internal/postgres: change buildcontext key in getSymbolHistory

Instead of using a custom string as the key in getSymbolHistory, just
use internal.BuildContext.

For golang/go#37102

Change-Id: I87feabd36a6b33fc9a34bd5cf3ab0012bdbbf012
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/294689
Trust: Julie Qiu <julie@golang.org>
Run-TryBot: Julie Qiu <julie@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>

internal/build_context.go

@@ -14,15 +14,23 @@ type BuildContext struct {
 // All represents all values for a build context element (GOOS or GOARCH).
 const All = "all"
 
+var (
+	BuildContextAll     = BuildContext{All, All}
+	BuildContextLinux   = BuildContext{"linux", "amd64"}
+	BuildContextWindows = BuildContext{"windows", "amd64"}
+	BuildContextDarwin  = BuildContext{"darwin", "amd64"}
+	BuildContextJS      = BuildContext{"js", "wasm"}
+)
+
 // BuildContexts are the build contexts we check when loading a package (see
 // internal/fetch/load.go).
 // We store documentation for all of the listed contexts.
 // The order determines which environment's docs we will show as the default.
 var BuildContexts = []BuildContext{
-	{"linux", "amd64"},
-	{"windows", "amd64"},
-	{"darwin", "amd64"},
-	{"js", "wasm"},
+	BuildContextLinux,
+	BuildContextWindows,
+	BuildContextDarwin,
+	BuildContextJS,
 }
 
 // CompareBuildContexts returns a negative number, 0, or a positive number depending on

internal/postgres/symbol.go

@@ -45,7 +45,7 @@ func insertSymbols(ctx context.Context, db *database.DB, modulePath, version str
 				builds = internal.BuildContexts
 			}
 			for _, build := range builds {
-				nameToSymbol := buildToNameToSym[goosgoarch(build.GOOS, build.GOARCH)]
+				nameToSymbol := buildToNameToSym[internal.BuildContext{GOOS: build.GOOS, GOARCH: build.GOARCH}]
 				updateSymbols(doc.API, func(s *internal.Symbol) (err error) {
 					defer derrors.WrapStack(&err, "updateSymbols(%q)", s.Name)
 					if !shouldUpdateSymbolHistory(s.Name, version, nameToSymbol) {
@@ -207,7 +207,7 @@ func upsertSymbolNamesReturningIDs(ctx context.Context, db *database.DB, pathToD
 	return symbols, nil
 }
 
-func getSymbolHistory(ctx context.Context, db *database.DB, packagePath, modulePath string) (_ map[string]map[string]*internal.Symbol, err error) {
+func getSymbolHistory(ctx context.Context, db *database.DB, packagePath, modulePath string) (_ map[internal.BuildContext]map[string]*internal.Symbol, err error) {
 	defer derrors.Wrap(&err, "getSymbolHistoryForPath(ctx, db, %q, %q)", packagePath, modulePath)
 	query := `
         SELECT
@@ -228,7 +228,7 @@ func getSymbolHistory(ctx context.Context, db *database.DB, packagePath, moduleP
         WHERE p1.path = $1 AND p2.path = $2;`
 
 	// Map from GOOS/GOARCH to (map from symbol name to symbol).
-	buildToNameToSym := map[string]map[string]*internal.Symbol{}
+	buildToNameToSym := map[internal.BuildContext]map[string]*internal.Symbol{}
 	collect := func(rows *sql.Rows) error {
 		var (
 			sh internal.Symbol
@@ -245,10 +245,10 @@ func getSymbolHistory(ctx context.Context, db *database.DB, packagePath, moduleP
 		); err != nil {
 			return fmt.Errorf("row.Scan(): %v", err)
 		}
-		nameToSym, ok := buildToNameToSym[goosgoarch(sh.GOOS, sh.GOARCH)]
+		nameToSym, ok := buildToNameToSym[internal.BuildContext{GOOS: sh.GOOS, GOARCH: sh.GOARCH}]
 		if !ok {
 			nameToSym = map[string]*internal.Symbol{}
-			buildToNameToSym[goosgoarch(sh.GOOS, sh.GOARCH)] = nameToSym
+			buildToNameToSym[internal.BuildContext{GOOS: sh.GOOS, GOARCH: sh.GOARCH}] = nameToSym
 		}
 		nameToSym[sh.Name] = &sh
 		return nil
@@ -259,10 +259,6 @@ func getSymbolHistory(ctx context.Context, db *database.DB, packagePath, moduleP
 	return buildToNameToSym, nil
 }
 
