#+title: nix-prefetch-github

* Introduction
  This module implements a python function and a command line tool to
  help you fetch sources from github when using =fetchFromGitHub=.

  This program can be distributed under the conditions of the GNU
  Public License Version 3. Check out =LICENSE.txt= to read the
  license text.

* Dependencies
  - Python and its standard library
  - nix-prefetch-url
  - nix-prefech-github
  - git
  - nix

* Command Line Example
  #+begin_src sh :results verbatim :export :wrap example :exports both
    result/bin/nix-prefetch-github seppeljordan nix-prefetch-github
  #+end_src

  #+RESULTS:
  #+begin_example
  {
      "owner": "seppeljordan",
      "repo": "nix-prefetch-github",
      "rev": "9578399cadb1cb2b252438cf14663333e8c3ee00",
      "hash": "sha256-JFC1+y+FMs2TwWjJxlAKAyDbSLFBE9J65myp7+slp50="
  }
  #+end_example

* Available Commands
** nix-prefetch-github
   This command downloads the code from a github repository and puts
   it into the local nix store. It also prints the function arguments
   to =fetchFromGitHub= to the standard output. :

   #+begin_src sh :results verbatim :wrap example :exports results
     result/bin/nix-prefetch-github --help
   #+end_src

   #+RESULTS:
   #+begin_example
   usage: nix-prefetch-github [-h] [--fetch-submodules] [--no-fetch-submodules]
			      [--leave-dot-git] [--no-leave-dot-git]
			      [--deep-clone] [--no-deep-clone] [--verbose]
			      [--quiet] [--nix] [--json] [--meta] [--version]
			      [--rev REV]
			      owner repo

   positional arguments:
     owner
     repo

   options:
     -h, --help            show this help message and exit
     --fetch-submodules    Include git submodules in the output derivation
     --no-fetch-submodules
			   Don't include git submodules in output derivation
     --leave-dot-git       Include .git folder in output derivation. Use this if
			   you need repository data, e.g. current commit hash,
			   for the build process.
     --no-leave-dot-git    Don't include .git folder in output derivation.
     --deep-clone          Include all of the repository history in the output
			   derivation. This option implies --leave-dot-git.
     --no-deep-clone       Don't include the repository history in the output
			   derivation.
     --verbose, -v         Print additional information about the programs
			   execution. This is useful if you want to issue a bug
			   report.
     --quiet, -q           Print less information about the programs execution.
     --nix                 Output the results as valid nix code.
     --json                Output the results in the JSON format
     --meta                Output the results in JSON format where the arguments
			   to fetchFromGitHub are located under the src key of
			   the resulting json dictionary and meta information
			   about the prefetched repository is located under the
			   meta key of the output.
     --version             show program's version number and exit
     --rev REV
   #+end_example

** nix-prefetch-github-directory
   This command examins the current working directory and tries to
   figure out if it is part of a git repository linked to github. If
   this was successful the program prefetches the currently checked
   out commit from the =origin= remote repository similar to the
   command =nix-prefetch-github=.

   #+begin_src sh :results verbatim :wrap example :exports results
     result/bin/nix-prefetch-github-directory --help
   #+end_src

   #+RESULTS:
   #+begin_example
   usage: .nix-prefetch-github-directory-wrapped [-h] [--fetch-submodules]
						 [--no-fetch-submodules]
						 [--leave-dot-git]
						 [--no-leave-dot-git]
						 [--deep-clone] [--no-deep-clone]
						 [--verbose] [--quiet] [--nix]
						 [--json] [--meta] [--version]
						 [--directory DIRECTORY]
						 [--remote REMOTE]

   options:
     -h, --help            show this help message and exit
     --fetch-submodules    Include git submodules in the output derivation
     --no-fetch-submodules
			   Don't include git submodules in output derivation
     --leave-dot-git       Include .git folder in output derivation. Use this if
			   you need repository data, e.g. current commit hash,
			   for the build process.
     --no-leave-dot-git    Don't include .git folder in output derivation.
     --deep-clone          Include all of the repository history in the output
			   derivation. This option implies --leave-dot-git.
     --no-deep-clone       Don't include the repository history in the output
			   derivation.
     --verbose, -v         Print additional information about the programs
			   execution. This is useful if you want to issue a bug
			   report.
     --quiet, -q           Print less information about the programs execution.
     --nix                 Output the results as valid nix code.
     --json                Output the results in the JSON format
     --meta                Output the results in JSON format where the arguments
			   to fetchFromGitHub are located under the src key of
			   the resulting json dictionary and meta information
			   about the prefetched repository is located under the
			   meta key of the output.
     --version             show program's version number and exit
     --directory DIRECTORY
     --remote REMOTE
   #+end_example

** nix-prefetch-github-latest-release
   This command fetches the code for the latest release of the
   specified repository.

