all: add LatestVersion to ModuleInfo

- Add LatestVersion field to internal.ModuleInfo and update tests
  accordingly.
- Changed some test formatting to improve readability.

Change-Id: I1238e54614ef276d219b31d125cd2cad6b5a66f7
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/756901
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
kokoro-CI: kokoro <noreply+kokoro@google.com>
Auto-Submit: Ethan Lee <ethanalee@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>

11 files changed, 125 insertions, 19 deletions

diff --git a/internal/api/api.go b/internal/api/api.go
index d1419c40..4f4fcf7b 100644
--- a/internal/api/api.go
+++ b/internal/api/api.go
@@ -198,6 +198,7 @@ func ServePackage(w http.ResponseWriter, r *http.Request, ds internal.DataSource
 		ModuleVersion:     unit.Version,
 		Synopsis:          synopsis,
 		IsStandardLibrary: stdlib.Contains(unit.ModulePath),
+		IsLatest:          unit.Version == unit.LatestVersion,
 		GOOS:              goos,
 		GOARCH:            goarch,
 		Docs:              docs,
diff --git a/internal/api/api_test.go b/internal/api/api_test.go
index 16a92278..595a3d25 100644
--- a/internal/api/api_test.go
+++ b/internal/api/api_test.go
@@ -30,12 +30,20 @@ func TestServePackage(t *testing.T) {
 	)
 
 	ds.MustInsertModule(ctx, &internal.Module{
-		ModuleInfo: internal.ModuleInfo{ModulePath: "example.com", Version: version},
+		ModuleInfo: internal.ModuleInfo{
+			ModulePath:    "example.com",
+			Version:       version,
+			LatestVersion: "v1.2.4",
+		},
 		Units: []*internal.Unit{{
 			UnitMeta: internal.UnitMeta{
-				Path:       "example.com/pkg",
-				ModuleInfo: internal.ModuleInfo{ModulePath: "example.com", Version: version},
-				Name:       "pkg",
+				Path: "example.com/pkg",
+				ModuleInfo: internal.ModuleInfo{
+					ModulePath:    "example.com",
+					Version:       version,
+					LatestVersion: "v1.2.4",
+				},
+				Name: "pkg",
 			},
 			Documentation: []*internal.Documentation{sample.Documentation("linux", "amd64", sample.DocContents)},
 		}},
@@ -46,8 +54,9 @@ func TestServePackage(t *testing.T) {
 			UnitMeta: internal.UnitMeta{
 				Path: pkgPath,
 				ModuleInfo: internal.ModuleInfo{
-					ModulePath: mp,
-					Version:    version,
+					ModulePath:    mp,
+					Version:       version,
+					LatestVersion: version,
 				},
 				Name: "b",
 			},
@@ -61,13 +70,38 @@ func TestServePackage(t *testing.T) {
 		}
 		ds.MustInsertModule(ctx, &internal.Module{
 			ModuleInfo: internal.ModuleInfo{
-				ModulePath: mp,
-				Version:    version,
+				ModulePath:    mp,
+				Version:       version,
+				LatestVersion: version,
 			},
 			Units: []*internal.Unit{u},
 		})
 	}
 