-func goosgoarch(goos, goarch string) string {
-	return fmt.Sprintf("goos=%s_goarch=%s", goos, goarch)
-}
-
 func updateSymbols(symbols []*internal.Symbol, updateFunc func(s *internal.Symbol) error) error {
 	for _, s := range symbols {
 		if err := updateFunc(s); err != nil {
@@ -292,7 +288,7 @@ func (db *DB) CompareStdLib(ctx context.Context) (map[string][]string, error) {
 			return nil, err
 		}
 		// symbol.ParsePackageAPIInfo does not support OS/ARCH-dependent symbols.
-		data := hist[goosgoarch("linux", "amd64")]
+		data := hist[internal.BuildContext{GOOS: "linux", GOARCH: "amd64"}]
 		errs := symbol.CompareStdLib(path, apiVersions[path], data)
 		if len(errs) > 0 {
 			pkgToErrors[path] = errs

internal/postgres/symbol_test.go

@@ -196,11 +196,11 @@ func TestInsertSymbolHistory(t *testing.T) {
 			SinceVersion: "v1.0.0",
 		},
 	}
-	wantHist := map[string]map[string]*internal.Symbol{
-		goosgoarch("darwin", "amd64"):  symbols,
-		goosgoarch("js", "wasm"):       symbols,
-		goosgoarch("linux", "amd64"):   symbols,
-		goosgoarch("windows", "amd64"): symbols,
+	wantHist := map[internal.BuildContext]map[string]*internal.Symbol{
+		internal.BuildContextDarwin:  symbols,
+		internal.BuildContextJS:      symbols,
+		internal.BuildContextLinux:   symbols,
+		internal.BuildContextWindows: symbols,
 	}
 	if diff := cmp.Diff(wantHist, gotHist,
 		cmpopts.IgnoreFields(internal.Symbol{}, "GOOS", "GOARCH")); diff != "" {
@@ -259,11 +259,11 @@ func TestInsertSymbolHistory_MultiVersions(t *testing.T) {
 		"Foo.A": methodA,
 		"Foo.B": methodB,
 	}
-	wantHist := map[string]map[string]*internal.Symbol{
-		goosgoarch("darwin", "amd64"):  symbols,
-		goosgoarch("js", "wasm"):       symbols,
-		goosgoarch("linux", "amd64"):   symbols,
-		goosgoarch("windows", "amd64"): symbols,
+	wantHist := map[internal.BuildContext]map[string]*internal.Symbol{
+		internal.BuildContextDarwin:  symbols,
+		internal.BuildContextJS:      symbols,
+		internal.BuildContextLinux:   symbols,
+		internal.BuildContextWindows: symbols,
 	}
 	if diff := cmp.Diff(wantHist, gotHist,
 		cmpopts.IgnoreFields(internal.Symbol{}, "GOOS", "GOARCH")); diff != "" {
@@ -342,23 +342,23 @@ func TestInsertSymbolHistory_MultiGOOS(t *testing.T) {
 	b1 := func() *internal.Symbol { b := methodB; b.SinceVersion = "v1.2.0"; return &b }()
 	a2 := func() *internal.Symbol { a := methodA; a.SinceVersion = "v1.2.0"; return &a }()
 	b2 := func() *internal.Symbol { b := methodB; b.SinceVersion = "v1.1.0"; return &b }()
-	wantHist := map[string]map[string]*internal.Symbol{
-		goosgoarch("linux", "amd64"): {
+	wantHist := map[internal.BuildContext]map[string]*internal.Symbol{
+		internal.BuildContextLinux: {
 			"Foo":   parent,
 			"Foo.A": a1,
 			"Foo.B": b1,
 		},
-		goosgoarch("windows", "amd64"): {
+		internal.BuildContextWindows: {
 			"Foo":   parent,
 			"Foo.A": a1,
 			"Foo.B": b1,
 		},
-		goosgoarch("darwin", "amd64"): {
+		internal.BuildContextDarwin: {
 			"Foo":   parent,
 			"Foo.A": a2,
 			"Foo.B": b2,
 		},
-		goosgoarch("js", "wasm"): {
+		internal.BuildContextJS: {
 			"Foo":   parent,
 			"Foo.A": a2,
 			"Foo.B": b2,