Add deprecated-removed directive to Sphinx (#4912)

* Add `deprecated-removed` directive to Sphinx

* Add equivalent function to internal utils

docs/_ext/deprecated_removed.py

@@ -0,0 +1,129 @@
+"""
+A Sphinx extension adding a ``deprecated-removed`` directive that works
+similarly to CPython's directive with the same name.
+
+The key difference is that instead of passing the version of planned removal,
+the writer must provide the minimum amount of days that must pass
+since the date of the release it was deprecated in.
+
+Due to lack of a concrete release schedule for Red, this ensures that
+we give enough time to people affected by the changes no matter
+when the releases actually happen.
+
+`DeprecatedRemoved` class is heavily based on
+`sphinx.domains.changeset.VersionChange` class that is available at:
+https://github.com/sphinx-doc/sphinx/blob/0949735210abaa05b6448e531984f159403053f4/sphinx/domains/changeset.py
+
+Copyright 2007-2020 by the Sphinx team, see AUTHORS:
+https://github.com/sphinx-doc/sphinx/blob/82f495fed386c798735adf675f867b95d61ee0e1/AUTHORS
+
+The original copy was distributed under BSD License and this derivative work
+is distributed under GNU GPL Version 3.
+"""
+
+import datetime
+import multiprocessing
+import subprocess
+from typing import Any, Dict, List, Optional
+
+from docutils import nodes
+from sphinx import addnodes
+from sphinx.application import Sphinx
+from sphinx.util.docutils import SphinxDirective
+
+
+class TagDateCache:
+    def __init__(self) -> None:
+        self._tags: Dict[str, datetime.date] = {}
+
+    def _populate_tags(self) -> None:
+        with _LOCK:
+            if self._tags:
+                return
+            out = subprocess.check_output(
+                ("git", "tag", "-l", "--format", "%(creatordate:raw)\t%(refname:short)"),
+                text=True,
+            )
+            lines = out.splitlines(False)
+            for line in lines:
+                creator_date, tag_name = line.split("\t", maxsplit=1)
+                timestamp = int(creator_date.split(" ", maxsplit=1)[0])
+                self._tags[tag_name] = datetime.datetime.fromtimestamp(
+                    timestamp, tz=datetime.timezone.utc
+                ).date()
+
+    def get_tag_date(self, tag_name: str) -> Optional[datetime.date]:
+        self._populate_tags()
+        return self._tags.get(tag_name)
+
+
+_LOCK = multiprocessing.Manager().Lock()
+_TAGS = TagDateCache()
+
+
+class DeprecatedRemoved(SphinxDirective):
+    has_content = True
+    required_arguments = 2
+    optional_arguments = 1
+    final_argument_whitespace = True
+
+    def run(self) -> List[nodes.Node]:
+        # Some Sphinx stuff
+        node = addnodes.versionmodified()
+        node.document = self.state.document
+        self.set_source_info(node)
+        node["type"] = self.name
+        node["version"] = tuple(self.arguments)
+        if len(self.arguments) == 3:
+            inodes, messages = self.state.inline_text(self.arguments[2], self.lineno + 1)
+            para = nodes.paragraph(self.arguments[2], "", *inodes, translatable=False)
+            self.set_source_info(para)
+            node.append(para)
+        else:
+            messages = []
+
+        # Text generation
+        deprecation_version = self.arguments[0]
+        minimum_days = int(self.arguments[1])
+        tag_date = _TAGS.get_tag_date(deprecation_version)
+        text = (
+            f"Will be deprecated in version {deprecation_version},"
+            " and removed in the first minor version that gets released"
+            f" after {minimum_days} days since deprecation"
+            if tag_date is None
+            else f"Deprecated since version {deprecation_version},"
+            " will be removed in the first minor version that gets released"
+            f" after {tag_date + datetime.timedelta(days=minimum_days)}"
+        )
+
+        # More Sphinx stuff
+        if self.content:
+            self.state.nested_parse(self.content, self.content_offset, node)
+        classes = ["versionmodified"]
+        if len(node):
+            if isinstance(node[0], nodes.paragraph) and node[0].rawsource:
+                content = nodes.inline(node[0].rawsource, translatable=True)
+                content.source = node[0].source
+                content.line = node[0].line
+                content += node[0].children
+                node[0].replace_self(nodes.paragraph("", "", content, translatable=False))
+
+            node[0].insert(0, nodes.inline("", f"{text}: ", classes=classes))
+        else:
+            para = nodes.paragraph(
+                "", "", nodes.inline("", f"{text}.", classes=classes), translatable=False
+            )
+            node.append(para)
+
+        ret = [node]
+        ret += messages
+
+        return ret
+
+
+def setup(app: Sphinx) -> Dict[str, Any]:
+    app.add_directive("deprecated-removed", DeprecatedRemoved)
+    return {
+        "version": "1.0",
+        "parallel_read_safe": True,
+    }

docs/conf.py

@@ -21,6 +21,7 @@ import os
 import sys
 
 sys.path.insert(0, os.path.abspath(".."))
+sys.path.insert(0, os.path.abspath("_ext"))
 
 os.environ["BUILDING_DOCS"] = "1"
 
@@ -42,6 +43,7 @@ extensions = [
     "sphinx.ext.napoleon",
     "sphinx.ext.doctest",
     "sphinxcontrib_trio",
+    "deprecated_removed",
 ]
 
 # Add any paths that contain templates here, relative to this directory.

redbot/core/utils/_internal_utils.py

@@ -8,6 +8,7 @@ import os
 import re
 import shutil
 import tarfile
+import warnings
 from datetime import datetime
 from pathlib import Path
 from typing import (
@@ -46,6 +47,7 @@ __all__ = (
     "send_to_owners_with_prefix_replaced",
     "expected_version",
     "fetch_latest_red_version_info",
+    "deprecated_removed",
 )
 
 
@@ -317,3 +319,19 @@ async def fetch_latest_red_version_info() -> Tuple[Optional[VersionInfo], Option
         required_python = data["info"]["requires_python"]
 
         return release, required_python
+
+
+def deprecated_removed(
+    deprecation_target: str,
+    deprecation_version: str,
+    minimum_days: int,
+    message: str = "",
+    stacklevel: int = 1,
+) -> None:
+    warnings.warn(
+        f"{deprecation_target} is deprecated since version {deprecation_version}"
+        " and will be removed in the first minor version that gets released"
+        f" after {minimum_days} days since deprecation. {message}",
+        DeprecationWarning,
+        stacklevel=stacklevel + 1,
+    )