Merge branch 'MDL-43820-master' of https://github.com/ilyatregubov/moodle

admin/tool/uploadcourse/classes/course.php

@@ -1022,16 +1022,10 @@ class tool_uploadcourse_course {
         }
 
         $enrolmentplugins = tool_uploadcourse_helper::get_enrolment_plugins();
-        $instances = enrol_get_instances($course->id, false);
         foreach ($enrolmentdata as $enrolmethod => $method) {
 
-            $instance = null;
-            foreach ($instances as $i) {
-                if ($i->enrol == $enrolmethod) {
-                    $instance = $i;
-                    break;
-                }
-            }
+            $plugin = $enrolmentplugins[$enrolmethod];
+            $instance = $plugin->find_instance($method, $course->id);
 
             $todelete = isset($method['delete']) && $method['delete'];
             $todisable = isset($method['disable']) && $method['disable'];

admin/tool/uploadcourse/tests/behat/cohorts.feature

@@ -38,14 +38,15 @@ Feature: An admin can create courses with cohort enrolments using a CSV file
     Given I upload "admin/tool/uploadcourse/tests/fixtures/enrolment_cohort.csv" file to "File" filemanager
     And I click on "Preview" "button"
     And I should see "Unknown cohort (Not exist)!"
-    And I should see "Cohort Cohort 3 not allowed in this context."
+    And I should see "Cohort CV3 not allowed in this context."
     When I click on "Upload courses" "button"
     And I should see "Unknown cohort (Not exist)!"
-    And I should see "Cohort Cohort 3 not allowed in this context."
-    And I should see "Cohort Cohort 4 not allowed in this context."
+    And I should see "Cohort CV3 not allowed in this context."
+    And I should see "Cohort CV4 not allowed in this context."
+    And I should see "Invalid role names: student1"
     And I should see "Courses created: 2"
     And I should see "Courses updated: 0"
-    And I should see "Courses errors: 3"
+    And I should see "Courses errors: 4"
     And I am on the "Course 1" "enrolment methods" page
     Then I should not see "Cohort sync (Cohort 3 - Student)"
     And I am on the "Course 2" "enrolment methods" page
@@ -54,6 +55,13 @@ Feature: An admin can create courses with cohort enrolments using a CSV file
     And I should see "Cohort sync (Cohort 5 - Student)"
     And I click on "Edit" "link" in the "Cohort 5" "table_row"
     And the field "Add to group" matches value "None"
+    And I navigate to "Courses > Upload courses" in site administration
+    And I set the field "Upload mode" to "Create new courses, or update existing ones"
+    And I set the field "Update mode" to "Update with CSV data only"
+    And I upload "admin/tool/uploadcourse/tests/fixtures/enrolment_cohort_missing_fields.csv" file to "File" filemanager
+    And I click on "Preview" "button"
+    And I should see "Missing value for mandatory fields: cohortidnumber, role"
+    And "Upload courses" "button" should exist
 
   @javascript
   Scenario: Validation of groups for uploaded courses with cohort enrolments
@@ -103,3 +111,18 @@ Feature: An admin can create courses with cohort enrolments using a CSV file
     And the field "Add to group" matches value "group1"
     And I am on the "Course 1" "groups" page
     And I should see "group1"
+
+  @javascript
+  Scenario: Upload multiple enrolment methods of same type to the same course
+    Given I upload "admin/tool/uploadcourse/tests/fixtures/enrolment_cohort_multiple.csv" file to "File" filemanager
+    And I click on "Preview" "button"
+    When I click on "Upload courses" "button"
+    And I should see "Courses updated: 2"
+    And I am on the "Course 1" "enrolment methods" page
+    Then I should see "Cohort sync (Cohort 1 - Student)"
+    And I should see "Cohort sync (Cohort 4 - Non-editing teacher)"
+    And I click on "Edit" "link" in the "Cohort 1" "table_row"
+    And the field "Assign role" matches value "Student"
+    And I press "Cancel"
+    And I click on "Edit" "link" in the "Cohort 4" "table_row"
+    And the field "Assign role" matches value "Non-editing teacher"

