From 0f61bd060e2afb93659382a2805b1bde88659118 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20Mudr=C3=A1k?= <david@moodle.com>
Date: Mon, 19 Jan 2026 22:47:12 +0100
Subject: [PATCH] MDL-87520 core: Fix interpretation of CFG->branch in update
 API client

Starting in version 3.10, Moodle started to use a different format for
the $CFG->branch that has not been fixed here. This is to make sure that
we request the correct version of the plugin.
---
 lib/classes/update/api.php    | 19 +++++++++++++++----
 lib/tests/update_api_test.php | 19 +++++++++++++++++--
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/lib/classes/update/api.php b/lib/classes/update/api.php
index 60467f0ce9c..a3237dface2 100644
--- a/lib/classes/update/api.php
+++ b/lib/classes/update/api.php
@@ -297,15 +297,26 @@ class api {
      * versioning and stable branches numbering scheme. The API at
      * download.moodle.org uses the X.Y numbering scheme.
      *
-     * @param int $branch moodle branch in the XY format (e.g. 29, 30, 31 etc)
-     * @return string moodle branch in the X.Y format (e.g. 2.9, 3.0, 3.1 etc)
+     * Branch integers are interpreted differently from Moodle 3.10 onwards.
+     * 299 = 29.9 (prior to 3.10).
+     * 399 = 3.99 (3.10 onwards).
+     *
+     * @param int $branch moodle branch in the XY format (e.g. 29, 30, 31, 311, 502 etc)
+     * @return string moodle branch in the X.Y format (e.g. 2.9, 3.0, 3.1, 3.11, 5.2 etc)
      */
     protected function convert_branch_numbering_format($branch) {
 
-        $branch = (string)$branch;
+        $branch = (string) $branch;
 
         if (strpos($branch, '.') === false) {
-            $branch = substr($branch, 0, -1).'.'.substr($branch, -1);
+            $intbranch = (int) $branch;
+            if ($intbranch >= 310) {
+                $major = floor($intbranch / 100);
+                $minor = $intbranch - 100 * $major;
+                $branch = (string) ($major . '.' . $minor);
+            } else {
+                $branch = substr($branch, 0, -1) . '.' . substr($branch, -1);
+            }
         }
 
         return $branch;
diff --git a/lib/tests/update_api_test.php b/lib/tests/update_api_test.php
index 781d613c469..ce5646a6020 100644
--- a/lib/tests/update_api_test.php
+++ b/lib/tests/update_api_test.php
@@ -45,11 +45,26 @@ final class update_api_test extends \advanced_testcase {
         $client = \core\update\testable_api::client();
 
         $this->assertSame('2.9', $client->convert_branch_numbering_format(29));
+        $this->assertSame('29.9', $client->convert_branch_numbering_format(299));
         $this->assertSame('3.0', $client->convert_branch_numbering_format('30'));
         $this->assertSame('3.1', $client->convert_branch_numbering_format(3.1));
+        $this->assertSame('3.1', $client->convert_branch_numbering_format(3.10));
         $this->assertSame('3.1', $client->convert_branch_numbering_format('3.1'));
-        $this->assertSame('10.1', $client->convert_branch_numbering_format(101));
-        $this->assertSame('10.2', $client->convert_branch_numbering_format('102'));
+        $this->assertSame('3.10', $client->convert_branch_numbering_format(310));
+        $this->assertSame('3.10', $client->convert_branch_numbering_format('310'));
+        $this->assertSame('3.10', $client->convert_branch_numbering_format('3.10'));
+        $this->assertSame('3.11', $client->convert_branch_numbering_format(311));
+        $this->assertSame('3.99', $client->convert_branch_numbering_format(399));
+        $this->assertSame('4.0', $client->convert_branch_numbering_format(400));
+        $this->assertSame('4.1', $client->convert_branch_numbering_format(401));
+        $this->assertSame('5.2', $client->convert_branch_numbering_format(502));
+        $this->assertSame('5.2', $client->convert_branch_numbering_format('502'));
+        $this->assertSame('9.0', $client->convert_branch_numbering_format(900));
+        $this->assertSame('9.9', $client->convert_branch_numbering_format(909));
+        $this->assertSame('9.99', $client->convert_branch_numbering_format(999));
+        $this->assertSame('10.0', $client->convert_branch_numbering_format(1000));
+        $this->assertSame('10.1', $client->convert_branch_numbering_format(1001));
+        $this->assertSame('10.10', $client->convert_branch_numbering_format(1010));
     }
 
     /**