internal/postgres: update LegacyGetModuleInfo to prefer non-incompati…

…ble modules

Updates LegacyGetModuleInfo to use orderByLatest in the query to prefer
compatible modules.

Updates golang/go#37714

Change-Id: I83bbbf3a8f5753533f3b2d8d5e329e82400951df
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/249277
Run-TryBot: Miguel Acero <acero@google.com>
Run-TryBot: Julie Qiu <julie@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>

internal/postgres/details.go

@@ -216,22 +216,15 @@ func (db *DB) LegacyGetModuleInfo(ctx context.Context, modulePath string, versio
 			redistributable,
 			has_go_mod
 		FROM
-			modules`
+			modules m`
 
 	args := []interface{}{modulePath}
 	if version == internal.LatestVersion {
-		query += `
-			WHERE module_path = $1
-			ORDER BY
-				-- Order the versions by release then prerelease.
-				-- The default version should be the first release
-				-- version available, if one exists.
-				version_type = 'release' DESC,
-				sort_version DESC
-			LIMIT 1;`
+		query += fmt.Sprintf(`
+			WHERE m.module_path = $1 %s LIMIT 1;`, orderByLatest)
 	} else {
 		query += `
-			WHERE module_path = $1 AND version = $2;`
+			WHERE m.module_path = $1 AND m.version = $2;`
 		args = append(args, version)
 	}
 

internal/postgres/details_test.go

@@ -112,6 +112,7 @@ func TestPostgres_GetVersionInfo_Latest(t *testing.T) {
 				sample.Module("mod.1", "v1.1.0-alpha.1", sample.Suffix),
 				sample.Module("mod.1", "v1.0.0", sample.Suffix),
 				sample.Module("mod.1", "v1.0.0-20190311183353-d8887717615a", sample.Suffix),
+				sample.Module("mod.1", "v2.0.0+incompatible", sample.Suffix),
 			},
 			wantIndex: 1,
 		},