all: Add build constants for runtime.GOOS comparisons (#8442)

all: Add package runtimeos for runtime.GOOS comparisons

I grew tired of hand written string comparisons. This adds generated
constants for the GOOS values, and predefined Is$OS constants that can
be iffed on. In a couple of places I rewrote trivial switch:es to if:s,
and added Illumos where we checked for Solaris (because they are
effectively the same, and if we're going to target one of them that
would be Illumos...).

build.go

@@ -31,6 +31,8 @@ import (
 	"strings"
 	"text/template"
 	"time"
+
+	buildpkg "github.com/syncthing/syncthing/lib/build"
 )
 
 var (
@@ -393,7 +395,7 @@ func test(tags []string, pkgs ...string) {
 
 	if runtime.GOARCH == "amd64" {
 		switch runtime.GOOS {
-		case "darwin", "linux", "freebsd": // , "windows": # See https://github.com/golang/go/issues/27089
+		case buildpkg.Darwin, buildpkg.Linux, buildpkg.FreeBSD: // , "windows": # See https://github.com/golang/go/issues/27089
 			args = append(args, "-race")
 		}
 	}

cmd/strelaysrv/main.go

@@ -14,7 +14,6 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"sync/atomic"
 	"syscall"
@@ -146,7 +145,7 @@ func main() {
 		log.Println("Connection limit", descriptorLimit)
 
 		go monitorLimits()
-	} else if err != nil && runtime.GOOS != "windows" {
+	} else if err != nil && !build.IsWindows {
 		log.Println("Assuming no connection limit, due to error retrieving rlimits:", err)
 	}
 

cmd/syncthing/main.go

@@ -199,7 +199,7 @@ func defaultVars() kong.Vars {
 	// Windows, the "default" options.logFile will later be replaced with the
 	// default path, unless the user has manually specified "-" or
 	// something else.
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		vars["logFile"] = "default"
 	} else {
 		vars["logFile"] = "-"

cmd/syncthing/monitor.go

@@ -15,11 +15,11 @@ import (
 	"os/exec"
 	"os/signal"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"syscall"
 	"time"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/locations"
 	"github.com/syncthing/syncthing/lib/osutil"
@@ -66,7 +66,7 @@ func monitorMain(options serveOptions) {
 		if err != nil {
 			l.Warnln("Failed to setup logging to file, proceeding with logging to stdout only:", err)
 		} else {
-			if runtime.GOOS == "windows" {
+			if build.IsWindows {
 				// Translate line breaks to Windows standard
 				fileDst = osutil.ReplacingWriter{
 					Writer: fileDst,
@@ -315,7 +315,7 @@ func restartMonitor(args []string) error {
 	// opening the browser on startup.
 	os.Setenv("STRESTART", "yes")
 
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		// syscall.Exec is the cleanest way to restart on Unixes as it
 		// replaces the current process with the new one, keeping the pid and
 		// controlling terminal and so on

cmd/syncthing/openurl_unix.go

@@ -11,20 +11,18 @@ package main
 
 import (
 	"os/exec"
-	"runtime"
 	"syscall"
+
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 func openURL(url string) error {
-	switch runtime.GOOS {
-	case "darwin":
+	if build.IsDarwin {
 		return exec.Command("open", url).Run()
-
-	default:
-		cmd := exec.Command("xdg-open", url)
-		cmd.SysProcAttr = &syscall.SysProcAttr{
-			Setpgid: true,
-		}
-		return cmd.Run()
 	}
+	cmd := exec.Command("xdg-open", url)
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setpgid: true,
+	}
+	return cmd.Run()
 }

lib/api/api.go

@@ -1925,7 +1925,7 @@ func shouldRegenerateCertificate(cert tls.Certificate) error {
 	// On macOS, check for certificates issued on or after July 1st, 2019,
 	// with a longer validity time than 825 days.
 	cutoff := time.Date(2019, 7, 1, 0, 0, 0, 0, time.UTC)
-	if runtime.GOOS == "darwin" &&
+	if build.IsDarwin &&
 		leaf.NotBefore.After(cutoff) &&
 		leaf.NotAfter.Sub(leaf.NotBefore) > 825*24*time.Hour {
 		return errors.New("certificate incompatible with macOS 10.15 (Catalina)")

lib/api/api_test.go

@@ -19,7 +19,6 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
-	"runtime"
 	"strconv"
 	"strings"
 	"testing"
@@ -27,6 +26,7 @@ import (
 
