gitcalver 20260517.1

Deterministic calendar versioning from git history

gitcalver

A Python implementation of GitCalVer, which derives calendar-based version numbers from git history.

Each commit on the default branch gets a unique, strictly increasing version of the form YYYYMMDD.N, where N is the number of commits on that UTC date.

See the GitCalVer specification for full details.

Installation

uv add gitcalver
# or
pip install gitcalver

See Requirements below.

CLI usage

gitcalver [OPTIONS] [REVISION | VERSION]

With no arguments, prints the version for HEAD:

$ gitcalver
20260411.3

Pass a revision to compute its version:

$ gitcalver HEAD~1
20260411.2

Version prefix

Use --prefix to prepend a literal string:

Use case	Command	Example output
Default	gitcalver	20260411.3
SemVer	gitcalver --prefix "0."	0.20260411.3
Go	gitcalver --prefix "v0."	v0.20260411.3

Dirty workspace

By default, gitcalver exits with status 2 if the workspace has uncommitted changes. Use --dirty STRING to produce a version instead; the output will include the given string and a short commit hash (e.g. --dirty "-dirty" produces 20260411.3-dirty.abc1234).

Use --no-dirty-hash with --dirty to suppress the hash suffix. Use --no-dirty to explicitly refuse dirty versions (overrides --dirty).

Dirty versions are a convenience and are not necessarily unique.

Reverse lookup

Pass a version number to get the corresponding commit hash:

$ gitcalver 20260411.3
a1b2c3d4e5f6...

$ gitcalver --short --prefix "0." 0.20260411.3
a1b2c3d

If the version was generated with --prefix, pass the same --prefix for reverse lookup. Dirty versions cannot be reversed.

Options

Option	Description
--prefix PREFIX	Literal string prepended to version
--dirty STRING	Enable dirty versions; append STRING.HASH
--no-dirty	Refuse dirty versions (overrides --dirty)
--no-dirty-hash	Suppress .HASH suffix (requires --dirty)
--branch BRANCH	Base branch name; overrides auto-detection. This is the branch versions are minted on, not the branch you are working on.
--short	Output short commit hash (reverse lookup mode)
--help	Show help

Exit codes

Code	Meaning
0	Success
1	Error (not a git repo, no commits, non-monotonic dates, shallow clone)
2	Dirty workspace or off default branch (without --dirty)
3	Cannot trace to default branch

Python API

import gitcalver

# Forward: compute a version for HEAD (or a specific revision).
version = gitcalver.get_version(repo="/path/to/repo")
# e.g. "20260411.3"

version = gitcalver.get_version(
    repo="/path/to/repo",
    revision="HEAD~1",
    prefix="v0.",
    dirty="-dirty",
)

# Reverse: resolve a version back to a commit hash.
commit = gitcalver.find_commit("20260411.3", repo="/path/to/repo")

# If the version was generated with --prefix, pass the same prefix:
commit = gitcalver.find_commit(
    "v0.20260411.3", prefix="v0.", repo="/path/to/repo"
)

Errors are raised as gitcalver.ExitError, which carries a code attribute matching the CLI exit codes above.

Hatch plugin

gitcalver ships a Hatch version source plugin. To use it in pyproject.toml:

[build-system]
requires = ["hatchling", "gitcalver"]
build-backend = "hatchling.build"

[tool.hatch.version]
source = "gitcalver"
# Optional:
# prefix = "0."
# dirty = "-dirty"
# no-dirty-hash = true
# branch = "main"

Requirements

• Python 3.10+
• git on $PATH
• Full commit history (shallow clones made with --depth are rejected; partial clones made with --filter=blob:none are fine)

License

MIT