yamllint version 1.31.0

Using `setup.py` is deprecated and the new recommanded way is to declare
a `pyproject.toml` file (see PEP 517 [^1]).

This commit proposes to use setuptools to achieve that, because
setuptools is already used by yamllint, is standard and referenced by
the official Python packaging documentation [^2], and seems to be the
most lightweight solution. An alternative could have been to use Poetry,
see the dedicated pull request and discussion [^3].

For some period, the `setup.py` file will be kept (although almost
empty), to allow old tools versions to keep working.

Closes https://github.com/adrienverge/yamllint/issues/509.

[^1]: https://peps.python.org/pep-0517/
[^2]: https://packaging.python.org/en/latest/tutorials/installing-packages/
[^3]: https://github.com/adrienverge/yamllint/pull/557

.flake8

@@ -0,0 +1,4 @@
+[flake8]
+import-order-style = pep8
+application-import-names = yamllint
+ignore = W503,W504

.github/workflows/ci.yaml

@@ -21,14 +21,15 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v4
       - run:
-          python -m pip install flake8 flake8-import-order sphinx
-            rstcheck[sphinx] doc8
-      - run: python -m pip install .
+          pip install flake8 flake8-import-order sphinx rstcheck[sphinx] doc8
+      - run: pip install .
       - run: flake8 .
       - run: doc8 $(git ls-files '*.rst')
       - run: rstcheck --ignore-directives automodule $(git ls-files '*.rst')
       - run: yamllint --strict $(git ls-files '*.yaml' '*.yml')
-      - run: python setup.py build_sphinx
+      - run: make -C docs html
+      - name: Check for broken links in documentation
+        run: make -C docs linkcheck
 
   test:
     name: Tests
@@ -51,8 +52,10 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Append GitHub Actions system path
         run: echo "$HOME/.local/bin" >> $GITHUB_PATH
-      - run: pip install coveralls
+      - run: pip install coverage
       - run: pip install .
-      - run: coverage run --source=yamllint -m unittest discover
+      # https://github.com/AndreMiras/coveralls-python-action/issues/18
+      - run: echo -e "[run]\nrelative_files = True" > .coveragerc
+      - run: coverage run -m unittest discover
       - name: Coveralls
         uses: AndreMiras/coveralls-python-action@develop

CHANGELOG.rst

@@ -1,6 +1,22 @@
 Changelog
 =========
 
+1.31.0 (2023-04-21)
+-------------------
+
+- Build: migrate from ``setup.py`` to ``pyproject.toml``
+- Docs: update some outdated URLs
+- Rule ``colons``: prevent error when space before is mandatory
+
+1.30.0 (2023-03-22)
+-------------------
+
+- Rule ``anchors``: add new rule to detect undeclared or duplicated anchors
+- Python API: prevent using ``is_file_ignored()`` with null ``filepath``
+- Docs: fix misleading Python API example
+- Docs: fix plain text code snippet example
+- Docs: update pre-commit hook example
+
 1.29.0 (2023-01-10)
 -------------------
 

MANIFEST.in

@@ -1,4 +0,0 @@
-include LICENSE
-include README.rst
-include docs/*
-include tests/*.py tests/rules/*.py tests/yaml-1.2-spec-examples/*

README.rst

@@ -8,8 +8,8 @@ repetition and cosmetic problems such as lines length, trailing spaces,
 indentation, etc.
 
 .. image::
-   https://travis-ci.org/adrienverge/yamllint.svg?branch=master
-   :target: https://travis-ci.org/adrienverge/yamllint
+   https://github.com/adrienverge/yamllint/actions/workflows/ci.yaml/badge.svg?branch=master
+   :target: https://github.com/adrienverge/yamllint/actions/workflows/ci.yaml?query=branch%3Amaster
    :alt: CI tests status
 .. image::
    https://coveralls.io/repos/github/adrienverge/yamllint/badge.svg?branch=master

docs/Makefile

@@ -2,7 +2,7 @@
 #
 
 # You can set these variables from the command line.
-SPHINXOPTS    =
+SPHINXOPTS    = -W
 SPHINXBUILD   = sphinx-build
 PAPER         =
 BUILDDIR      = _build

docs/configuration.rst

@@ -190,8 +190,8 @@ or ignore paths only for specific rules:
 
