Compute the source fingerprint with mesh-sdk's one function (issue 1214)

internal/builder/source.go

@@ -10,6 +10,7 @@ import (
 	"sort"
 	"strings"
 
+	"git.novox.be/novox/mesh-sdk/go/delivery"
 	"github.com/novox/mesh-controller/internal/catalogue"
 )
 
@@ -36,7 +37,7 @@ import (
 // (novox/hq ADR 0097 refuses the unpinned bases; what a RUN step downloads is not seen here).
 
 // sourcePrefix names the fingerprint's form, so a later form is never compared equal to this one.
-const sourcePrefix = "src1:"
+const sourcePrefix = delivery.SourcePrefix
 
 // sourceInputs collects what one build was made from.
 type sourceInputs struct {
@@ -262,40 +263,33 @@ func (s *sourceInputs) notPinned(why string) {
 	}
 }
 
+// sourceFingerprint is the one function the controller's builder and the indexer both call (novox/hq ADR 0437 §5);
+// a variable only so a test can see it called.
+var sourceFingerprint = delivery.SourceFingerprint
+
+// inputs are what the build's fingerprint is of, as the SDK names them.
+func (s *sourceInputs) inputs() delivery.SourceInputs {
+	if s == nil {
+		return delivery.SourceInputs{}
+	}
+	return delivery.SourceInputs{
+		Module: s.module, Tree: s.tree, Bases: s.bases,
+		Contexts: s.contexts, Toolchains: s.toolchains, Unpinned: s.unpinned,
+	}
+}
+
 // fingerprint is the build's source fingerprint, or empty when the source does not pin the build.
 func (s *sourceInputs) fingerprint() string {
-	if s == nil || s.unpinned != "" || s.tree == "" {
+	if s == nil {
 		return ""
 	}
-	var lines []string
-	lines = append(lines, "module "+s.module, "tree "+s.tree)
-	bases := map[string]bool{}
-	for _, b := range s.bases {
-		bases[referenceDigest(b)] = true
-	}
-	for b := range bases {
-		lines = append(lines, "base "+b)
-	}
-	for a, t := range s.contexts {
-		lines = append(lines, "context "+a+" "+t)
-	}
-	for a, t := range s.toolchains {
-		lines = append(lines, "toolchain "+a+" "+t)
-	}
-	// The module and its tree first, the rest in a fixed order.
-	sort.Strings(lines[2:])
-	sum := sha256.Sum256([]byte(strings.Join(lines, "\n")))
-	return sourcePrefix + hex.EncodeToString(sum[:])
+	fp, _ := sourceFingerprint(s.inputs())
+	return fp
 }
 
 // referenceDigest is a reference's digest — `sha256:…` — so the registry address it was copied into does not
 // enter the fingerprint; the reference itself when it carries none.
-func referenceDigest(reference string) string {
-	if _, digest, pinned := strings.Cut(reference, "@"); pinned && digest != "" {
-		return digest
-	}
-	return reference
-}
+func referenceDigest(reference string) string { return delivery.ReferenceDigest(reference) }
 
 // gitTree is the git tree of a directory of a clone at its checked-out commit: the whole tree for an
 // empty path.