admin/tool/uploadcourse/tests/fixtures/enrolment_cohort.csv

@@ -1,5 +1,6 @@
-shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortname
+shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortidnumber
 C1,Course 1,CAT1,cohort,student,Not exist
-C1,Course 1,CAT1,cohort,student,Cohort 3
-C2,Course 2,CAT2,cohort,student,Cohort 4
-C3,Course 3,CAT1,cohort,student,Cohort 5
+C1,Course 1,CAT1,cohort,student,CV3
+C2,Course 2,CAT2,cohort,student,CV4
+C3,Course 3,CAT1,cohort,student,CV5
+C4,Course 3,CAT1,cohort,student1,CV6

admin/tool/uploadcourse/tests/fixtures/enrolment_cohort_addtogroup.csv

@@ -1,3 +1,3 @@
-shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortname,enrolment_1_addtogroup
-C2,Course 2,CAT2,cohort,student,Cohort 2,1
-C3,Course 3,CAT1,cohort,student,Cohort 1,0
+shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortidnumber,enrolment_1_addtogroup
+C2,Course 2,CAT2,cohort,student,CV2,1
+C3,Course 3,CAT1,cohort,student,CV1,0

admin/tool/uploadcourse/tests/fixtures/enrolment_cohort_addtogroup_groupname.csv

@@ -1,2 +1,2 @@
-shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortname,enrolment_1_addtogroup,enrolment_1_groupname
-C1,Course 1,CAT1,cohort,student,Cohort 1,0,group1
+shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortidnumber,enrolment_1_addtogroup,enrolment_1_groupname
+C1,Course 1,CAT1,cohort,student,CV1,0,group1

admin/tool/uploadcourse/tests/fixtures/enrolment_cohort_groups.csv

@@ -1,3 +1,3 @@
-shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortname,enrolment_1_groupname
-C1,Course 1,CAT1,cohort,student,Cohort 1,notexist
-C1,Course 1,CAT1,cohort,student,Cohort 1,group1
+shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortidnumber,enrolment_1_groupname
+C1,Course 1,CAT1,cohort,student,CV1,notexist
+C1,Course 1,CAT1,cohort,student,CV1,group1

admin/tool/uploadcourse/tests/fixtures/enrolment_cohort_missing_fields.csv

@@ -0,0 +1,2 @@
+shortname,fullname,category_idnumber,enrolment_1
+C1,Course 1,CAT1,cohort

admin/tool/uploadcourse/tests/fixtures/enrolment_cohort_multiple.csv

@@ -0,0 +1,3 @@
+shortname,fullname,category_idnumber,enrolment_1,enrolment_1_role,enrolment_1_cohortidnumber
+C1,Course 1,CAT1,cohort,student,CV1
+C1,Course 1,CAT1,cohort,teacher,CV4

enrol/cohort/lib.php

@@ -550,20 +550,37 @@ class enrol_cohort_plugin extends enrol_plugin {
             }
         }
 
-        if (!isset($enrolmentdata['cohortname'])) {
-            $errors['missingmandatoryfields'] =
-                new lang_string('missingmandatoryfields', 'tool_uploadcourse',
-                    'cohortname');
+        if (!isset($enrolmentdata['cohortidnumber'])) {
+            $missingmandatoryfields = 'cohortidnumber';
         } else {
-            $cohortname = $enrolmentdata['cohortname'];
-            // Cohort name is not unique.
-            $cohortid = $DB->get_field('cohort', 'MIN(id)', ['name' => $cohortname]);
+            $cohortidnumber = $enrolmentdata['cohortidnumber'];
+            // Cohort idnumber is unique.
+            $cohortid = $DB->get_field('cohort', 'id', ['idnumber' => $cohortidnumber]);
 
             if (!$cohortid) {
                 $errors['unknowncohort'] =
-                    new lang_string('unknowncohort', 'cohort', $cohortname);
+                    new lang_string('unknowncohort', 'cohort', $cohortidnumber);
             }
         }
+
+        if (!isset($enrolmentdata['role'])) {
+            // We require role since we need it to identify enrol instance.
+            if (isset($missingmandatoryfields)) {
+                $missingmandatoryfields .= ', role';
+            } else {
+                $missingmandatoryfields = 'role';
+            }
+            $errors['missingmandatoryfields'] =
+                new lang_string('missingmandatoryfields', 'tool_uploadcourse',
+                    $missingmandatoryfields);
+        } else {
+            $roleid = $DB->get_field('role', 'id', ['shortname' => $enrolmentdata['role']]);
+            if (!$roleid) {
+                $errors['unknownrole'] =
+                    new lang_string('unknownrole', 'error', s($enrolmentdata['role']));
+            }
+        }
+
         return $errors;
     }
 