+	ds.MustInsertModule(ctx, &internal.Module{
+		ModuleInfo: internal.ModuleInfo{
+			ModulePath:    "example.com",
+			Version:       "v1.2.4",
+			LatestVersion: "v1.2.4",
+		},
+		Units: []*internal.Unit{{
+			UnitMeta: internal.UnitMeta{
+				Path: "example.com/pkg",
+				ModuleInfo: internal.ModuleInfo{
+					ModulePath:    "example.com",
+					Version:       "v1.2.4",
+					LatestVersion: "v1.2.4",
+				},
+				Name: "pkg",
+			},
+			Documentation: []*internal.Documentation{{
+				GOOS:     "linux",
+				GOARCH:   "amd64",
+				Synopsis: "Basic synopsis",
+			}},
+		}},
+	})
+
 	for _, test := range []struct {
 		name       string
 		url        string
@@ -83,6 +117,7 @@ func TestServePackage(t *testing.T) {
 				ModulePath:    "example.com",
 				ModuleVersion: version,
 				Synopsis:      "This is a package synopsis for GOOS=linux, GOARCH=amd64",
+				IsLatest:      false,
 				GOOS:          "linux",
 				GOARCH:        "amd64",
 			},
@@ -109,6 +144,7 @@ func TestServePackage(t *testing.T) {
 				ModulePath:    modulePath1,
 				ModuleVersion: version,
 				Synopsis:      "Synopsis for " + modulePath1,
+				IsLatest:      true,
 				GOOS:          "linux",
 				GOARCH:        "amd64",
 			},
@@ -122,6 +158,21 @@ func TestServePackage(t *testing.T) {
 				ModulePath:    "example.com",
 				ModuleVersion: version,
 				Synopsis:      "This is a package synopsis for GOOS=linux, GOARCH=amd64",
+				IsLatest:      false,
+				GOOS:          "linux",
+				GOARCH:        "amd64",
+			},
+		},
+		{
+			name:       "latest version",
+			url:        "/v1/package/example.com/pkg?version=v1.2.4",
+			wantStatus: http.StatusOK,
+			want: &Package{
+				Path:          "example.com/pkg",
+				ModulePath:    "example.com",
+				ModuleVersion: "v1.2.4",
+				Synopsis:      "Basic synopsis",
+				IsLatest:      true,
 				GOOS:          "linux",
 				GOARCH:        "amd64",
 			},
@@ -161,7 +212,6 @@ func TestServePackage(t *testing.T) {
 					if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
 						t.Fatalf("json.Unmarshal Package: %v", err)
 					}
-					got.IsLatest = false
 					if diff := cmp.Diff(want, &got); diff != "" {
 						t.Errorf("mismatch (-want +got):\n%s", diff)
 					}
diff --git a/internal/discovery.go b/internal/discovery.go
index 16e17d0b..88b48c31 100644
--- a/internal/discovery.go
+++ b/internal/discovery.go
@@ -52,6 +52,8 @@ type ModuleInfo struct {
 	HasGoMod   bool
 	SourceInfo *source.Info
 
+	// LatestVersion is the latest good version of the module.
+	LatestVersion string
 	// Deprecated describes whether the module is deprecated.
 	Deprecated bool
 	// DeprecationComment is the comment describing the deprecation, if any.
diff --git a/internal/latest.go b/internal/latest.go
index 14ccf166..8b820b29 100644
--- a/internal/latest.go
+++ b/internal/latest.go
@@ -64,6 +64,7 @@ func isDeprecated(mf *modfile.File) (bool, string) {
 
 // PopulateModuleInfo uses the LatestModuleVersions to populate fields of the given module.
 func (li *LatestModuleVersions) PopulateModuleInfo(mi *ModuleInfo) {
+	mi.LatestVersion = li.GoodVersion
 	mi.Deprecated = li.Deprecated
 	mi.DeprecationComment = li.deprecationComment
 	mi.Retracted, mi.RetractionRationale = isRetracted(li.GoModFile, mi.Version)
diff --git a/internal/postgres/details_test.go b/internal/postgres/details_test.go
index 53f55dd2..b2d83d66 100644
--- a/internal/postgres/details_test.go
+++ b/internal/postgres/details_test.go
@@ -180,6 +180,11 @@ func TestPostgres_GetModuleInfo(t *testing.T) {
 		},
 	}
 
