Always look up task definition, but limit when it's added to traversa…

cli/integration_tests/basic_monorepo/filter-run.t

@@ -2,8 +2,11 @@ Setup
   $ . ${TESTDIR}/../setup.sh
   $ . ${TESTDIR}/setup.sh $(pwd)
 
-# Running with --filter works and exits
-  $ ${TURBO} run build --filter=main
+# Running with --filter works and exits with success
+  $ git branch
+  * main
+
+  $ ${TURBO} run build --filter="[main]"
   \xe2\x80\xa2 Packages in scope:  (esc)
   \xe2\x80\xa2 Running build in 0 packages (esc)
   \xe2\x80\xa2 Remote caching disabled (esc)
@@ -13,4 +16,21 @@ Setup
    Tasks:    0 successful, 0 total
   Cached:    0 cached, 0 total
     Time:\s*[\.0-9]+m?s  (re)
+
+
+# with unstaged changes
+  $ echo "new file contents" >> bar.txt
+  $ git branch
+  * main
+
+  $ ${TURBO} run build --filter="[main]"
+  \xe2\x80\xa2 Packages in scope: // (esc)
+  \xe2\x80\xa2 Running build in 1 packages (esc)
+  \xe2\x80\xa2 Remote caching disabled (esc)
+
+  No tasks were executed as part of this run.
+
+   Tasks:    0 successful, 0 total
+  Cached:    0 cached, 0 total
+    Time:\s*[\.0-9]+m?s  (re)
 

cli/integration_tests/basic_monorepo/monorepo/bar.txt

@@ -0,0 +1 @@
+other file, not a global dependency

cli/internal/core/engine.go

@@ -172,27 +172,39 @@ func (e *Engine) Prepare(options *EngineBuildingOptions) error {
 	// We do this by taking the input taskNames, and pkgs
 	// and creating a queue of taskIDs that we can traverse and gather dependencies from.
 	for _, pkg := range pkgs {
-		isRootPkg := pkg == util.RootPkgName
 		for _, taskName := range taskNames {
-			// If it's not a task from the root workspace (i.e. tasks from every other workspace)
-			// or if it's a task that we know is rootEnabled task, add it to the traversal queue.
-			if !isRootPkg || e.rootEnabledTasks.Includes(taskName) {
-				taskID := util.GetTaskId(pkg, taskName)
-				// Skip tasks that don't have a definition
-				if _, err := e.getTaskDefinition(pkg, taskName, taskID); err != nil {
-					var e *MissingTaskError
-					if errors.As(err, &e) {
-						// Initially, non-package tasks are not required to exist, as long as some
-						// package in the list packages defines it as a package-task. Dependencies
-						// *are* required to have a definition.
-						continue
-					}
-
-					return err
+			taskID := util.GetTaskId(pkg, taskName)
+
+			// Look up the task in the package
+			foundTask, err := e.getTaskDefinition(pkg, taskName, taskID)
+
+			// We can skip MissingTaskErrors because we'll validate against them later
+			// Return all other errors
+			if err != nil {
+				var e *MissingTaskError
+				if errors.As(err, &e) {
+					// Initially, non-package tasks are not required to exist, as long as some
+					// package in the list packages defines it as a package-task. Dependencies
+					// *are* required to have a definition.
+					continue
 				}
+
+				return err
+			}
+
+			// If we found a task definition, remove it from the msising list
+			if foundTask != nil {
 				// delete taskName if it was found
 				missing.Delete(taskName)
-				traversalQueue = append(traversalQueue, taskID)
+
+				// Even if a task definition was found, we _only_ want to add it as an entry point to
+				// the task graph (i.e. the traversalQueue), if it's:
+				// - A task from the non-root workspace (i.e. tasks from every other workspace)
+				// - A task that we *know* is rootEnabled task (in which case, the root workspace is acceptable)
+				isRootPkg := pkg == util.RootPkgName
+				if !isRootPkg || e.rootEnabledTasks.Includes(taskName) {
+					traversalQueue = append(traversalQueue, taskID)
+				}
 			}
 		}
 	}