Honor RESTIC_CACHE_DIR on Mac and Windows

changelog/unreleased/pull-2607

@@ -0,0 +1,7 @@
+Bugfix: Honor RESTIC_CACHE_DIR environment variable on Mac and Windows
+
+On Mac and Windows, the RESTIC_CACHE_DIR environment variable was ignored.
+This variable can now be used on all platforms to set the directory where
+restic stores caches.
+
+https://github.com/restic/restic/pull/2607

internal/cache/dir.go

@@ -1,75 +1,29 @@
 package cache
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
-	"runtime"
 
 	"github.com/pkg/errors"
 	"github.com/restic/restic/internal/debug"
 	"github.com/restic/restic/internal/fs"
 )
 
-// xdgCacheDir returns the cache directory according to XDG basedir spec, see
-// http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
-// unless RESTIC_CACHE_DIR is defined
-func xdgCacheDir() (string, error) {
-	cachedir := os.Getenv("RESTIC_CACHE_DIR")
-	xdgcache := os.Getenv("XDG_CACHE_HOME")
-	home := os.Getenv("HOME")
-
+// DefaultDir returns $RESTIC_CACHE_DIR, or the default cache directory
+// for the current OS if that variable is not set.
+func DefaultDir() (cachedir string, err error) {
+	cachedir = os.Getenv("RESTIC_CACHE_DIR")
 	if cachedir != "" {
 		return cachedir, nil
-	} else if xdgcache != "" {
-		return filepath.Join(xdgcache, "restic"), nil
-	} else if home != "" {
-		return filepath.Join(home, ".cache", "restic"), nil
-	}
-
-	return "", errors.New("unable to locate cache directory (RESTIC_CACHE_DIR, XDG_CACHE_HOME and HOME unset)")
-}
-
-// windowsCacheDir returns the cache directory for Windows.
-//
-// Uses LOCALAPPDATA, where application data not synchronized between machines
-// is stored. (Browser caches stored here).
-func windowsCacheDir() (string, error) {
-	appdata := os.Getenv("LOCALAPPDATA")
-	if appdata == "" {
-		return "", errors.New("unable to locate cache directory (LOCALAPPDATA unset)")
-	}
-	return filepath.Join(appdata, "restic"), nil
-}
-
-// darwinCacheDir returns the cache directory for darwin.
-//
-// Uses ~/Library/Caches/, which is recommended by Apple, see
-// https://developer.apple.com/library/content/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/MacOSXDirectories/MacOSXDirectories.html
-func darwinCacheDir() (string, error) {
-	home := os.Getenv("HOME")
-	if home == "" {
-		return "", errors.New("unable to locate cache directory (HOME unset)")
-	}
-	return filepath.Join(home, "Library", "Caches", "restic"), nil
-}
-
-// DefaultDir returns the default cache directory for the current OS.
-func DefaultDir() (cachedir string, err error) {
-	switch runtime.GOOS {
-	case "darwin":
-		cachedir, err = darwinCacheDir()
-	case "windows":
-		cachedir, err = windowsCacheDir()
-	default:
-		// Default to XDG for Linux and any other OSes.
-		cachedir, err = xdgCacheDir()
 	}
 
+	cachedir, err = os.UserCacheDir()
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("unable to locate cache directory: %v", err)
 	}
 
-	return cachedir, nil
+	return filepath.Join(cachedir, "restic"), nil
 }
 
 // mkdirCacheDir ensures that the cache directory exists. It it didn't, created

internal/cache/dir_test.go

@@ -0,0 +1,26 @@
+package cache
+
+import (
+	"os"
+	"testing"
+
+	rtest "github.com/restic/restic/internal/test"
+)
+
+// DefaultDir should honor RESTIC_CACHE_DIR on all platforms.
+func TestCacheDirEnv(t *testing.T) {
+	cachedir := os.Getenv("RESTIC_CACHE_DIR")
+
+	if cachedir == "" {
+		cachedir = "/doesnt/exist"
+		err := os.Setenv("RESTIC_CACHE_DIR", cachedir)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer os.Unsetenv("RESTIC_CACHE_DIR")
+	}
+
+	dir, err := DefaultDir()
+	rtest.Equals(t, cachedir, dir)
+	rtest.OK(t, err)
+}