 	"github.com/d4l3k/messagediff"
 	"github.com/syncthing/syncthing/lib/assets"
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 	connmocks "github.com/syncthing/syncthing/lib/connections/mocks"
 	discovermocks "github.com/syncthing/syncthing/lib/discover/mocks"
@@ -1255,7 +1255,7 @@ func TestShouldRegenerateCertificate(t *testing.T) {
 		t.Error("expected no error:", err)
 	}
 
-	if runtime.GOOS == "darwin" {
+	if build.IsDarwin {
 		// Certificates with too long an expiry time are not allowed on macOS
 		crt, err = tlsutil.NewCertificateInMemory("foo.example.com", 1000)
 		if err != nil {
@@ -1416,7 +1416,7 @@ func TestSanitizedHostname(t *testing.T) {
 // be prone to false negatives if things change in the future, but likely
 // not false positives.
 func runningInContainer() bool {
-	if runtime.GOOS != "linux" {
+	if !build.IsLinux {
 		return false
 	}
 

lib/build/runtimeos.gen.go

@@ -0,0 +1,38 @@
+// Code generated by runtimeos.sh. DO NOT EDIT.
+package build
+
+import "runtime"
+
+const (
+	AIX       = "aix"
+	Android   = "android"
+	Darwin    = "darwin"
+	Dragonfly = "dragonfly"
+	FreeBSD   = "freebsd"
+	Illumos   = "illumos"
+	IOS       = "ios"
+	JS        = "js"
+	Linux     = "linux"
+	NetBSD    = "netbsd"
+	OpenBSD   = "openbsd"
+	Plan9     = "plan9"
+	Solaris   = "solaris"
+	Windows   = "windows"
+)
+
+const (
+	IsAIX       = runtime.GOOS == AIX
+	IsAndroid   = runtime.GOOS == Android
+	IsDarwin    = runtime.GOOS == Darwin
+	IsDragonfly = runtime.GOOS == Dragonfly
+	IsFreeBSD   = runtime.GOOS == FreeBSD
+	IsIllumos   = runtime.GOOS == Illumos
+	IsIOS       = runtime.GOOS == IOS
+	IsJS        = runtime.GOOS == JS
+	IsLinux     = runtime.GOOS == Linux
+	IsNetBSD    = runtime.GOOS == NetBSD
+	IsOpenBSD   = runtime.GOOS == OpenBSD
+	IsPlan9     = runtime.GOOS == Plan9
+	IsSolaris   = runtime.GOOS == Solaris
+	IsWindows   = runtime.GOOS == Windows
+)

lib/build/runtimeos.sh

@@ -0,0 +1,43 @@
+# Copyright (C) 2022 The Syncthing Authors.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at https://mozilla.org/MPL/2.0/.
+
+#!/bin/sh
+
+# List known operating system/architecture combos, removing the
+# architecture, and making constants of them.
+
+osname() {
+    echo "$1" | awk '{print toupper(substr($1, 1, 1)) substr($1, 2)}' \
+        | sed s/aix/AIX/i \
+        | sed s/bsd/BSD/i \
+        | sed s/ios/IOS/i \
+        | sed s/js/JS/i
+}
+
+osconstants() {
+    echo "// Code generated by runtimeos.sh. DO NOT EDIT."
+    echo "package build"
+    echo "import \"runtime\""
+
+    echo "const ("
+    for OS in $(go tool dist list | sed 's|/.*||' | sort | uniq) ; do
+        name=$(osname "$OS")
+        echo "$name = \"$OS\""
+    done
+    echo ")"
+    echo
+
+    echo "const ("
+    for OS in $(go tool dist list | sed 's|/.*||' | sort | uniq) ; do
+        name=$(osname "$OS")
+        echo "Is$name = runtime.GOOS == $name"
+    done
+    echo ")"
+}
+
+osconstants > runtimeos.gen.go
+
+gofmt -w -s runtimeos.gen.go

lib/config/config.go

@@ -15,13 +15,13 @@ import (
 	"net"
 	"net/url"
 	"os"
-	"runtime"
 	"sort"
 	"strconv"
 	"strings"
 
 	"github.com/pkg/errors"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/util"
@@ -549,7 +549,7 @@ loop:
 }
 
 func cleanSymlinks(filesystem fs.Filesystem, dir string) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		// We don't do symlinks on Windows. Additionally, there may
 		// be things that look like symlinks that are not, which we
 		// should leave alone. Deduplicated files, for example.

lib/config/config_test.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/d4l3k/messagediff"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/events"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
@@ -445,7 +446,7 @@ func TestVersioningConfig(t *testing.T) {
 }
 
 func TestIssue1262(t *testing.T) {
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skipf("path gets converted to absolute as part of the filesystem initialization on linux")
 	}
 
