Give a candidate's module its named paths' objects from the preview, so the builder's fetch for it names them (issue 1758, ADR 0499 §4; mesh-sdk CandidateModule.Paths)

modules/mesh-delivery-indexer/internal/index/candidate_manifests_test.go

@@ -3,6 +3,7 @@ package index
 import (
 	"context"
 	"errors"
+	"reflect"
 	"strings"
 	"testing"
 
@@ -43,7 +44,7 @@ func TestACandidateGivesEachTouchedModuleItsManifestAndTheReasonItHasNoPreview(t
 	}
 	c := candidateOf(t, ix.Store.(*memStore)) // DecodeCandidate has run Candidate.check
 	want := delivery.CandidateModule{Manifest: delivery.ManifestDigest([]byte(avahi)), None2: "no merge preview is computed"}
-	if len(c.Pulls) != 1 || len(c.Pulls[0].Fps) != 1 || c.Pulls[0].Fps["avahi"] != want {
+	if len(c.Pulls) != 1 || len(c.Pulls[0].Fps) != 1 || !reflect.DeepEqual(c.Pulls[0].Fps["avahi"], want) {
 		t.Fatalf("pulls = %+v, want Fps[avahi] = %+v", c.Pulls, want)
 	}
 	if c.FPSet == "" || c.FPSet != delivery.FingerprintSet(c.Pulls) {
@@ -55,7 +56,7 @@ func TestACandidateGivesEachTouchedModuleItsManifestAndTheReasonItHasNoPreview(t
 	if err := ix.Apply(context.Background(), again); err != nil {
 		t.Fatal(err)
 	}
-	if c2 := candidateOf(t, ix.Store.(*memStore)); c2.Pulls[0].Fps["avahi"] != want || c2.FPSet != c.FPSet {
+	if c2 := candidateOf(t, ix.Store.(*memStore)); !reflect.DeepEqual(c2.Pulls[0].Fps["avahi"], want) || c2.FPSet != c.FPSet {
 		t.Errorf("after a message without directories: %+v fpset %q", c2.Pulls[0].Fps, c2.FPSet)
 	}
 }

modules/mesh-delivery-indexer/internal/index/candidates.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"reflect"
 	"slices"
 	"strings"
 	"sync"
@@ -284,7 +285,7 @@ func (ix *Indexer) refuseDisagreement(c delivery.Candidate) error {
 				first[module] = p
 				continue
 			}
-			if before.Fps[module] != m {
+			if !reflect.DeepEqual(before.Fps[module], m) {
 				err := fmt.Errorf("%w: candidates.%s: %s#%d and %s#%d give the module %q different manifests (%s and %s), so the group is not written",
 					ErrUnreadable, c.Group, before.Repository, before.Number, p.Repository, p.Number, module, before.Fps[module].Manifest, m.Manifest)
 				return err

modules/mesh-delivery-indexer/internal/index/named_test.go

@@ -81,7 +81,11 @@ func TestACandidatesModuleTakesTheNamedPathsObjectsFromThePreview(t *testing.T)
 	if got := ix.candidateModule(context.Background(), "mesh-sdk", ".", without); !strings.Contains(got.None2, "named paths") {
 		t.Errorf("without the objects: %+v, want none naming the named paths", got)
 	}
-	if got := ix.candidateModule(context.Background(), "mesh-sdk", ".", with); strings.Contains(got.None2, "named paths") || got.Manifest != digest {
+	got := ix.candidateModule(context.Background(), "mesh-sdk", ".", with)
+	if strings.Contains(got.None2, "named paths") || got.Manifest != digest {
 		t.Errorf("with the objects: %+v, want them taken (none only for what else is missing)", got)
 	}
+	if got.FP2 != "" && !reflect.DeepEqual(got.Paths, sdkObjects) {
+		t.Errorf("with a fingerprint: %+v, want the named paths' objects carried for the builder's fetch", got)
+	}
 }

modules/mesh-delivery-indexer/internal/index/previews.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"maps"
+	"reflect"
 	"slices"
 	"strings"
 
@@ -184,12 +185,12 @@ func (ix *Indexer) withPreviews(ctx context.Context, c *delivery.Candidate) bool
 			if fps == nil {
 				fps = map[string]delivery.CandidateModule{}
 			}
-			if fps[m] != next {
+			if !reflect.DeepEqual(fps[m], next) {
 				fps[m] = next
 				changed = true
 			}
 		}
-		if changed || !maps.Equal(fps, p.Fps) {
+		if changed || !maps.EqualFunc(fps, p.Fps, func(a, b delivery.CandidateModule) bool { return reflect.DeepEqual(a, b) }) {
 			p.Fps = fps
 		}
 	}
@@ -269,5 +270,8 @@ func (ix *Indexer) candidateModule(ctx context.Context, m, dir string, pv delive
 		return out
 	}
 	out.FP2 = fp
+	if len(inputs.Paths) > 0 {
+		out.Paths = inputs.Paths // the builder's fetch for the candidate names them (ADR 0499 clause 4)
+	}
 	return out
 }