From 48f5a7d3a99a54756175aae9bfbdb3295e439b72 Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Sat, 17 Oct 2026 18:18:22 +0200
Subject: [PATCH] module check refuses an artifact context naming another
 repository (issue 1019)

---
 cmd/mesh-controller/check.go      | 15 +++++++++++++
 cmd/mesh-controller/check_test.go | 37 +++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/cmd/mesh-controller/check.go b/cmd/mesh-controller/check.go
index 0aeebb18..ce08029d 100644
--- a/cmd/mesh-controller/check.go
+++ b/cmd/mesh-controller/check.go
@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/novox/mesh-controller/internal/catalogue"
+	"github.com/novox/mesh-controller/internal/link"
 )
 
 // moduleCheck judges manifests where they are written, with no mesh (novox/hq ADR 0037, issue 148).
@@ -114,6 +115,20 @@ func moduleCheckFor(paths []string, longestMachine int, out io.Writer) error {
 			failed += len(wrong)
 			faulted[m.Module] = true
 		}
+		// A module lives whole in one repository (novox/hq ADR 0420 §1, issue 1019): when the check is told the
+		// repository it runs for (MESH_CHECK_REPOSITORY, set by the build's check), an artifact building from
+		// another is refused, as the merge gate refuses it. A run by hand names no repository and judges none.
+		if repo := os.Getenv("MESH_CHECK_REPOSITORY"); repo != "" && m.Build != nil {
+			for _, a := range m.Build.Artifacts {
+				if a.Context != nil && a.Context.Repository != "" && !sameRepository(a.Context.Repository,
+					link.SourceMoved{Owner: ownerOf(repo), Repo: repoOf(repo)}) {
+					fmt.Fprintf(out, "%s: %s builds artifact %s from %s: a module lives whole in one repository "+
+						"(novox/hq ADR 0420 §1)\n", path, m.Module, a.Name, a.Context.Repository)
+					failed++
+					faulted[m.Module] = true
+				}
+			}
+		}
 		if named := catalogue.InstallationProblems(m); len(named) > 0 {
 			for _, p := range named {
 				fmt.Fprintf(out, "%s: %s\n", path, p)
diff --git a/cmd/mesh-controller/check_test.go b/cmd/mesh-controller/check_test.go
index 210fe9f5..eecf6139 100644
--- a/cmd/mesh-controller/check_test.go
+++ b/cmd/mesh-controller/check_test.go
@@ -122,3 +122,40 @@ func TestASeatAnotherModuleDeclaresIsANoteOverSomeManifests(t *testing.T) {
 		t.Fatalf("the note was not said:\n%s", out.String())
 	}
 }
+
+// **A module lives whole in one repository** (novox/hq ADR 0420 §1, issue 1019): `module check`, told the
+// repository it runs for, refuses an artifact whose build context names another; run by hand, it does not know.
+func TestModuleCheckRefusesAnArtifactContextNamingAnotherRepository(t *testing.T) {
+	dir := t.TempDir()
+	write := func(name, context string) string {
+		path := filepath.Join(dir, name+".json")
+		raw := `{"module":"` + name + `","version":"1","build":{"artifacts":[{"name":"server","kind":"image","from":"Dockerfile"` + context + `}]}}`
+		if err := os.WriteFile(path, []byte(raw), 0o600); err != nil {
+			t.Fatal(err)
+		}
+		return path
+	}
+	other := write("other", `,"context":{"seat":"git","repository":"novox/mesh-controller","ref":"main"}`)
+	own := write("own", `,"context":{"seat":"git","repository":"novox/mesh-catalog","ref":"main"}`)
+	none := write("none", ``)
+
+	t.Setenv("MESH_CHECK_REPOSITORY", "novox/mesh-catalog")
+	var out bytes.Buffer
+	if err := moduleCheck([]string{other}, &out); err == nil {
+		t.Fatalf("a context naming another repository passed:\n%s", out.String())
+	}
+	if !strings.Contains(out.String(), "other builds artifact server from novox/mesh-controller: a module lives whole in one repository (novox/hq ADR 0420 §1)") {
+		t.Errorf("the refusal is not in the words of the gate:\n%s", out.String())
+	}
+	for _, path := range []string{own, none} {
+		out.Reset()
+		if err := moduleCheck([]string{path}, &out); err != nil {
+			t.Errorf("%s was refused: %v\n%s", path, err, out.String())
+		}
+	}
+	t.Setenv("MESH_CHECK_REPOSITORY", "")
+	out.Reset()
+	if err := moduleCheck([]string{other}, &out); err != nil {
+		t.Errorf("a local run, with no repository named, refused it: %v\n%s", err, out.String())
+	}
+}