@@ -538,7 +539,7 @@ func TestFolderCheckPath(t *testing.T) {
 			path: "link",
 			err:  nil,
 		})
-	} else if runtime.GOOS != "windows" {
+	} else if !build.IsWindows {
 		t.Log("running without symlink check")
 		t.Fatal(err)
 	}
@@ -593,7 +594,7 @@ func TestNewSaveLoad(t *testing.T) {
 }
 
 func TestWindowsLineEndings(t *testing.T) {
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skip("Windows specific")
 	}
 

lib/config/folderconfiguration.go

@@ -9,13 +9,13 @@ package config
 import (
 	"errors"
 	"fmt"
-	"runtime"
 	"sort"
 	"strings"
 	"time"
 
 	"github.com/shirou/gopsutil/v3/disk"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
@@ -64,7 +64,7 @@ func (f FolderConfiguration) Filesystem(fset *db.FileSet) fs.Filesystem {
 
 func (f FolderConfiguration) ModTimeWindow() time.Duration {
 	dur := time.Duration(f.RawModTimeWindowS) * time.Second
-	if f.RawModTimeWindowS < 1 && runtime.GOOS == "android" {
+	if f.RawModTimeWindowS < 1 && build.IsAndroid {
 		if usage, err := disk.Usage(f.Filesystem(nil).URI()); err != nil {
 			dur = 2 * time.Second
 			l.Debugf(`Detecting FS at "%v" on android: Setting mtime window to 2s: err == "%v"`, f.Path, err)
@@ -90,7 +90,7 @@ func (f *FolderConfiguration) CreateMarker() error {
 	}
 
 	permBits := fs.FileMode(0777)
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		// Windows has no umask so we must chose a safer set of bits to
 		// begin with.
 		permBits = 0700
@@ -145,7 +145,7 @@ func (f *FolderConfiguration) CreateRoot() (err error) {
 	// Directory permission bits. Will be filtered down to something
 	// sane by umask on Unixes.
 	permBits := fs.FileMode(0777)
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		// Windows has no umask so we must chose a safer set of bits to
 		// begin with.
 		permBits = 0700

lib/config/migrations.go

@@ -11,11 +11,11 @@ import (
 	"os"
 	"path"
 	"path/filepath"
-	"runtime"
 	"sort"
 	"strings"
 	"sync"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/upgrade"
 	"github.com/syncthing/syncthing/lib/util"
@@ -189,7 +189,7 @@ func migrateToConfigV24(cfg *Configuration) {
 
 func migrateToConfigV23(cfg *Configuration) {
 	permBits := fs.FileMode(0777)
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		// Windows has no umask so we must chose a safer set of bits to
 		// begin with.
 		permBits = 0700

lib/fs/basicfs.go

@@ -11,11 +11,11 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"time"
 
 	"github.com/shirou/gopsutil/v3/disk"
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 var (
@@ -79,7 +79,7 @@ func newBasicFilesystem(root string, opts ...Option) *BasicFilesystem {
 
 	// Attempt to enable long filename support on Windows. We may still not
 	// have an absolute path here if the previous steps failed.
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		root = longFilenameSupport(root)
 	}
 

lib/fs/basicfs_test.go

@@ -9,13 +9,13 @@ package fs
 import (
 	"os"
 	"path/filepath"
-	"runtime"
 	"sort"
 	"strconv"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/rand"
 )
 
@@ -55,7 +55,7 @@ func TestChmodFile(t *testing.T) {
 }
 
 func TestChownFile(t *testing.T) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("Not supported on Windows")
 		return
 	}
@@ -106,7 +106,7 @@ func TestChmodDir(t *testing.T) {
 	path := filepath.Join(dir, "dir")
 
 	mode := os.FileMode(0755)
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		mode = os.FileMode(0777)
 	}
 
@@ -177,7 +177,7 @@ func TestCreate(t *testing.T) {
 }
 
 func TestCreateSymlink(t *testing.T) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("windows not supported")
 	}
 
@@ -336,7 +336,7 @@ func TestUsage(t *testing.T) {
 	fs, _ := setup(t)
 	usage, err := fs.Usage(".")
 	if err != nil {
-		if runtime.GOOS == "netbsd" || runtime.GOOS == "openbsd" || runtime.GOOS == "solaris" {
+		if build.IsNetBSD || build.IsOpenBSD || build.IsSolaris || build.IsIllumos {
 			t.Skip()
 		}
 		t.Errorf("Unexpected error: %s", err)
@@ -429,7 +429,7 @@ func TestRooted(t *testing.T) {
 		{"/", ".", "/", true},
 	}
 
