fix(core): fix dependency with multiple dependent packages (#28669)

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## Current Behavior
<!-- This is the behavior we have today -->
- we introduce a feature to allow circular project dependencies to
execute tasks in pr https://github.com/nrwl/nx/pull/28227/files
- for this feature, we introduce the concept of dummy task as a
temporary placeholder so we can still generate a task graph even if
dependencies contain circular dependencies
- however, it does not handle a task graph of multiple dummy task deps.
for example:
lib1 -> lib2 -> lib3 -> lib4
if we got task graph like:
lib1:build -> lib2:dummy
lib2:dummy -> lib3:dummy
lib3:dummy -> lib4:rebuild
currently, it does not create a dependency between
lib1:build->lib4:prebuild

## Expected Behavior
<!-- This is the behavior we should expect with the changes in this PR
-->
it should link the dependency when it contains multiple level of
depending on dummy tasks

## Related Issue(s)
<!-- Please link the issue being fixed so it gets closed when this is
merged. -->

Fixes #28599 and
#28380

packages/nx/src/tasks-runner/create-task-graph.spec.ts

@@ -1624,7 +1624,7 @@ describe('createTaskGraph', () => {
       }
     );
     expect(taskGraph).toEqual({
-      roots: [],
+      roots: ['lib2:build'],
       tasks: {
         'lib1:build': expect.objectContaining({
           id: 'lib1:build',
@@ -1668,7 +1668,7 @@ describe('createTaskGraph', () => {
       },
       dependencies: {
         'lib1:build': ['lib2:build'],
-        'lib2:build': ['lib4:build'],
+        'lib2:build': [],
         'lib4:build': ['lib1:build'],
       },
     });
@@ -1870,7 +1870,7 @@ describe('createTaskGraph', () => {
     });
   });
 
-  it('should handle cycles between projects that do not create cycles between tasks and not contain the same task target (app1:build -> app2 <-> app3:build)``', () => {
+  it('should handle cycles between projects that do not create cycles between tasks and not contain the same task target (app1:build -> app2 <-> app3:build)', () => {
     projectGraph = {
       nodes: {
         app1: {
@@ -2488,6 +2488,175 @@ describe('createTaskGraph', () => {
       }
     `);
   });
+
+  it('should handle mulitple projects that are dependent on each other (app1->app2->app3->app4)', () => {
+    projectGraph = {
+      nodes: {
+        app1: {
+          name: 'app1',
+          type: 'app',
+          data: {
+            root: 'app1-root',
+            targets: {
+              compile: {
+                executor: 'nx:run-commands',
+                dependsOn: ['precompiple', '^precompile'],
+              },
+            },
+          },
+        },
+        app2: {
+          name: 'app2',
+          type: 'app',
+          data: {
+            root: 'app2-root',
+            targets: {
+              compile: {
+                executor: 'nx:run-commands',
+                dependsOn: ['precompiple', '^precompile'],
+              },
+            },
+          },
+        },
+        app3: {
+          name: 'app3',
+          type: 'app',
+          data: {
+            root: 'app3-root',
+            targets: {
+              compile: {
+                executor: 'nx:run-commands',
+                dependsOn: ['precompiple', '^precompile'],
+              },
+            },
+          },
+        },
+        app4: {
+          name: 'app4',
+          type: 'app',
+          data: {
+            root: 'app4-root',
+            targets: {
+              precompile: {
+                executor: 'nx:run-commands',
+              },
+            },
+          },
+        },
+      },
+      dependencies: {
+        app1: [{ source: 'app1', target: 'app2', type: 'implicit' }],
+        app2: [{ source: 'app2', target: 'app3', type: 'implicit' }],
+        app3: [{ source: 'app3', target: 'app4', type: 'implicit' }],
+      },
+    };
+
+    let taskGraph = createTaskGraph(
+      projectGraph,
+      {},
+      ['app1'],
+      ['compile'],
+      'development',
+      {
+        __overrides_unparsed__: [],
+      }
+    );
+    expect(taskGraph).toEqual({
+      roots: ['app4:precompile'],
+      tasks: {
+        'app1:compile': {
+          id: 'app1:compile',
+          target: {
+            project: 'app1',
+            target: 'compile',
+          },
+          outputs: [],
+          overrides: {
+            __overrides_unparsed__: [],
+          },
+          projectRoot: 'app1-root',
+          parallelism: true,
+        },
+        'app4:precompile': {
+          id: 'app4:precompile',
+          target: {
+            project: 'app4',
+            target: 'precompile',
+          },
+          outputs: [],
+          overrides: {
+            __overrides_unparsed__: [],
+          },
+          projectRoot: 'app4-root',
+          parallelism: true,
+        },
+      },
+      dependencies: {
+        'app1:compile': ['app4:precompile'],
+        'app4:precompile': [],
+      },
+    });
+
+    taskGraph = createTaskGraph(
+      projectGraph,
+      {},
+      ['app2', 'app3'],
+      ['compile'],
+      'development',
+      {
+        __overrides_unparsed__: [],
+      }
+    );
+    expect(taskGraph).toEqual({
+      roots: ['app4:precompile'],
+      tasks: {
+        'app2:compile': {
+          id: 'app2:compile',
+          target: {
+            project: 'app2',
+            target: 'compile',
+          },
+          outputs: [],
+          overrides: {
+            __overrides_unparsed__: [],
+          },
+          projectRoot: 'app2-root',
+          parallelism: true,
+        },
+        'app3:compile': {
+          id: 'app3:compile',
+          target: {
+            project: 'app3',
+            target: 'compile',
+          },
+          outputs: [],
+          overrides: {
+            __overrides_unparsed__: [],
+          },
+          projectRoot: 'app3-root',
+          parallelism: true,
+        },
+        'app4:precompile': {
+          id: 'app4:precompile',
+          target: {
+            project: 'app4',
+            target: 'precompile',
+          },
+          outputs: [],
+          overrides: {
+            __overrides_unparsed__: [],
+          },
+          projectRoot: 'app4-root',
+          parallelism: true,
+        },
+      },
+      dependencies: {
+        'app2:compile': ['app4:precompile'],
+        'app3:compile': ['app4:precompile'],
+        'app4:precompile': [],
+      },
+    });
+  });
 });
 
