74 lines
3.1 KiB
Markdown
74 lines
3.1 KiB
Markdown
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# Nixpkgs lib
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This directory contains the implementation, documentation and tests for the Nixpkgs `lib` library.
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## Overview
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The evaluation entry point for `lib` is [`default.nix`](default.nix).
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This file evaluates to an attribute set containing two separate kinds of attributes:
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- Sub-libraries:
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Attribute sets grouping together similar functionality.
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Each sub-library is defined in a separate file usually matching its attribute name.
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Example: `lib.lists` is a sub-library containing list-related functionality such as `lib.lists.take` and `lib.lists.imap0`.
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These are defined in the file [`lists.nix`](lists.nix).
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- Aliases:
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Attributes that point to an attribute of the same name in some sub-library.
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Example: `lib.take` is an alias for `lib.lists.take`.
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Most files in this directory are definitions of sub-libraries, but there are a few others:
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- [`minver.nix`](minver.nix): A string of the minimum version of Nix that is required to evaluate Nixpkgs.
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- [`tests`](tests): Tests, see [Running tests](#running-tests)
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- [`release.nix`](tests/release.nix): A derivation aggregating all tests
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- [`misc.nix`](tests/misc.nix): Evaluation unit tests for most sub-libraries
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- `*.sh`: Bash scripts that run tests for specific sub-libraries
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- All other files in this directory exist to support the tests
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- [`systems`](systems): The `lib.systems` sub-library, structured into a directory instead of a file due to its complexity
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- [`path`](path): The `lib.path` sub-library, which includes tests as well as a document describing the design goals of `lib.path`
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- All other files in this directory are sub-libraries
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### Module system
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The [module system](https://nixos.org/manual/nixpkgs/#module-system) spans multiple sub-libraries:
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- [`modules.nix`](modules.nix): `lib.modules` for the core functions and anything not relating to option definitions
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- [`options.nix`](options.nix): `lib.options` for anything relating to option definitions
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- [`types.nix`](types.nix): `lib.types` for module system types
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## Reference documentation
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Reference documentation for library functions is written above each function as a multi-line comment.
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These comments are processed using [nixdoc](https://github.com/nix-community/nixdoc) and [rendered in the Nixpkgs manual](https://nixos.org/manual/nixpkgs/stable/#chap-functions).
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The nixdoc README describes the [comment format](https://github.com/nix-community/nixdoc#comment-format).
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See the [chapter on contributing to the Nixpkgs manual](https://nixos.org/manual/nixpkgs/#chap-contributing) for how to build the manual.
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## Running tests
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All library tests can be run by building the derivation in [`tests/release.nix`](tests/release.nix):
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```bash
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nix-build tests/release.nix
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```
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Some commands for quicker iteration over parts of the test suite are also available:
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```bash
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# Run all evaluation unit tests in tests/misc.nix
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# if the resulting list is empty, all tests passed
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nix-instantiate --eval --strict tests/misc.nix
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# Run the module system tests
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tests/modules.sh
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# Run the lib.sources tests
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tests/sources.sh
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# Run the lib.filesystem tests
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tests/filesystem.sh
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# Run the lib.path property tests
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path/tests/prop.sh
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```
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