MDL-50624 environment: add PHP7 as unsupported version

Added PHP7 as an unsupported version for Moodle 2.8 and 2.9 in
the environment checks

admin/environment.xml

@@ -1150,6 +1150,7 @@
       <VENDOR name="oracle" version="10.2" />
     </DATABASE>
     <PHP version="5.4.4" level="required">
+      <RESTRICT function="restrict_php_version_7" message="unsupportedphpversion7" />
     </PHP>
     <PCREUNICODE level="optional">
       <FEEDBACK>
@@ -1273,6 +1274,7 @@
       <VENDOR name="oracle" version="10.2" />
     </DATABASE>
     <PHP version="5.4.4" level="required">
+      <RESTRICT function="restrict_php_version_7" message="unsupportedphpversion7" />
     </PHP>
     <PCREUNICODE level="optional">
       <FEEDBACK>

lang/en/admin.php

@@ -1072,6 +1072,7 @@
 $string['unsupported'] = 'Unsupported';
 $string['unsupporteddbstorageengine'] = 'The database storage engine being used is no longer supported.';
 $string['unsupporteddbtablerowformat'] = 'Your database has tables using Antelope as the file format. You are recommended to convert the tables to the Barracuda file format. See the documentation <a href="https://docs.moodle.org/en/cli">Administration via command line</a> for details of a tool for converting InnoDB tables to Barracuda.';
+$string['unsupportedphpversion7'] = 'PHP version 7 is not supported.';
 $string['unsuspenduser'] = 'Activate user account';
 $string['updateaccounts'] = 'Update existing accounts';
 $string['updatecomponent'] = 'Update component';

lib/environmentlib.php

@@ -1538,3 +1538,37 @@ function process_environment_result($element, &$result) {
 /// Process restrict, modifying $result if needed.
     process_environment_restrict($element, $result);
 }
+
+/**
+ * Check if the current PHP version is greater than or equal to
+ * PHP version 7.
+ *
+ * @param object $result an environment_results instance
+ * @return bool result of version check
+ */
+function restrict_php_version_7(&$result) {
+    return restrict_php_version($result, '7');
+}
+
+/**
+ * Check if the current PHP version is greater than or equal to an
+ * unsupported version.
+ *
+ * @param object $result an environment_results instance
+ * @param string $version the version of PHP that can't be used
+ * @return bool result of version check
+ */
+function restrict_php_version(&$result, $version) {
+
+    // Get the current PHP version.
+    $currentversion = normalize_version(phpversion());
+
+    // Confirm we're using a supported PHP version.
+    if (version_compare($currentversion, $version, '<')) {
+        // Everything is ok, the restriction doesn't apply.
+        return false;
+    } else {
+        // We're using an unsupported PHP version, apply restriction.
+        return true;
+    }
+}

lib/tests/environment_test.php

@@ -128,4 +128,69 @@ public function test_verify_plugin() {
         $this->assertFalse(environment_verify_plugin('mod_someother', $plugin1['PLUGIN']));
         $this->assertFalse(environment_verify_plugin('mod_someother', $plugin2['PLUGIN']));
     }
+
+    /**
+     * Test the restrict_php_version() function returns true if the current
+     * PHP version is greater than the restricted version
+     */
+    public function test_restrict_php_version_greater_than_restricted_version() {
+        global $CFG;
+        require_once($CFG->libdir.'/environmentlib.php');
+
+        $result = new environment_results('php');
+        $delimiter = '.';
+        // Get the current PHP version.
+        $currentversion = explode($delimiter, normalize_version(phpversion()));
+        // Lets drop back one major version to ensure we trip the restriction.
+        $currentversion[0]--;
+        $restrictedversion = implode($delimiter, $currentversion);
+
+        // Make sure the status is true before the test to see it flip to false.
+        $result->setStatus(true);
+
+        $this->assertTrue(restrict_php_version($result, $restrictedversion),
+            'restrict_php_version returns true if the current version exceeds the restricted version');
+    }
+
+    /**
+     * Test the restrict_php_version() function returns true if the current
+     * PHP version is equal to the restricted version
+     */
+    public function test_restrict_php_version_equal_to_restricted_version() {
+        global $CFG;
+        require_once($CFG->libdir.'/environmentlib.php');
+
+        $result = new environment_results('php');
+        // Get the current PHP version.
+        $currentversion = normalize_version(phpversion());
+
+        // Make sure the status is true before the test to see it flip to false.
+        $result->setStatus(true);
+
+        $this->assertTrue(restrict_php_version($result, $currentversion),
+            'restrict_php_version returns true if the current version is equal to the restricted version');
+    }
+
+    /**
+     * Test the restrict_php_version() function returns false if the current
+     * PHP version is less than the restricted version
+     */
+    public function test_restrict_php_version_less_than_restricted_version() {
+        global $CFG;
+        require_once($CFG->libdir.'/environmentlib.php');
+
+        $result = new environment_results('php');
+        $delimiter = '.';
+        // Get the current PHP version.
+        $currentversion = explode($delimiter, normalize_version(phpversion()));
+        // Lets increase the major version to ensure don't trip the restriction.
+        $currentversion[0]++;
+        $restrictedversion = implode($delimiter, $currentversion);
+
+        // Make sure the status is true before the test to see it flip to false.
+        $result->setStatus(true);
+
+        $this->assertFalse(restrict_php_version($result, $restrictedversion),
+            'restrict_php_version returns false if the current version is less than the restricted version');
+    }
 }