add debug option to SystemSettings. and error page shows stacktrace only for admin or debug settings.

src/main/scala/gitbucket/core/controller/SystemSettingsController.scala

@@ -62,8 +62,9 @@ trait SystemSettingsControllerBase extends AccountManagementControllerBase {
         "mailAttribute"            -> trim(label("Mail address attribute", optional(text()))),
         "tls"                      -> trim(label("Enable TLS", optional(boolean()))),
         "ssl"                      -> trim(label("Enable SSL", optional(boolean()))),
-        "keystore"                 -> trim(label("Keystore", optional(text())))
-    )(Ldap.apply))
+        "keystore"                 -> trim(label("Keystore", optional(text()))),
+    )(Ldap.apply)),
+    "debug" -> trim(label("Debug", boolean()))
   )(SystemSettings.apply).verifying { settings =>
     Vector(
       if(settings.ssh && settings.baseUrl.isEmpty){

src/main/scala/gitbucket/core/service/SystemSettingsService.scala

@@ -54,6 +54,7 @@ trait SystemSettingsService {
           ldap.keystore.foreach(x => props.setProperty(LdapKeystore, x))
         }
       }
+      props.setProperty(Debug, settings.debug.toString)
       using(new java.io.FileOutputStream(GitBucketConf)){ out =>
         props.store(out, null)
       }
@@ -111,7 +112,8 @@ trait SystemSettingsService {
             getOptionValue(props, LdapKeystore, None)))
         } else {
           None
-        }
+        },
+        getValue(props, Debug, false)
       )
     }
   }
@@ -136,7 +138,8 @@ object SystemSettingsService {
     useSMTP: Boolean,
     smtp: Option[Smtp],
     ldapAuthentication: Boolean,
-    ldap: Option[Ldap]){
+    ldap: Option[Ldap],
+    debug: Boolean){
     def baseUrl(request: HttpServletRequest): String = baseUrl.fold(request.baseUrl)(_.stripSuffix("/"))
 
     def sshAddress:Option[SshAddress] =
@@ -219,6 +222,7 @@ object SystemSettingsService {
   private val LdapTls = "ldap.tls"
   private val LdapSsl = "ldap.ssl"
   private val LdapKeystore = "ldap.keystore"
+  private val Debug = "debug"
 
   private def getValue[A: ClassTag](props: java.util.Properties, key: String, default: A): A = {
     getSystemProperty(key).getOrElse(getEnvironmentVariable(key).getOrElse {

src/main/twirl/gitbucket/core/error.scala.html

@@ -3,6 +3,7 @@
   <div class="content-wrapper main-center">
     <div class="content body">
       <h1>@title</h1>
+      @if(context.loginAccount.map{_.isAdmin}.getOrElse(false) || context.settings.debug){
         @e.map { ex =>
           <h2>@ex.getMessage</h2>
           <table class="table table-condensed table-striped table-hover">
@@ -13,6 +14,9 @@
             </tbody>
           </table>
         }
+      } else {
+        <div>Please contact your administrator.</div>
+      }
     </div>
   </div>
 }

src/test/scala/gitbucket/core/view/AvatarImageProviderSpec.scala

@@ -118,7 +118,8 @@ class AvatarImageProviderSpec extends FunSpec with MockitoSugar {
       useSMTP                  = false,
       smtp                     = None,
       ldapAuthentication       = false,
-      ldap                     = None)
+      ldap                     = None,
+      debug                    = false)
 
   /**
    * Adapter to test AvatarImageProviderImpl.