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		extraCases := []testcase{
 			{`c:\`, `foo`, `c:\foo`, true},
 			{`\\?\c:\`, `foo`, `\\?\c:\foo`, true},
@@ -503,7 +503,7 @@ func TestRooted(t *testing.T) {
 }
 
 func TestNewBasicFilesystem(t *testing.T) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("non-windows root paths")
 	}
 
@@ -550,7 +550,7 @@ func TestRel(t *testing.T) {
 		{"/", "/Test", "Test"},
 		{"/Test", "/Test/test", "test"},
 	}
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		for i := range testCases {
 			testCases[i].root = filepath.FromSlash(testCases[i].root)
 			testCases[i].abs = filepath.FromSlash(testCases[i].abs)

lib/fs/basicfs_watch_test.go

@@ -15,7 +15,6 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strconv"
 	"strings"
 	"syscall"
@@ -23,6 +22,7 @@ import (
 	"time"
 
 	"github.com/syncthing/notify"
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 func TestMain(m *testing.M) {
@@ -41,7 +41,7 @@ func TestMain(m *testing.M) {
 	}
 
 	testDirAbs = filepath.Join(dir, testDir)
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		testDirAbs = longFilenameSupport(testDirAbs)
 	}
 
@@ -68,7 +68,7 @@ var (
 )
 
 func TestWatchIgnore(t *testing.T) {
-	if runtime.GOOS == "openbsd" {
+	if build.IsOpenBSD {
 		t.Skip(failsOnOpenBSD)
 	}
 	name := "ignore"
@@ -92,7 +92,7 @@ func TestWatchIgnore(t *testing.T) {
 }
 
 func TestWatchInclude(t *testing.T) {
-	if runtime.GOOS == "openbsd" {
+	if build.IsOpenBSD {
 		t.Skip(failsOnOpenBSD)
 	}
 	name := "include"
@@ -119,7 +119,7 @@ func TestWatchInclude(t *testing.T) {
 }
 
 func TestWatchRename(t *testing.T) {
-	if runtime.GOOS == "openbsd" {
+	if build.IsOpenBSD {
 		t.Skip(failsOnOpenBSD)
 	}
 	name := "rename"
@@ -134,7 +134,7 @@ func TestWatchRename(t *testing.T) {
 	destEvent := Event{new, Remove}
 	// Only on these platforms the removed file can be differentiated from
 	// the created file during renaming
-	if runtime.GOOS == "windows" || runtime.GOOS == "linux" || runtime.GOOS == "solaris" || runtime.GOOS == "freebsd" {
+	if build.IsWindows || build.IsLinux || build.IsSolaris || build.IsIllumos || build.IsFreeBSD {
 		destEvent = Event{new, NonRemove}
 	}
 	expectedEvents := []Event{
@@ -154,7 +154,7 @@ func TestWatchRename(t *testing.T) {
 // out of root event on every event.
 // https://github.com/syncthing/syncthing/issues/5695
 func TestWatchWinRoot(t *testing.T) {
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skip("Windows specific test")
 	}
 
@@ -288,7 +288,7 @@ func TestWatchSubpath(t *testing.T) {
 
 // TestWatchOverflow checks that an event at the root is sent when maxFiles is reached
 func TestWatchOverflow(t *testing.T) {
-	if runtime.GOOS == "openbsd" {
+	if build.IsOpenBSD {
 		t.Skip(failsOnOpenBSD)
 	}
 	name := "overflow"
@@ -313,7 +313,7 @@ func TestWatchOverflow(t *testing.T) {
 }
 
 func TestWatchErrorLinuxInterpretation(t *testing.T) {
-	if runtime.GOOS != "linux" {
+	if !build.IsLinux {
 		t.Skip("testing of linux specific error codes")
 	}
 
@@ -341,7 +341,7 @@ func TestWatchErrorLinuxInterpretation(t *testing.T) {
 }
 
 func TestWatchSymlinkedRoot(t *testing.T) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("Involves symlinks")
 	}
 
@@ -385,7 +385,7 @@ func TestUnrootedChecked(t *testing.T) {
 }
 
 func TestWatchIssue4877(t *testing.T) {
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skip("Windows specific test")
 	}
 
@@ -440,7 +440,7 @@ func TestWatchModTime(t *testing.T) {
 
 	var allowedEvents []Event
 	// Apparently an event for the parent is also sent on mac
-	if runtime.GOOS == "darwin" {
+	if build.IsDarwin {
 		allowedEvents = []Event{
 			{name, NonRemove},
 		}

lib/fs/fakefs_test.go

@@ -17,6 +17,8 @@ import (
 	"sort"
 	"testing"
 	"time"
+
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 func TestFakeFS(t *testing.T) {
@@ -563,7 +565,7 @@ func testFakeFSRenameInsensitive(t *testing.T, fs Filesystem) {
 	}
 