@@ -577,9 +594,11 @@ class enrol_cohort_plugin extends enrol_plugin {
     public function fill_enrol_custom_fields(array $enrolmentdata, int $courseid) : array {
         global $DB;
 
-        // Cohort name is not unique.
-        $enrolmentdata['customint1'] =
-            $DB->get_field('cohort', 'MIN(id)', ['name' => $enrolmentdata['cohortname']]);
+        if (isset($enrolmentdata['cohortidnumber'])) {
+            // Cohort idnumber is unique.
+            $enrolmentdata['customint1'] =
+                $DB->get_field('cohort', 'id', ['idnumber' => $enrolmentdata['cohortidnumber']]);
+        }
 
         if (isset($enrolmentdata['addtogroup'])) {
             if ($enrolmentdata['addtogroup'] == COHORT_NOGROUP) {
@@ -602,10 +621,12 @@ class enrol_cohort_plugin extends enrol_plugin {
      */
     public function validate_plugin_data_context(array $enrolmentdata, ?int $courseid = null) : ?lang_string {
         $error = null;
-        $cohortid = $enrolmentdata['customint1'];
-        $coursecontext = \context_course::instance($courseid);
-        if (!cohort_get_cohort($cohortid, $coursecontext)) {
-            $error = new lang_string('contextcohortnotallowed', 'cohort', $enrolmentdata['cohortname']);
+        if (isset($enrolmentdata['customint1'])) {
+            $cohortid = $enrolmentdata['customint1'];
+            $coursecontext = \context_course::instance($courseid);
+            if (!cohort_get_cohort($cohortid, $coursecontext)) {
+                $error = new lang_string('contextcohortnotallowed', 'cohort', $enrolmentdata['cohortidnumber']);
+            }
         }
         return $error;
     }
@@ -634,6 +655,33 @@ class enrol_cohort_plugin extends enrol_plugin {
     public function is_csv_upload_supported(): bool {
         return true;
     }
+
+    /**
+     * Finds matching instances for a given course.
+     *
+     * @param array $enrolmentdata enrolment data.
+     * @param int $courseid Course ID.
+     * @return stdClass|null Matching instance
+     */
+    public function find_instance(array $enrolmentdata, int $courseid) : ?stdClass {
+        global $DB;
+        $instances = enrol_get_instances($courseid, false);
+
+        $instance = null;
+        if (isset($enrolmentdata['cohortidnumber']) && isset($enrolmentdata['role'])) {
+            $cohortid = $DB->get_field('cohort', 'id', ['idnumber' => $enrolmentdata['cohortidnumber']]);
+            $roleid = $DB->get_field('role', 'id', ['shortname' => $enrolmentdata['role']]);
+            if ($cohortid && $roleid) {
+                foreach ($instances as $i) {
+                    if ($i->enrol == 'cohort' && $i->customint1 == $cohortid && $i->roleid == $roleid) {
+                        $instance = $i;
+                        break;
+                    }
+                }
+            }
+        }
+        return $instance;
+    }
 }
 
 /**

enrol/cohort/tests/lib_test.php

@@ -226,12 +226,18 @@ class lib_test extends \advanced_testcase {
 
         $course = $this->getDataGenerator()->create_course(['category' => $cat1->id, 'shortname' => 'ANON']);
 
-        $cohort1 = $this->getDataGenerator()->create_cohort(['contextid' => \context_coursecat::instance($cat1->id)->id]);
-        $cohort2 = $this->getDataGenerator()->create_cohort(['contextid' => \context_coursecat::instance($cat2->id)->id]);
+        $cohort1 = $this->getDataGenerator()->create_cohort([
+            'contextid' => \context_coursecat::instance($cat1->id)->id,
+            'idnumber' => 'one',
+        ]);
+        $cohort2 = $this->getDataGenerator()->create_cohort([
+            'contextid' => \context_coursecat::instance($cat2->id)->id,
+            'idnumber' => 'two',
+        ]);
 
         $enrolmentdata = [
             'customint1' => $cohort2->id,
-            'cohortname' => $cohort2->name,
+            'cohortidnumber' => $cohort2->idnumber,
         ];
         $error = $cohortplugin->validate_plugin_data_context($enrolmentdata, $course->id);
         $this->assertInstanceOf('lang_string', $error);
@@ -239,7 +245,7 @@ class lib_test extends \advanced_testcase {
 
