fix(core): remove trailing slash in outputs that prevents correct cac…

…hing (#10708)

Fix by removing trailing slash when performing `cp -a` into cache.

Add test to confirm fix.

Resolves #10549

(cherry picked from commit 2889372)

e2e/nx-misc/src/extras.test.ts

@@ -1,4 +1,5 @@
 import {
+  checkFilesExist,
   cleanupProject,
   isNotWindows,
   newProject,
@@ -221,5 +222,46 @@ describe('Extra Nx Misc Tests', () => {
         })
       ).not.toThrow();
     }, 1000000);
+
+    it('should handle caching output directories containing trailing slashes', async () => {
+      // this test relates to https://github.com/nrwl/nx/issues/10549
+      // 'cp -a /path/dir/ dest/' operates differently to 'cp -a /path/dir dest/'
+      // --> which means actual build works but subsequent populate from cache (using cp -a) does not
+      // --> the fix is to remove trailing slashes to ensure consistent & expected behaviour
+
+      const mylib = uniq('lib');
+
+      const folder = `dist/libs/${mylib}/some-folder`;
+
+      runCLI(`generate @nrwl/workspace:lib ${mylib}`);
+
+      runCLI(
+        `generate @nrwl/workspace:run-commands build --command=echo --outputs=${folder}/ --project=${mylib}`
+      );
+
+      const commands = [
+        process.platform === 'win32'
+          ? `mkdir ${folder}` // Windows
+          : `mkdir -p ${folder}`,
+        `echo dummy > ${folder}/dummy.txt`,
+      ];
+      updateProjectConfig(mylib, (config) => {
+        delete config.targets.build.options.command;
+        config.targets.build.options = {
+          ...config.targets.build.options,
+          parallel: false,
+          commands: commands,
+        };
+        return config;
+      });
+
+      // confirm that it builds correctly
+      runCLI(`build ${mylib}`);
+      checkFilesExist(`${folder}/dummy.txt`);
+
+      // confirm that it populates correctly from the cache
+      runCLI(`build ${mylib}`);
+      checkFilesExist(`${folder}/dummy.txt`);
+    }, 120000);
   });
 });

packages/nx/src/tasks-runner/cache.ts

@@ -181,6 +181,11 @@ export class Cache {
   }
 
   private async copy(src: string, destination: string): Promise<void> {
+    // 'cp -a /path/dir/ dest/' operates differently to 'cp -a /path/dir dest/'
+    // --> which means actual build works but subsequent populate from cache (using cp -a) does not
+    // --> the fix is to remove trailing slashes to ensure consistent & expected behaviour
+    src = src.replace(/[\/\\]$/, '');
+
     if (this.useFsExtraToCopyAndRemove) {
       return copy(src, destination);
     }