Filter out summaries of tasks that didn't execute (#4238)

We don't want to exclude tasks entirely from the task graph,
because they could be used as virtual wrappers to trigger
downstream tasks (via dependsOn), but we can filter them
out of the task summary to reduce noise. Another reason to
do this, is that the task summary is initialized in "building"
phase, which is a bit presumptuous, and also wrong for tasks
that end up being a no-op because they aren't implemented.

cli/integration_tests/basic_monorepo/cache_state.t

@@ -4,8 +4,8 @@ Setup
 
 Run a build to get a local cache.
   $ ${TURBO} run build --output-logs=none
-  \xe2\x80\xa2 Packages in scope: my-app, util (esc)
-  \xe2\x80\xa2 Running build in 2 packages (esc)
+  \xe2\x80\xa2 Packages in scope: another, my-app, util (esc)
+  \xe2\x80\xa2 Running build in 3 packages (esc)
   \xe2\x80\xa2 Remote caching disabled (esc)
 
    Tasks:    2 successful, 2 total

cli/integration_tests/basic_monorepo/dry_run.t

@@ -9,9 +9,10 @@ Setup
 # The first part of the file is Packages in Scope
   $ cat tmp-1.txt
   Packages in Scope
-  Name   Path          
-  my-app apps/my-app   
-  util   packages/util 
+  Name    Path             
+  another packages/another 
+  my-app  apps/my-app      
+  util    packages/util    
 
 # Part 2 of the logs are Global Hash INputs
   $ cat tmp-2.txt

cli/integration_tests/basic_monorepo/infer_pkg.t

@@ -5,6 +5,7 @@ Setup
 Run a dry run
   $ ${TURBO} build --dry=json | jq .packages
   [
+    "another",
     "my-app",
     "util"
   ]
@@ -19,6 +20,7 @@ Run a dry run in a directory
 Ensure we don't infer packages if --cwd is supplied
   $ ${TURBO} build --cwd=../.. --dry=json | jq .packages
   [
+    "another",
     "my-app",
     "util"
   ]

cli/integration_tests/basic_monorepo/monorepo/packages/another/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "another",
+  "scripts": {}
+}

cli/integration_tests/basic_monorepo/run.t

@@ -29,8 +29,8 @@ Setup
 
 # Bad command
   $ ${TURBO} run something
-  \xe2\x80\xa2 Packages in scope: //, my-app, util (esc)
-  \xe2\x80\xa2 Running something in 3 packages (esc)
+  \xe2\x80\xa2 Packages in scope: //, another, my-app, util (esc)
+  \xe2\x80\xa2 Running something in 4 packages (esc)
   \xe2\x80\xa2 Remote caching disabled (esc)
   root task something (turbo run build) looks like it invokes turbo and might cause a loop
 

cli/integration_tests/basic_monorepo/run_summary.t

@@ -43,6 +43,9 @@ Setup
     "apps/my-app/.turbo/turbo-build.log"
   ]
 
+  $ cat $(/bin/ls .turbo/runs/*.json | head -n1) | jq '.tasks | map(select(.taskId == "another#build"))'
+  []
+
 # Without env var, no summary file is generated
   $ rm -rf .turbo/runs
   $ ${TURBO} run build > /dev/null

cli/internal/run/real_run.go

@@ -94,18 +94,26 @@ func RealRun(
 	taskSummaries := []*runsummary.TaskSummary{}
 	execFunc := func(ctx gocontext.Context, packageTask *nodes.PackageTask, taskSummary *runsummary.TaskSummary) error {
 		deps := engine.TaskGraph.DownEdges(packageTask.TaskID)
-		mu.Lock()
-		taskSummaries = append(taskSummaries, taskSummary)
-		// don't hold the lock while we run ec.exec
-		mu.Unlock()
-
 		// deps here are passed in to calculate the task hash
 		taskExecutionSummary, err := ec.exec(ctx, packageTask, deps)
 		if err != nil {
 			return err
 		}
-		taskSummary.Execution = taskExecutionSummary
-		taskSummary.ExpandedOutputs = taskHashTracker.GetExpandedOutputs(taskSummary.TaskID)
+
+		// taskExecutionSummary will be nil if the task never executed
+		// (i.e. if the workspace didn't implement the script corresponding to the task)
+		// We don't need to collect any of the outputs or execution if the task didn't execute.
+		if taskExecutionSummary != nil {
+			taskSummary.ExpandedOutputs = taskHashTracker.GetExpandedOutputs(taskSummary.TaskID)
+			taskSummary.Execution = taskExecutionSummary
+
+			// lock since multiple things to be appending to this array at the same time
+			mu.Lock()
+			taskSummaries = append(taskSummaries, taskSummary)
+			// not using defer, just release the lock
+			mu.Unlock()
+		}
+
 		return nil
 	}
 
@@ -196,7 +204,8 @@ func (ec *execContext) exec(ctx gocontext.Context, packageTask *nodes.PackageTas
 	if packageTask.Command == "" {
 		progressLogger.Debug("no task in package, skipping")
 		progressLogger.Debug("done", "status", "skipped", "duration", time.Since(cmdTime))
-		return taskExecutionSummary, nil
+		// Return nil here because there was no execution, so there is no task execution summary
+		return nil, nil
 	}
 
 	var prefix string