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

2 files changed, 34 insertions, 3 deletions

diff --git a/tpl/partials/integration_test.go b/tpl/partials/integration_test.go
index fcebe6c05..3dbaf2ce4 100644
--- a/tpl/partials/integration_test.go
+++ b/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")
+
+}
diff --git a/tpl/partials/partials.go b/tpl/partials/partials.go
index d9a826aa4..26ce0f5c6 100644
--- a/tpl/partials/partials.go
+++ b/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)
 		}