Fix various segfaults when running `go test` manually (#8448)

* failing to find i18n shouldn't segfault

The server was trying to handle the fact that it couldn't find the i18n
directory, by emitting a translated log message...

* fix utils.FindDir

The attempts to find the directory in the parent or grandparent directory
don't work if the current working directory was inside `enterprise`, with
`enterprise` itself being a symlink as per the usual developer setup.

Recurse to the root of the filesystem, cleaning the path along the way
to work around this limitation (and allow tests to be run from an
arbitrarily deep nesting level.)

Fix corresponding usages to employ filepath.Join.

* failing to find html templates shouldn't segfault

* fail fast if the test user cannot be created

* rework utils.FindDir to retain backwards compatibility

15 files changed, 60 insertions, 41 deletions

diff --git a/api/file_test.go b/api/file_test.go
index 8e5fc6f67..7a04674cd 100644
--- a/api/file_test.go
+++ b/api/file_test.go
@@ -10,6 +10,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 	"time"
@@ -870,7 +871,7 @@ func TestGetInfoForFilename(t *testing.T) {
 
 func readTestFile(name string) ([]byte, error) {
 	path, _ := utils.FindDir("tests")
-	file, err := os.Open(path + "/" + name)
+	file, err := os.Open(filepath.Join(path, name))
 	if err != nil {
 		return nil, err
 	}
diff --git a/api/user_test.go b/api/user_test.go
index f65d7c45b..518379305 100644
--- a/api/user_test.go
+++ b/api/user_test.go
@@ -12,6 +12,7 @@ import (
 	"mime/multipart"
 	"net/http"
 	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 	"time"
@@ -778,7 +779,7 @@ func TestUserUploadProfileImage(t *testing.T) {
 		}
 
 		path, _ := utils.FindDir("tests")
-		file, err := os.Open(path + "/test.png")
+		file, err := os.Open(filepath.Join(path, "test.png"))
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/api4/apitestlib.go b/api4/apitestlib.go
index 6edd37812..386afdadd 100644
--- a/api4/apitestlib.go
+++ b/api4/apitestlib.go
@@ -11,6 +11,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"path/filepath"
 	"reflect"
 	"strconv"
 	"strings"
@@ -302,7 +303,11 @@ func (me *TestHelper) CreateUserWithClient(client *model.Client4) *model.User {
 	}
 
 	utils.DisableDebugLogForTest()
-	ruser, _ := client.CreateUser(user)
+	ruser, response := client.CreateUser(user)
+	if response.Error != nil {
+		panic(response.Error)
+	}
+
 	ruser.Password = "Password1"
 	store.Must(me.App.Srv.Store.User().VerifyEmail(ruser.Id))
 	utils.EnableDebugLogForTest()
@@ -675,7 +680,7 @@ func CheckInternalErrorStatus(t *testing.T, resp *model.Response) {
 
 func readTestFile(name string) ([]byte, error) {
 	path, _ := utils.FindDir("tests")
-	file, err := os.Open(path + "/" + name)
+	file, err := os.Open(filepath.Join(path, name))
 	if err != nil {
 		return nil, err
 	}
diff --git a/api4/oauth.go b/api4/oauth.go
index d0f43256a..a173159b6 100644
--- a/api4/oauth.go
+++ b/api4/oauth.go
@@ -6,6 +6,7 @@ package api4
 import (
 	"net/http"
 	"net/url"
+	"path/filepath"
 	"strings"
 
 	l4g "github.com/alecthomas/log4go"
@@ -375,7 +376,7 @@ func authorizeOAuthPage(c *Context, w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Cache-Control", "no-cache, max-age=31556926, public")
 
 	staticDir, _ := utils.FindDir(model.CLIENT_DIR)
-	http.ServeFile(w, r, staticDir+"root.html")
+	http.ServeFile(w, r, filepath.Join(staticDir, "root.html"))
 }
 
