Preserve subprocess wait failures

internal/adapters/subprocess/execution.go

@@ -2,6 +2,7 @@ package subprocess
 
 import (
 	"context"
+	"fmt"
 	"os/exec"
 	"time"
 )
@@ -58,10 +59,10 @@ func executeOwnedCommand(ctx context.Context, cmd *exec.Cmd, abort <-chan error)
 		} else {
 			outcome.reason = executionCanceled
 		}
-		outcome.cleanupErr = terminateAndReap(tree, waitCh)
+		outcome.waitErr, outcome.cleanupErr = terminateAndReap(tree, waitCh)
 	case outcome.abortErr = <-abort:
 		outcome.reason = executionAborted
-		outcome.cleanupErr = terminateAndReap(tree, waitCh)
+		outcome.waitErr, outcome.cleanupErr = terminateAndReap(tree, waitCh)
 	}
 	if cmd.ProcessState != nil {
 		outcome.exitCode = cmd.ProcessState.ExitCode()
@@ -69,22 +70,22 @@ func executeOwnedCommand(ctx context.Context, cmd *exec.Cmd, abort <-chan error)
 	return outcome
 }
 
-func terminateAndReap(tree ownedProcessTree, waitCh <-chan error) error {
-	cleanupErr := tree.TerminateGracefully()
+func terminateAndReap(tree ownedProcessTree, waitCh <-chan error) (waitErr, cleanupErr error) {
+	cleanupErr = tree.TerminateGracefully()
 	timer := time.NewTimer(gracefulTerminationWait)
 	defer timer.Stop()
 	select {
-	case <-waitCh:
-		return joinErrors(cleanupErr, tree.TerminateForcefully())
+	case waitErr = <-waitCh:
+		return waitErr, joinErrors(cleanupErr, tree.TerminateForcefully())
 	case <-timer.C:
 	}
 	cleanupErr = joinErrors(cleanupErr, tree.TerminateForcefully())
 	forcefulTimer := time.NewTimer(forcefulTerminationWait)
 	defer forcefulTimer.Stop()
 	select {
-	case <-waitCh:
-		return cleanupErr
+	case waitErr = <-waitCh:
+		return waitErr, cleanupErr
 	case <-forcefulTimer.C:
-		return joinErrors(cleanupErr, context.DeadlineExceeded)
+		return nil, joinErrors(cleanupErr, fmt.Errorf("owned subprocess did not reap within %s after forceful termination", forcefulTerminationWait))
 	}
 }

internal/adapters/subprocess/execution_test.go

@@ -0,0 +1,54 @@
+package subprocess
+
+import (
+	"errors"
+	"os/exec"
+	"testing"
+)
+
+func TestTerminateAndReapPreservesWaitAndCleanupErrors(t *testing.T) {
+	waitErr := errors.New("wait failed")
+	gracefulErr := errors.New("graceful termination failed")
+	forcefulErr := errors.New("forceful termination failed")
+	tree := &recordingProcessTree{
+		gracefulErr: gracefulErr,
+		forcefulErr: forcefulErr,
+	}
+	waitCh := make(chan error, 1)
+	waitCh <- waitErr
+
+	gotWaitErr, gotCleanupErr := terminateAndReap(tree, waitCh)
+	if !errors.Is(gotWaitErr, waitErr) {
+		t.Fatalf("wait error = %v, want %v", gotWaitErr, waitErr)
+	}
+	for _, want := range []error{gracefulErr, forcefulErr} {
+		if !errors.Is(gotCleanupErr, want) {
+			t.Fatalf("cleanup error = %v, want wrapped %v", gotCleanupErr, want)
+		}
+	}
+	if tree.gracefulCalls != 1 || tree.forcefulCalls != 1 {
+		t.Fatalf("termination calls = graceful %d, forceful %d; want 1 each", tree.gracefulCalls, tree.forcefulCalls)
+	}
+}
+
+type recordingProcessTree struct {
+	gracefulErr error
+	forcefulErr error
+
+	gracefulCalls int
+	forcefulCalls int
+}
+
+func (*recordingProcessTree) Start(*exec.Cmd) error { return nil }
+
+func (tree *recordingProcessTree) TerminateGracefully() error {
+	tree.gracefulCalls++
+	return tree.gracefulErr
+}
+
+func (tree *recordingProcessTree) TerminateForcefully() error {
+	tree.forcefulCalls++
+	return tree.forcefulErr
+}
+
+func (*recordingProcessTree) Dispose() error { return nil }