   #+begin_src sh :results verbatim :wrap example :exports results
     result/bin/nix-prefetch-github-latest-release --help
   #+end_src

   #+RESULTS:
   #+begin_example
   usage: nix-prefetch-github-latest-release [-h] [--fetch-submodules]
					     [--no-fetch-submodules]
					     [--leave-dot-git]
					     [--no-leave-dot-git] [--deep-clone]
					     [--no-deep-clone] [--verbose]
					     [--quiet] [--nix] [--json] [--meta]
					     [--version]
					     owner repo

   positional arguments:
     owner
     repo

   options:
     -h, --help            show this help message and exit
     --fetch-submodules    Include git submodules in the output derivation
     --no-fetch-submodules
			   Don't include git submodules in output derivation
     --leave-dot-git       Include .git folder in output derivation. Use this if
			   you need repository data, e.g. current commit hash,
			   for the build process.
     --no-leave-dot-git    Don't include .git folder in output derivation.
     --deep-clone          Include all of the repository history in the output
			   derivation. This option implies --leave-dot-git.
     --no-deep-clone       Don't include the repository history in the output
			   derivation.
     --verbose, -v         Print additional information about the programs
			   execution. This is useful if you want to issue a bug
			   report.
     --quiet, -q           Print less information about the programs execution.
     --nix                 Output the results as valid nix code.
     --json                Output the results in the JSON format
     --meta                Output the results in JSON format where the arguments
			   to fetchFromGitHub are located under the src key of
			   the resulting json dictionary and meta information
			   about the prefetched repository is located under the
			   meta key of the output.
     --version             show program's version number and exit
   #+end_example

* development environment
  Use =nix develop= with flake support enabled. Development without
  nix flake support is not officially supported. Run the provided
  tests via =pytest=. You can control what kind of tests are run via
  the variable =DISABLED_TESTS=:

  #+begin_example
    # Only run tests that don't hit network and don't use nix
    DISABLED_TESTS="network requires_nix_build" pytest
  #+end_example

  Currently =network= and =requires_nix_build= are the only values
  that make sense with this environment variable.

  You can visualize the dependency graph of the individual python
  modules via the =./generate-dependency-graph= program.

  You can generate a coverage report for the tests via

  #+begin_example
    coverage run -m nix_prefetch_github.run_tests && coverage html
  #+end_example

  

* changes
** v8.0.0 (not released yet)
   - Drop official support for Python versions <3.11 and introduce
     official support for Python version 3.12
   - Drop nix-build based prefetcher. This means that users need to
     have =nix-prefetch-git= and =nix-prefetch=url= available in their
     PATH.
   - Meta information the program outputs now contains the store path
     of prefetched repositories.

** v7.1.0
   - Add =-q= / =--quiet= option to decrease logging verbosity
   - Add =--meta= option to include the commit timestamp of the latest
     prefetched commit in the output
   - Use content of ==GITHUB_TOKEN== environment variable for
     authenticating with GitHub API

** v7.0.0
   - The output format changed. In previous versions the json and nix
     output included =sha256= as a field. This field was removed in
     favour of a =hash= field. The value of this field is an SRI hash.

** v6.0.1
   - Fix bug in repository detection for
     =nix-prefetch-github-directory=

** v6.0.0
   - Drop support for python3.8
   - Drop default arguments to fetchFromGitHub from json output
     (e.g. =leaveDotGit = false;=, =fetchSubmodule = false;=,
     =deepClone = false;=)

** v5.2.2
   - Add more info to error messages

** v5.2.1
   - Fixed a bug that broke the program for users without the
     experimental `nix-command` feature

** v5.2.0
   - Emit warning if unsafe options --deep-clone and --leave-dot-git
     are used.
   - Improve --help output slightly
   - Declutter verbose logging output

** v5.1.2
   - Use old prefetch implementation because of bug in
     =nix-prefetch-git=.  See [[https://github.com/NixOS/nixpkgs/issues/168147][this github issue]]
** v5.1.1
   - Fix bug that broke =nix-prefetch-github --version=

** v5.1.0
   - Use =nix-prefetch-git= and =nix-prefetch-url= for calculating
     sha256 sums when possible. The application will fall back to the
     old method when =nix-prefetch-*= are not available.

** v5.0.1
   - Fix breaking bug in hash generation

** v5.0.0
   - Remove all dependencies to other python packages other than
     "core" ones
   - Allow users to control debugging output via the =--verbosity= cli
     option
   - All commands now understand =--fetch-submodules= and
     =--no-fetch-submodules= options
   - Commands now understand =--leave-dot-git= and
     =--no-leave-dot-git= options
   - Commands now understand =--deep-clone= and =--no-deep-clone=

** v4.0.4
   - Print standard error output of subprocesses for better debugging

** v4.0.3
   - Generated hashes now don't have a "sha256-" prefix
   - jinja2 is no longer a dependency of nix-prefetch-github

** v4.0.2
   - packaging release, no bugfixes or features

** v4.0.1
   - Fix issue #38

** v4.0
   - Make fetching submodules the default in calls to python
     routines. The CLI should be uneffected by this change.
   - Remove default values for =fetch_submodules= in all internal
     classes.
   - Implement =nix-prefetch-github-latest-release= command

** v3.0
   - major changes to the internal module structure
   - introduction of the =nix-prefetch-github-directory= command
   - code repository now functions as a nix flake

** v2.4
   - added =--fetch-submodules= flag
   - Fixed incompability with nix 2.4

** v2.3.2
   - fix issues #21, #22
   - nix-prefetch-github now accepts full ref names, e.g.
     =refs/heads/master= which was broken since 2.3 (#23)

** v2.3.1
   - Fix bug in generated nix expression
   - Fix bug that prevented targeting tags with prefetch command
   - Improve error message format in case revision is not found

** v2.3
   - Remove dependency to =requests=
   - Default to =master= branch instead of first branch in list

** v2.2
   - Add =--version= flag
   - Fix bug in output formatting

** v2.1
   - Fix bug (#4) that made =nix-prefetch-github= incompatible with
     =nix 2.2=.

** v2.0
   - The result of nix_pretch_github and its corresponding command
     line tool now contains always the actual commit hash as detected
     by the tool instead of the branch or tag name.
   - Add a new flag =--nix= that makes the command line tool output a
     valid nix expression
   - Removed the =--hash-only= and =--no-hash-only= flags and changed
     add =--prefetch= and =--no-prefetch= flags to replace them.