 Note that this ``.gitignore``-style path pattern allows complex path
 exclusion/inclusion, see the `pathspec README file
-<https://pypi.python.org/pypi/pathspec>`_ for more details.
-Here is a more complex example:
+<https://pypi.org/project/pathspec/>`_ for more details. Here is a more complex
+example:
 
 .. code-block:: yaml
 

docs/development.rst

@@ -11,7 +11,7 @@ Basic example of running the linter from Python:
    import yamllint
 
    yaml_config = yamllint.config.YamlLintConfig("extends: default")
-   for p in yamllint.linter.run("example.yaml", yaml_config):
+   for p in yamllint.linter.run(open("example.yaml", "r"), yaml_config):
        print(p.desc, p.line, p.rule)
 
 .. automodule:: yamllint.linter

docs/disable_with_comments.rst

@@ -117,7 +117,7 @@ post-template processing).
 Example of a Jinja2 code that cannot be parsed as YAML because it contains
 invalid tokens ``{%`` and ``%}``:
 
-.. code-block::
+.. code-block:: text
 
  # This file IS NOT valid YAML and will produce syntax errors
  {% if extra_info %}

docs/index.rst

@@ -11,7 +11,7 @@ Screenshot
 
 .. note::
 
-   The default output format is inspired by `eslint <http://eslint.org/>`_, a
+   The default output format is inspired by `eslint <https://eslint.org/>`_, a
    great linting tool for Javascript.
 
 Table of contents

docs/integration.rst

@@ -4,7 +4,7 @@ Integration with other software
 Integration with pre-commit
 ---------------------------
 
-You can integrate yamllint in `pre-commit <http://pre-commit.com/>`_ tool.
+You can integrate yamllint in the `pre-commit <https://pre-commit.com/>`_ tool.
 Here is an example, to add in your .pre-commit-config.yaml
 
 .. code:: yaml
@@ -12,11 +12,13 @@ Here is an example, to add in your .pre-commit-config.yaml
   ---
   # Update the rev variable with the release version that you want, from the yamllint repo
   # You can pass your custom .yamllint with args attribute.
-  - repo: https://github.com/adrienverge/yamllint.git
-    rev: v1.17.0
-    hooks:
-      - id: yamllint
-        args: [-c=/path/to/.yamllint]
+  repos:
+    - repo: https://github.com/adrienverge/yamllint.git
+      rev: v1.29.0
+      hooks:
+        - id: yamllint
+          args: [--strict, -c=/path/to/.yamllint]
+
 
 Integration with GitHub Actions
 -------------------------------

docs/quickstart.rst

@@ -4,7 +4,7 @@ Quickstart
 Installing yamllint
 -------------------
 
-On Fedora / CentOS (note: `EPEL <https://fedoraproject.org/wiki/EPEL>`_ is
+On Fedora / CentOS (note: `EPEL <https://docs.fedoraproject.org/en-US/epel/>`_ is
 required on CentOS):
 
 .. code:: bash
@@ -45,7 +45,7 @@ If you prefer installing from source, you can run, from the source directory:
 
 .. code:: bash
 
- python setup.py sdist
+ python -m build
  pip install --user dist/yamllint-*.tar.gz
 
 Running yamllint

docs/rules.rst

@@ -14,6 +14,11 @@ This page describes the rules and their options.
    :local:
    :depth: 1
 
+anchors
+-------
+
+.. automodule:: yamllint.rules.anchors
+
 braces
 ------
 

docs/text_editors.rst

@@ -13,7 +13,7 @@ Assuming that the `ALE <https://github.com/dense-analysis/ale>`_ plugin is
 installed, yamllint is supported by default. It is automatically enabled when
 editing YAML files.
 
-If you instead use the `syntastic <https://github.com/scrooloose/syntastic>`_
+If you instead use the `syntastic <https://github.com/vim-syntastic/syntastic>`_
 plugin, add this to your ``.vimrc``:
 
 ::
@@ -23,7 +23,7 @@ plugin, add this to your ``.vimrc``:
 Neovim
 ------
 
-Assuming that the `neomake <https://github.com/benekastah/neomake>`_ plugin is
+Assuming that the `neomake <https://github.com/neomake/neomake>`_ plugin is
 installed, yamllint is supported by default. It is automatically enabled when
 editing YAML files.
 