 class GraphBuilder {

packages/nx/src/tasks-runner/create-task-graph.ts

@@ -8,6 +8,7 @@ import { Task, TaskGraph } from '../config/task-graph';
 import { TargetDefaults, TargetDependencies } from '../config/nx-json';
 import { output } from '../utils/output';
 import { TargetDependencyConfig } from '../config/workspace-json-project-json';
+import { findCycle } from './task-graph-utils';
 
 const DUMMY_TASK_TARGET = '__nx_dummy_task__';
 
@@ -105,7 +106,7 @@ export class ProcessTasks {
     projectUsedToDeriveDependencies: string,
     configuration: string,
     overrides: Object
-  ) {
+  ): void {
     const seenKey = `${task.id}-${projectUsedToDeriveDependencies}`;
     if (this.seen.has(seenKey)) {
       return;
@@ -233,7 +234,7 @@ export class ProcessTasks {
     task: Task,
     taskOverrides: Object | { __overrides_unparsed__: any[] },
     overrides: Object
-  ) {
+  ): void {
     if (
       !this.projectGraph.dependencies.hasOwnProperty(
         projectUsedToDeriveDependencies
@@ -292,7 +293,7 @@ export class ProcessTasks {
           undefined
         );
         this.dependencies[task.id].push(dummyId);
-        this.dependencies[dummyId] = [];
+        this.dependencies[dummyId] ??= [];
         const noopTask = this.createDummyTask(dummyId, task);
         this.processTask(noopTask, depProject.name, configuration, overrides);
       }
@@ -377,22 +378,53 @@ export class ProcessTasks {
     return id;
   }
 
+  /**
+   * this function is used to get the non dummy dependencies of a task recursively
+   * For example, when we have the following dependencies:
+   * {
+   *   'app1:compile': [ 'app2:__nx_dummy_task__' ],
+   *   'app2:__nx_dummy_task__': [ 'app3:__nx_dummy_task__' ],
+   *   'app3:__nx_dummy_task__': [ 'app4:precompile' ],
+   *   'app4:precompile': []
+   * }
+   * getNonDummyDeps('app1:compile') will return ['app1:compile']
+   * getNonDummyDeps('app2:__nx_dummy_task__') will return ['app4:precompile']
+   * getNonDummyDeps('app3:__nx_dummy_task__') will return ['app4:precompile']
+   * getNonDummyDeps('app4:precompile') will return ['app4:precompile']
+   */
+  private getNonDummyDeps(
+    currentTask: string,
+    originalTask: string,
+    cycle?: string[]
+  ): string[] {
+    if (currentTask === originalTask) {
+      return [];
+    } else if (currentTask.endsWith(DUMMY_TASK_TARGET)) {
+      if (cycle?.length && cycle?.includes(currentTask)) {
+        return [];
+      }
+      // if not a cycle, recursively get the non dummy dependencies
+      return (
+        this.dependencies[currentTask]?.flatMap((dep) =>
+          this.getNonDummyDeps(dep, originalTask, cycle)
+        ) ?? []
+      );
+    } else {
+      return [currentTask];
+    }
+  }
+
   private filterDummyTasks() {
+    const cycle = findCycle({ dependencies: this.dependencies });
     for (const [key, deps] of Object.entries(this.dependencies)) {
-      const normalizedDeps = [];
-      for (const dep of deps) {
-        if (dep.endsWith(DUMMY_TASK_TARGET)) {
-          normalizedDeps.push(
-            ...this.dependencies[dep].filter(
-              (d) => !d.endsWith(DUMMY_TASK_TARGET)
-            )
-          );
-        } else {
-          normalizedDeps.push(dep);
+      if (!key.endsWith(DUMMY_TASK_TARGET)) {
+        const normalizedDeps = [];
+        for (const dep of deps) {
+          normalizedDeps.push(...this.getNonDummyDeps(dep, key, cycle));
         }
-      }
 
-      this.dependencies[key] = normalizedDeps;
+        this.dependencies[key] = normalizedDeps;
+      }
     }
 
     for (const key of Object.keys(this.dependencies)) {

packages/nx/src/tasks-runner/task-graph-utils.ts

@@ -1,10 +1,6 @@
-import { readNxJson } from '../config/configuration';
 import { ProjectGraph } from '../config/project-graph';
-import { Task, TaskGraph } from '../config/task-graph';
-import { isNxCloudUsed } from '../utils/nx-cloud-utils';
+import { TaskGraph } from '../config/task-graph';
 import { output } from '../utils/output';
-import { serializeTarget } from '../utils/serialize-target';
-import chalk = require('chalk');
 
 function _findCycle(
   graph: { dependencies: Record<string, string[]> },