From 3f1519f2e739cb8bab4aba4c5b2e0674ff2a6790 Mon Sep 17 00:00:00 2001
From: Daniel Mensinger <daniel@mensinger-ka.de>
Date: Wed, 1 Dec 2021 23:41:48 +0100
Subject: [PATCH] cmake: Deprecate CMake <3.14 and warn for <3.17 (#9677)

* cmake: Deprecate CMake <3.14 and warn for <3.17

See:

- #7832
- #9676

* cmake: Add deprecation release note snippet
---
 docs/markdown/snippets/cmake_deprecated.md |  7 +++++++
 mesonbuild/cmake/interpreter.py            | 14 ++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100644 docs/markdown/snippets/cmake_deprecated.md

diff --git a/docs/markdown/snippets/cmake_deprecated.md b/docs/markdown/snippets/cmake_deprecated.md
new file mode 100644
index 000000000..9e456e7a8
--- /dev/null
+++ b/docs/markdown/snippets/cmake_deprecated.md
@@ -0,0 +1,7 @@
+## Support for CMake <3.14 is now deprecated for CMake subprojects
+
+In CMake 3.14, the File API was introduced and the old CMake server API was
+deprecated (and removed in CMake 3.20). Thus support for this API will also
+be removed from Meson in future releases.
+
+This deprecation only affects CMake subprojects.
diff --git a/mesonbuild/cmake/interpreter.py b/mesonbuild/cmake/interpreter.py
index a8ed67cb0..c2e2d2722 100644
--- a/mesonbuild/cmake/interpreter.py
+++ b/mesonbuild/cmake/interpreter.py
@@ -33,6 +33,7 @@ from functools import lru_cache
 from pathlib import Path
 import typing as T
 import re
+import textwrap
 from os import environ
 
 from ..mparser import (
@@ -832,6 +833,19 @@ class CMakeInterpreter:
         if version_compare(cmake_exe.version(), '>=3.14'):
             self.cmake_api = CMakeAPI.FILE
             self.fileapi.setup_request()
+        else:
+            mlog.deprecation(f'Support for CMake <3.14 (Meson found {cmake_exe.version()}) is deprecated since Meson 0.61.0')
+
+        if version_compare(cmake_exe.version(), '<3.17.0'):
+            mlog.warning(textwrap.dedent(f'''\
+                The minimum recommended CMake version is 3.17.0.
+                |
+                |   However, Meson was only able to find CMake {cmake_exe.version()} at {cmake_exe.cmakebin.command}.
+                |
+                |   Support for all CMake versions below 3.17.0 will be deprecated and
+                |   removed once newer CMake versions are more widely adopted. If you encounter
+                |   any errors please try upgrading CMake to a newer version first.
+            '''))
 
         # Run CMake
         mlog.log()