pyproject.toml

@@ -0,0 +1,54 @@
+[project]
+name = "yamllint"
+description = "A linter for YAML files."
+readme = {file = "README.rst", content-type = "text/x-rst"}
+requires-python = ">=3.7"
+license = {text = "GPL-3.0-only"}
+authors = [{name = "Adrien Vergé"}]
+keywords = ["yaml", "lint", "linter", "syntax", "checker"]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Environment :: Console",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
+    "Programming Language :: Python",
+    "Topic :: Software Development",
+    "Topic :: Software Development :: Debuggers",
+    "Topic :: Software Development :: Quality Assurance",
+    "Topic :: Software Development :: Testing",
+]
+dependencies = [
+    "pathspec >= 0.5.3",
+    "pyyaml",
+]
+dynamic = ["version"]
+
+[project.optional-dependencies]
+dev = [
+    "doc8",
+    "flake8",
+    "flake8-import-order",
+    "rstcheck[sphinx]",
+    "sphinx",
+]
+
+[project.scripts]
+yamllint = "yamllint.cli:run"
+
+[project.urls]
+homepage = "https://github.com/adrienverge/yamllint"
+repository = "https://github.com/adrienverge/yamllint"
+documentation = "https://yamllint.readthedocs.io"
+
+[build-system]
+build-backend = "setuptools.build_meta"
+requires = ["setuptools >= 61"]
+
+[tool.setuptools]
+packages = ["yamllint", "yamllint.conf", "yamllint.rules"]
+
+[tool.setuptools.package-data]
+yamllint = ["conf/*.yaml"]
+
+[tool.setuptools.dynamic]
+version = {attr = "yamllint.__version__"}

setup.cfg

@@ -1,69 +0,0 @@
-[flake8]
-import-order-style = pep8
-application-import-names = yamllint
-ignore = W503,W504
-
-[build_sphinx]
-all-files = 1
-source-dir = docs
-build-dir = docs/_build
-warning-is-error = 1
-
-[metadata]
-keywords =
-  yaml
-  lint
-  linter
-  syntax
-  checker
-
-url = https://github.com/adrienverge/yamllint
-classifiers =
-  Development Status :: 5 - Production/Stable
-  Environment :: Console
-  Intended Audience :: Developers
-  License :: OSI Approved :: GNU General Public License v3 (GPLv3)
-  Programming Language :: Python :: 3
-  Programming Language :: Python :: 3.7
-  Programming Language :: Python :: 3.8
-  Programming Language :: Python :: 3.9
-  Programming Language :: Python :: 3.10
-  Programming Language :: Python :: 3.11
-  Topic :: Software Development
-  Topic :: Software Development :: Debuggers
-  Topic :: Software Development :: Quality Assurance
-  Topic :: Software Development :: Testing
-
-project_urls =
-  Documentation = https://yamllint.readthedocs.io
-  Download = https://pypi.org/project/yamllint/#files
-  Bug Tracker = https://github.com/adrienverge/yamllint/issues
-  Source Code = https://github.com/adrienverge/yamllint
-
-[options]
-packages = find:
-
-python_requires = >=3.7
-
-include_package_data = True
-install_requires =
-  pathspec >= 0.5.3
-  pyyaml
-  setuptools
-
-test_suite = tests
-
-[options.packages.find]
-exclude =
-  tests
-  tests.*
-
-[options.package_data]
-yamllint = conf/*.yaml
-
-[options.entry_points]
-console_scripts =
-  yamllint = yamllint.cli:run
-
-[coverage:run]
-relative_files = True

setup.py

@@ -15,15 +15,6 @@
 
 from setuptools import setup
 
-from yamllint import (__author__, __license__,
-                      APP_NAME, APP_VERSION, APP_DESCRIPTION)
-
-
-setup(
-    name=APP_NAME,
-    version=APP_VERSION,
-    author=__author__,
-    description=APP_DESCRIPTION.split('\n')[0],
-    long_description=APP_DESCRIPTION,
-    license=__license__,
-)
+# This is only kept for backward-compatibility with older versions that don't
+# support new packaging standards (e.g. PEP 517 or PEP 660):
+setup()