         $enrolmentdata = [
             'customint1' => $cohort1->id,
-            'cohortname' => $cohort1->name,
+            'cohortidnumber' => $cohort1->idnumber,
         ];
         $error = $cohortplugin->validate_plugin_data_context($enrolmentdata, $course->id);
         $this->assertNull($error);
@@ -257,22 +263,25 @@ class lib_test extends \advanced_testcase {
 
         $cat = $this->getDataGenerator()->create_category();
         $course = $this->getDataGenerator()->create_course(['category' => $cat->id, 'shortname' => 'ANON']);
-        $cohort = $this->getDataGenerator()->create_cohort(['contextid' => \context_coursecat::instance($cat->id)->id]);
+        $cohort = $this->getDataGenerator()->create_cohort([
+            'contextid' => \context_coursecat::instance($cat->id)->id,
+            'idnumber' => 'one',
+        ]);
         $group = $this->getDataGenerator()->create_group(['courseid' => $course->id]);
 
-        $enrolmentdata['cohortname'] = $cohort->name;
+        $enrolmentdata['cohortidnumber'] = $cohort->idnumber;
         $enrolmentdata = $cohortplugin->fill_enrol_custom_fields($enrolmentdata, $course->id);
         $this->assertArrayHasKey('customint1', $enrolmentdata);
         $this->assertEquals($cohort->id, $enrolmentdata['customint1']);
         $this->assertArrayNotHasKey('customint2', $enrolmentdata);
 
-        $enrolmentdata['cohortname'] = 'notexist';
+        $enrolmentdata['cohortidnumber'] = 'notexist';
         $enrolmentdata = $cohortplugin->fill_enrol_custom_fields($enrolmentdata, $course->id);
         $this->assertArrayHasKey('customint1', $enrolmentdata);
-        $this->assertNull($enrolmentdata['customint1']);
+        $this->assertFalse($enrolmentdata['customint1']);
         $this->assertArrayNotHasKey('customint2', $enrolmentdata);
 
-        $enrolmentdata['cohortname'] = $cohort->name;
+        $enrolmentdata['cohortidnumber'] = $cohort->idnumber;
 
         $enrolmentdata['addtogroup'] = COHORT_NOGROUP;
         $enrolmentdata = $cohortplugin->fill_enrol_custom_fields($enrolmentdata, $course->id);
@@ -313,8 +322,14 @@ class lib_test extends \advanced_testcase {
 
         $group1 = $this->getDataGenerator()->create_group(['courseid' => $course->id, 'name' => 'Group 1']);
 
-        $cohort1 = $this->getDataGenerator()->create_cohort(['contextid' => \context_coursecat::instance($cat1->id)->id]);
-        $cohort2 = $this->getDataGenerator()->create_cohort(['contextid' => \context_coursecat::instance($cat2->id)->id]);
+        $cohort1 = $this->getDataGenerator()->create_cohort([
+            'contextid' => \context_coursecat::instance($cat1->id)->id,
+            'idnumber' => 'one',
+        ]);
+        $cohort2 = $this->getDataGenerator()->create_cohort([
+            'contextid' => \context_coursecat::instance($cat2->id)->id,
+            'idnumber' => 'two',
+        ]);
 
         enrol::enable_plugin('cohort', false);
 
@@ -328,13 +343,14 @@ class lib_test extends \advanced_testcase {
 
         enrol::enable_plugin('cohort', true);
 
-        // Unknown cohort name.
-        $enrolmentdata['cohortname'] = 'test';
+        // Unknown cohort idnumber and missing role.
+        $enrolmentdata['cohortidnumber'] = 'test';
         $errors = $cohortplugin->validate_enrol_plugin_data($enrolmentdata);
+        $this->assertArrayHasKey('missingmandatoryfields', $errors);
         $this->assertArrayHasKey('unknowncohort', $errors);
 
         // Non-valid 'addtogroup' option.
-        $enrolmentdata['cohortname'] = $cohort1->name;
+        $enrolmentdata['cohortidnumber'] = $cohort1->idnumber;
         $enrolmentdata['addtogroup'] = 2;
         $errors = $cohortplugin->validate_enrol_plugin_data($enrolmentdata, $course->id);
         $this->assertArrayHasKey('erroraddtogroup', $errors);
@@ -346,7 +362,7 @@ class lib_test extends \advanced_testcase {
         $this->assertArrayHasKey('erroraddtogroupgroupname', $errors);
 
