From a821a18fd4bc6cda46e114f0da69eda2891d1a5a Mon Sep 17 00:00:00 2001
From: Hugo van Kemenade <hugovk@users.noreply.github.com>
Date: Sun, 30 Apr 2023 08:02:03 +0300
Subject: [PATCH] Replace Netlify with Read the Docs build previews (#103843)

Co-authored-by: Oleg Iarygin <dralife@yandex.ru>
Co-authored-by: C.A.M. Gerlach <CAM.Gerlach@Gerlach.CAM>
(cherry picked from commit accb417c338630ac6e836a5c811a89d54a3cd1d3)
---
 .github/workflows/documentation-links.yml | 27 +++++++++++++++++++++++
 .readthedocs.yml                          | 18 +++++++++++++++
 Doc/conf.py                               |  9 ++++++++
 Doc/tools/templates/layout.html           |  8 +++++++
 4 files changed, 62 insertions(+)
 create mode 100644 .github/workflows/documentation-links.yml
 create mode 100644 .readthedocs.yml

diff --git a/.github/workflows/documentation-links.yml b/.github/workflows/documentation-links.yml
new file mode 100644
index 00000000000000..43a7afec73884e
--- /dev/null
+++ b/.github/workflows/documentation-links.yml
@@ -0,0 +1,27 @@
+name: Read the Docs PR preview
+# Automatically edits a pull request's descriptions with a link
+# to the documentation's preview on Read the Docs.
+
+on:
+  pull_request_target:
+    types:
+      - opened
+    paths:
+    - 'Doc/**'
+    - '.github/workflows/doc.yml'
+
+permissions:
+  pull-requests: write
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  documentation-links:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: readthedocs/actions/preview@v1
+        with:
+          project-slug: "cpython-previews"
+          single-version: "true"
diff --git a/.readthedocs.yml b/.readthedocs.yml
new file mode 100644
index 00000000000000..898a9ae89dbb92
--- /dev/null
+++ b/.readthedocs.yml
@@ -0,0 +1,18 @@
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+# Project page: https://readthedocs.org/projects/cpython-previews/
+
+version: 2
+
+sphinx:
+   configuration: Doc/conf.py
+
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3"
+
+  commands:
+    - make -C Doc venv html
+    - mkdir _readthedocs
+    - mv Doc/build/html _readthedocs/html
diff --git a/Doc/conf.py b/Doc/conf.py
index 216f12dd7ef2aa..138a18409983fc 100644
--- a/Doc/conf.py
+++ b/Doc/conf.py
@@ -109,6 +109,15 @@
 # Short title used e.g. for <title> HTML tags.
 html_short_title = '%s Documentation' % release
 
+# Deployment preview information
+# (See .readthedocs.yml and https://docs.readthedocs.io/en/stable/reference/environment-variables.html)
+repository_url = os.getenv("READTHEDOCS_GIT_CLONE_URL")
+html_context = {
+    "is_deployment_preview": os.getenv("READTHEDOCS_VERSION_TYPE") == "external",
+    "repository_url": repository_url.removesuffix(".git") if repository_url else None,
+    "pr_id": os.getenv("READTHEDOCS_VERSION")
+}
+
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
 html_last_updated_fmt = '%b %d, %Y'
diff --git a/Doc/tools/templates/layout.html b/Doc/tools/templates/layout.html
index 98ccf4224804b2..b91f8138553e62 100644
--- a/Doc/tools/templates/layout.html
+++ b/Doc/tools/templates/layout.html
@@ -8,6 +8,14 @@
     <a href="/3/{{ pagename }}{{ file_suffix }}">{% trans %} Python documentation for the current stable release{% endtrans %}</a>.
 </div>
 {%- endif %}
+
+{%- if is_deployment_preview %}
+<div id="deployment-preview-warning" style="padding: .5em; text-align: center; background-color: #fff2ba; color: #6a580e;">
+  {% trans %}This is a deploy preview created from a <a href="{{ repository_url }}/pull/{{ pr_id }}">pull request</a>.
+  For authoritative documentation, see the {% endtrans %}
+  <a href="https://docs.python.org/3/{{ pagename }}{{ file_suffix }}">{% trans %} the current stable release{% endtrans %}</a>.
+</div>
+{%- endif %}
 {% endblock %}
 
 {% block rootrellink %}