 	// not checking on darwin due to https://github.com/golang/go/issues/35222
-	if runtime.GOOS != "darwin" {
+	if !build.IsDarwin {
 		if err := fs.Rename("/foo/bar/BAZ", "/FOO/BAR/bAz"); err != nil {
 			t.Errorf("Could not perform in-place case-only directory rename: %s", err)
 		}
@@ -786,7 +788,7 @@ func testFakeFSSameFile(t *testing.T, fs Filesystem) {
 			t.Fatalf("Could not create %s: %s", filename, err)
 		} else {
 			fd.Close()
-			if runtime.GOOS == "windows" {
+			if build.IsWindows {
 				time.Sleep(1 * time.Millisecond)
 			}
 		}

lib/fs/filesystem_test.go

@@ -8,8 +8,9 @@ package fs
 
 import (
 	"path/filepath"
-	"runtime"
 	"testing"
+
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 func TestIsInternal(t *testing.T) {
@@ -120,7 +121,7 @@ func TestIsParent(t *testing.T) {
 	testBoth := func(path, parent string, expected bool) {
 		t.Helper()
 		test(path, parent, expected)
-		if runtime.GOOS == "windows" {
+		if build.IsWindows {
 			test("C:/"+path, "C:/"+parent, expected)
 		} else {
 			test("/"+path, "/"+parent, expected)
@@ -130,7 +131,7 @@ func TestIsParent(t *testing.T) {
 	// rel - abs
 	for _, parent := range []string{"/", "/foo", "/foo/bar"} {
 		for _, path := range []string{"", ".", "foo", "foo/bar", "bas", "bas/baz"} {
-			if runtime.GOOS == "windows" {
+			if build.IsWindows {
 				parent = "C:/" + parent
 			}
 			test(parent, path, false)
@@ -140,7 +141,7 @@ func TestIsParent(t *testing.T) {
 
 	// equal
 	for i, path := range []string{"/", "/foo", "/foo/bar", "", ".", "foo", "foo/bar"} {
-		if i < 3 && runtime.GOOS == "windows" {
+		if i < 3 && build.IsWindows {
 			path = "C:" + path
 		}
 		test(path, path, false)
@@ -164,7 +165,7 @@ func TestIsParent(t *testing.T) {
 		for _, path := range []string{"foo/bar/baz", "foo/bar/baz/bas"} {
 			testBoth(path, parent, true)
 			testBoth(parent, path, false)
-			if runtime.GOOS == "windows" {
+			if build.IsWindows {
 				test("C:/"+path, "D:/"+parent, false)
 			}
 		}

lib/fs/mtimefs_test.go

@@ -10,9 +10,10 @@ import (
 	"errors"
 	"os"
 	"path/filepath"
-	"runtime"
 	"testing"
 	"time"
+
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 func TestMtimeFS(t *testing.T) {
@@ -181,11 +182,10 @@ func TestMtimeFSOpen(t *testing.T) {
 }
 
 func TestMtimeFSInsensitive(t *testing.T) {
-	switch runtime.GOOS {
-	case "darwin", "windows":
+	if build.IsDarwin || build.IsWindows {
 		// blatantly assume file systems here are case insensitive. Might be
 		// a spurious failure on oddly configured systems.
-	default:
+	} else {
 		t.Skip("need case insensitive FS")
 	}
 

lib/fs/tempname.go

@@ -9,9 +9,9 @@ package fs
 import (
 	"fmt"
 	"path/filepath"
-	"runtime"
 	"strings"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/sha256"
 )
 
@@ -21,7 +21,7 @@ const (
 )
 
 func tempPrefix() string {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		return WindowsTempPrefix
 	} else {
 		return UnixTempPrefix

lib/fs/util.go

@@ -10,9 +10,10 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"unicode"
+
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 const pathSeparatorString = string(PathSeparator)
@@ -35,7 +36,7 @@ func ExpandTilde(path string) (string, error) {
 }
 
 func getHomeDir() (string, error) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		// Legacy -- we prioritize this for historical reasons, whereas
 		// os.UserHomeDir uses %USERPROFILE% always.
 		home := filepath.Join(os.Getenv("HomeDrive"), os.Getenv("HomePath"))
@@ -196,7 +197,7 @@ func CommonPrefix(first, second string) string {
 	}
 