         // Cohort is not allowed on a given category context.
-        $enrolmentdata['cohortname'] = $cohort2->name;
+        $enrolmentdata['cohortidnumber'] = $cohort2->idnumber;
         $errors = $cohortplugin->validate_enrol_plugin_data($enrolmentdata, $course->id);
         $this->assertArrayHasKey('contextnotallowed', $errors);
 
@@ -355,8 +371,14 @@ class lib_test extends \advanced_testcase {
         $errors = $cohortplugin->validate_enrol_plugin_data($enrolmentdata, $course->id);
         $this->assertArrayHasKey('errorinvalidgroup', $errors);
 
+        // Unknown role.
+        $enrolmentdata['role'] = 'test';
+        $errors = $cohortplugin->validate_enrol_plugin_data($enrolmentdata, $course->id);
+        $this->assertArrayHasKey('unknownrole', $errors);
+
         // Valid data when trying to create a group.
-        $enrolmentdata['cohortname'] = $cohort1->name;
+        $enrolmentdata['cohortidnumber'] = $cohort1->idnumber;
+        $enrolmentdata['role'] = 'student';
         $enrolmentdata['addtogroup'] = 1;
         unset($enrolmentdata['groupname']);
         $errors = $cohortplugin->validate_enrol_plugin_data($enrolmentdata, $course->id);
@@ -375,4 +397,80 @@ class lib_test extends \advanced_testcase {
         $this->assertEmpty($errors);
     }
 
+    /**
+     * Test the behaviour of find_instance().
+     *
+     * @covers ::find_instance
+     */
+    public function test_find_instance() {
+        global $DB;
+        $this->resetAfterTest();
+
+        $cat = $this->getDataGenerator()->create_category();
+        $course = $this->getDataGenerator()->create_course(['category' => $cat->id, 'shortname' => 'ANON']);
+
+        $cohort1 = $this->getDataGenerator()->create_cohort([
+            'contextid' => \context_coursecat::instance($cat->id)->id,
+            'idnumber' => 'one',
+        ]);
+        $cohort2 = $this->getDataGenerator()->create_cohort([
+            'contextid' => \context_coursecat::instance($cat->id)->id,
+            'idnumber' => 'two',
+        ]);
+
+        $cohort3 = $this->getDataGenerator()->create_cohort([
+            'contextid' => \context_coursecat::instance($cat->id)->id,
+            'idnumber' => 'three',
+        ]);
+
+        $studentrole = $DB->get_record('role', ['shortname' => 'student']);
+        $teacherrole = $DB->get_record('role', ['shortname' => 'teacher']);
+        $managerrole = $DB->get_record('role', ['shortname' => 'manager']);
+        $cohortplugin = enrol_get_plugin('cohort');
+
+        // Add three cohort enrol instances.
+        $instanceid1 = $cohortplugin->add_instance($course, ['customint1' => $cohort1->id, 'roleid' => $teacherrole->id]);
+        $instanceid2 = $cohortplugin->add_instance($course, ['customint1' => $cohort2->id, 'roleid' => $managerrole->id]);
+        $instanceid3 = $cohortplugin->add_instance($course, ['customint1' => $cohort2->id, 'roleid' => $studentrole->id]);
+
+        $instance1 = $DB->get_record('enrol', ['id' => $instanceid1]);
+        $instance2 = $DB->get_record('enrol', ['id' => $instanceid2]);
+
+        $enrolmentdata = [];
+        $instance = $cohortplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertNull($instance);
+
+        // Unknown idnumber.
+        $enrolmentdata['cohortidnumber'] = 'test';
+        $instance = $cohortplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertNull($instance);
+
+        // Unknown role.
+        $enrolmentdata['role'] = 'test';
+        $enrolmentdata['cohortidnumber'] = $cohort1->idnumber;
+        $instance = $cohortplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertNull($instance);
+
+        // Cohort3 instance has not matching role and cohort.
+        $enrolmentdata['role'] = $teacherrole->shortname;
+        $enrolmentdata['cohortidnumber'] = $cohort3->idnumber;
+        $instance = $cohortplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertNull($instance);
+
+        // Cohort2 instance has matching cohort, but not matching role.
+        $enrolmentdata['role'] = $teacherrole->shortname;
+        $enrolmentdata['cohortidnumber'] = $cohort2->idnumber;
+        $instance = $cohortplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertNull($instance);
+
+        $enrolmentdata['role'] = $teacherrole->shortname;
+        $enrolmentdata['cohortidnumber'] = $cohort1->idnumber;
+        $instance = $cohortplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertEquals($instance1->id, $instance->id);
+
+        $enrolmentdata['role'] = $managerrole->shortname;
+        $enrolmentdata['cohortidnumber'] = $cohort2->idnumber;
+        $instance = $cohortplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertEquals($instance2->id, $instance->id);
+    }
 }

