Add more support materials for contributors

.clang-format

@@ -0,0 +1,20 @@
+# Copyright 2025 The TensorFlow Quantum Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+
+# Summary: configure clang-format for this project's style guidelines.
+# This should be kept in sync with TensorFlow's .clang-format.
+
+BasedOnStyle: Google
+DerivePointerAlignment: false

.editorconfig

@@ -11,22 +11,15 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
-# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-# Common editor configurations for this project.
-#
-# EditorConfig is a file format for specifying some common style parameters.
-# Many IDEs & editors read .editorconfig files, either natively or via plugins.
-# We mostly follow Google's style guides (https://google.github.io/styleguide/)
-# with only a few deviations for line length and indentation in some files.
-# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+# ============================================================================
 
 root = true
 
-# IMPORTANT: some of the other config files (.markdownlintrc, .jsonlintrc.yaml,
-# etc.) also have settings for indent and line length. When making changes to
-# this file, make sure to update the other files to match.
+# We follow the TensorFlow coding style
+# https://www.tensorflow.org/community/contribute/code_style
 
+# IMPORTANT: some of the other config files (.clang-format, etc.) also have
+# the same settings and need to be updated if changes are made to this file.
 [*]
 charset = utf-8
 indent_style = space
@@ -35,7 +28,7 @@ spelling_language = en-US
 trim_trailing_whitespace = true
 max_line_length = 80
 
-[{BUILD,*.BUILD,*.bzl,*.bazel,.bazelrc}]
+[{BUILD,*.BUILD,*.bzl,*.bazel,.bazelrc,WORKSPACE}]
 indent_size = 4
 
 [{*.cc,*.h}]
@@ -48,7 +41,7 @@ indent_size = 2
 indent_size = 4
 
 [*.sh]
-indent_size = 4
+indent_size = 2
 
-[*.yml,*.yaml]
+[{*.yaml,*.yml,*.cff}]
 indent_size = 2

.git-blame-ignore-revs

@@ -0,0 +1,9 @@
+# Usage: run the following command to configure git to use this file:
+#
+#   git config blame.ignoreRevsFile .git-blame-ignore-revs
+#
+# Summary: `git-blame` can be instructed to ignore certain commits. This is
+# useful to do for commits that only involve large refactoring and reformatting
+# operations. The format of this file is one full 40-character commit hash
+# (SHA-1) per line. Blank lines and comments (such as this) are allowed.
+# ==============================================================================

.gitattributes

@@ -0,0 +1,24 @@
+# Copyright 2025 The TensorFlow Quantum Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+
+# Include Markdown files in GitHub's file statistics for this repo.
+*.md linguist-detectable
+
+# Exclude config files from GitHub's file statistics. Most are YAML files and
+# Linguist already treats .yaml files as data, so only add some exceptions.
+.clang-format   linguist-documentation
+.editorconfig   linguist-documentation
+.markdownlintrc linguist-documentation
+.shfmt          linguist-documentation

.github/actionlint.yaml

@@ -0,0 +1,26 @@
+# Copyright 2020 The TensorFlow Probability Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+
+# Summary: configure actionlint (https://github.com/rhysd/actionlint) to
+# recognize action runner names/labels that we use.
+
+self-hosted-runner:
+  labels:
+    # Google self-hosted runners defined in TensorFlow org.
+    - linux-x86-n2-32
+
+    # New from GitHub (late 2025) but currently not known by actionlint.
+    # https://docs.github.com/en/actions/reference/runners/github-hosted-runners
+    - ubuntu-slim

.github/problem-matchers/README.md

@@ -6,5 +6,26 @@ This directory contains Problem Matchers used by the GitHub Actions workflows in
 
 The following problem matcher JSON files found in this directory were copied from the [Home Assistant](https://github.com/home-assistant/core) project on GitHub. The Home Assistant project is licensed under the Apache 2.0 open-source license. The version of the files at the time they were copied was 2025.1.2.
 