 	if isAbs {
-		if runtime.GOOS == "windows" && isVolumeNameOnly(common) {
+		if build.IsWindows && isVolumeNameOnly(common) {
 			// Because strings.Split strips out path separators, if we're at the volume name, we end up without a separator
 			// Wedge an empty element to be joined with.
 			common = append(common, "")

lib/fs/util_test.go

@@ -8,10 +8,11 @@ package fs
 
 import (
 	"math/rand"
-	"runtime"
 	"testing"
 	"unicode"
 	"unicode/utf8"
+
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 func TestCommonPrefix(t *testing.T) {
@@ -23,7 +24,7 @@ func TestCommonPrefix(t *testing.T) {
 		}
 	}
 
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		test(`c:\Audrius\Downloads`, `c:\Audrius\Docs`, `c:\Audrius`)
 		test(`c:\Audrius\Downloads`, `C:\Audrius\Docs`, ``) // Case differences :(
 		test(`C:\Audrius-a\Downloads`, `C:\Audrius-b\Docs`, `C:\`)

lib/fs/walkfs_test.go

@@ -11,12 +11,13 @@ import (
 	"fmt"
 	osexec "os/exec"
 	"path/filepath"
-	"runtime"
 	"testing"
+
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 func testWalkSkipSymlink(t *testing.T, fsType FilesystemType, uri string) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("Symlinks skipping is not tested on windows")
 	}
 
@@ -53,7 +54,7 @@ func createDirJunct(target string, name string) error {
 }
 
 func testWalkTraverseDirJunct(t *testing.T, fsType FilesystemType, uri string) {
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skip("Directory junctions are available and tested on windows only")
 	}
 
@@ -86,7 +87,7 @@ func testWalkTraverseDirJunct(t *testing.T, fsType FilesystemType, uri string) {
 }
 
 func testWalkInfiniteRecursion(t *testing.T, fsType FilesystemType, uri string) {
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skip("Infinite recursion detection is tested on windows only")
 	}
 

lib/ignore/ignore.go

@@ -13,12 +13,12 @@ import (
 	"fmt"
 	"io"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"time"
 
 	"github.com/gobwas/glob"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/sha256"
@@ -35,7 +35,7 @@ const (
 var defaultResult Result = resultInclude
 
 func init() {
-	if runtime.GOOS == "darwin" || runtime.GOOS == "windows" {
+	if build.IsDarwin || build.IsWindows {
 		defaultResult |= resultFoldCase
 	}
 }

lib/ignore/ignore_test.go

@@ -12,11 +12,11 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/osutil"
 )
@@ -210,10 +210,9 @@ func TestCaseSensitivity(t *testing.T) {
 	match := []string{"test"}
 	dontMatch := []string{"foo"}
 
-	switch runtime.GOOS {
-	case "darwin", "windows":
+	if build.IsDarwin || build.IsWindows {
 		match = append(match, "TEST", "Test", "tESt")
-	default:
+	} else {
 		dontMatch = append(dontMatch, "TEST", "Test", "tESt")
 	}
 
@@ -618,7 +617,7 @@ func TestHashOfEmpty(t *testing.T) {
 func TestWindowsPatterns(t *testing.T) {
 	// We should accept patterns as both a/b and a\b and match that against
 	// both kinds of slash as well.
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skip("Windows specific test")
 		return
 	}
@@ -643,7 +642,7 @@ func TestWindowsPatterns(t *testing.T) {
 
 func TestAutomaticCaseInsensitivity(t *testing.T) {
 	// We should do case insensitive matching by default on some platforms.
-	if runtime.GOOS != "windows" && runtime.GOOS != "darwin" {
+	if !build.IsWindows && !build.IsDarwin {
 		t.Skip("Windows/Mac specific test")
 		return
 	}
@@ -1205,7 +1204,7 @@ func TestEmptyPatterns(t *testing.T) {
 }
 
 func TestWindowsLineEndings(t *testing.T) {
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skip("Windows specific")
 	}
 

lib/locations/locations.go

@@ -14,6 +14,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/fs"
 )
 
@@ -133,13 +134,13 @@ func expandLocations() error {
 // trying.
 func defaultConfigDir(userHome string) string {
 	switch runtime.GOOS {
-	case "windows":
+	case build.Windows:
 		if p := os.Getenv("LocalAppData"); p != "" {
 			return filepath.Join(p, "Syncthing")
 		}
 		return filepath.Join(os.Getenv("AppData"), "Syncthing")
 