enrol/guest/lib.php

@@ -497,6 +497,28 @@ class enrol_guest_plugin extends enrol_plugin {
     public function is_csv_upload_supported(): bool {
         return true;
     }
+
+    /**
+     * Finds matching instances for a given course.
+     *
+     * @param array $enrolmentdata enrolment data.
+     * @param int $courseid Course ID.
+     * @return stdClass|null Matching instance
+     */
+    public function find_instance(array $enrolmentdata, int $courseid) : ?stdClass {
+
+        $instances = enrol_get_instances($courseid, false);
+        $instance = null;
+        foreach ($instances as $i) {
+            if ($i->enrol == 'guest') {
+                // There can be only one guest enrol instance so find first available.
+                $instance = $i;
+                break;
+            }
+        }
+        return $instance;
+    }
+
 }
 
 /**

enrol/guest/tests/lib_test.php

@@ -0,0 +1,59 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Guest enrolment tests.
+ *
+ * @package    enrol_guest
+ * @category   phpunit
+ * @copyright  2023 Ilya Tregubov <ilya.a.tregubov@gmail.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+namespace enrol_guest;
+
+class lib_test extends \advanced_testcase {
+
+    /**
+     * Test the behaviour of find_instance().
+     *
+     * @covers ::find_instance
+     */
+    public function test_find_instance() {
+        global $DB;
+        $this->resetAfterTest();
+
+        $cat = $this->getDataGenerator()->create_category();
+        // When we create a course, a guest enrolment instance is also created.
+        $course = $this->getDataGenerator()->create_course(['category' => $cat->id, 'shortname' => 'ANON']);
+
+        $guestplugin = enrol_get_plugin('guest');
+
+        $expected = $DB->get_record('enrol', ['courseid' => $course->id, 'enrol' => 'guest']);
+
+        // Let's try to add second instance - only 1 guest instance is possible.
+        $instanceid2 = null;
+        // Have to do this check since add_instance doesn't block adding second instance for guest plugin.
+        if ($guestplugin->can_add_instance($course->id)) {
+            $instanceid2 = $guestplugin->add_instance($course, []);
+        }
+        $this->assertNull($instanceid2);
+
+        $enrolmentdata = [];
+        $actual = $guestplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertEquals($expected->id, $actual->id);
+    }
+
+}

enrol/manual/lib.php

@@ -655,6 +655,26 @@ class enrol_manual_plugin extends enrol_plugin {
         return true;
     }
 
+    /**
+     * Finds matching instances for a given course.
+     *
+     * @param array $enrolmentdata enrolment data.
+     * @param int $courseid Course ID.
+     * @return stdClass|null Matching instance
+     */
+    public function find_instance(array $enrolmentdata, int $courseid) : ?stdClass {
+
+        $instances = enrol_get_instances($courseid, false);
+        $instance = null;
+        foreach ($instances as $i) {
+            if ($i->enrol == 'manual') {
+                // There can be only one manual enrol instance so find first available.
+                $instance = $i;
+                break;
+            }
+        }
+        return $instance;
+    }
 }
 
