[PATCH v2] build: automatically report minimum meson version

[Bruce Richardson <bruce.richardson@intel.com>]

Add a script to buildtools to report the minimum meson version given in
our meson.build file. Then use this script in two ways:

1. in the .ci/linux-setup.sh script, use the auto-determined minimum
   version to set up the CI, rather than hard-coding it.
2. in meson.build call the script to report the version. This serves as
   a sanity check to ensure that any changes to meson.build file do not
   break the script.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Patrick Robb <probb@iol.unh.edu>
---
v2: rebased to latest main
---
 .ci/linux-setup.sh                  |  6 +++++-
 buildtools/get-min-meson-version.py | 26 ++++++++++++++++++++++++++
 buildtools/meson.build              |  5 +++++
 3 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100755 buildtools/get-min-meson-version.py

diff --git a/.ci/linux-setup.sh b/.ci/linux-setup.sh
index 938d492cbb..e025ca0243 100755
--- a/.ci/linux-setup.sh
+++ b/.ci/linux-setup.sh
@@ -3,8 +3,12 @@
 # Builds are run as root in containers, no need for sudo
 [ "$(id -u)" != '0' ] || alias sudo=
 
+# determine minimum meson version
+ci_dir=$(dirname $(readlink -f $0))
+meson_ver=$(python3 $ci_dir/../buildtools/get-min-meson-version.py)
+
 # need to install as 'root' since some of the unit tests won't run without it
-sudo python3 -m pip install --upgrade 'meson==0.57.2'
+sudo python3 -m pip install --upgrade "meson==$meson_ver"
 
 # setup hugepages. error ignored because having hugepage is not mandatory.
 cat /proc/meminfo
diff --git a/buildtools/get-min-meson-version.py b/buildtools/get-min-meson-version.py
new file mode 100755
index 0000000000..f0de8fdf2b
--- /dev/null
+++ b/buildtools/get-min-meson-version.py
@@ -0,0 +1,26 @@
+#! /usr/bin/env python3
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2024 Intel Corporation
+
+import os
+import re
+import sys
+from os.path import dirname, realpath, join
+
+buildtools_path = dirname(realpath(__file__))
+basedir = dirname(buildtools_path)
+
+with open(join(basedir, "meson.build")) as f:
+    for ln in f.readlines():
+        if "meson_version" not in ln:
+            continue
+
+        ln = ln.strip()
+        ver_match = re.search(r"meson_version:\s*'>=\s*([0-9\.]+)'", ln)
+        if not ver_match:
+            print(
+                f"Meson version specifier not in recognised format: '{ln}'",
+                file=sys.stderr,
+            )
+            sys.exit(1)
+        print(ver_match.group(1), end="")
diff --git a/buildtools/meson.build b/buildtools/meson.build
index 1cd1ce02fd..cc0198081d 100644
--- a/buildtools/meson.build
+++ b/buildtools/meson.build
@@ -26,6 +26,11 @@ header_gen_cmd = py3 + files('gen-header.py')
 has_hugepages_cmd = py3 + files('has-hugepages.py')
 cmdline_gen_cmd = py3 + files('dpdk-cmdline-gen.py')
 check_dts_requirements = py3 + files('check-dts-requirements.py')
+get_min_meson_version_cmd = py3 + files('get-min-meson-version.py')
+
+# check that we can correctly report minimum meson version
+min_ver = run_command(get_min_meson_version_cmd, check: true, capture: true)
+message('Minimum meson required version is ' + min_ver.stdout())
 
 # install any build tools that end-users might want also
 install_data([
-- 
2.45.2