-- [`pylint.json`](https://github.com/home-assistant/core/blob/dev/.github/workflows/matchers/pylint.json)
-- [`yamllint.json`](https://github.com/home-assistant/core/blob/dev/.github/workflows/matchers/yamllint.json)
+*   [`pylint.json`](https://github.com/home-assistant/core/blob/dev/.github/workflows/matchers/pylint.json)
+*   [`yamllint.json`](https://github.com/home-assistant/core/blob/dev/.github/workflows/matchers/yamllint.json)
+
+The Pytest problem matcher originally came from the
+[gh-problem-matcher-wrap](https://github.com/liskin/gh-problem-matcher-wrap/tree/master/problem-matchers)
+repository (copied 2025-03-04, version 3.0.0), and was subsequently modified by
+Michael Hucka. The original JSON file is Copyright © 2020 Tomáš Janoušek and
+made available under the terms of the MIT license.
+
+*   [`pytest.json`](https://github.com/liskin/gh-problem-matcher-wrap/blob/master/problem-matchers/pytest.json)
+
+The following problem matcher for gcc came from the [Microsoft
+vscode-cpptools](https://github.com/microsoft/vscode-cpptools) repository as it appeared on
+2025-12-04. The last commit was by user michelleangela on 2020-01-09. The file is licensed under the
+MIT license.
+
+*   [`gcc.json`](https://github.com/microsoft/vscode-cpptools/blob/acdd5ca9d21cb1dda535594bee461beb9e8a5f06/Extension/package.json)
+
+The following problem matcher for yapf came from the [Google
+SCAAML](https://github.com/google/scaaml) repository as it appeared on 2025-12-08. The last commit
+was by user jmichelp on 2022-07-03. The file is licensed under the Apache 2.0 license.
+
+*   [`yapf.json`](https://github.com/google/scaaml/blob/6d9c3a42c527212ef77f2877419dd8f6e77eb442/.github/python_matcher.json)

.github/problem-matchers/gcc.json

@@ -0,0 +1,17 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "gcc",
+      "pattern": [
+        {
+          "regexp": "^(.*):(\\d+):(\\d+):\\s+(?:fatal\\s+)?(warning|error):\\s+(.*)$",
+          "file": 1,
+          "line": 2,
+          "column": 3,
+          "severity": 4,
+          "message": 5
+        }
+      ]
+    }
+  ]
+}

.github/problem-matchers/pytest.json

@@ -0,0 +1,16 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "pytest",
+      "severity": "error",
+      "pattern": [
+        {
+          "regexp": "^(\\S+):(\\d+): (.*)$",
+          "file": 1,
+          "line": 2,
+          "message": 3
+        }
+      ]
+    }
+  ]
+}

.github/problem-matchers/yapf.json

@@ -0,0 +1,22 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "yapf-diff",
+      "pattern": [
+        {
+          "regexp": "^---\\s*([^\\s]*)\\s*\\(original\\)$",
+          "file": 1
+        },
+        {
+          "regexp": "^\\+\\+\\+\\s*([^\\s]*)\\s*\\((.*)\\)$",
+          "message": 2
+        },
+        {
+          "regexp": "^@@\\s*-(\\d+),(\\d+)\\s*\\+(\\d+),(\\d+)\\s*@@$",
+          "line": 1
+        }
+      ]
+    },
+  }
+  ]
+}

