refactor(core): renames checkNoChangesMode to be clearer (#39277)

getCheckNoChangesMode was discovered to be unclear as to the purpose of
it. This refactor is a simple renaming to make it much clearer what that
method and property does.

PR Close #39277

packages/core/src/render3/bindings.ts

@@ -11,7 +11,7 @@ import {assertIndexInRange, assertLessThan, assertNotSame} from '../util/assert'
 
 import {getExpressionChangedErrorDetails, throwErrorIfNoChangesMode} from './errors';
 import {LView} from './interfaces/view';
-import {getCheckNoChangesMode} from './state';
+import {isInCheckNoChangesMode} from './state';
 import {NO_CHANGE} from './tokens';
 
 
@@ -52,7 +52,7 @@ export function bindingUpdated(lView: LView, bindingIndex: number, value: any):
   if (Object.is(oldValue, value)) {
     return false;
   } else {
-    if (ngDevMode && getCheckNoChangesMode()) {
+    if (ngDevMode && isInCheckNoChangesMode()) {
       // View engine didn't report undefined values as changed on the first checkNoChanges pass
       // (before the change detection was run).
       const oldValueToCompare = oldValue !== NO_CHANGE ? oldValue : undefined;

packages/core/src/render3/hooks.ts

@@ -13,7 +13,7 @@ import {NgOnChangesFeatureImpl} from './features/ng_onchanges_feature';
 import {DirectiveDef} from './interfaces/definition';
 import {TNode} from './interfaces/node';
 import {FLAGS, HookData, InitPhaseState, LView, LViewFlags, PREORDER_HOOK_FLAGS, PreOrderHookFlags, TView} from './interfaces/view';
-import {getCheckNoChangesMode} from './state';
+import {isInCheckNoChangesMode} from './state';
 
 
 
@@ -205,8 +205,8 @@ function callHooks(
     currentNodeIndex: number|null|undefined): void {
   ngDevMode &&
       assertEqual(
-          getCheckNoChangesMode(), false,
+          isInCheckNoChangesMode(), false,
-          'Hooks should never be run in the check no changes mode.');
+          'Hooks should never be run when in check no changes mode.');
   const startIndex = currentNodeIndex !== undefined ?
       (currentView[PREORDER_HOOK_FLAGS] & PreOrderHookFlags.IndexOfTheNextPreOrderHookMaskMask) :
       0;

packages/core/src/render3/instructions/advance.ts

@@ -8,7 +8,7 @@
 import {assertGreaterThan, assertIndexInRange} from '../../util/assert';
 import {executeCheckHooks, executeInitAndCheckHooks} from '../hooks';
 import {FLAGS, HEADER_OFFSET, InitPhaseState, LView, LViewFlags, TView} from '../interfaces/view';
-import {getCheckNoChangesMode, getLView, getSelectedIndex, getTView, setSelectedIndex} from '../state';
+import {getLView, getSelectedIndex, getTView, isInCheckNoChangesMode, setSelectedIndex} from '../state';
 
 
 /**
@@ -36,7 +36,7 @@ import {getCheckNoChangesMode, getLView, getSelectedIndex, getTView, setSelected
  */
 export function ɵɵadvance(delta: number): void {
   ngDevMode && assertGreaterThan(delta, 0, 'Can only advance forward');
-  selectIndexInternal(getTView(), getLView(), getSelectedIndex() + delta, getCheckNoChangesMode());
+  selectIndexInternal(getTView(), getLView(), getSelectedIndex() + delta, isInCheckNoChangesMode());
 }
 
