[BUGFIX] Prevent multiple FlexContainers of same name

Extend the identifier used within the DOM by an additional field, as
already done in #97042 to make flexform sections within inline child
records work.

A styleguide example makes it easy to reproduce the edge case.

Resolves: #100937
Related: #97042
Releases: main, 12.4
Change-Id: I40120ea13b892c6387833dab444dad86951cf96f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/85189


Tested-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>

typo3/sysext/backend/Classes/Form/Container/FlexFormSectionContainer.php

@@ -71,8 +71,8 @@ class FlexFormSectionContainer extends AbstractContainer
             $resultArray = $this->mergeChildReturnIntoExistingResult($resultArray, $flexFormContainerContainerResult);
         }
 
-        $containerId = sprintf('flexform-section-container-%s-%s-%s', $flexFormSheetName, $this->data['fieldName'], $flexFormFieldName);
-        $sectionContainerId = sprintf('flexform-section-%s-%s-%s', $flexFormSheetName, $this->data['fieldName'], $flexFormFieldName);
+        $containerId = sprintf('flexform-section-container-%s-%s-%s-%s', $flexFormSheetName, $this->data['fieldName'], $flexFormFieldName, md5($this->data['elementBaseName']));
+        $sectionContainerId = sprintf('flexform-section-%s-%s-%s-%s', $flexFormSheetName, $this->data['fieldName'], $flexFormFieldName, md5($this->data['elementBaseName']));
         $hashedSectionContainerId = 'section-' . md5($sectionContainerId);
 
         // "New container" handling: Creates buttons for each possible container with all relevant information for the ajax call.

typo3/sysext/styleguide/Configuration/FlexForms/SimpleSection.xml

+<T3DataStructure>
+    <sheets>
+        <sDEF>
+            <ROOT>
+                <type>array</type>
+                <el>
+                    <answers>
+                        <type>array</type>
+                        <section>1</section>
+                        <el>
+                            <answer>
+                                <type>array</type>
+                                <title>Answer</title>
+                                <el>
+                                    <text>
+                                        <label>Text</label>
+                                        <config>
+                                            <type>input</type>
+                                        </config>
+                                    </text>
+                                </el>
+                            </answer>
+                        </el>
+                    </answers>
+                </el>
+            </ROOT>
+        </sDEF>
+    </sheets>
+</T3DataStructure>

typo3/sysext/styleguide/Configuration/TCA/tx_styleguide_inline_1n1n_child.php

@@ -43,12 +43,30 @@ return [
                 'foreign_table_field' => 'parenttable',
             ],
         ],
+        'inline_2' => [
+            'label' => 'inline_2',
+            'config' => [
+                'type' => 'flex',
+                'ds' => [
+                    'default' => 'FILE:EXT:styleguide/Configuration/FlexForms/SimpleSection.xml',
+                ],
+            ],
+        ],
+        'inline_3' => [
+            'label' => 'inline_3',
+            'config' => [
+                'type' => 'flex',
+                'ds' => [
+                    'default' => 'FILE:EXT:styleguide/Configuration/FlexForms/MultipleSheets.xml',
+                ],
+            ],
+        ],
     ],
 
     'types' => [
         '0' => [
             'showitem' => '
-                inline_1,
+                inline_1,inline_2,inline_3,
                 --div--;meta,
                     disable, sys_language_uid, l10n_parent, l10n_source,
             ',