resolves #1586 preserve workspace styles while applying theme

server/src/main/java/io/kroki/server/service/Structurizr.java

@@ -152,11 +152,19 @@ private byte[] convert(String source, FileFormat fileFormat, JsonObject options)
   private static void applyTheme(ViewSet viewSet, StructurizrTheme theme) {
     List<ElementStyle> elementStyles = theme.getElementStyles();
     for (ElementStyle elementStyle : elementStyles) {
-      viewSet.getConfiguration().getStyles().add(elementStyle);
+      String tag = elementStyle.getTag();
+      ElementStyle currentElementStyle = viewSet.getConfiguration().getStyles().getElementStyle(tag);
+      if (currentElementStyle == null) {
+        viewSet.getConfiguration().getStyles().add(elementStyle);
+      }
     }
     List<RelationshipStyle> relationshipStyles = theme.getRelationshipStyle();
     for (RelationshipStyle relationshipStyle : relationshipStyles) {
-      viewSet.getConfiguration().getStyles().add(relationshipStyle);
+      String tag = relationshipStyle.getTag();
+      ElementStyle currentRelationshipStyle = viewSet.getConfiguration().getStyles().getElementStyle(tag);
+      if (currentRelationshipStyle == null) {
+        viewSet.getConfiguration().getStyles().add(relationshipStyle);
+      }
     }
   }
 

server/src/test/java/io/kroki/server/service/StructurizrServiceTest.java

@@ -134,6 +134,13 @@ public void should_throw_exception_when_script_directive_used() throws IOExcepti
       .hasMessage("Unable to parse the Structurizr DSL. Error running inline script, caused by java.lang.RuntimeException: Could not load a scripting engine for extension \"kts\" at line 5: }.");
   }
 
+  @Test
+  public void should_preserve_styles_defined_in_workspace_while_applying_theme() throws IOException, InterruptedException {
+    String source = read("./workspace-style-with-theme.structurizr");
+    byte[] convert = Structurizr.convert(source, FileFormat.SVG, plantumlCommand, new StructurizrPlantUMLExporter(), new JsonObject());
+    assertThat(new String(convert)).isEqualTo(read("./workspace-style-with-theme.svg"));
+  }
+
   private String stripComments(String xmlContent) {
     return xmlContent.replaceAll("<!--[\\s\\S]*?-->", "");
   }

server/src/test/resources/workspace-style-with-theme.structurizr

@@ -0,0 +1,21 @@
+workspace {
+
+    model {
+        softwareSystem "Software System"
+    }
+
+    views {
+        theme default
+
+        systemLandscape "SystemLandscape" {
+            include *
+            autoLayout
+        }
+
+        styles {
+            element "Software System" {
+                background orange
+            }
+        }
+    }
+}