[TASK] Warn when code-block has no content

packages/guides-restructured-text/src/RestructuredText/Directives/CodeBlockDirective.php

@@ -62,6 +62,12 @@ public function process(
         BlockContext $blockContext,
         Directive $directive,
     ): Node|null {
+        if ($blockContext->getDocumentIterator()->isEmpty()) {
+            $this->logger->warning('The code-block has no content. Did you properly indent the code? ', $blockContext->getLoggerInformation());
+
+            return null;
+        }
+
         $node = new CodeNode(
             $blockContext->getDocumentIterator()->toArray(),
         );

packages/guides-restructured-text/src/RestructuredText/Parser/LinesIterator.php

@@ -17,6 +17,7 @@
 use OutOfBoundsException;
 
 use function chr;
+use function count;
 use function explode;
 use function max;
 use function mb_strpos;
@@ -133,6 +134,11 @@ public function toArray(): array
         return $this->lines;
     }
 
+    public function isEmpty(): bool
+    {
+        return count($this->lines) === 0 || (count($this->lines) === 1 && trim($this->lines[0]) === '');
+    }
+
     /** @psalm-assert-if-false non-empty-string $line */
     public static function isEmptyLine(string|null $line): bool
     {

tests/Integration/tests/code/code-block-empty/expected/index.html

@@ -0,0 +1,8 @@
+<!-- content start -->
+    <div class="section" id="title">
+            <h1>Title</h1>
+
+            <p>Some paragraph.</p>
+    </div>
+
+<!-- content end -->

tests/Integration/tests/code/code-block-empty/expected/logs/warning.log

@@ -0,0 +1 @@
+app.WARNING: The code-block has no content. Did you properly indent the code?

tests/Integration/tests/code/code-block-empty/input/index.rst

@@ -0,0 +1,6 @@
+Title
+=====
+
+..  code-block:: xml
+
+Some paragraph.

tests/Integration/tests/directives/directive-configuration-block/expected/index.html

@@ -1,30 +1,29 @@
 <!-- content start -->
     <div class="section" id="directive-tests">
-        <h1>Directive tests</h1>
+            <h1>Directive tests</h1>
 
-        <div class="configuration-block">
-            <div role="tablist" aria-label="Configuration formats" class="configuration-tabs configuration-tabs-length-2">
-                <button role="tab" type="button" data-language="yaml"
-                        aria-controls="configuration-block-tabpanel-523eafc9524d67db5f21ecae2362d532" aria-selected="true"
-                        data-active="true" >
-                    <span>Yaml</span>
-                </button>
-                <button role="tab" type="button" data-language="custom"
-                        aria-controls="configuration-block-tabpanel-a51ba27b3c76153f629592baf23834dc" aria-selected="false"
-                        tabindex="-1">
-                    <span>CUSTOM</span>
-                </button>
+            <div class="configuration-block">
+    <div role="tablist" aria-label="Configuration formats" class="configuration-tabs configuration-tabs-length-2">
+                    <button role="tab" type="button" data-language="yaml"
+                    aria-controls="configuration-block-tabpanel-523eafc9524d67db5f21ecae2362d532" aria-selected="true"
+                    data-active="true" >
+                <span>Yaml</span>
+            </button>
+                    <button role="tab" type="button" data-language="custom"
+                    aria-controls="configuration-block-tabpanel-a51ba27b3c76153f629592baf23834dc" aria-selected="false"
+                     tabindex="-1">
+                <span>CUSTOM</span>
+            </button>
             </div>
 
             <div role="tabpanel" id="configuration-block-tabpanel-523eafc9524d67db5f21ecae2362d532" aria-label="Yaml" class="configuration-codeblock" data-language="yaml" style="">
-                <pre><code class="language-yaml"># app/config/services.yml</code></pre>
-            </div>
+            <pre><code class="language-yaml"># app/config/services.yml</code></pre>
+        </div>
             <div role="tabpanel" id="configuration-block-tabpanel-a51ba27b3c76153f629592baf23834dc" aria-label="CUSTOM" class="configuration-codeblock" data-language="custom" style="display: none">
-                <pre><code class="language-php">// config/routes.php</code></pre>
-            </div>
+            <pre><code class="language-php">// config/routes.php</code></pre>
         </div>
-
     </div>
 
+    </div>
 
 <!-- content end -->