[rush] When using cobuilds, no-op operations should not be treated as uncacheable

build-tests/rush-redis-cobuild-plugin-integration-test/sandbox/repo/projects/a/config/rush-project.json

@@ -7,10 +7,6 @@
  {
  "operationName": "cobuild",
  "outputFolderNames": ["dist"]
- },
- {
- "operationName": "_phase:build",
- "outputFolderNames": ["dist"]
  }
  ]
 }

build-tests/rush-redis-cobuild-plugin-integration-test/sandbox/repo/projects/b/config/rush-project.json

@@ -7,10 +7,6 @@
  {
  "operationName": "cobuild",
  "outputFolderNames": ["dist"]
- },
- {
- "operationName": "_phase:build",
- "outputFolderNames": ["dist"]
  }
  ]
 }

build-tests/rush-redis-cobuild-plugin-integration-test/sandbox/repo/projects/c/config/rush-project.json

@@ -7,10 +7,6 @@
  {
  "operationName": "cobuild",
  "outputFolderNames": ["dist"]
- },
- {
- "operationName": "_phase:build",
- "outputFolderNames": ["dist"]
  }
  ]
 }

build-tests/rush-redis-cobuild-plugin-integration-test/sandbox/repo/projects/d/config/rush-project.json

@@ -7,10 +7,6 @@
  {
  "operationName": "cobuild",
  "outputFolderNames": ["dist"]
- },
- {
- "operationName": "_phase:build",
- "outputFolderNames": ["dist"]
  }
  ]
 }

build-tests/rush-redis-cobuild-plugin-integration-test/sandbox/repo/projects/e/config/rush-project.json

@@ -7,10 +7,6 @@
  {
  "operationName": "cobuild",
  "outputFolderNames": ["dist"]
- },
- {
- "operationName": "_phase:build",
- "outputFolderNames": ["dist"]
  }
  ]
 }

build-tests/rush-redis-cobuild-plugin-integration-test/sandbox/repo/projects/f/config/rush-project.json

@@ -8,10 +8,6 @@
  {
  "operationName": "cobuild",
  "outputFolderNames": ["dist"]
- },
- {
- "operationName": "_phase:build",
- "outputFolderNames": ["dist"]
  }
  ]
 }

build-tests/rush-redis-cobuild-plugin-integration-test/sandbox/repo/projects/h/config/rush-project.json

@@ -7,10 +7,6 @@
  {
  "operationName": "cobuild",
  "outputFolderNames": ["dist"]
- },
- {
- "operationName": "_phase:build",
- "outputFolderNames": ["dist"]
  }
  ]
 }

common/changes/@microsoft/rush/fix-caching-behavior-undefined_2024-04-17-14-52.json

@@ -0,0 +1,10 @@
+{
+ "changes": [
+ {
+ "packageName": "@microsoft/rush",
+ "comment": "Fixes a bug where no-op operations were treated as having build cache disabled.",
+ "type": "none"
+ }
+ ],
+ "packageName": "@microsoft/rush"
+}

common/reviews/api/rush-lib.api.md

@@ -1376,7 +1376,7 @@ export class RushLifecycleHooks {
 // @alpha
 export class RushProjectConfiguration {
  readonly disableBuildCacheForProject: boolean;
- getCacheDisabledReason(trackedFileNames: Iterable<string>, phaseName: string): string | undefined;
+ getCacheDisabledReason(trackedFileNames: Iterable<string>, phaseName: string, operation?: Operation): string | undefined;
  readonly incrementalBuildIgnoredGlobs: ReadonlyArray<string>;
  // (undocumented)
  readonly operationSettingsByOperationName: ReadonlyMap<string, Readonly<IOperationSettings>>;

libraries/rush-lib/src/api/RushProjectConfiguration.ts

@@ -12,6 +12,7 @@ import type { IPhase } from './CommandLineConfiguration';
 import { OverlappingPathAnalyzer } from '../utilities/OverlappingPathAnalyzer';
 import schemaJson from '../schemas/rush-project.schema.json';
 import anythingSchemaJson from '../schemas/rush-project.schema.json';
+import type { Operation } from '../logic/operations/Operation';
 
 /**
  * Describes the file structure for the `<project root>/config/rush-project.json` config file.
@@ -299,12 +300,19 @@ export class RushProjectConfiguration {
  * Examines the list of source files for the project and the target phase and returns a reason
  * why the project cannot enable the build cache for that phase, or undefined if it is safe to so do.
  */
- public getCacheDisabledReason(trackedFileNames: Iterable<string>, phaseName: string): string | undefined {
+ public getCacheDisabledReason(
+ trackedFileNames: Iterable<string>,
+ phaseName: string,
+ operation?: Operation
+ ): string | undefined {
  if (this.disableBuildCacheForProject) {
  return 'Caching has been disabled for this project.';
  }
 
- const normalizedProjectRelativeFolder: string = Path.convertToSlashes(this.project.projectRelativeFolder);
+ // Skip no-op operations as they won't have any output/cacheable things.
+ if (operation?.runner?.isNoOp) {
+ return undefined;
+ }
 
  const operationSettings: IOperationSettings | undefined =
  this.operationSettingsByOperationName.get(phaseName);
@@ -320,6 +328,7 @@ export class RushProjectConfiguration {
  if (!outputFolderNames) {
  return;
  }
+ const normalizedProjectRelativeFolder: string = Path.convertToSlashes(this.project.projectRelativeFolder);
 
  const normalizedOutputFolders: string[] = outputFolderNames.map(
  (outputFolderName) => `${normalizedProjectRelativeFolder}/${outputFolderName}/`