Say a placeholder or replaced mesh-sdk pin as a local mesh-sdk, not as a version

internal/builder/check.go

@@ -1637,35 +1637,52 @@ func dialable(ctx context.Context, address string) error {
 	return fmt.Errorf("nothing took a connection at %s", address)
 }
 
-// sdkPin is the mesh-sdk version the controller in dir takes (its go.mod's go requirement), or "" when it names none.
-func sdkPin(dir string) string {
+// sdkPin is the mesh-sdk version the controller in dir takes (its go.mod's go requirement), or "" when it names none; and
+// local says that version is no real one: the placeholder v0.0.0, or a replace of mesh-sdk by a directory, which a
+// workspace or a fixture uses and no release holds.
+func sdkPin(dir string) (version string, local bool) {
 	body, err := os.ReadFile(filepath.Join(dir, "go.mod"))
 	if err != nil {
-		return ""
+		return "", false
 	}
+	const path = "git.novox.be/novox/mesh-sdk/go"
+	replaced := false
 	for _, line := range strings.Split(string(body), "\n") {
-		f := strings.Fields(strings.TrimPrefix(strings.TrimSpace(line), "require "))
-		if len(f) >= 2 && f[0] == "git.novox.be/novox/mesh-sdk/go" {
-			return f[1]
+		f := strings.Fields(strings.TrimPrefix(strings.TrimPrefix(strings.TrimSpace(line), "require "), "replace "))
+		switch {
+		case len(f) >= 3 && f[0] == path && f[len(f)-2] == "=>" && (strings.HasPrefix(f[len(f)-1], ".") || strings.HasPrefix(f[len(f)-1], "/")):
+			replaced = true
+		case len(f) >= 2 && f[0] == path && version == "" && f[1] != "=>":
+			version = f[1]
 		}
 	}
-	return ""
+	return version, version == "v0.0.0" || (replaced && version != "")
 }
 
-// validatorAt names the validator of the controller in dir as mesh-sdk's at that controller's pin (issue 1391).
+// validatorAt names the validator of the controller in dir as mesh-sdk's at that controller's pin (issue 1391): the
+// version when it is a real one, and a local mesh-sdk said as such when it is not.
 func validatorAt(dir string) string {
-	if v := sdkPin(dir); v != "" {
+	switch v, local := sdkPin(dir); {
+	case v == "":
+		return "mesh-sdk's validator at the controller's pin"
+	case local:
+		return "mesh-sdk's validator from a local mesh-sdk (" + v + ", replaced)"
+	default:
 		return "mesh-sdk's validator at " + v
 	}
-	return "mesh-sdk's validator at the controller's pin"
 }
 
-// pinNote is the version of that pin, for a sentence that already says "the pin of": ", " and the version, or nothing.
+// pinNote is the pin for a sentence that already says "the pin of": the version in brackets when it is a real one, a
+// local mesh-sdk said as such when it is not, or nothing.
 func pinNote(dir string) string {
-	if v := sdkPin(dir); v != "" {
+	switch v, local := sdkPin(dir); {
+	case v == "":
+		return ""
+	case local:
+		return " (a local mesh-sdk, " + v + ", replaced)"
+	default:
 		return " (" + v + ")"
 	}
-	return ""
 }
 
 // judge builds the controller that judges a change: the one the mesh runs, beside the check as