internal/frontend: use unversioned module links in overview

If the request URL is unversioned, the module link on the overview
page should be too.

Updates b/144217401.

Change-Id: I4d10555639a1ffd44948206694b2cea3cb2a036b
Reviewed-on: https://team-review.git.corp.google.com/c/golang/discovery/+/601915
CI-Result: Cloud Build <devtools-proctor-result-processor@system.gserviceaccount.com>
Reviewed-by: Robert Findley <rfindley@google.com>

internal/frontend/directory.go

@@ -75,7 +75,7 @@ func (s *Server) serveDirectoryPage(w http.ResponseWriter, r *http.Request, dirP
 		header.URL = constructDirectoryURL(dbDir.Path, dbDir.ModulePath, internal.LatestVersion)
 	}
 
-	details, err := constructDetailsForDirectory(r, tab, s.ds, dbDir, licenses)
+	details, err := constructDetailsForDirectory(r, tab, dbDir, licenses)
 	if err != nil {
 		log.Errorf("serveDirectoryPage for %s@%s: %v", dirPath, version, err)
 		s.serveErrorPage(w, r, http.StatusInternalServerError, nil)

internal/frontend/overview.go

@@ -33,11 +33,18 @@ type OverviewDetails struct {
 	RepositoryURL    string
 }
 
+// versionedLinks says whether the constructed URLs should have versions.
 // constructOverviewDetails uses the given version to construct an OverviewDetails.
-func constructOverviewDetails(vi *internal.VersionInfo, licmetas []*license.Metadata) *OverviewDetails {
+func constructOverviewDetails(vi *internal.VersionInfo, licmetas []*license.Metadata, versionedLinks bool) *OverviewDetails {
+	var lv string
+	if versionedLinks {
+		lv = linkableVersion(vi.Version, vi.ModulePath)
+	} else {
+		lv = internal.LatestVersion
+	}
 	overview := &OverviewDetails{
 		ModulePath:      vi.ModulePath,
-		ModuleURL:       constructModuleURL(vi.ModulePath, linkableVersion(vi.Version, vi.ModulePath)),
+		ModuleURL:       constructModuleURL(vi.ModulePath, lv),
 		RepositoryURL:   vi.SourceInfo.RepoURL(),
 		Redistributable: license.AreRedistributable(licmetas),
 	}
@@ -49,8 +56,8 @@ func constructOverviewDetails(vi *internal.VersionInfo, licmetas []*license.Meta
 }
 
 // constructPackageOverviewDetails uses data for the given package to return an OverviewDetails.
-func constructPackageOverviewDetails(pkg *internal.VersionedPackage) *OverviewDetails {
-	od := constructOverviewDetails(&pkg.VersionInfo, pkg.Licenses)
+func constructPackageOverviewDetails(pkg *internal.VersionedPackage, versionedLinks bool) *OverviewDetails {
+	od := constructOverviewDetails(&pkg.VersionInfo, pkg.Licenses, versionedLinks)
 	od.PackageSourceURL = pkg.SourceInfo.DirectoryURL(packageSubdir(pkg.Path, pkg.ModulePath))
 	if !pkg.IsRedistributable() {
 		od.Redistributable = false

internal/frontend/overview_test.go

@@ -45,7 +45,7 @@ func TestFetchOverviewDetails(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	got := constructOverviewDetails(&tc.version.VersionInfo, sample.LicenseMetadata)
+	got := constructOverviewDetails(&tc.version.VersionInfo, sample.LicenseMetadata, true)
 	if diff := cmp.Diff(tc.wantDetails, got); diff != "" {
 		t.Errorf("constructOverviewDetails(%q, %q) mismatch (-want +got):\n%s", tc.version.Packages[0].Path, tc.version.Version, diff)
 	}

internal/frontend/server_test.go

@@ -411,7 +411,7 @@ func TestServer(t *testing.T) {
 				in(".Overview-module",
 					text("Module"),
 					in("a",
-						href("/mod/github.com/valid_module_name@v1.0.0"),
+						href("/mod/github.com/valid_module_name"),
 						text("github.com/valid_module_name"))),
 				in(".Overview-sourceCodeLink",
 					text("Repository"),
@@ -495,8 +495,7 @@ func TestServer(t *testing.T) {
 			want: in("",
 				pagecheck.ModuleHeader(mod, unversioned),
 				in(".Overview-module a",
-					// TODO(b/144217401): should be unversioned
-					href(fmt.Sprintf("/mod/%s@%s", sample.ModulePath, sample.VersionString)),
+					href("/mod/"+sample.ModulePath),
 					text("^"+sample.ModulePath+"$")),
 				in(".Overview-readmeContent", text(`readme`))),
 		},

internal/frontend/tabs.go

@@ -8,6 +8,8 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"net/url"
+	"strings"
 
 	"golang.org/x/discovery/internal"
 	"golang.org/x/discovery/internal/license"
@@ -154,11 +156,15 @@ func fetchDetailsForPackage(ctx context.Context, r *http.Request, tab string, ds
 	case "licenses":
 		return fetchPackageLicensesDetails(ctx, ds, pkg)
 	case "overview":
-		return constructPackageOverviewDetails(pkg), nil
+		return constructPackageOverviewDetails(pkg, urlIsVersioned(r.URL)), nil
 	}
 	return nil, fmt.Errorf("BUG: unable to fetch details: unknown tab %q", tab)
 }
 
+func urlIsVersioned(url *url.URL) bool {
+	return strings.ContainsRune(url.Path, '@')
+}
+
 // fetchDetailsForModule returns tab details by delegating to the correct detail
 // handler.
 func fetchDetailsForModule(ctx context.Context, r *http.Request, tab string, ds DataSource, vi *internal.VersionInfo, licenses []*license.License) (interface{}, error) {
@@ -171,17 +177,17 @@ func fetchDetailsForModule(ctx context.Context, r *http.Request, tab string, ds
 		return fetchModuleVersionsDetails(ctx, ds, vi)
 	case "overview":
 		// TODO(b/138448402): implement remaining module views.
-		return constructOverviewDetails(vi, license.ToMetadatas(licenses)), nil
+		return constructOverviewDetails(vi, license.ToMetadatas(licenses), urlIsVersioned(r.URL)), nil
 	}
 	return nil, fmt.Errorf("BUG: unable to fetch details: unknown tab %q", tab)
 }
 
 // constructDetailsForDirectory returns tab details by delegating to the correct
 // detail handler.
-func constructDetailsForDirectory(r *http.Request, tab string, ds DataSource, dir *internal.Directory, licenses []*license.License) (interface{}, error) {
+func constructDetailsForDirectory(r *http.Request, tab string, dir *internal.Directory, licenses []*license.License) (interface{}, error) {
 	switch tab {
 	case "overview":
-		return constructOverviewDetails(&dir.VersionInfo, license.ToMetadatas(licenses)), nil
+		return constructOverviewDetails(&dir.VersionInfo, license.ToMetadatas(licenses), urlIsVersioned(r.URL)), nil
 	case "subdirectories":
 		// Ideally we would just use fetchDirectoryDetails here so that it
 		// follows the same code path as fetchDetailsForModule and