rebases, and cherry-picks:

{
  mergiraf.enable = true;
}

This installs Mergiraf, registers its merge driver through git.config, and selects it for all files through git.attributes. Unsupported formats fall back to text merging. Repository attributes can override the selected driver.

The integration defaults merge.conflictStyle to diff3, which includes the base revision needed by mergiraf solve path/to/file for existing conflicts. Use mergiraf review to inspect syntax-aware resolutions when prompted. To temporarily use Git’s text merging, run mergiraf=0 git merge <branch>.