 export function selectIndexInternal(

packages/core/src/render3/instructions/shared.ts

@@ -33,7 +33,7 @@ import {isComponentDef, isComponentHost, isContentQueryHost, isLContainer, isRoo
 import {CHILD_HEAD, CHILD_TAIL, CLEANUP, CONTEXT, DECLARATION_COMPONENT_VIEW, DECLARATION_VIEW, FLAGS, HEADER_OFFSET, HOST, InitPhaseState, INJECTOR, LView, LViewFlags, NEXT, PARENT, RENDERER, RENDERER_FACTORY, RootContext, RootContextFlags, SANITIZER, T_HOST, TData, TRANSPLANTED_VIEWS_TO_REFRESH, TVIEW, TView, TViewType} from '../interfaces/view';
 import {assertNodeNotOfTypes, assertNodeOfPossibleTypes} from '../node_assert';
 import {isInlineTemplate, isNodeMatchingSelectorList} from '../node_selector_matcher';
-import {enterView, getBindingsEnabled, getCheckNoChangesMode, getCurrentDirectiveIndex, getCurrentTNode, getSelectedIndex, isCurrentTNodeParent, leaveView, setBindingIndex, setBindingRootForHostBindings, setCheckNoChangesMode, setCurrentDirectiveIndex, setCurrentQueryIndex, setCurrentTNode, setSelectedIndex} from '../state';
+import {enterView, getBindingsEnabled, getCurrentDirectiveIndex, getCurrentTNode, getSelectedIndex, isCurrentTNodeParent, isInCheckNoChangesMode, leaveView, setBindingIndex, setBindingRootForHostBindings, setCurrentDirectiveIndex, setCurrentQueryIndex, setCurrentTNode, setIsInCheckNoChangesMode, setSelectedIndex} from '../state';
 import {NO_CHANGE} from '../tokens';
 import {isAnimationProp, mergeHostAttrs} from '../util/attrs_utils';
 import {INTERPOLATION_DELIMITER, renderStringify, stringifyForError} from '../util/misc_utils';
@@ -383,7 +383,9 @@ export function refreshView<T>(
   const flags = lView[FLAGS];
   if ((flags & LViewFlags.Destroyed) === LViewFlags.Destroyed) return;
   enterView(lView);
-  const checkNoChangesMode = getCheckNoChangesMode();
+  // Check no changes mode is a dev only mode used to verify that bindings have not changed
+  // since they were assigned. We do not want to execute lifecycle hooks in that mode.
+  const isInCheckNoChangesPass = isInCheckNoChangesMode();
   try {
     resetPreOrderHookFlags(lView);
 
@@ -397,7 +399,7 @@ export function refreshView<T>(
 
     // execute pre-order hooks (OnInit, OnChanges, DoCheck)
     // PERF WARNING: do NOT extract this to a separate function without running benchmarks
-    if (!checkNoChangesMode) {
+    if (!isInCheckNoChangesPass) {
       if (hooksInitPhaseCompleted) {
         const preOrderCheckHooks = tView.preOrderCheckHooks;
         if (preOrderCheckHooks !== null) {
@@ -425,7 +427,7 @@ export function refreshView<T>(
 
     // execute content hooks (AfterContentInit, AfterContentChecked)
     // PERF WARNING: do NOT extract this to a separate function without running benchmarks
-    if (!checkNoChangesMode) {
+    if (!isInCheckNoChangesPass) {
       if (hooksInitPhaseCompleted) {
         const contentCheckHooks = tView.contentCheckHooks;
         if (contentCheckHooks !== null) {
@@ -459,7 +461,7 @@ export function refreshView<T>(
 
     // execute view hooks (AfterViewInit, AfterViewChecked)
     // PERF WARNING: do NOT extract this to a separate function without running benchmarks
-    if (!checkNoChangesMode) {
+    if (!isInCheckNoChangesPass) {
       if (hooksInitPhaseCompleted) {
         const viewCheckHooks = tView.viewCheckHooks;
         if (viewCheckHooks !== null) {
@@ -489,7 +491,7 @@ export function refreshView<T>(
     // refresh a `NgClass` binding should work. If we would reset the dirty state in the check
     // no changes cycle, the component would be not be dirty for the next update pass. This would
     // be different in production mode where the component dirty state is not reset.
-    if (!checkNoChangesMode) {
+    if (!isInCheckNoChangesPass) {
       lView[FLAGS] &= ~(LViewFlags.Dirty | LViewFlags.FirstLViewPass);
     }
     if (lView[FLAGS] & LViewFlags.RefreshTransplantedView) {
@@ -504,7 +506,7 @@ export function refreshView<T>(
 export function renderComponentOrTemplate<T>(
     tView: TView, lView: LView, templateFn: ComponentTemplate<{}>|null, context: T) {
   const rendererFactory = lView[RENDERER_FACTORY];
-  const normalExecutionPath = !getCheckNoChangesMode();
+  const normalExecutionPath = !isInCheckNoChangesMode();
   const creationModeIsActive = isCreationMode(lView);
   try {
     if (normalExecutionPath && !creationModeIsActive && rendererFactory.begin) {
@@ -529,7 +531,7 @@ function executeTemplate<T>(
     if (rf & RenderFlags.Update && lView.length > HEADER_OFFSET) {
       // When we're updating, inherently select 0 so we don't
       // have to generate that instruction for most update blocks.
-      selectIndexInternal(tView, lView, 0, getCheckNoChangesMode());
+      selectIndexInternal(tView, lView, 0, isInCheckNoChangesMode());
     }
     templateFn(rf, context);
   } finally {
@@ -1918,11 +1920,11 @@ export function detectChangesInRootView(lView: LView): void {
 }
 
 export function checkNoChangesInternal<T>(tView: TView, view: LView, context: T) {
-  setCheckNoChangesMode(true);
+  setIsInCheckNoChangesMode(true);
   try {
     detectChangesInternal(tView, view, context);
   } finally {
-    setCheckNoChangesMode(false);
+    setIsInCheckNoChangesMode(false);
   }
 }
 