-	case "darwin":
+	case build.Darwin:
 		return filepath.Join(userHome, "Library/Application Support/Syncthing")
 
 	default:
@@ -153,30 +154,28 @@ func defaultConfigDir(userHome string) string {
 // defaultDataDir returns the default data directory, which usually is the
 // config directory but might be something else.
 func defaultDataDir(userHome, config string) string {
-	switch runtime.GOOS {
-	case "windows", "darwin":
-		return config
-
-	default:
-		// If a database exists at the "normal" location, use that anyway.
-		if _, err := os.Lstat(filepath.Join(config, LevelDBDir)); err == nil {
-			return config
-		}
-		// Always use this env var, as it's explicitly set by the user
-		if xdgHome := os.Getenv("XDG_DATA_HOME"); xdgHome != "" {
-			return filepath.Join(xdgHome, "syncthing")
-		}
-		// Only use the XDG default, if a syncthing specific dir already
-		// exists. Existence of ~/.local/share is not deemed enough, as
-		// it may also exist erroneously on non-XDG systems.
-		xdgDefault := filepath.Join(userHome, ".local/share/syncthing")
-		if _, err := os.Lstat(xdgDefault); err == nil {
-			return xdgDefault
-		}
-		// FYI: XDG_DATA_DIRS is not relevant, as it is for system-wide
-		// data dirs, not user specific ones.
+	if build.IsWindows || build.IsDarwin {
 		return config
 	}
+
+	// If a database exists at the "normal" location, use that anyway.
+	if _, err := os.Lstat(filepath.Join(config, LevelDBDir)); err == nil {
+		return config
+	}
+	// Always use this env var, as it's explicitly set by the user
+	if xdgHome := os.Getenv("XDG_DATA_HOME"); xdgHome != "" {
+		return filepath.Join(xdgHome, "syncthing")
+	}
+	// Only use the XDG default, if a syncthing specific dir already
+	// exists. Existence of ~/.local/share is not deemed enough, as
+	// it may also exist erroneously on non-XDG systems.
+	xdgDefault := filepath.Join(userHome, ".local/share/syncthing")
+	if _, err := os.Lstat(xdgDefault); err == nil {
+		return xdgDefault
+	}
+	// FYI: XDG_DATA_DIRS is not relevant, as it is for system-wide
+	// data dirs, not user specific ones.
+	return config
 }
 
 // userHomeDir returns the user's home directory, or dies trying.

lib/model/folder_sendrecv.go

@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"io"
 	"path/filepath"
-	"runtime"
 	"sort"
 	"strconv"
 	"strings"
@@ -19,6 +18,7 @@ import (
 
 	"github.com/pkg/errors"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/events"
@@ -344,7 +344,7 @@ func (f *sendReceiveFolder) processNeeded(snap *db.Snapshot, dbUpdateChan chan<-
 			l.Debugln(f, "Handling ignored file", file)
 			dbUpdateChan <- dbUpdateJob{file, dbUpdateInvalidate}
 
-		case runtime.GOOS == "windows" && fs.WindowsInvalidFilename(file.Name) != nil:
+		case build.IsWindows && fs.WindowsInvalidFilename(file.Name) != nil:
 			if file.IsDeleted() {
 				// Just pretend we deleted it, no reason to create an error
 				// about a deleted file that we can't have anyway.
@@ -394,7 +394,7 @@ func (f *sendReceiveFolder) processNeeded(snap *db.Snapshot, dbUpdateChan chan<-
 				f.queue.Push(file.Name, file.Size, file.ModTime())
 			}
 
-		case runtime.GOOS == "windows" && file.IsSymlink():
+		case build.IsWindows && file.IsSymlink():
 			if err := f.handleSymlinkCheckExisting(file, snap, scanChan); err != nil {
 				f.newPullError(file.Name, fmt.Errorf("handling unsupported symlink: %w", err))
 				break
@@ -2115,7 +2115,7 @@ func (f *sendReceiveFolder) maybeAdjustOwnership(file *protocol.FileInfo, name s
 }
 
 func (f *sendReceiveFolder) copyOwnershipFromParent(path string) error {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		// Can't do anything.
 		return nil
 	}

lib/model/folder_sendrecv_test.go

@@ -15,12 +15,12 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strconv"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/events"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/ignore"
@@ -205,7 +205,7 @@ func TestHandleFileWithTemp(t *testing.T) {
 
 func TestCopierFinder(t *testing.T) {
 	methods := []fs.CopyRangeMethod{fs.CopyRangeMethodStandard, fs.CopyRangeMethodAllWithFallback}
-	if runtime.GOOS == "linux" {
+	if build.IsLinux {
 		methods = append(methods, fs.CopyRangeMethodSendFile)
 	}
 	for _, method := range methods {
@@ -789,7 +789,7 @@ func TestCopyOwner(t *testing.T) {
 	// Verifies that owner and group are copied from the parent, for both
 	// files and directories.
 