+	latestGoodVersions := map[string]string{
+		"mod.1": "v1.1.0",
+		"mod.2": "v1.1.0",
+	}
+
 	for _, test := range testCases {
 		t.Run(test.name, func(t *testing.T) {
 			for _, v := range test.modules {
@@ -200,7 +205,11 @@ func TestPostgres_GetModuleInfo(t *testing.T) {
 				t.Fatal("wantIndex too large")
 			}
 			wantVI := &test.modules[test.wantIndex].ModuleInfo
-			if diff := cmp.Diff(wantVI, gotVI, cmpopts.EquateEmpty(), cmp.AllowUnexported(source.Info{})); diff != "" {
+			wantVI.LatestVersion = latestGoodVersions[wantVI.ModulePath]
+			if diff := cmp.Diff(wantVI, gotVI,
+				cmpopts.EquateEmpty(),
+				cmp.AllowUnexported(source.Info{}),
+			); diff != "" {
 				t.Errorf("mismatch (-want +got):\n%s", diff)
 			}
 		})
diff --git a/internal/postgres/insert_module_test.go b/internal/postgres/insert_module_test.go
index 37dd8b7a..3ae278a7 100644
--- a/internal/postgres/insert_module_test.go
+++ b/internal/postgres/insert_module_test.go
@@ -108,7 +108,9 @@ func checkModule(ctx context.Context, t *testing.T, db *DB, want *internal.Modul
 	if err != nil {
 		t.Fatal(err)
 	}
-	if diff := cmp.Diff(want.ModuleInfo, *got, cmp.AllowUnexported(source.Info{})); diff != "" {
+	if diff := cmp.Diff(want.ModuleInfo, *got,
+		cmp.AllowUnexported(source.Info{}),
+	); diff != "" {
 		t.Fatalf("testDB.GetModuleInfo(%q, %q) mismatch (-want +got):\n%s", want.ModulePath, want.Version, diff)
 	}
 
diff --git a/internal/postgres/unit_test.go b/internal/postgres/unit_test.go
index a35d5658..2decf185 100644
--- a/internal/postgres/unit_test.go
+++ b/internal/postgres/unit_test.go
@@ -92,6 +92,7 @@ func testGetUnitMeta(t *testing.T, ctx context.Context) {
 				ModulePath:        modPath,
 				Version:           version,
 				IsRedistributable: true,
+				LatestVersion:     "v1.1.0",
 			},
 			Name: name,
 		}
@@ -192,6 +193,19 @@ func testGetUnitMeta(t *testing.T, ctx context.Context) {
 				test.want.Name,
 				true,
 			)
+			latestGood := map[string]string{
+				"m.com":                                "v1.1.0",
+				"m.com/a":                              "v1.1.0",
+				"m.com/b":                              "v2.0.0+incompatible",
+				"cloud.google.com/go":                  "v0.74.0",
+				"cloud.google.com/go/pubsublite":       "v0.4.0",
+				"cloud.google.com/go/compute/metadata": "v0.0.0-20181115181204-d50f0e9b2506",
+			}
+			want.LatestVersion = latestGood[want.ModulePath]
+			if want.LatestVersion == "" {
+				// Fallback to version if not in map (e.g. stdlib)
+				want.LatestVersion = want.Version
+			}
 			want.IsRedistributable = true
 			want.CommitTime = sample.CommitTime
 			want.Retracted = test.want.Retracted
@@ -819,6 +833,7 @@ func unitNoLicenses(fullPath, modulePath, version, name string, readme *internal
 				ModulePath:        modulePath,
 				Version:           version,
 				IsRedistributable: true,
+				LatestVersion:     version,
 			},
 			Path: fullPath,
 			Name: name,
diff --git a/internal/postgres/version_test.go b/internal/postgres/version_test.go
index 66c0453e..3f4eaebc 100644
--- a/internal/postgres/version_test.go
+++ b/internal/postgres/version_test.go
@@ -229,6 +229,18 @@ func TestGetVersions(t *testing.T) {
 		},
 	}
 
