[wrynose][PATCH 02/20] upstream-stable-release-point.bbclass: add bbclass for stable point upgrade

[<daniel.turull@ericsson.com>]

From: Chen Qi <Qi.Chen@windriver.com>

If a recipe can do stable version upgrade and the stable parts of the version
is seperated by '.', then it can inherit this bbclass.

By default, the stable parts number is 2, which means the following upgrades
are stable version upgrades:
x.y.z -> x.y.z+1
x.y.z+1 -> x.y.z+1.zz
x.y.z+1.zz -> x.y.z+2

Recipes that have different stable version parts can also inherit this bbclass
and set STABLE_VERSION_PARTS. For example, systemd sets this variable to "1".

For recipes whose stable version part is not separated by '.', they should not
inherit this bbclass and intead set UPSTREAM_STABLE_RELEASE_REGEX themselves.
For example, openssh's stable part is separted by 'p' and should not inherit
this bbclass.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

(cherry picked from commit a1e069d04cb13e990b362804bd56a4935338ef96)
Signed-off-by: Daniel Turull <daniel.turull@ericsson.com>
---
 .../upstream-stable-release-point.bbclass     | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 meta/classes-recipe/upstream-stable-release-point.bbclass

diff --git a/meta/classes-recipe/upstream-stable-release-point.bbclass b/meta/classes-recipe/upstream-stable-release-point.bbclass
new file mode 100644
index 0000000000..98fdb5b808
--- /dev/null
+++ b/meta/classes-recipe/upstream-stable-release-point.bbclass
@@ -0,0 +1,21 @@
+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: MIT
+#
+
+#
+# This bbclass is expected to be inherited by recipes explicitly.
+# If a recipe's version is separated by point and we know for sure
+# which parts of the version represent the stable part, then the
+# recipe could inherit this bbclass.
+#
+
+STABLE_VERSION_PARTS ?= "2"
+def get_majmin_version_regex(d):
+    pv = d.getVar('PV')
+    stable_parts = pv.split('.')[:int(d.getVar('STABLE_VERSION_PARTS'))]
+    return r'\.'.join(stable_parts)
+
+STABLE_VERSION_REGEX = "${@get_majmin_version_regex(d)}"
+UPSTREAM_STABLE_RELEASE_REGEX ?= "^${STABLE_VERSION_REGEX}(\.\d+)*$"