[Bug fix] A lax search for presence of binding during save page to match client algorithm to reduce page save error (#3698)

* Lax mustache binding check added to match the client side check when client recognizes a field to have a dynamic binding. This would reduce/remove bad bindings from throwing a 400 during save page.

* Added a test to assert that update layout does not fail in case the binding is technically incorrect because part of the mustache's lie inside quotes. Since client has a lax way of finding a dynamic path, server also follows suite.

app/server/appsmith-interfaces/src/main/java/com/appsmith/external/helpers/MustacheHelper.java

@@ -41,6 +41,8 @@ public class MustacheHelper {
     private static Pattern quoteQuestionPattern = Pattern.compile(regexQuotesTrimming);
     // The final replacement string of ? for replacing '?' or "?"
     private static String postQuoteTrimmingQuestionMark = "\\?";
+    private static String laxMustacheBindingRegex = "\\{\\{([\\s\\S]*?)\\}\\}";
+    private static Pattern laxMustacheBindingPattern = Pattern.compile(laxMustacheBindingRegex);
 
 
     /**
@@ -364,4 +366,8 @@ public class MustacheHelper {
 
         return body;
     }
+
+    public static Boolean laxIsBindingPresentInString(String input) {
+        return laxMustacheBindingPattern.matcher(input).find();
+    }
 }

app/server/appsmith-server/src/main/java/com/appsmith/server/services/LayoutActionServiceImpl.java

@@ -353,19 +353,20 @@ public class LayoutActionServiceImpl implements LayoutActionService {
                 }
                 // Only extract mustache keys from leaf nodes
                 if (isLeafNode) {
-                    Set<String> mustacheKeysFromFields = MustacheHelper.extractMustacheKeysFromFields(parent);
 
                     // We found the path. But if the path does not have any mustache bindings, throw the error
-                    if (mustacheKeysFromFields.isEmpty()) {
+                    if (!MustacheHelper.laxIsBindingPresentInString((String) parent)) {
                         try {
                             String bindingAsString = objectMapper.writeValueAsString(parent);
                             throw new AppsmithException(AppsmithError.INVALID_DYNAMIC_BINDING_REFERENCE, widgetType,
-                                widgetName, widgetId, fieldPath, pageId, layoutId, bindingAsString);
+                                    widgetName, widgetId, fieldPath, pageId, layoutId, bindingAsString);
                         } catch (JsonProcessingException e) {
                             throw new AppsmithException(AppsmithError.JSON_PROCESSING_ERROR, parent);
                         }
                     }
 
+                    // Stricter extraction of dynamic bindings
+                    Set<String> mustacheKeysFromFields = MustacheHelper.extractMustacheKeysFromFields(parent);
                     dynamicBindings.addAll(mustacheKeysFromFields);
                 }
             }

app/server/appsmith-server/src/test/java/com/appsmith/server/services/LayoutServiceTest.java

@@ -452,7 +452,7 @@ public class LayoutServiceTest {
 
     @Test
     @WithUserDetails(value = "api_user")
-    public void testIncorrectDynamicBinding() {
+    public void testIncorrectDynamicBindingPathInDsl() {
         Mockito.when(pluginExecutorHelper.getPluginExecutor(Mockito.any())).thenReturn(Mono.just(new MockPluginExecutor()));
 
         PageDTO testPage = new PageDTO();
@@ -525,6 +525,80 @@ public class LayoutServiceTest {
                 .verify();
     }
 
+    @Test
+    @WithUserDetails(value = "api_user")
+    public void testIncorrectMustacheExpressionInBindingInDsl() {
+        Mockito.when(pluginExecutorHelper.getPluginExecutor(Mockito.any())).thenReturn(Mono.just(new MockPluginExecutor()));
+
+        PageDTO testPage = new PageDTO();
+        testPage.setName("testIncorrectMustacheExpressionInBinding Test Page");
+
+        Application app = new Application();
+        app.setName("newApplication-testIncorrectMustacheExpressionInBinding-Test");
+
+        PageDTO page = createPage(app, testPage).block();
+        String pageId = page.getId();
+        String layoutId = page.getLayouts().get(0).getId();
+
+        Mono<LayoutDTO> testMono = Mono.just(page)
+                .flatMap(page1 -> {
+                    List<Mono<ActionDTO>> monos = new ArrayList<>();
+
+                    ActionDTO action = new ActionDTO();
+                    action.setName("aGetAction");
+                    action.setActionConfiguration(new ActionConfiguration());
+                    action.getActionConfiguration().setHttpMethod(HttpMethod.GET);
+                    action.setPageId(page1.getId());
+                    action.setDatasource(datasource);
+                    monos.add(newActionService.createAction(action));
+
+                    return Mono.zip(monos, objects -> page1);
+                })
+                .zipWhen(page1 -> {
+                    Layout layout = new Layout();
+
+                    JSONObject obj = new JSONObject(Map.of(
+                            "key", "value"
+                    ));
+                    layout.setDsl(obj);
+
+                    return layoutService.createLayout(page1.getId(), layout);
+                })
+                .flatMap(tuple2 -> {
+                    final PageDTO page1 = tuple2.getT1();
+                    final Layout layout = tuple2.getT2();
+
+                    Layout newLayout = new Layout();
+
+                    JSONObject obj = new JSONObject(Map.of(
+                            "widgetName", "testWidget",
+                            "widgetId", "id",
+                            "type", "test_type",
+                            "key", "value-updated",
+                            "dynamicGet", "a\"{{aGetAction\"/'\"'}}\"\""
+                    ));
+                    JSONArray dynamicBindingsPathList = new JSONArray();
+                    dynamicBindingsPathList.addAll(List.of(
+                            new JSONObject(Map.of("key", "dynamicGet"))
+                    ));
+
+                    obj.put("dynamicBindingPathList", dynamicBindingsPathList);
+                    newLayout.setDsl(obj);
+
+                    return layoutActionService.updateLayout(page1.getId(), layout.getId(), newLayout);
+                });
+
+        StepVerifier
+                .create(testMono)
+                .assertNext(layoutDTO -> {
+                    // We have reached here means we didnt get a throwable. Thats good
+                    assertThat(layoutDTO).isNotNull();
+                    // Since this is still a bad mustache binding, we couldn't have extracted the action name
+                    assertThat(layoutDTO.getLayoutOnLoadActions().size()).isEqualTo(0);
+                })
+                .verifyComplete();
+    }
+
     @After
     public void purgePages() {
         newPageService.deleteAll();