tests/rules/test_anchors.py

@@ -0,0 +1,209 @@
+# Copyright (C) 2023 Adrien Vergé
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from tests.common import RuleTestCase
+
+
+class AnchorsTestCase(RuleTestCase):
+    rule_id = 'anchors'
+
+    def test_disabled(self):
+        conf = 'anchors: disable'
+        self.check('---\n'
+                   '- &b true\n'
+                   '- &i 42\n'
+                   '- &s hello\n'
+                   '- &f_m {k: v}\n'
+                   '- &f_s [1, 2]\n'
+                   '- *b\n'
+                   '- *i\n'
+                   '- *s\n'
+                   '- *f_m\n'
+                   '- *f_s\n'
+                   '---\n'  # redeclare anchors in a new document
+                   '- &b true\n'
+                   '- &i 42\n'
+                   '- &s hello\n'
+                   '- *b\n'
+                   '- *i\n'
+                   '- *s\n'
+                   '---\n'
+                   'block mapping: &b_m\n'
+                   '  key: value\n'
+                   'extended:\n'
+                   '  <<: *b_m\n'
+                   '  foo: bar\n'
+                   '---\n'
+                   '{a: 1, &x b: 2, c: &y 3, *x : 4, e: *y}\n'
+                   '...\n', conf)
+        self.check('---\n'
+                   '- &i 42\n'
+                   '---\n'
+                   '- &b true\n'
+                   '- &b true\n'
+                   '- &b true\n'
+                   '- &s hello\n'
+                   '- *b\n'
+                   '- *i\n'    # declared in a previous document
+                   '- *f_m\n'  # never declared
+                   '- *f_m\n'
+                   '- *f_m\n'
+                   '- *f_s\n'  # declared after
+                   '- &f_s [1, 2]\n'
+                   '---\n'
+                   'block mapping: &b_m\n'
+                   '  key: value\n'
+                   '---\n'
+                   'block mapping 1: &b_m_bis\n'
+                   '  key: value\n'
+                   'block mapping 2: &b_m_bis\n'
+                   '  key: value\n'
+                   'extended:\n'
+                   '  <<: *b_m\n'
+                   '  foo: bar\n'
+                   '---\n'
+                   '{a: 1, &x b: 2, c: &x 3, *x : 4, e: *y}\n'
+                   '...\n', conf)
+
+    def test_forbid_undeclared_aliases(self):
+        conf = ('anchors:\n'
+                '  forbid-undeclared-aliases: true\n'
+                '  forbid-duplicated-anchors: false\n')
+        self.check('---\n'
+                   '- &b true\n'
+                   '- &i 42\n'
+                   '- &s hello\n'
+                   '- &f_m {k: v}\n'
+                   '- &f_s [1, 2]\n'
+                   '- *b\n'
+                   '- *i\n'
+                   '- *s\n'
+                   '- *f_m\n'
+                   '- *f_s\n'
+                   '---\n'  # redeclare anchors in a new document
+                   '- &b true\n'
+                   '- &i 42\n'
+                   '- &s hello\n'
+                   '- *b\n'
+                   '- *i\n'
+                   '- *s\n'
+                   '---\n'
+                   'block mapping: &b_m\n'
+                   '  key: value\n'
+                   'extended:\n'
+                   '  <<: *b_m\n'
+                   '  foo: bar\n'
+                   '---\n'
+                   '{a: 1, &x b: 2, c: &y 3, *x : 4, e: *y}\n'
+                   '...\n', conf)
+        self.check('---\n'
+                   '- &i 42\n'
+                   '---\n'
+                   '- &b true\n'
+                   '- &b true\n'
+                   '- &b true\n'
+                   '- &s hello\n'
+                   '- *b\n'
+                   '- *i\n'    # declared in a previous document
+                   '- *f_m\n'  # never declared
+                   '- *f_m\n'
+                   '- *f_m\n'
+                   '- *f_s\n'  # declared after
+                   '- &f_s [1, 2]\n'
+                   '---\n'
+                   'block mapping: &b_m\n'
+                   '  key: value\n'
+                   '---\n'
+                   'block mapping 1: &b_m_bis\n'
+                   '  key: value\n'
+                   'block mapping 2: &b_m_bis\n'
+                   '  key: value\n'
+                   'extended:\n'
+                   '  <<: *b_m\n'
+                   '  foo: bar\n'
+                   '---\n'
+                   '{a: 1, &x b: 2, c: &x 3, *x : 4, e: *y}\n'
+                   '...\n', conf,
+                   problem1=(9, 3),
+                   problem2=(10, 3),
+                   problem3=(11, 3),
+                   problem4=(12, 3),
+                   problem5=(13, 3),
+                   problem6=(24, 7),
+                   problem7=(27, 37))
+
+    def test_forbid_duplicated_anchors(self):
+        conf = ('anchors:\n'
+                '  forbid-undeclared-aliases: false\n'
+                '  forbid-duplicated-anchors: true\n')
+        self.check('---\n'
+                   '- &b true\n'
+                   '- &i 42\n'
+                   '- &s hello\n'
+                   '- &f_m {k: v}\n'
+                   '- &f_s [1, 2]\n'
+                   '- *b\n'
+                   '- *i\n'
+                   '- *s\n'
+                   '- *f_m\n'
+                   '- *f_s\n'
+                   '---\n'  # redeclare anchors in a new document
+                   '- &b true\n'
+                   '- &i 42\n'
+                   '- &s hello\n'
+                   '- *b\n'
+                   '- *i\n'
+                   '- *s\n'
+                   '---\n'
+                   'block mapping: &b_m\n'
+                   '  key: value\n'
+                   'extended:\n'
+                   '  <<: *b_m\n'
+                   '  foo: bar\n'
+                   '---\n'
+                   '{a: 1, &x b: 2, c: &y 3, *x : 4, e: *y}\n'
+                   '...\n', conf)
+        self.check('---\n'
+                   '- &i 42\n'
+                   '---\n'
+                   '- &b true\n'
+                   '- &b true\n'
+                   '- &b true\n'
+                   '- &s hello\n'
+                   '- *b\n'
+                   '- *i\n'    # declared in a previous document
+                   '- *f_m\n'  # never declared
+                   '- *f_m\n'
+                   '- *f_m\n'
+                   '- *f_s\n'  # declared after
+                   '- &f_s [1, 2]\n'
+                   '---\n'
+                   'block mapping: &b_m\n'
+                   '  key: value\n'
+                   '---\n'
+                   'block mapping 1: &b_m_bis\n'
+                   '  key: value\n'
+                   'block mapping 2: &b_m_bis\n'
+                   '  key: value\n'
+                   'extended:\n'
+                   '  <<: *b_m\n'
+                   '  foo: bar\n'
+                   '---\n'
+                   '{a: 1, &x b: 2, c: &x 3, *x : 4, e: *y}\n'
+                   '...\n', conf,
+                   problem1=(5, 3),
+                   problem2=(6, 3),
+                   problem3=(21, 18),
+                   problem4=(27, 20))