@@ -1936,11 +1938,11 @@ export function checkNoChangesInternal<T>(tView: TView, view: LView, context: T)
  * @param lView The view which the change detection should be checked on.
  */
 export function checkNoChangesInRootView(lView: LView): void {
-  setCheckNoChangesMode(true);
+  setIsInCheckNoChangesMode(true);
   try {
     detectChangesInRootView(lView);
   } finally {
-    setCheckNoChangesMode(false);
+    setIsInCheckNoChangesMode(false);
   }
 }
 

packages/core/src/render3/state.ts

@@ -159,14 +159,17 @@ interface InstructionState {
    * In this mode, any changes in bindings will throw an ExpressionChangedAfterChecked error.
    *
    * Necessary to support ChangeDetectorRef.checkNoChanges().
+   *
+   * checkNoChanges Runs only in devmode=true and verifies that no unintended changes exist in
+   * the change detector or its children.
    */
-  checkNoChangesMode: boolean;
+  isInCheckNoChangesMode: boolean;
 }
 
 export const instructionState: InstructionState = {
   lFrame: createLFrame(null),
   bindingsEnabled: true,
-  checkNoChangesMode: false,
+  isInCheckNoChangesMode: false,
 };
 
 
@@ -287,13 +290,13 @@ export function getContextLView(): LView {
   return instructionState.lFrame.contextLView;
 }
 
-export function getCheckNoChangesMode(): boolean {
+export function isInCheckNoChangesMode(): boolean {
   // TODO(misko): remove this from the LView since it is ngDevMode=true mode only.
-  return instructionState.checkNoChangesMode;
+  return instructionState.isInCheckNoChangesMode;
 }
 
-export function setCheckNoChangesMode(mode: boolean): void {
+export function setIsInCheckNoChangesMode(mode: boolean): void {
-  instructionState.checkNoChangesMode = mode;
+  instructionState.isInCheckNoChangesMode = mode;
 }
 
 // top level variables should not be exported for performance reasons (PERF_NOTES.md)

packages/core/test/bundling/cyclic_import/bundle.golden_symbols.json

@@ -156,7 +156,7 @@
     "name": "generatePropertyAliases"
   },
   {
-    "name": "getCheckNoChangesMode"
+    "name": "isInCheckNoChangesMode"
   },
   {
     "name": "getClosureSafeProperty"

packages/core/test/bundling/forms/bundle.golden_symbols.json

@@ -948,7 +948,7 @@
     "name": "generatePropertyAliases"
   },
   {
-    "name": "getCheckNoChangesMode"
+    "name": "isInCheckNoChangesMode"
   },
   {
     "name": "getClosureSafeProperty"
@@ -1485,7 +1485,7 @@
     "name": "setBindingRootForHostBindings"
   },
   {
-    "name": "setCheckNoChangesMode"
+    "name": "setIsInCheckNoChangesMode"
   },
   {
     "name": "setCurrentDirectiveIndex"

packages/core/test/bundling/hello_world/bundle.golden_symbols.json

@@ -108,7 +108,7 @@
     "name": "extractPipeDef"
   },
   {
-    "name": "getCheckNoChangesMode"
+    "name": "isInCheckNoChangesMode"
   },
   {
     "name": "getClosureSafeProperty"

packages/core/test/bundling/router/bundle.golden_symbols.json

@@ -1260,7 +1260,7 @@
     "name": "getBootstrapListener"
   },
   {
-    "name": "getCheckNoChangesMode"
+    "name": "isInCheckNoChangesMode"
   },
   {
     "name": "getClosureSafeProperty"
@@ -1818,7 +1818,7 @@
     "name": "setBindingRootForHostBindings"
   },
   {
-    "name": "setCheckNoChangesMode"
+    "name": "setIsInCheckNoChangesMode"
   },
   {
     "name": "setCurrentDirectiveIndex"

packages/core/test/bundling/todo/bundle.golden_symbols.json

@@ -330,7 +330,7 @@
     "name": "generatePropertyAliases"
   },
   {
-    "name": "getCheckNoChangesMode"
+    "name": "isInCheckNoChangesMode"
   },
   {
     "name": "getClosureSafeProperty"
@@ -642,7 +642,7 @@
     "name": "setBindingRootForHostBindings"
   },
   {
-    "name": "setCheckNoChangesMode"
+    "name": "setIsInCheckNoChangesMode"
   },
   {
     "name": "setCurrentDirectiveIndex"