.markdownlintrc

@@ -0,0 +1,159 @@
+{ // -*- jsonc -*-
+  //
+  // Copyright 2025 Google LLC
+  //
+  // Licensed under the Apache License, Version 2.0 (the "License");
+  // you may not use this file except in compliance with the License.
+  // You may obtain a copy of the License at
+  //
+  //     https://www.apache.org/licenses/LICENSE-2.0
+  //
+  // Unless required by applicable law or agreed to in writing, software
+  // distributed under the License is distributed on an "AS IS" BASIS,
+  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  // See the License for the specific language governing permissions and
+  // limitations under the License.
+
+  // IMPORTANT: if you change values here, update .editorconfig to match.
+
+  // These settings try to stay close to the Google Markdown Style as
+  // described at https://google.github.io/styleguide/docguide/style.html
+  // with very few differences.
+
+  // Note: there are multiple programs programs named "markdownlint". We use
+  // https://github.com/igorshubovych/markdownlint-cli/, which is the one you
+  // get with "brew install markdownlint" on MacOS.
+  //
+  // For a list of possible configuration options, see the following page:
+  // https://github.com/DavidAnson/markdownlint/blob/main/doc/Rules.md
+  // (Beware that the above looks similar but is NOT the same as the page
+  // https://github.com/markdownlint/markdownlint/blob/main/docs/RULES.md.)
+
+  "$schema": "https://raw.githubusercontent.com/DavidAnson/markdownlint/main/schema/markdownlint-config-schema.json",
+
+  // Require ATX-style headings.
+  // https://google.github.io/styleguide/docguide/style.html#atx-style-headings
+  "headings": {
+    "style": "atx"
+  },
+
+  // Google style does not require that the first line of a file is a heading
+  // for the title; it only states that the first heading should be a level 1.
+  // https://google.github.io/styleguide/docguide/style.html#document-layout
+  "first-line-heading": false,
+
+  // The Google style does not define what to do about trailing punctuation in
+  // headings. The markdownlint default disallows exclamation points, which
+  // seems likely to be more annoying than useful – I have definitely seen
+  // people use exclamation points in headings in README files on GitHub.
+  // This setting removes exclamation point from the banned characters.
+  "no-trailing-punctuation": {
+    "punctuation": ".,;:。，；："
+  },
+
+  // No trailing spaces.
+  // https://google.github.io/styleguide/docguide/style.html#trailing-whitespace
+  "whitespace": {
+    "br_spaces": 0
+  },
+
+  // Google style is 80 characters.
+  // Google style exempts some constructs from the line-length limit:
+  // https://google.github.io/styleguide/docguide/style.html#exceptions
+  "line-length": {
+    "line_length": 80,
+    "code_block_line_length": 80,
+    "heading_line_length": 80,
+    "code_blocks": false,
+    "headings": false,
+    "tables": false
+  },
+
+  // Google Markdown style specifies 2 spaces after item numbers, 3 spaces
+  // after bullets, so that the text itself is consistently indented 4 spaces.
+  // https://google.github.io/styleguide/docguide/style.html#nested-list-spacing
+  "list-marker-space": {
+    "ol_multi": 2,
+    "ol_single": 2,
+    "ul_multi": 3,
+    "ul_single": 3
+  },
+
+  "ul-indent": {
+    "indent": 4
+  },
+
+  // Bare URLs are allowed in GitHub-flavored Markdown and in Google’s style.
+  "no-bare-urls": false,
+
+  // Basic Markdown allows raw HTML. Both GitHub & PyPI support subsets of
+  // HTML, though it's unclear what subset PyPI supports. Google's style guide
+  // recommends against using raw HTML, but does allow it. (C.f. the bottom of
+  // https://google.github.io/styleguide/docguide/style.html) Google's in-house
+  // documentation system allows many inline and block-level tags, but strips
+  // others that can pose security risks (e.g., <object> and standalone <svg>).
+  // The list below tries to capture the intersection of what GitHub allows
+  // (c.f. https://github.com/github/markup/issues/245#issuecomment-682231577),
+  // what PyPI seems to allow, what Google allows, and what seems likely to be
+  // most useful in situations where someone needs to reach for HTML.
+  "html": {
+    "allowed_elements": [
+      "a",
+      "abbr",
+      "b",
+      "blockquote",
+      "br",
+      "caption",
+      "cite",
+      "code",
+      "dd",
+      "del",
+      "details",
+      "dfn",
+      "div",
+      "dl",
+      "dt",
+      "em",
+      "figcaption",
+      "figure",
+      "h1",
+      "h2",
+      "h3",
+      "h4",
+      "h5",
+      "h6",
+      "hr",
+      "i",
+      "img",
+      "ins",
+      "kbd",
+      "li",
+      "mark",
+      "ol",
+      "p",
+      "picture",
+      "pre",
+      "q",
+      "s",
+      "samp",
+      "small",
+      "span",
+      "strong",
+      "sub",
+      "summary",
+      "sup",
+      "table",
+      "tbody",
+      "td",
+      "tfoot",
+      "th",
+      "thead",
+      "time",
+      "tr",
+      "tt",
+      "ul",
+      "var",
+      "wbr"
+    ]
+  }
+}

.pylintrc

@@ -1,3 +1,18 @@
+# Copyright 2020 The TensorFlow Probability Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+
 # Summary: TFQ config file for Pylint versions 3.0 and above.
 # See https://pylint.readthedocs.io/ for info about options available.