 func getAccessToken(c *Context, w http.ResponseWriter, r *http.Request) {
diff --git a/api4/plugin_test.go b/api4/plugin_test.go
index e385b5c8c..045ae9212 100644
--- a/api4/plugin_test.go
+++ b/api4/plugin_test.go
@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/mattermost/mattermost-server/model"
@@ -53,7 +54,7 @@ func TestPlugin(t *testing.T) {
 	}()
 
 	path, _ := utils.FindDir("tests")
-	file, err := os.Open(path + "/testplugin.tar.gz")
+	file, err := os.Open(filepath.Join(path, "testplugin.tar.gz"))
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/app/app.go b/app/app.go
index f5e5dd21e..48e95fb99 100644
--- a/app/app.go
+++ b/app/app.go
@@ -439,7 +439,11 @@ func (a *App) WaitForGoroutines() {
 }
 
 func (a *App) HTMLTemplates() *template.Template {
-	return a.htmlTemplateWatcher.Templates()
+	if a.htmlTemplateWatcher != nil {
+		return a.htmlTemplateWatcher.Templates()
+	}
+
+	return nil
 }
 
 func (a *App) HTTPClient(trustURLs bool) *http.Client {
diff --git a/app/auto_posts.go b/app/auto_posts.go
index 379c74ab7..a2adb9d6c 100644
--- a/app/auto_posts.go
+++ b/app/auto_posts.go
@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"io"
 	"os"
+	"path/filepath"
 
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/utils"
@@ -43,7 +44,7 @@ func (cfg *AutoPostCreator) UploadTestFile() ([]string, bool) {
 	filename := cfg.ImageFilenames[utils.RandIntFromRange(utils.Range{Begin: 0, End: len(cfg.ImageFilenames) - 1})]
 
 	path, _ := utils.FindDir("web/static/images")
-	file, err := os.Open(path + "/" + filename)
+	file, err := os.Open(filepath.Join(path, filename))
 	if err != nil {
 		return nil, false
 	}
diff --git a/app/import_test.go b/app/import_test.go
index 6a284f63d..f294c8731 100644
--- a/app/import_test.go
+++ b/app/import_test.go
@@ -4,6 +4,7 @@
 package app
 
 import (
+	"path/filepath"
 	"runtime/debug"
 	"strings"
 	"testing"
@@ -370,7 +371,7 @@ func TestImportValidateUserImportData(t *testing.T) {
 	// Test a valid User with all fields populated.
 	testsDir, _ := utils.FindDir("tests")
 	data = UserImportData{
-		ProfileImage: ptrStr(testsDir + "test.png"),
+		ProfileImage: ptrStr(filepath.Join(testsDir, "test.png")),
 		Username:     ptrStr("bob"),
 		Email:        ptrStr("bob@example.com"),
 		AuthService:  ptrStr("ldap"),
@@ -1487,7 +1488,7 @@ func TestImportImportUser(t *testing.T) {
 	username := model.NewId()
 	testsDir, _ := utils.FindDir("tests")
 	data = UserImportData{
-		ProfileImage: ptrStr(testsDir + "test.png"),
+		ProfileImage: ptrStr(filepath.Join(testsDir, "test.png")),
 		Username:     &username,
 		Email:        ptrStr(model.NewId() + "@example.com"),
 		Nickname:     ptrStr(model.NewId()),
@@ -1543,7 +1544,7 @@ func TestImportImportUser(t *testing.T) {
 
 	// Alter all the fields of that user.
 	data.Email = ptrStr(model.NewId() + "@example.com")
-	data.ProfileImage = ptrStr(testsDir + "testgif.gif")
+	data.ProfileImage = ptrStr(filepath.Join(testsDir, "testgif.gif"))
 	data.AuthService = ptrStr("ldap")
 	data.AuthData = &username
 	data.Nickname = ptrStr(model.NewId())
diff --git a/app/saml.go b/app/saml.go
index bd9f647a1..29d5f8772 100644
--- a/app/saml.go
+++ b/app/saml.go
@@ -8,7 +8,6 @@ import (
 	"mime/multipart"
 	"net/http"
 	"os"
-
 	"path/filepath"
 
