fix(core): reduce total memory usage of various migration schematics (#60776)

JoostK · atscott · commit 9241615ad082 · 2025-04-08T16:12:57.000-07:00
This commit changes Tsurge's operation within angular-devkit (i.e. the CLI) to no longer retain all programs across all migrations. This isn't necessary for so-called "funnel" migrations so not retaining the programs for those migrations is a pure performance win. The "complex" migrations may see increased execution time given that the program is now being recreated for the actual migration phase to run, although reduced memory pressure may help alleviate this overhead. Since this new approach should help prevent Node from running out of memory and failing entirely this is preferred over a potentially increased execution time. Fixes #59813 PR Close #60776
diff --git a/packages/core/schematics/ng-generate/cleanup-unused-imports/index.ts b/packages/core/schematics/ng-generate/cleanup-unused-imports/index.ts
@@ -7,16 +7,20 @@
  */
 
 import {Rule} from '@angular-devkit/schematics';
+import {MigrationStage, runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
 import {UnusedImportsMigration} from './unused_imports_migration';
-import {runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
 
 export function migrate(): Rule {
   return async (tree, context) => {
     await runMigrationInDevkit({
       getMigration: () => new UnusedImportsMigration(),
       tree,
-      beforeProgramCreation: (tsconfigPath) => {
-        context.logger.info(`Preparing analysis for ${tsconfigPath}`);
+      beforeProgramCreation: (tsconfigPath, stage) => {
+        if (stage === MigrationStage.Analysis) {
+          context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+        } else {
+          context.logger.info(`Running migration for: ${tsconfigPath}...`);
+        }
       },
       beforeUnitAnalysis: (tsconfigPath) => {
         context.logger.info(`Scanning for unused imports using ${tsconfigPath}`);
diff --git a/packages/core/schematics/ng-generate/output-migration/index.ts b/packages/core/schematics/ng-generate/output-migration/index.ts
@@ -8,7 +8,7 @@
 
 import {Rule} from '@angular-devkit/schematics';
 import {OutputMigration} from '../../migrations/output-migration/output-migration';
-import {runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
+import {MigrationStage, runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
 
 interface Options {
   path: string;
@@ -28,8 +28,12 @@ export function migrate(options: Options): Rule {
             );
           },
         }),
-      beforeProgramCreation: (tsconfigPath) => {
-        context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+      beforeProgramCreation: (tsconfigPath, stage) => {
+        if (stage === MigrationStage.Analysis) {
+          context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+        } else {
+          context.logger.info(`Running migration for: ${tsconfigPath}...`);
+        }
       },
       afterProgramCreation: (info, fs) => {
         const analysisPath = fs.resolve(options.analysisDir);
diff --git a/packages/core/schematics/ng-generate/self-closing-tags-migration/index.ts b/packages/core/schematics/ng-generate/self-closing-tags-migration/index.ts
@@ -8,7 +8,7 @@
 
 import {Rule} from '@angular-devkit/schematics';
 import {SelfClosingTagsMigration} from '../../migrations/self-closing-tags-migration/self-closing-tags-migration';
-import {runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
+import {MigrationStage, runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
 
 interface Options {
   path: string;
@@ -28,8 +28,12 @@ export function migrate(options: Options): Rule {
             );
           },
         }),
-      beforeProgramCreation: (tsconfigPath) => {
-        context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+      beforeProgramCreation: (tsconfigPath, stage) => {
+        if (stage === MigrationStage.Analysis) {
+          context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+        } else {
+          context.logger.info(`Running migration for: ${tsconfigPath}...`);
+        }
       },
       beforeUnitAnalysis: (tsconfigPath) => {
         context.logger.info(`Scanning for component tags: ${tsconfigPath}...`);
diff --git a/packages/core/schematics/ng-generate/signal-input-migration/index.ts b/packages/core/schematics/ng-generate/signal-input-migration/index.ts
@@ -8,7 +8,7 @@
 
 import {Rule} from '@angular-devkit/schematics';
 import {SignalInputMigration} from '../../migrations/signal-migration/src';
-import {runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
+import {MigrationStage, runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
 
 interface Options {
   path: string;
@@ -32,8 +32,12 @@ export function migrate(options: Options): Rule {
             );
           },
         }),
-      beforeProgramCreation: (tsconfigPath) => {
-        context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+      beforeProgramCreation: (tsconfigPath, stage) => {
+        if (stage === MigrationStage.Analysis) {
+          context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+        } else {
+          context.logger.info(`Running migration for: ${tsconfigPath}...`);
+        }
       },
       afterProgramCreation: (info, fs) => {
         const analysisPath = fs.resolve(options.analysisDir);
diff --git a/packages/core/schematics/ng-generate/signal-queries-migration/index.ts b/packages/core/schematics/ng-generate/signal-queries-migration/index.ts
@@ -8,7 +8,7 @@
 