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("copying owner not supported on Windows")
 	}
 
@@ -986,7 +986,7 @@ func TestDeleteBehindSymlink(t *testing.T) {
 	must(t, ffs.RemoveAll(link))
 
 	if err := fs.DebugSymlinkForTestsOnly(destFs, ffs, "", link); err != nil {
-		if runtime.GOOS == "windows" {
+		if build.IsWindows {
 			// Probably we require permissions we don't have.
 			t.Skip("Need admin permissions or developer mode to run symlink test on Windows: " + err.Error())
 		} else {
@@ -1145,7 +1145,7 @@ func TestPullCaseOnlyDir(t *testing.T) {
 }
 
 func TestPullCaseOnlySymlink(t *testing.T) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("symlinks not supported on windows")
 	}
 	testPullCaseOnlyDirOrSymlink(t, false)
@@ -1275,7 +1275,7 @@ func TestPullCaseOnlyRename(t *testing.T) {
 }
 
 func TestPullSymlinkOverExistingWindows(t *testing.T) {
-	if runtime.GOOS != "windows" {
+	if !build.IsWindows {
 		t.Skip()
 	}
 

lib/model/folder_test.go

@@ -8,11 +8,11 @@ package model
 
 import (
 	"path/filepath"
-	"runtime"
 	"testing"
 
 	"github.com/d4l3k/messagediff"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 )
 
@@ -96,7 +96,7 @@ func unifySubsCases() []unifySubsCase {
 		},
 	}
 
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		// Fixup path separators
 		for i := range cases {
 			for j, p := range cases[i].in {

lib/model/model.go

@@ -27,6 +27,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/thejerf/suture/v4"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/connections"
 	"github.com/syncthing/syncthing/lib/db"
@@ -2399,7 +2400,7 @@ func (m *model) numHashers(folder string) int {
 		return folderCfg.Hashers
 	}
 
-	if runtime.GOOS == "windows" || runtime.GOOS == "darwin" || runtime.GOOS == "android" {
+	if build.IsWindows || build.IsDarwin || build.IsAndroid {
 		// Interactive operating systems; don't load the system too heavily by
 		// default.
 		return 1

lib/model/model_test.go

@@ -15,7 +15,6 @@ import (
 	"math/rand"
 	"os"
 	"path/filepath"
-	"runtime"
 	"runtime/pprof"
 	"sort"
 	"strconv"
@@ -26,6 +25,7 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/db/backend"
@@ -1463,7 +1463,7 @@ func changeIgnores(t *testing.T, m *testModel, expected []string) {
 		t.Errorf("Incorrect ignores: %v != %v", ignores2, ignores)
 	}
 
-	if runtime.GOOS == "darwin" {
+	if build.IsDarwin {
 		// see above
 		time.Sleep(time.Second)
 	} else {
@@ -2130,7 +2130,7 @@ func TestIssue4357(t *testing.T) {
 func TestIssue2782(t *testing.T) {
 	// CheckHealth should accept a symlinked folder, when using tilde-expanded path.
 
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("not reliable on Windows")
 		return
 	}
@@ -2471,7 +2471,7 @@ func TestNoRequestsFromPausedDevices(t *testing.T) {
 
 // TestIssue2571 tests replacing a directory with content with a symlink
 func TestIssue2571(t *testing.T) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("Scanning symlinks isn't supported on windows")
 	}
 
@@ -2510,7 +2510,7 @@ func TestIssue2571(t *testing.T) {
 
 // TestIssue4573 tests that contents of an unavailable dir aren't marked deleted
 func TestIssue4573(t *testing.T) {
-	if runtime.GOOS == "windows" {
+	if build.IsWindows {
 		t.Skip("Can't make the dir inaccessible on windows")
 	}
 
@@ -2802,7 +2802,7 @@ func TestVersionRestore(t *testing.T) {
 		"dir/file.txt",
 		"dir/existing.txt",
 	} {
-		if runtime.GOOS == "windows" {
+		if build.IsWindows {
 			file = filepath.FromSlash(file)
 		}
 		dir := filepath.Dir(file)
@@ -2886,7 +2886,7 @@ func TestVersionRestore(t *testing.T) {
 
 	// Check that content of files matches to the version they've been restored.
 	for file, version := range restore {
-		if runtime.GOOS == "windows" {
+		if build.IsWindows {
 			file = filepath.FromSlash(