tests/rules/test_colons.py

@@ -256,3 +256,19 @@ class ColonTestCase(RuleTestCase):
                    '  property: {a: 1, b:  2, c : 3}\n', conf,
                    problem1=(3, 11), problem2=(4, 4),
                    problem3=(8, 23), problem4=(8, 28))
+
+    # Although accepted by PyYAML, `{*x: 4}` is not valid YAML: it should be
+    # noted `{*x : 4}`. The reason is that a colon can be part of an anchor
+    # name. See commit message for more details.
+    def test_with_alias_as_key(self):
+        conf = 'colons: {max-spaces-before: 0, max-spaces-after: 1}'
+        self.check('---\n'
+                   '- anchor: &a key\n'
+                   '- *a: 42\n'
+                   '- {*a: 42}\n'
+                   '- *a : 42\n'
+                   '- {*a : 42}\n'
+                   '- *a  : 42\n'
+                   '- {*a  : 42}\n',
+                   conf,
+                   problem1=(7, 6), problem2=(8, 7))

yamllint/__init__.py

@@ -21,7 +21,7 @@ indentation, etc."""
 
 
 APP_NAME = 'yamllint'
-APP_VERSION = '1.29.0'
+APP_VERSION = '1.31.0'
 APP_DESCRIPTION = __doc__
 
 __author__ = 'Adrien Vergé'

yamllint/conf/default.yaml

@@ -6,6 +6,7 @@ yaml-files:
   - '.yamllint'
 
 rules:
+  anchors: enable
   braces: enable
   brackets: enable
   colons: enable

yamllint/linter.py

@@ -223,7 +223,7 @@ def run(input, conf, filepath=None):
     :param input: buffer, string or stream to read from
     :param conf: yamllint configuration object
     """
-    if conf.is_file_ignored(filepath):
+    if filepath is not None and conf.is_file_ignored(filepath):
         return ()
 
     if isinstance(input, (bytes, str)):

yamllint/rules/__init__.py

@@ -14,6 +14,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from yamllint.rules import (
+    anchors,
     braces,
     brackets,
     colons,
@@ -39,6 +40,7 @@ from yamllint.rules import (
 )
 
