camel-diagram: Fix route source name stripping line numbers

components/camel-diagram/src/main/java/org/apache/camel/diagram/RouteDiagramHelper.java

@@ -86,10 +86,15 @@ static String extractSourceName(String source) {
         if (source == null || source.isBlank()) {
             return null;
         }
-        // strip scheme prefix (e.g. "file:")
-        int colon = source.lastIndexOf(':');
-        if (colon >= 0 && colon < source.length() - 1) {
-            source = source.substring(colon + 1);
+        // strip URI scheme prefix (e.g. "file:", "classpath:") — only if the part
+        // before the first colon is all letters (a valid scheme). This avoids
+        // stripping line numbers from sources like "cheese.java:9".
+        int colon = source.indexOf(':');
+        if (colon > 0) {
+            String scheme = source.substring(0, colon);
+            if (scheme.chars().allMatch(Character::isLetter)) {
+                source = source.substring(colon + 1);
+            }
         }
         // return just the filename part
         int slash = Math.max(source.lastIndexOf('/'), source.lastIndexOf('\\'));

components/camel-diagram/src/test/java/org/apache/camel/diagram/RouteDiagramTest.java

@@ -806,6 +806,46 @@ void testNodeTextPaddingScalesWithNodeWidth() {
                 "Text padding should increase with wider nodes");
     }
 
+    @Test
+    void testExtractSourceNameWithScheme() {
+        assertEquals("my-route.yaml", RouteDiagramHelper.extractSourceName("file:/path/to/my-route.yaml"));
+    }
+
+    @Test
+    void testExtractSourceNameClasspath() {
+        assertEquals("my-route.yaml", RouteDiagramHelper.extractSourceName("classpath:my-route.yaml"));
+    }
+
+    @Test
+    void testExtractSourceNameWithLineNumber() {
+        assertEquals("cheese.java:9", RouteDiagramHelper.extractSourceName("cheese.java:9"));
+    }
+
+    @Test
+    void testExtractSourceNameSchemeAndLineNumber() {
+        assertEquals("cheese.java:9", RouteDiagramHelper.extractSourceName("file:/path/to/cheese.java:9"));
+    }
+
+    @Test
+    void testExtractSourceNamePlainFilename() {
+        assertEquals("my-route.yaml", RouteDiagramHelper.extractSourceName("my-route.yaml"));
+    }
+
+    @Test
+    void testExtractSourceNameWindowsPath() {
+        assertEquals("route.yaml", RouteDiagramHelper.extractSourceName("C:\\Users\\test\\route.yaml"));
+    }
+
+    @Test
+    void testExtractSourceNameNull() {
+        assertNull(RouteDiagramHelper.extractSourceName(null));
+    }
+
+    @Test
+    void testExtractSourceNameBlank() {
+        assertNull(RouteDiagramHelper.extractSourceName(""));
+    }
+
     private static NodeInfo node(String type, String code, int level) {
         return node(type, code, level, null);
     }