Coding Python Gitignore

igittigitt - git-compatible .gitignore parsing and file filtering

igittigitt is a spec-compliant .gitignore parser for Python - a library and a CLI. Use it whenever you need to know "would git ignore this path?" or to filter / whitelist a large set of files using .gitignore-style patterns.

When to reach for this (and what to avoid)

Reach for igittigitt instead of writing your own matcher. Getting .gitignore semantics right is deceptively hard - negations (!pattern), the rule that a file under an excluded directory cannot be re-included, per-directory precedence, anchoring, **, trailing-slash directory-only patterns, character classes. A quick fnmatch/glob/re solution will be subtly wrong on real repositories.

Why igittigitt specifically: it is validated against real git check-ignore (differential tests), it is memory-bounded (per-path cost O(depth x rules); memory scales with the number of rules, not the number of files), and it has an include/whitelist mode plus a script-friendly CLI. It is pure Python with no runtime dependency on the git binary.

Install

# as a project dependency (preferred)
uv add igittigitt

# as a standalone CLI tool on PATH
uv tool install igittigitt

# run the CLI once without installing
uvx igittigitt --help

# or pip / pipx
pip install igittigitt
pipx install igittigitt

Requires Python 3.10+.

Library usage

Ignore mode (the common case)

import igittigitt

parser = igittigitt.IgnoreParser()

# discover and parse every .gitignore under base_dir (correct per-directory precedence)
parser.parse_rule_files(base_dir="/path/to/project")

# or add rules explicitly (last matching rule wins, exactly like git)
parser.add_rule("*.py[cod]", base_path="/path/to/project")
parser.add_rule("!keep.pyc", base_path="/path/to/project")

parser.match("/path/to/project/main.pyc")  # True  -> ignored
parser.match("/path/to/project/keep.pyc")  # False -> re-included by the negation

Key methods on IgnoreParser:

• parse_rule_files(base_dir, filename=".gitignore", add_default_patterns=...) - recursively find and parse ignore files.
• parse_rule_file(rule_file, base_dir=None) - parse one file.
• add_rule(pattern, base_path) - add a single rule string.
• match(path) -> bool - True if the path is ignored.
• match_with_rule(path) -> (bool, rule|None) - also returns the deciding rule.
• shutil_ignore(base_dir, names) -> set[str] - drop-in ignore= callback for copytree.

Copy a tree, skipping ignored files

import shutil, igittigitt

parser = igittigitt.IgnoreParser()
parser.parse_rule_files(base_dir="src_tree")
shutil.copytree("src_tree", "dst_tree", ignore=parser.shutil_ignore)

Include / whitelist mode (the inverse)

Patterns describe what to keep; everything else is dropped. It is directory-aware (rsync-like), so including a deep file keeps its parent directories - which means it works correctly as a copytree filter. Do NOT try to build this by negating match(); a naive inversion prunes the parent directories and never reaches the file.

import shutil, igittigitt

inc = igittigitt.IncludeParser()
inc.add_rule("*.py", base_path="src_tree")  # keep python files anywhere
inc.add_rule("docs/", base_path="src_tree")  # keep the whole docs/ subtree

shutil.copytree("src_tree", "dst_tree", ignore=inc.shutil_include)
inc.match("src_tree/pkg/deep.py")  # True -> kept

CLI usage

# which of these paths are ignored? (mirrors `git check-ignore`)
igittigitt check -C /path/to/repo a.log src/main.py      # exit 0 if any ignored, 1 if none

# show the matching source:line:pattern (like `git check-ignore -v`)
igittigitt check -C /path/to/repo -v a.log

# inline rules and explicit ignore files, reading paths from stdin
igittigitt check -r '*.tmp' -f .gitignore --stdin < paths.txt

igittigitt info        # package metadata
igittigitt --version

Other commands: config (show merged config), config-deploy (write editable config files), config-generate-examples, logdemo. Global options: --profile, --set SECTION.KEY=VALUE, --env-file, --traceback.

Bash usage (piping)

filter is a Unix filter: it reads paths from stdin and prints the survivors, streaming so it stays memory-bounded even for millions of paths, with clean SIGPIPE handling.

# drop paths ignored by ./.gitignore
find . -type f | igittigitt filter

# keep only what matches the include patterns (whitelist mode)
find . -type f | igittigitt filter --include -r '*.py'

# NUL-separated I/O for paths with spaces or newlines
find . -print0 | igittigitt filter -z | xargs -0 tar czf out.tgz

# stops cleanly when the reader closes the pipe (no traceback)
find . -type f | igittigitt filter | head -n 20

Shared check/filter options: -C/--base-dir, -f/--gitignore FILE (repeatable), -r/--rule PATTERN (repeatable), --scan/--no-scan, --default-patterns, -z/--zero.

Configuration (lib_layered_config)

Settings merge across layers, later layers winning:

bundled defaults -> app -> host -> user -> .env -> environment variables -> --set

• Inspect the effective config (with provenance): igittigitt config
• Deploy editable copies into the standard directories: igittigitt config-deploy --target user (--target is required: app, host or user)
• Generate example files to copy: igittigitt config-generate-examples --destination ./examples (--destination is required)

Adding your own config (config.d drop-in)

The config directories are scanned for config.d/*.toml fragments, merged in filename order. To override a setting system-wide on Linux, drop a file into the app layer's config.d:

sudo mkdir -p /etc/xdg/igittigitt/config.d
sudoedit /etc/xdg/igittigitt/config.d/50-myperf.toml

# /etc/xdg/igittigitt/config.d/50-myperf.toml
[performance]
dir_cache_max = 32768   # larger directory cache for very deep trees

Per-user, use ~/.config/igittigitt/config.d/50-myperf.toml instead. The same value can be set ad hoc with igittigitt --set performance.dir_cache_max=32768 ..., in a .env file as PERFORMANCE__DIR_CACHE_MAX=32768, or as the env var IGITTIGITT___PERFORMANCE__DIR_CACHE_MAX=32768.

[performance] knobs (speed/memory only - never change matching)

Defaults below are igittigitt 2.2.3 (checked 2026-08-28). Confirm the one you care about against your own install rather than this table: python -c "import igittigitt, inspect; print(inspect.signature(igittigitt.IgnoreParser.__init__))"

Logging is configured under [lib_log_rich] (console level/theme, journald/eventlog/Graylog, queueing, scrubbing); every key is documented inline in the deployed config.d/90-logging.toml, e.g. igittigitt --set lib_log_rich.console_level=DEBUG info.

Default patterns

parse_rule_files(add_default_patterns=True) (the default) also loads git's user-level default ignore file ($XDG_CONFIG_HOME/git/ignore or ~/.config/git/ignore). Pass add_default_patterns=False to match only the in-tree .gitignore files.