i18n: look into core snaps when checking for translations (#2654)

i18n/i18n.go

@@ -29,6 +29,7 @@ import (
 
 	"github.com/ojii/gettext.go"
 
+	"github.com/snapcore/snapd/dirs"
 	"github.com/snapcore/snapd/osutil"
 )
 
@@ -45,24 +46,31 @@ func init() {
 	setLocale("")
 }
 
-func langpackResolver(root string, locale string, domain string) string {
-
+func langpackResolver(baseRoot string, locale string, domain string) string {
 	// first check for the real locale (e.g. de_DE)
 	// then try to simplify the locale (e.g. de_DE -> de)
 	locales := []string{locale, strings.SplitN(locale, "_", 2)[0]}
 	for _, locale := range locales {
 		r := filepath.Join(locale, "LC_MESSAGES", fmt.Sprintf("%s.mo", domain))
 
-		// ubuntu uses /usr/lib/locale-langpack and patches the glibc gettext
-		// implementation
-		langpack := filepath.Join(root, "..", "locale-langpack", r)
-		if osutil.FileExists(langpack) {
-			return langpack
+		// look into the core snaps first for translations,
+		// then the main system
+		candidateDirs := []string{
+			filepath.Join(dirs.SnapMountDir, "/core/current/", baseRoot),
+			baseRoot,
 		}
-
-		regular := filepath.Join(root, r)
-		if osutil.FileExists(regular) {
-			return regular
+		for _, root := range candidateDirs {
+			// ubuntu uses /usr/lib/locale-langpack and patches the glibc gettext
+			// implementation
+			langpack := filepath.Join(root, "..", "locale-langpack", r)
+			if osutil.FileExists(langpack) {
+				return langpack
+			}
+
+			regular := filepath.Join(root, r)
+			if osutil.FileExists(regular) {
+				return regular
+			}
 		}
 	}
 

i18n/i18n_test.go

@@ -27,6 +27,8 @@ import (
 	"testing"
 
 	. "gopkg.in/check.v1"
+
+	"github.com/snapcore/snapd/dirs"
 )
 
 // Hook up check.v1 into the "go test" runner
@@ -35,7 +37,7 @@ func Test(t *testing.T) { TestingT(t) }
 var mockLocalePo = []byte(`
 msgid ""
 msgstr ""
-"Project-Id-Version: snappy\n"
+"Project-Id-Version: snappy-test\n"
 "Report-Msgid-Bugs-To: snappy-devel@lists.ubuntu.com\n"
 "POT-Creation-Date: 2015-06-16 09:08+0200\n"
 "Language: en_DK\n"
@@ -127,3 +129,34 @@ func (s *i18nTestSuite) TestInvalidTextDomainDir(c *C) {
 	var Gtest = G
 	c.Assert(Gtest("singular"), Equals, "singular")
 }
+
+func (s *i18nTestSuite) TestLangpackResolverFromLangpack(c *C) {
+	root := c.MkDir()
+	localeDir := filepath.Join(root, "/usr/share/locale")
+	err := os.MkdirAll(localeDir, 0755)
+	c.Assert(err, IsNil)
+
+	d := filepath.Join(root, "/usr/share/locale-langpack")
+	makeMockTranslations(c, d)
+	bindTextDomain("snappy-test", localeDir)
+	setLocale("")
+
+	// no G() to avoid adding the test string to snappy-pot
+	var Gtest = G
+	c.Assert(Gtest("singular"), Equals, "translated singular", Commentf("test with %q failed", d))
+}
+
+func (s *i18nTestSuite) TestLangpackResolverFromCore(c *C) {
+	origSnapMountDir := dirs.SnapMountDir
+	defer func() { dirs.SnapMountDir = origSnapMountDir }()
+	dirs.SnapMountDir = c.MkDir()
+
+	d := filepath.Join(dirs.SnapMountDir, "/core/current/usr/share/locale")
+	makeMockTranslations(c, d)
+	bindTextDomain("snappy-test", "/usr/share/locale")
+	setLocale("")
+
+	// no G() to avoid adding the test string to snappy-pot
+	var Gtest = G
+	c.Assert(Gtest("singular"), Equals, "translated singular", Commentf("test with %q failed", d))
+}