internal/builder/source_sdk_test.go

@@ -0,0 +1,83 @@
+package builder
+
+import (
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// 1214/AC1: the inputs of three builds the live builder recorded a source fingerprint for, copied from mesh-sdk
+// go/delivery/fingerprint_test.go (TestFingerprintLiveBuilds), where each value is captured, never written by hand.
+func TestTheBuildersFingerprintEqualsWhatTheLiveBuilderRecorded(t *testing.T) {
+	const ts = "typescript sha256:4b81682df5665c1f461d3f720a3a0fd7593f4aa71e4fc272dbfdc4bbd235b489 20125bd590041690"
+	for _, c := range []struct {
+		name     string
+		in       sourceInputs
+		recorded string
+	}{
+		{"mailu", sourceInputs{
+			module:     "mailu",
+			tree:       "cfc6fa8ff5fc1e220132e51ade653b9d3f387b3e",
+			bases:      []string{"sha256:25f3cfeaceca14921366af4d1240b56457ef46273bdb508c7b0e8f469f6fd228"},
+			toolchains: map[string]string{"code": ts},
+		}, "src1:539f2e64000d436c572ef53b40e524012455945f8c5a1c6bb173ee0707e88ef4"},
+		{"radarr", sourceInputs{
+			module: "radarr",
+			tree:   "42b9c918b5af75cba2bbc75845012e7f64e16df9",
+			toolchains: map[string]string{
+				"code":     ts,
+				"tools-go": "go sha256:2054591ca034b68323d87ec887ba34f56819cb3364034360c0777da4b314dd54 0995d85edc9a6a23",
+			},
+		}, "src1:b3c150d39c395b99dd68974a48490e9a42467aa5d486d0c604d6ef1e8e9c910a"},
+		{"build-agent", sourceInputs{
+			module: "build-agent",
+			tree:   "11c0b4f90cae0d6e4ef9cc48cbfdf9f6dbe52bca",
+			bases: []string{
+				"sha256:d9e853e87e55526f6b2917df91a2115c36dd7c696a35be12163d44e6e2a4b6bc",
+				"sha256:8ac98ca534ac3f51e1f420a1dd2c15e74c75cfa0f23f3ad27eb5d7236c349a0c",
+			},
+			contexts: map[string]string{"server": "narrow:d51ca744fd11af59d616c858f76c27b3e58e16e11fbdc0c720eb9d7d19d55fac"},
+		}, "src1:e846efe73716b78e80860baaac96153de2cb76551325753838ca245d2160a3d7"},
+	} {
+		if got := c.in.fingerprint(); got != c.recorded {
+			t.Errorf("%s: fingerprint = %q, the live builder recorded %q", c.name, got, c.recorded)
+		}
+	}
+}
+
+// 1214/AC2: a build with no tree, or one that resolves packages when built, gets no fingerprint.
+func TestABuildWithoutATreeOrUnpinnedGetsNoFingerprint(t *testing.T) {
+	if (&sourceInputs{module: "app"}).fingerprint() != "" {
+		t.Error("a build with no tree has a fingerprint")
+	}
+	s := &sourceInputs{module: "app", tree: "aaaa"}
+	s.notPinned("it resolves packages from the mesh's registry at build time")
+	if got := s.fingerprint(); got != "" {
+		t.Errorf("an unpinned build has a fingerprint: %s", got)
+	}
+	if got := orNoTree(""); got != "its tree was not named" {
+		t.Errorf("the reason for no tree = %q", got)
+	}
+	if got := orNoTree(s.unpinned); got != s.unpinned {
+		t.Errorf("the reason for unpinned = %q", got)
+	}
+}
+
+// 1214/AC3: the builder has no hash of its own: its fingerprint is what delivery.SourceFingerprint says, whatever
+// that is (a stand-in proves it is called), and the reuse key does not move with it.
+func TestTheBuilderFingerprintsWithTheSDKFunction(t *testing.T) {
+	was := sourceFingerprint
+	t.Cleanup(func() { sourceFingerprint = was })
+	var got delivery.SourceInputs
+	sourceFingerprint = func(in delivery.SourceInputs) (string, string) {
+		got = in
+		return "src1:stand-in", ""
+	}
+	s := &sourceInputs{module: "m", tree: "t", bases: []string{"x@sha256:a"}, contexts: map[string]string{"c": "ct"}, toolchains: map[string]string{"c": "go"}}
+	if fp := s.fingerprint(); fp != "src1:stand-in" {
+		t.Fatalf("fingerprint = %q, not the SDK function's", fp)
+	}
+	if got.Module != "m" || got.Tree != "t" || len(got.Bases) != 1 || got.Contexts["c"] != "ct" || got.Toolchains["c"] != "go" {
+		t.Errorf("the SDK function was given %+v", got)
+	}
+}