+	latestVersions := map[string]string{
+		stdlib.ModulePath:     "v1.14.6", // v1.15.0-beta.1 is pre-release
+		taggedModuleV3:        "v3.1.0",  // v3.2.0-beta is pre-release
+		taggedModuleV2:        "v2.0.1",
+		taggedAndPseudoModule: "v1.5.2", // v1.5.3-pre1 is pre-release
+		pseudoModule:          "v0.0.0-20200101120012-000000000000",
+		otherModule:           "v3.0.0",
+		incompatibleModule:    "v0.0.0", // v2.0.0+incompatible is incompatible
+		rootModule:            "v0.11.6",
+		nestedModule:          "v1.0.4",
+	}
+
 	for _, test := range testCases {
 		t.Run(test.name, func(t *testing.T) {
 			for _, w := range test.want {
@@ -237,13 +249,16 @@ func TestGetVersions(t *testing.T) {
 				w.IsRedistributable = mod.IsRedistributable
 				w.HasGoMod = mod.HasGoMod
 				w.SourceInfo = mod.SourceInfo
+				w.LatestVersion = latestVersions[w.ModulePath]
 			}
 
 			got, err := testDB.GetVersionsForPath(ctx, test.path)
 			if err != nil {
 				t.Fatal(err)
 			}
-			if diff := cmp.Diff(test.want, got, cmp.AllowUnexported(source.Info{})); diff != "" {
+			if diff := cmp.Diff(test.want, got,
+				cmp.AllowUnexported(source.Info{}),
+			); diff != "" {
 				t.Errorf("testDB.GetVersionsForPath(%q) mismatch (-want +got):\n%s", test.path, diff)
 			}
 		})
diff --git a/internal/testing/sample/sample.go b/internal/testing/sample/sample.go
index 610dcab2..f08d3bfa 100644
--- a/internal/testing/sample/sample.go
+++ b/internal/testing/sample/sample.go
@@ -273,6 +273,7 @@ func ModuleInfo(modulePath, versionString string) *internal.ModuleInfo {
 		SourceInfo:        source.NewGitHubInfo("https://"+modulePath, "", versionString),
 		IsRedistributable: true,
 		HasGoMod:          true,
+		LatestVersion:     versionString,
 	}
 }
 
@@ -363,6 +364,7 @@ func UnitMeta(path, modulePath, version, name string, moduleIsRedistributable bo
 			CommitTime:        NowTruncated(),
 			IsRedistributable: moduleIsRedistributable,
 			SourceInfo:        source.NewGitHubInfo("https://"+modulePath, "", version),
+			LatestVersion:     version,
 		},
 	}
 }
diff --git a/internal/worker/fetch_test.go b/internal/worker/fetch_test.go
index b99ed7ea..5c40ca1f 100644
--- a/internal/worker/fetch_test.go
+++ b/internal/worker/fetch_test.go
@@ -58,6 +58,7 @@ func TestFetchAndUpdateState(t *testing.T) {
 				CommitTime:        testProxyCommitTime,
 				SourceInfo:        source.NewGitHubInfo("https://example.com/multi", "", sample.VersionString),
 				IsRedistributable: true,
+				LatestVersion:     sample.VersionString,
 			},
 			Path: "example.com/multi/bar",
 			Name: "bar",
@@ -114,6 +115,7 @@ func TestFetchAndUpdateState(t *testing.T) {
 						CommitTime:        testProxyCommitTime,
 						SourceInfo:        source.NewGitHubInfo("https://example.com/nonredist", "", sample.VersionString),
 						IsRedistributable: true,
+						LatestVersion:     sample.VersionString,
 					},
 					Path: "example.com/nonredist/bar/baz",
 					Name: "baz",
@@ -144,6 +146,7 @@ func TestFetchAndUpdateState(t *testing.T) {
 						CommitTime:        testProxyCommitTime,
 						SourceInfo:        source.NewGitHubInfo("https://example.com/nonredist", "", sample.VersionString),
 						IsRedistributable: true,
+						LatestVersion:     sample.VersionString,
 					},
 					Path: "example.com/nonredist/unk",
 					Name: "unk",
@@ -168,6 +171,7 @@ func TestFetchAndUpdateState(t *testing.T) {
 						CommitTime:        testProxyCommitTime,
 						SourceInfo:        source.NewGitHubInfo("https://"+buildConstraintsModulePath, "", sample.VersionString),
 						IsRedistributable: true,
+						LatestVersion:     "v1.0.0",
 					},
 					Path: buildConstraintsModulePath + "/cpu",
 					Name: "cpu",
@@ -209,7 +213,10 @@ func TestFetchAndUpdateState(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			if diff := cmp.Diff(test.want.UnitMeta, *got, cmpopts.EquateEmpty(), cmp.AllowUnexported(source.Info{})); diff != "" {
+			if diff := cmp.Diff(test.want.UnitMeta, *got,
+				cmpopts.EquateEmpty(),
+				cmp.AllowUnexported(source.Info{}),
+			); diff != "" {
 				t.Fatalf("testDB.GetUnitMeta(ctx, %q, %q) mismatch (-want +got):\n%s", test.modulePath, test.version, diff)
 			}
 
