From 70ef99595aa904f25e75f3662eabef1fdf76198a Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Fri, 23 Oct 2026 22:21:41 +0200
Subject: [PATCH] mesh-build-go: build_go_test takes packages as a typed list
 too (issue 1925)

---
 .../cmd/mesh-build-go/packages_shape_test.go  | 79 +++++++++++++++++++
 .../mesh-build-go/cmd/mesh-build-go/test.go   | 20 +++--
 2 files changed, 93 insertions(+), 6 deletions(-)
 create mode 100644 modules/mesh-build-go/cmd/mesh-build-go/packages_shape_test.go

diff --git a/modules/mesh-build-go/cmd/mesh-build-go/packages_shape_test.go b/modules/mesh-build-go/cmd/mesh-build-go/packages_shape_test.go
new file mode 100644
index 00000000..fe3a7d8a
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/packages_shape_test.go
@@ -0,0 +1,79 @@
+package main
+
+import (
+	"context"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/buildstep"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// 1925/AC1: packagesArg takes the list as the bus's JSON shape ([]any) and as the typed list an ask hands in process
+// ([]string), and refuses a bad element in either.
+func TestPackagesArgTakesBothShapes(t *testing.T) {
+	cases := []struct {
+		name    string
+		in      any
+		want    []string
+		refused bool
+	}{
+		{"absent", nil, nil, false},
+		{"typed", []string{"x/a", "x/b/..."}, []string{"x/a", "x/b/..."}, false},
+		{"json", []any{"x/a", "x/b/..."}, []string{"x/a", "x/b/..."}, false},
+		{"typed empty", []string{}, []string{}, false},
+		{"typed dotdot", []string{"x/../y"}, nil, true},
+		{"json dotdot", []any{"x/../y"}, nil, true},
+		{"typed bad", []string{"x a"}, nil, true},
+		{"json bad", []any{"x a"}, nil, true},
+		{"json not a string", []any{3}, nil, true},
+		{"a string", "x/a", nil, true},
+	}
+	for _, c := range cases {
+		got, err := packagesArg(c.in)
+		if c.refused != (err != nil) {
+			t.Errorf("%s: err = %v, refused want %v", c.name, err, c.refused)
+			continue
+		}
+		if !c.refused && !reflect.DeepEqual(got, c.want) {
+			t.Errorf("%s: got %#v, want %#v", c.name, got, c.want)
+		}
+	}
+}
+
+// 1925/AC2: a check ask through the module's real build_go_test body gets past the packages argument: the digest names
+// a package, buildstep.RunAsk hands it in as a typed list, and the step fails only later, on the workspace nobody fetched.
+func TestACheckAskReachesTheTestStepPastItsPackages(t *testing.T) {
+	m := &Module{Node: "ace", Work: t.TempDir()}
+	var calls []string
+	steps := fakeSteps(&calls)
+	for i := range steps {
+		switch steps[i].Name {
+		case "build_go_digest":
+			steps[i].Run = func(ctx context.Context, args map[string]any) (any, error) {
+				return map[string]any{"level": "unit", "packages": map[string]string{"x/a": "d1"}}, nil
+			}
+		case "build_go_test":
+			for _, real := range m.StepTools() {
+				if real.Name == "build_go_test" {
+					steps[i].Run = real.Run
+				}
+			}
+		}
+	}
+	a := delivery.StepAsk{ID: buildstep.NewID(), Kind: delivery.AskCheck, Language: delivery.AskGo, Asker: "mesh-delivery-checker",
+		At: time.Now(), Check: &delivery.CheckJob{Fetch: map[string]any{"repository": "novox/x", "commit": askCommit}, Levels: []string{delivery.LevelUnit}}}
+	out, err := buildstep.RunAsk(context.Background(), m.askSteps(steps), a)
+	got := ""
+	if err != nil {
+		got = err.Error()
+	}
+	if strings.Contains(got, "packages is a list") {
+		t.Fatalf("the test step refused the ask's packages: %s", got)
+	}
+	if !strings.Contains(got, "no workspace") {
+		t.Fatalf("want the step to fail on the unfetched workspace, past its packages; err=%v out=%+v", err, out)
+	}
+}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/test.go b/modules/mesh-build-go/cmd/mesh-build-go/test.go
index d3b42c9e..613fe61c 100644
--- a/modules/mesh-build-go/cmd/mesh-build-go/test.go
+++ b/modules/mesh-build-go/cmd/mesh-build-go/test.go
@@ -127,17 +127,25 @@ func (m *Module) besideEnv(workspace string) []string {
 	return []string{"MESH_CHECK_BESIDE=" + dir}
 }
 
+// packagesArg reads the packages argument: a list of package patterns, as []any when it came over the bus as JSON and
+// as []string when an ask handed it in process (issue 1925).
 func packagesArg(v any) ([]string, error) {
-	if v == nil {
+	var list []string
+	switch t := v.(type) {
+	case nil:
 		return nil, nil
-	}
-	list, ok := v.([]any)
-	if !ok {
+	case []string:
+		list = t
+	case []any:
+		for _, e := range t {
+			s, _ := e.(string)
+			list = append(list, s)
+		}
+	default:
 		return nil, fmt.Errorf("packages is a list of package patterns")
 	}
 	out := []string{}
-	for _, e := range list {
-		s, _ := e.(string)
+	for _, s := range list {
 		if !packageOK.MatchString(s) || strings.Contains(strings.TrimSuffix(s, "/..."), "..") {
 			return nil, fmt.Errorf("%q is not a package pattern", s)
 		}