 import {Rule} from '@angular-devkit/schematics';
 import {SignalQueriesMigration} from '../../migrations/signal-queries-migration/migration';
-import {runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
+import {MigrationStage, runMigrationInDevkit} from '../../utils/tsurge/helpers/angular_devkit';
 
 interface Options {
   path: string;
@@ -32,8 +32,12 @@ export function migrate(options: Options): Rule {
             );
           },
         }),
-      beforeProgramCreation: (tsconfigPath) => {
-        context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+      beforeProgramCreation: (tsconfigPath, stage) => {
+        if (stage === MigrationStage.Analysis) {
+          context.logger.info(`Preparing analysis for: ${tsconfigPath}...`);
+        } else {
+          context.logger.info(`Running migration for: ${tsconfigPath}...`);
+        }
       },
       afterProgramCreation: (info, fs) => {
         const analysisPath = fs.resolve(options.analysisDir);
diff --git a/packages/core/schematics/utils/tsurge/helpers/angular_devkit/run_in_devkit.ts b/packages/core/schematics/utils/tsurge/helpers/angular_devkit/run_in_devkit.ts
@@ -18,6 +18,14 @@ import {ProjectRootRelativePath} from '../../project_paths';
 import {ProgramInfo} from '../../program_info';
 import {getProjectTsConfigPaths} from '../../../../utils/project_tsconfig_paths';
 
+export enum MigrationStage {
+  /** The migration is analyzing an entrypoint */
+  Analysis,
+
+  /** The migration is about to migrate an entrypoint */
+  Migrate,
+}
+
 /** Information necessary to run a Tsurge migration in the devkit. */
 export interface TsurgeDevkitMigration {
   /** Instantiates the migration. */
@@ -27,13 +35,13 @@ export interface TsurgeDevkitMigration {
   tree: Tree;
 
   /** Called before a program is created. Useful to notify the user before processing starts. */
-  beforeProgramCreation?: (tsconfigPath: string) => void;
+  beforeProgramCreation?: (tsconfigPath: string, stage: MigrationStage) => void;
 
   /**
    * Called after a program is created. Useful when the
    * structure needs to be modified (e.g. filtering files).
    */
-  afterProgramCreation?: (info: ProgramInfo, fileSystem: FileSystem) => void;
+  afterProgramCreation?: (info: ProgramInfo, fileSystem: FileSystem, stage: MigrationStage) => void;
 
   /** Called before a unit is analyzed. Useful for logging. */
   beforeUnitAnalysis?: (tsconfigPath: string) => void;
@@ -55,21 +63,21 @@ export async function runMigrationInDevkit(config: TsurgeDevkitMigration): Promi
   if (!buildPaths.length && !testPaths.length) {
     throw new SchematicsException('Could not find any tsconfig file. Cannot run the migration.');
   }
+  const tsconfigPaths = [...buildPaths, ...testPaths];
 
   const fs = new DevkitMigrationFilesystem(config.tree);
   setFileSystem(fs);
 
   const migration = config.getMigration(fs);
   const unitResults: unknown[] = [];
-  const programInfos = [...buildPaths, ...testPaths].map((tsconfigPath) => {
-    config.beforeProgramCreation?.(tsconfigPath);
+
+  const isFunnelMigration = migration instanceof TsurgeFunnelMigration;
+  for (const tsconfigPath of tsconfigPaths) {
+    config.beforeProgramCreation?.(tsconfigPath, MigrationStage.Analysis);
     const baseInfo = migration.createProgram(tsconfigPath, fs);
     const info = migration.prepareProgram(baseInfo);
-    config.afterProgramCreation?.(info, fs);
-    return {info, tsconfigPath};
-  });
+    config.afterProgramCreation?.(info, fs, MigrationStage.Analysis);
 
-  for (const {info, tsconfigPath} of programInfos) {
     config.beforeUnitAnalysis?.(tsconfigPath);
     unitResults.push(await migration.analyze(info));
   }
@@ -85,12 +93,17 @@ export async function runMigrationInDevkit(config: TsurgeDevkitMigration): Promi
   const globalMeta = await migration.globalMeta(combined);
   let replacements: Replacement[];
 
-  if (migration instanceof TsurgeFunnelMigration) {
+  if (isFunnelMigration) {
     replacements = (await migration.migrate(globalMeta)).replacements;
   } else {
     replacements = [];
 
-    for (const {info} of programInfos) {
+    for (const tsconfigPath of tsconfigPaths) {
+      config.beforeProgramCreation?.(tsconfigPath, MigrationStage.Migrate);
+      const baseInfo = migration.createProgram(tsconfigPath, fs);
+      const info = migration.prepareProgram(baseInfo);
+      config.afterProgramCreation?.(info, fs, MigrationStage.Migrate);
+
       const result = await migration.migrate(globalMeta, info);
       replacements.push(...result.replacements);
     }