 	"github.com/mattermost/mattermost-server/model"
@@ -42,7 +41,7 @@ func WriteSamlFile(fileData *multipart.FileHeader) *model.AppError {
 	defer file.Close()
 
 	configDir, _ := utils.FindDir("config")
-	out, err := os.Create(configDir + filename)
+	out, err := os.Create(filepath.Join(configDir, filename))
 	if err != nil {
 		return model.NewAppError("AddSamlCertificate", "api.admin.add_certificate.saving.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
diff --git a/app/user.go b/app/user.go
index 7a6dc0b49..8f393038a 100644
--- a/app/user.go
+++ b/app/user.go
@@ -18,6 +18,7 @@ import (
 	"io/ioutil"
 	"mime/multipart"
 	"net/http"
+	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -717,7 +718,7 @@ func CreateProfileImage(username string, userId string, initialFont string) ([]b
 	initial := string(strings.ToUpper(username)[0])
 
 	fontDir, _ := utils.FindDir("fonts")
-	fontBytes, err := ioutil.ReadFile(fontDir + initialFont)
+	fontBytes, err := ioutil.ReadFile(filepath.Join(fontDir, initialFont))
 	if err != nil {
 		return nil, model.NewAppError("CreateProfileImage", "api.user.create_profile_image.default_font.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
diff --git a/utils/config.go b/utils/config.go
index 93a870743..5e9849930 100644
--- a/utils/config.go
+++ b/utils/config.go
@@ -9,7 +9,6 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
-	"path"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -51,21 +50,17 @@ func FindConfigFile(fileName string) (path string) {
 	return ""
 }
 
+// FindDir looks for the given directory in nearby ancestors, falling back to `./` if not found.
 func FindDir(dir string) (string, bool) {
-	fileName := "."
-	found := false
-	if _, err := os.Stat("./" + dir + "/"); err == nil {
-		fileName, _ = filepath.Abs("./" + dir + "/")
-		found = true
-	} else if _, err := os.Stat("../" + dir + "/"); err == nil {
-		fileName, _ = filepath.Abs("../" + dir + "/")
-		found = true
-	} else if _, err := os.Stat("../../" + dir + "/"); err == nil {
-		fileName, _ = filepath.Abs("../../" + dir + "/")
-		found = true
+	for _, parent := range []string{".", "..", "../.."} {
+		foundDir, err := filepath.Abs(filepath.Join(parent, dir))
+		if err != nil {
+			continue
+		} else if _, err := os.Stat(foundDir); err == nil {
+			return foundDir, true
+		}
 	}
-
-	return fileName + "/", found
+	return "./", false
 }
 
 func DisableDebugLogForTest() {
@@ -136,11 +131,10 @@ func ConfigureLog(s *model.LogSettings) {
 
 func GetLogFileLocation(fileLocation string) string {
 	if fileLocation == "" {
-		logDir, _ := FindDir("logs")
-		return logDir + LOG_FILENAME
-	} else {
-		return path.Join(fileLocation, LOG_FILENAME)
+		fileLocation, _ = FindDir("logs")
 	}
+
+	return filepath.Join(fileLocation, LOG_FILENAME)
 }
 
 func SaveConfig(fileName string, config *model.Config) *model.AppError {
diff --git a/utils/html.go b/utils/html.go
index 6bbe55c6d..f9a7abe5b 100644
--- a/utils/html.go
+++ b/utils/html.go
@@ -5,8 +5,10 @@ package utils
 
 import (
 	"bytes"
+	"errors"
 	"html/template"
 	"io"
+	"path/filepath"
 	"reflect"
 	"sync/atomic"
 
@@ -39,7 +41,7 @@ func NewHTMLTemplateWatcher(directory string) (*HTMLTemplateWatcher, error) {
 		return nil, err
 	}
 
