Fix "context canceled" with partial

Make sure the context used for timeouts isn't created based on the incoming
context, as we have cases where this can cancel the context prematurely.

Fixes #10789

lazy/init.go

@@ -180,22 +180,23 @@ func (ini *Init) checkDone() {
 }
 
 func (ini *Init) withTimeout(ctx context.Context, timeout time.Duration, f func(ctx context.Context) (any, error)) (any, error) {
-	ctx, cancel := context.WithTimeout(ctx, timeout)
+	// Create a new context with a timeout not connected to the incoming context.
+	waitCtx, cancel := context.WithTimeout(context.Background(), timeout)
 	defer cancel()
 	c := make(chan verr, 1)
 
 	go func() {
 		v, err := f(ctx)
 		select {
-		case <-ctx.Done():
+		case <-waitCtx.Done():
 			return
 		default:
 			c <- verr{v: v, err: err}
 		}
 	}()
 
 	select {
-	case <-ctx.Done():
+	case <-waitCtx.Done():
 		return nil, errors.New("timed out initializing value. You may have a circular loop in a shortcode, or your site may have resources that take longer to build than the `timeout` limit in your Hugo config file.")
 	case ve := <-c:
 		return ve.v, ve.err

lazy/init_test.go

@@ -126,12 +126,6 @@ func TestInitAddWithTimeoutTimeout(t *testing.T) {
 
 	init := New().AddWithTimeout(100*time.Millisecond, func(ctx context.Context) (any, error) {
 		time.Sleep(500 * time.Millisecond)
-		select {
-		case <-ctx.Done():
-			return nil, nil
-		default:
-		}
-		t.Fatal("slept")
 		return nil, nil
 	})
 

resources/transform.go

@@ -164,12 +164,12 @@ type resourceAdapter struct {
 	*resourceAdapterInner
 }
 
-func (r *resourceAdapter) Content(context.Context) (any, error) {
+func (r *resourceAdapter) Content(ctx context.Context) (any, error) {
 	r.init(false, true)
 	if r.transformationsErr != nil {
 		return nil, r.transformationsErr
 	}
-	return r.target.Content(context.Background())
+	return r.target.Content(ctx)
 }
 
 func (r *resourceAdapter) Err() resource.ResourceError {

tpl/partials/integration_test.go

@@ -324,3 +324,31 @@ timeout = '200ms'
 	b.Assert(err.Error(), qt.Contains, "timed out")
 
 }
+
+// See Issue #10789
+func TestReturnExecuteFromTemplateInPartial(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- config.toml --
+baseURL = 'http://example.com/'
+-- layouts/index.html --
+{{ $r :=  partial "foo" }}
+FOO:{{ $r.Content }}
+-- layouts/partials/foo.html --
+{{ $r := §§{{ partial "bar" }}§§ | resources.FromString "bar.html" | resources.ExecuteAsTemplate "bar.html" . }}
+{{ return $r }}
+-- layouts/partials/bar.html --
+BAR
+  `
+
+	b := hugolib.NewIntegrationTestBuilder(
+		hugolib.IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+		},
+	).Build()
+
+	b.AssertFileContent("public/index.html", "OO:BAR")
+
+}

tpl/partials/partials.go

@@ -129,7 +129,10 @@ func (ns *Namespace) Include(ctx context.Context, name string, contextList ...an
 }
 
 func (ns *Namespace) includWithTimeout(ctx context.Context, name string, dataList ...any) includeResult {
-	ctx, cancel := context.WithTimeout(ctx, ns.deps.Timeout)
+	// There are situation where the ctx we pass on to the partial lives longer than
+	// the partial itself. For example, when the partial returns the result from reosurces.ExecuteAsTemplate.
+	// Because of that, create a completely new context here.
+	timeoutCtx, cancel := context.WithTimeout(context.Background(), ns.deps.Timeout)
 	defer cancel()
 
 	res := make(chan includeResult, 1)
@@ -141,8 +144,8 @@ func (ns *Namespace) includWithTimeout(ctx context.Context, name string, dataLis
 	select {
 	case r := <-res:
 		return r
-	case <-ctx.Done():
-		err := ctx.Err()
+	case <-timeoutCtx.Done():
+		err := timeoutCtx.Err()
 		if err == context.DeadlineExceeded {
 			err = fmt.Errorf("partial %q timed out after %s. This is most likely due to infinite recursion. If this is just a slow template, you can try to increase the 'timeout' config setting.", name, ns.deps.Timeout)
 		}