fix(compiler-cli): correct incremental behavior even with broken imports (#39967)

alxhub · mhevery · commit adeeb84a352c · 2020-12-04T16:06:23.000-08:00
When the compiler is invoked via ngc or the Angular CLI, its APIs are used under the assumption that Angular analysis/diagnostics are only requested if the program has no TypeScript-level errors. A result of this assumption is that the incremental engine has not needed to resolve changes via its dependency graph when the program contained broken imports, since broken imports are a TypeScript error. The Angular Language Service for Ivy is using the compiler as a backend, and exercising its incremental compilation APIs without enforcing this assumption. As a result, the Language Service has run into issues where broken imports cause incremental compilation to fail and produce incorrect results. This commit introduces a mechanism within the compiler to keep track of files for which dependency analysis has failed, and to always treat such files as potentially affected by future incremental steps. PR Close #39967
diff --git a/packages/compiler-cli/ngcc/src/analysis/util.ts b/packages/compiler-cli/ngcc/src/analysis/util.ts
@@ -18,6 +18,7 @@ class NoopDependencyTracker implements DependencyTracker {
   addResourceDependency(): void {}
   addTransitiveDependency(): void {}
   addTransitiveResources(): void {}
+  recordDependencyAnalysisFailure(): void {}
 }
 
 export const NOOP_DEPENDENCY_TRACKER: DependencyTracker = new NoopDependencyTracker();
diff --git a/packages/compiler-cli/src/ngtsc/incremental/api.ts b/packages/compiler-cli/src/ngtsc/incremental/api.ts
@@ -64,4 +64,12 @@ export interface DependencyTracker<T extends {fileName: string} = ts.SourceFile>
    * `resourcesOf` they will not automatically be added to `from`.
    */
   addTransitiveResources(from: T, resourcesOf: T): void;
+
+  /**
+   * Record that the given file contains unresolvable dependencies.
+   *
+   * In practice, this means that the dependency graph cannot provide insight into the effects of
+   * future changes on that file.
+   */
+  recordDependencyAnalysisFailure(file: T): void;
 }
diff --git a/packages/compiler-cli/src/ngtsc/incremental/src/dependency_tracking.ts b/packages/compiler-cli/src/ngtsc/incremental/src/dependency_tracking.ts
@@ -53,6 +53,10 @@ export class FileDependencyGraph<T extends {fileName: string} = ts.SourceFile> i
     }
   }
 
+  recordDependencyAnalysisFailure(file: T): void {
+    this.nodeFor(file).failedAnalysis = true;
+  }
+
   getResourceDependencies(from: T): AbsoluteFsPath[] {
     const node = this.nodes.get(from);
 
@@ -97,6 +101,7 @@ export class FileDependencyGraph<T extends {fileName: string} = ts.SourceFile> i
         this.nodes.set(sf, {
           dependsOn: new Set(node.dependsOn),
           usesResources: new Set(node.usesResources),
+          failedAnalysis: false,
         });
       }
     }
@@ -109,6 +114,7 @@ export class FileDependencyGraph<T extends {fileName: string} = ts.SourceFile> i
       this.nodes.set(sf, {
         dependsOn: new Set<string>(),
         usesResources: new Set<AbsoluteFsPath>(),
+        failedAnalysis: false,
       });
     }
     return this.nodes.get(sf)!;
@@ -122,6 +128,12 @@ export class FileDependencyGraph<T extends {fileName: string} = ts.SourceFile> i
 function isLogicallyChanged<T extends {fileName: string}>(
     sf: T, node: FileNode, changedTsPaths: ReadonlySet<string>, deletedTsPaths: ReadonlySet<string>,
     changedResources: ReadonlySet<AbsoluteFsPath>): boolean {
+  // A file is assumed to have logically changed if its dependencies could not be determined
+  // accurately.
+  if (node.failedAnalysis) {
+    return true;
+  }
+
   // A file is logically changed if it has physically changed itself (including being deleted).
   if (changedTsPaths.has(sf.fileName) || deletedTsPaths.has(sf.fileName)) {
     return true;
@@ -146,6 +158,7 @@ function isLogicallyChanged<T extends {fileName: string}>(
 interface FileNode {
   dependsOn: Set<string>;
   usesResources: Set<AbsoluteFsPath>;
+  failedAnalysis: boolean;
 }
 
 const EMPTY_SET: ReadonlySet<any> = new Set<any>();
diff --git a/packages/compiler-cli/src/ngtsc/partial_evaluator/src/interpreter.ts b/packages/compiler-cli/src/ngtsc/partial_evaluator/src/interpreter.ts
@@ -220,6 +220,15 @@ export class StaticInterpreter {
       if (node.originalKeywordKind === ts.SyntaxKind.UndefinedKeyword) {
         return undefined;
       } else {
+        // Check if the symbol here is imported.
+        if (this.dependencyTracker !== null && this.host.getImportOfIdentifier(node) !== null) {
+          // It was, but no declaration for the node could be found. This means that the dependency
+          // graph for the current file cannot be properly updated to account for this (broken)
+          // import. Instead, the originating file is reported as failing dependency analysis,
+          // ensuring that future compilations will always attempt to re-resolve the previously
+          // broken identifier.
+          this.dependencyTracker.recordDependencyAnalysisFailure(context.originatingFile);
+        }
         return DynamicValue.fromUnknownIdentifier(node);
       }
     }
diff --git a/packages/compiler-cli/src/ngtsc/partial_evaluator/test/evaluator_spec.ts b/packages/compiler-cli/src/ngtsc/partial_evaluator/test/evaluator_spec.ts
@@ -991,4 +991,5 @@ const fakeDepTracker: DependencyTracker = {
   addResourceDependency: () => undefined,
   addTransitiveDependency: () => undefined,
   addTransitiveResources: () => undefined,
+  recordDependencyAnalysisFailure: () => undefined,
 };

Original file line number	Diff line number	Diff line change
`@@ -18,6 +18,7 @@ class NoopDependencyTracker implements DependencyTracker {`
`18`	`18`	`addResourceDependency(): void {}`
`19`	`19`	`addTransitiveDependency(): void {}`
`20`	`20`	`addTransitiveResources(): void {}`
	`21`	`+ recordDependencyAnalysisFailure(): void {}`
`21`	`22`	`}`
`22`	`23`
`23`	`24`	`export const NOOP_DEPENDENCY_TRACKER: DependencyTracker = new NoopDependencyTracker();`