Carry a candidate module's named paths, so the builder's fetch for a candidate names them (issue 1758, ADR 0499 §2, the builder lane's request)

go/delivery/candidate_paths_test.go

@@ -0,0 +1,40 @@
+package delivery
+
+import (
+	"strings"
+	"testing"
+)
+
+// A candidate's module carries the git objects of its named paths at the preview (novox/hq ADR 0499 clause 2), so the
+// builder's fetch request for a candidate names them; an older candidate decodes without them, and a path that is not
+// clean and relative, or names no object, is refused.
+func TestACandidatesModuleCarriesItsNamedPaths(t *testing.T) {
+	c := sampleCandidate()
+	paths := map[string]string{"src": strings.Repeat("a", 40), "package.json": strings.Repeat("b", 40)}
+	c.Pulls[0].Fps = map[string]CandidateModule{"mesh-mail": {FP2: SourcePrefix2 + strings.Repeat("1", 64),
+		Manifest: strings.Repeat("2", 64), Paths: paths}}
+	c.FPSet = FingerprintSet(c.Pulls)
+	data, err := EncodeCandidate(c)
+	if err != nil {
+		t.Fatal(err)
+	}
+	back, err := DecodeCandidate(data)
+	if err != nil || back.Pulls[0].Fps["mesh-mail"].Paths["src"] != paths["src"] {
+		t.Fatalf("decoded %+v, %v", back.Pulls[0].Fps, err)
+	}
+	old := sampleCandidate()
+	old.Pulls[0].Fps = map[string]CandidateModule{"mesh-mail": {FP2: SourcePrefix2 + strings.Repeat("1", 64)}}
+	old.FPSet = FingerprintSet(old.Pulls)
+	if data, err := EncodeCandidate(old); err != nil {
+		t.Fatal(err)
+	} else if b, err := DecodeCandidate(data); err != nil || b.Pulls[0].Fps["mesh-mail"].Paths != nil {
+		t.Fatalf("an older candidate: %+v, %v", b, err)
+	}
+	for _, bad := range []map[string]string{{"../x": "a"}, {"/src": "a"}, {"": "a"}, {"src": ""}} {
+		c.Pulls[0].Fps = map[string]CandidateModule{"mesh-mail": {FP2: SourcePrefix2 + strings.Repeat("1", 64), Paths: bad}}
+		c.FPSet = FingerprintSet(c.Pulls)
+		if _, err := EncodeCandidate(c); err == nil {
+			t.Errorf("%v was accepted", bad)
+		}
+	}
+}

go/delivery/source.go

@@ -277,6 +277,9 @@ type CandidateModule struct {
 	FP2      string `json:"fp2,omitempty"`
 	None2    string `json:"none2,omitempty"`
 	Manifest string `json:"manifest,omitempty"`
+	// Paths are, of a module whose every artifact names its paths, each named path's git object id at the preview
+	// (novox/hq ADR 0499 clause 2), so the builder's fetch request for the candidate names them. Absent otherwise.
+	Paths map[string]string `json:"paths,omitempty"`
 }
 
 func (m CandidateModule) check() error {
@@ -286,6 +289,9 @@ func (m CandidateModule) check() error {
 	case m.FP2 == "" && m.None2 == "":
 		return fmt.Errorf("delivery: a module has neither fp2 nor none2")
 	}
+	if err := checkPathObjects(m.Paths); err != nil {
+		return err
+	}
 	return checkNewForm(m.FP2, m.Manifest)
 }
 
@@ -357,7 +363,7 @@ func (c Candidate) check() error {
 			if err := m.check(); err != nil {
 				return fmt.Errorf("delivery: the candidate's module %q: %w", module, err)
 			}
-			if before, ok := seen[module]; ok && before != m {
+			if before, ok := seen[module]; ok && !reflect.DeepEqual(before, m) {
 				return fmt.Errorf("delivery: two pull requests of the candidate give the module %q different fingerprints", module)
 			}
 			seen[module] = m
@@ -425,6 +431,19 @@ type KeptInputs2 struct {
 	Paths map[string]string `json:"paths,omitempty"`
 }
 
+// checkPathObjects refuses a named path that is not clean and relative to the module's directory, or names no object.
+func checkPathObjects(paths map[string]string) error {
+	for p, object := range paths {
+		if p == "" || p != path.Clean(p) || strings.HasPrefix(p, "/") || p == ".." || strings.HasPrefix(p, "../") {
+			return fmt.Errorf("delivery: the named path %q is not a clean path inside the module's directory", p)
+		}
+		if object == "" {
+			return fmt.Errorf("delivery: the named path %q names no git object", p)
+		}
+	}
+	return nil
+}
+
 // checkNamed refuses kept named paths that do not compute to the kept tree with the module's manifest digest.
 func checkNamed(tree, manifest string, paths map[string]string, of string) error {
 	if len(paths) == 0 {