 _RULES = {
+    anchors.ID: anchors,
     braces.ID: braces,
     brackets.ID: brackets,
     colons.ID: colons,

yamllint/rules/anchors.py

@@ -0,0 +1,118 @@
+# Copyright (C) 2023 Adrien Vergé
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Use this rule to report duplicated anchors and aliases referencing undeclared
+anchors.
+
+.. rubric:: Options
+
+* Set ``forbid-undeclared-aliases`` to ``true`` to avoid aliases that reference
+  an anchor that hasn't been declared (either not declared at all, or declared
+  later in the document).
+* Set ``forbid-duplicated-anchors`` to ``true`` to avoid duplications of a same
+  anchor.
+
+.. rubric:: Default values (when enabled)
+
+.. code-block:: yaml
+
+ rules:
+   anchors:
+     forbid-undeclared-aliases: true
+     forbid-duplicated-anchors: false
+
+.. rubric:: Examples
+
+#. With ``anchors: {forbid-undeclared-aliases: true}``
+
+   the following code snippet would **PASS**:
+   ::
+
+    ---
+    - &anchor
+      foo: bar
+    - *anchor
+
+   the following code snippet would **FAIL**:
+   ::
+
+    ---
+    - &anchor
+      foo: bar
+    - *unknown
+
+   the following code snippet would **FAIL**:
+   ::
+
+    ---
+    - &anchor
+      foo: bar
+    - <<: *unknown
+      extra: value
+
+#. With ``anchors: {forbid-duplicated-anchors: true}``
+
+   the following code snippet would **PASS**:
+   ::
+
+    ---
+    - &anchor1 Foo Bar
+    - &anchor2 [item 1, item 2]
+
+   the following code snippet would **FAIL**:
+   ::
+
+    ---
+    - &anchor Foo Bar
+    - &anchor [item 1, item 2]
+"""
+
+
+import yaml
+
+from yamllint.linter import LintProblem
+
+
+ID = 'anchors'
+TYPE = 'token'
+CONF = {'forbid-undeclared-aliases': bool,
+        'forbid-duplicated-anchors': bool}
+DEFAULT = {'forbid-undeclared-aliases': True,
+           'forbid-duplicated-anchors': False}
+
+
+def check(conf, token, prev, next, nextnext, context):
+    if conf['forbid-undeclared-aliases'] or conf['forbid-duplicated-anchors']:
+        if isinstance(token, (yaml.StreamStartToken, yaml.DocumentStartToken)):
+            context['anchors'] = set()
+
+    if (conf['forbid-undeclared-aliases'] and
+            isinstance(token, yaml.AliasToken) and
+            token.value not in context['anchors']):
+        yield LintProblem(
+            token.start_mark.line + 1, token.start_mark.column + 1,
+            f'found undeclared alias "{token.value}"')
+
+    if (conf['forbid-duplicated-anchors'] and
+            isinstance(token, yaml.AnchorToken) and
+            token.value in context['anchors']):
+        yield LintProblem(
+            token.start_mark.line + 1, token.start_mark.column + 1,
+            f'found duplicated anchor "{token.value}"')
+
+    if conf['forbid-undeclared-aliases'] or conf['forbid-duplicated-anchors']:
+        if isinstance(token, yaml.AnchorToken):
+            context['anchors'].add(token.value)

yamllint/rules/colons.py

@@ -92,7 +92,9 @@ DEFAULT = {'max-spaces-before': 0,
 
 
 def check(conf, token, prev, next, nextnext, context):
-    if isinstance(token, yaml.ValueToken):
+    if isinstance(token, yaml.ValueToken) and not (
+            isinstance(prev, yaml.AliasToken) and
+            token.start_mark.pointer - prev.end_mark.pointer == 1):
         problem = spaces_before(token, prev, next,
                                 max=conf['max-spaces-before'],
                                 max_desc='too many spaces before colon')

yamllint/rules/new_line_at_end_of_file.py

@@ -17,7 +17,7 @@
 Use this rule to require a new line character (``\\n``) at the end of files.
 
 The POSIX standard `requires the last line to end with a new line character
-<http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206>`_.
+<https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206>`_.
 All UNIX tools expect a new line at the end of files. Most text editors use
 this convention too.
 """