@@ -223,10 +230,9 @@ func TestFetchAndUpdateState(t *testing.T) {
 			if diff := cmp.Diff(test.want, gotPkg,
 				cmpopts.EquateEmpty(),
 				cmp.AllowUnexported(source.Info{}),
-				cmpopts.IgnoreFields(internal.Unit{}, "Documentation", "BuildContexts"),
-				cmpopts.IgnoreFields(internal.Unit{}, "SymbolHistory"),
-				cmpopts.IgnoreFields(internal.Unit{}, "Subdirectories")); diff != "" {
-				t.Errorf("mismatch on readme (-want +got):\n%s", diff)
+				cmpopts.IgnoreFields(internal.Unit{}, "Documentation", "BuildContexts", "SymbolHistory", "Subdirectories"),
+			); diff != "" {
+				t.Errorf("mismatch on unit (-want +got):\n%s", diff)
 			}
 			if got, want := gotPkg.Documentation, test.want.Documentation; got == nil || want == nil {
 				if !cmp.Equal(got, want) {
diff --git a/internal/worker/refetch_test.go b/internal/worker/refetch_test.go
index ef4bdc11..d7ef4be4 100644
--- a/internal/worker/refetch_test.go
+++ b/internal/worker/refetch_test.go
@@ -92,6 +92,7 @@ func TestReFetch(t *testing.T) {
 				CommitTime:        time.Date(2019, 1, 30, 0, 0, 0, 0, time.UTC),
 				IsRedistributable: true,
 				SourceInfo:        source.NewGitHubInfo("https://"+sample.ModulePath, "", sample.VersionString),
+				LatestVersion:     version,
 			},
 			Path: sample.ModulePath + "/bar",
 			Name: "bar",
@@ -127,7 +128,8 @@ func TestReFetch(t *testing.T) {
 	if diff := cmp.Diff(want.UnitMeta, *got,
 		cmp.AllowUnexported(source.Info{}),
 		cmpopts.IgnoreFields(licenses.Metadata{}, "Coverage"),
-		cmpopts.IgnoreFields(internal.UnitMeta{}, "HasGoMod")); diff != "" {
+		cmpopts.IgnoreFields(internal.UnitMeta{}, "HasGoMod"),
+	); diff != "" {
 		t.Fatalf("testDB.GetUnitMeta(ctx, %q, %q) mismatch (-want +got):\n%s", want.ModulePath, want.Version, diff)
 	}
 
@@ -139,7 +141,8 @@ func TestReFetch(t *testing.T) {
 		cmp.AllowUnexported(source.Info{}),
 		cmpopts.IgnoreFields(internal.Unit{}, "Documentation", "BuildContexts"),
 		cmpopts.IgnoreFields(licenses.Metadata{}, "Coverage"),
-		cmpopts.IgnoreFields(internal.UnitMeta{}, "HasGoMod")); diff != "" {
+		cmpopts.IgnoreFields(internal.UnitMeta{}, "HasGoMod"),
+	); diff != "" {
 		t.Errorf("mismatch on readme (-want +got):\n%s", diff)
 	}
 	if got, want := gotPkg.Documentation, want.Documentation; got == nil || want == nil {