Clarify support for an optional v-prefix in branch and tag names (#11712)

* Clarify support for an optional v-prefix in branch and tag names

* Add info about v-prefix in automation rules docs

Author: laymonage

docs/user/automation-rules.rst

@@ -46,7 +46,8 @@ Predefined matches
 Automation rules support two predefined version matches:
 
 - **Any version**: All new versions will match the rule.
-- **SemVer versions**: All new versions that follow `semantic versioning <https://semver.org/>`__ will match the rule.
+- **SemVer versions**: All new versions that follow `semantic versioning <https://semver.org/>`__
+  (with or without a `v` prefix) will match the rule.
 
 Custom matches
 ~~~~~~~~~~~~~~

docs/user/versions.rst

@@ -19,7 +19,8 @@ During initial setup, Read the Docs also creates a ``latest`` version
 that points to the default branch defined in your Git repository (usually ``main``).
 This version should always exist and is the default version for your project.
 
-If your project has any tags or branches with a name following `semantic versioning <https://semver.org/>`_,
+If your project has any tags or branches with a name following
+`semantic versioning <https://semver.org/>`_ (with or without a ``v`` prefix),
 we also create a ``stable`` version tracking your most recent release.
 If you want a custom ``stable`` version,
 create either a tag or branch in your project with that name.
@@ -135,6 +136,7 @@ all of which can be reconfigured if necessary:
 
   Semantic versioning allows "normal" version numbers like ``1.4.2``, as
   well as pre-releases like this: ``2.0a1``. The ``stable`` version of your documentation never includes a pre-release.
+  An optional ``v`` prefix like ``v1.4.2`` or ``v2.0a1`` is also allowed.
 
 - Branches are assumed to be **long-lived branches**,
   This is most useful for **release branches**, which are maintained over time for a specific release.

readthedocs/builds/constants.py

@@ -130,6 +130,8 @@
 
 # Pattern referred from
 # https://semver.org/#is-there-a-suggested-regular-expression-regex-to-check-a-semver-string
+# without naming the capturing groups and with the addition of
+# allowing an optional "v" prefix.
 SEMVER_VERSIONS_REGEX = r"^v?(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$"  # noqa