-	if htmlTemplates, err := template.ParseGlob(templatesDir + "*.html"); err != nil {
+	if htmlTemplates, err := template.ParseGlob(filepath.Join(templatesDir, "*.html")); err != nil {
 		return nil, err
 	} else {
 		ret.templates.Store(htmlTemplates)
@@ -56,7 +58,7 @@ func NewHTMLTemplateWatcher(directory string) (*HTMLTemplateWatcher, error) {
 			case event := <-watcher.Events:
 				if event.Op&fsnotify.Write == fsnotify.Write {
 					l4g.Info("Re-parsing templates because of modified file %v", event.Name)
-					if htmlTemplates, err := template.ParseGlob(templatesDir + "*.html"); err != nil {
+					if htmlTemplates, err := template.ParseGlob(filepath.Join(templatesDir, "*.html")); err != nil {
 						l4g.Error("Failed to parse templates %v", err)
 					} else {
 						ret.templates.Store(htmlTemplates)
@@ -103,6 +105,10 @@ func (t *HTMLTemplate) Render() string {
 }
 
 func (t *HTMLTemplate) RenderToWriter(w io.Writer) error {
+	if t.Templates == nil {
+		return errors.New("no html templates")
+	}
+
 	if err := t.Templates.ExecuteTemplate(w, t.TemplateName, t); err != nil {
 		l4g.Error(T("api.api.render.error"), t.TemplateName, err)
 		return err
diff --git a/utils/i18n.go b/utils/i18n.go
index 8ed82d19f..7b8d1fef0 100644
--- a/utils/i18n.go
+++ b/utils/i18n.go
@@ -23,13 +23,15 @@ var settings model.LocalizationSettings
 // this functions loads translations from filesystem
 // and assign english while loading server config
 func TranslationsPreInit() error {
+	// Set T even if we fail to load the translations. Lots of shutdown handling code will
+	// segfault trying to handle the error, and the untranslated IDs are strictly better.
+	T = TfuncWithFallback("en")
+	TDefault = TfuncWithFallback("en")
+
 	if err := InitTranslationsWithDir("i18n"); err != nil {
 		return err
 	}
 
-	T = TfuncWithFallback("en")
-	TDefault = TfuncWithFallback("en")
-
 	return nil
 }
 
@@ -51,9 +53,9 @@ func InitTranslationsWithDir(dir string) error {
 	for _, f := range files {
 		if filepath.Ext(f.Name()) == ".json" {
 			filename := f.Name()
-			locales[strings.Split(filename, ".")[0]] = i18nDirectory + filename
+			locales[strings.Split(filename, ".")[0]] = filepath.Join(i18nDirectory, filename)
 
-			if err := i18n.LoadTranslationFile(i18nDirectory + filename); err != nil {
+			if err := i18n.LoadTranslationFile(filepath.Join(i18nDirectory, filename)); err != nil {
 				return err
 			}
 		}
diff --git a/utils/license.go b/utils/license.go
index 2853a58d0..cf874b62b 100644
--- a/utils/license.go
+++ b/utils/license.go
@@ -12,6 +12,7 @@ import (
 	"encoding/pem"
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -114,7 +115,7 @@ func GetLicenseFileFromDisk(fileName string) []byte {
 func GetLicenseFileLocation(fileLocation string) string {
 	if fileLocation == "" {
 		configDir, _ := FindDir("config")
-		return configDir + "mattermost.mattermost-license"
+		return filepath.Join(configDir, "mattermost.mattermost-license")
 	} else {
 		return fileLocation
 	}
diff --git a/web/web.go b/web/web.go
index 22fe43923..c9d318397 100644
--- a/web/web.go
+++ b/web/web.go
@@ -5,6 +5,7 @@ package web
 
 import (
 	"net/http"
+	"path/filepath"
 	"strings"
 
 	"github.com/NYTimes/gziphandler"
@@ -102,5 +103,5 @@ func root(c *api.Context, w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Cache-Control", "no-cache, max-age=31556926, public")
 
 	staticDir, _ := utils.FindDir(model.CLIENT_DIR)
-	http.ServeFile(w, r, staticDir+"root.html")
+	http.ServeFile(w, r, filepath.Join(staticDir, "root.html"))
 }