 /**

enrol/manual/tests/lib_test.php

@@ -761,4 +761,32 @@ class lib_test extends \advanced_testcase {
             ],
         ];
     }
+
+    /**
+     * Test the behaviour of find_instance().
+     *
+     * @covers ::find_instance
+     */
+    public function test_find_instance() {
+        global $DB;
+        $this->resetAfterTest();
+
+        $cat = $this->getDataGenerator()->create_category();
+        // When we create a course, a manual enrolment instance is also created.
+        $course = $this->getDataGenerator()->create_course(['category' => $cat->id, 'shortname' => 'ANON']);
+
+        $teacherrole = $DB->get_record('role', ['shortname' => 'teacher']);
+        $manualplugin = enrol_get_plugin('manual');
+
+        $expected = $DB->get_record('enrol', ['courseid' => $course->id, 'enrol' => 'manual']);
+
+        // Let's try to add second instance - only 1 manual instance is possible.
+        $instanceid2 = $manualplugin->add_instance($course, ['roleid' => $teacherrole->id]);
+        $this->assertNull($instanceid2);
+
+        $enrolmentdata = [];
+        $actual = $manualplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertEquals($expected->id, $actual->id);
+    }
+
 }

enrol/self/lib.php

@@ -1088,6 +1088,28 @@ class enrol_self_plugin extends enrol_plugin {
     public function is_csv_upload_supported(): bool {
         return true;
     }
+
+    /**
+     * Finds matching instances for a given course.
+     *
+     * @param array $enrolmentdata enrolment data.
+     * @param int $courseid Course ID.
+     * @return stdClass|null Matching instance
+     */
+    public function find_instance(array $enrolmentdata, int $courseid) : ?stdClass {
+
+        $instances = enrol_get_instances($courseid, false);
+        $instance = null;
+        foreach ($instances as $i) {
+            if ($i->enrol == 'self') {
+                // This is bad - we can not really distinguish between self instances. So grab first available.
+                $instance = $i;
+                break;
+            }
+        }
+        return $instance;
+    }
+
 }
 
 /**

enrol/self/tests/self_test.php

@@ -961,4 +961,32 @@ class self_test extends \advanced_testcase {
         // Self enrol has 2 enrol actions -- edit and unenrol.
         $this->assertCount(2, $actions);
     }
+
+    /**
+     * Test the behaviour of find_instance().
+     *
+     * @covers ::find_instance
+     */
+    public function test_find_instance() {
+        global $DB;
+        $this->resetAfterTest();
+
+        $cat = $this->getDataGenerator()->create_category();
+        // When we create a course, a self enrolment instance is also created.
+        $course = $this->getDataGenerator()->create_course(['category' => $cat->id, 'shortname' => 'ANON']);
+
+        $teacherrole = $DB->get_record('role', ['shortname' => 'teacher']);
+        $selfplugin = enrol_get_plugin('self');
+
+        $instanceid1 = $DB->get_record('enrol', ['courseid' => $course->id, 'enrol' => 'self']);
+
+        // Let's add a second instance.
+        $instanceid2 = $selfplugin->add_instance($course, ['roleid' => $teacherrole->id]);
+
+        $enrolmentdata = [];
+        // The first instance should be returned - due to sorting in enrol_get_instances().
+        $actual = $selfplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertEquals($instanceid1->id, $actual->id);
+    }
+
 }

enrol/upgrade.txt

@@ -1,6 +1,16 @@
 This files describes API changes in /enrol/* - plugins,
 information provided here is intended especially for developers.
 
+=== 4.4 ===
+
+* New find_instance() function has been created. It finds a matching enrolment instance in a given course using provided
+ enrolment data (for example cohort idnumber for cohort enrolment). Defaults to null. Override this function in your
+ enrolment plugin if you want it to be supported in CSV course upload. Please be aware that sometimes it is not possible
+ to uniquely find an instance based on given data. For example lti entolment records do not have any unique data except
+ id in mod_lti_enrol table. Such plugins should not be supported in CSV course upload. The exception is self enrolment
+ plugin since it is already supported in CSV course upload. For self enrolment plugin, find_instance() returns first
+ available instance in the course.
+
 === 4.3 ===
 
 * New is_csv_upload_supported() function has been created. It checks whether enrolment plugin is supported

lib/enrollib.php

@@ -3510,4 +3510,17 @@ abstract class enrol_plugin {
         return null;
     }
 
+    /**
+     * Finds matching instances for a given course.
+     *
+     * @param array $enrolmentdata enrolment data.
+     * @param int $courseid Course ID.
+     * @return stdClass|null Matching instance
+     */
+    public function find_instance(array $enrolmentdata, int $courseid) : ?stdClass {
+
+        // By default, we assume we can't uniquely identify an instance so better not update any.
+        // Plugins can override this if they can uniquely identify an instance.
+        return null;
+    }
 }