5 files changed, 40 insertions, 5 deletions
diff --git a/app/controllers/concerns/confirm_email_warning.rb b/app/controllers/concerns/confirm_email_warning.rb
index ec5140bf223..2711c823275 100644
--- a/app/controllers/concerns/confirm_email_warning.rb
+++ b/app/controllers/concerns/confirm_email_warning.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 module ConfirmEmailWarning
+  include Gitlab::Utils::StrongMemoize
   extend ActiveSupport::Concern
 
   included do
@@ -17,11 +18,9 @@ module ConfirmEmailWarning
     return unless current_user
     return if current_user.confirmed?
 
-    email = current_user.unconfirmed_email || current_user.email
-
     flash.now[:warning] = format(
       confirm_warning_message,
-      email: email,
+      email: email_to_display,
       resend_link: view_context.link_to(_('Resend it'), user_confirmation_path(user: { email: email }), method: :post),
       update_link: view_context.link_to(_('Update it'), profile_path)
     ).html_safe
@@ -29,7 +28,16 @@ module ConfirmEmailWarning
 
   private
 
+  def email
+    current_user.unconfirmed_email || current_user.email
+  end
+  strong_memoize_attr :email
+
   def confirm_warning_message
     _("Please check your email (%{email}) to verify that you own this address and unlock the power of CI/CD. Didn't receive it? %{resend_link}. Wrong email address? %{update_link}.")
   end
+
+  def email_to_display
+    html_escape(email)
+  end
 end
diff --git a/app/controllers/projects/blob_controller.rb b/app/controllers/projects/blob_controller.rb
index 59cea00e26b..b71af82535a 100644
--- a/app/controllers/projects/blob_controller.rb
+++ b/app/controllers/projects/blob_controller.rb
@@ -31,6 +31,7 @@ class Projects::BlobController < Projects::ApplicationController
   before_action :authorize_edit_tree!, only: [:new, :create, :update, :destroy]
 
   before_action :commit, except: [:new, :create]
+  before_action :check_for_ambiguous_ref, only: [:show]
   before_action :blob, except: [:new, :create]
   before_action :require_branch_head, only: [:edit, :update]
   before_action :editor_variables, except: [:show, :preview, :diff]
@@ -145,6 +146,15 @@ class Projects::BlobController < Projects::ApplicationController
     end
   end
 
+  def check_for_ambiguous_ref
+    @ref_type = ref_type
+
+    if @ref_type == ExtractsRef::BRANCH_REF_TYPE && ambiguous_ref?(@project, @ref)
+      branch = @project.repository.find_branch(@ref)
+      redirect_to project_blob_path(@project, File.join(branch.target, @path))
+    end
+  end
+
   def commit
     @commit ||= @repository.commit(@ref)
 
diff --git a/app/controllers/projects/refs_controller.rb b/app/controllers/projects/refs_controller.rb
index 4c2bd2a9d42..f55fc2242a4 100644
--- a/app/controllers/projects/refs_controller.rb
+++ b/app/controllers/projects/refs_controller.rb
@@ -22,7 +22,7 @@ class Projects::RefsController < Projects::ApplicationController
           when "tree"
             project_tree_path(@project, @id)
           when "blob"
-            project_blob_path(@project, @id)
+            project_blob_path(@project, @id, ref_type: ref_type)
           when "graph"
             project_network_path(@project, @id, ref_type: ref_type)
           when "graphs"
diff --git a/app/controllers/projects/tree_controller.rb b/app/controllers/projects/tree_controller.rb
index 737a6290431..1f7912e15df 100644
--- a/app/controllers/projects/tree_controller.rb
+++ b/app/controllers/projects/tree_controller.rb
@@ -28,6 +28,15 @@ class Projects::TreeController < Projects::ApplicationController
   def show
     return render_404 unless @commit
 
+    @ref_type = ref_type
+    if @ref_type == BRANCH_REF_TYPE && ambiguous_ref?(@project, @ref)
+      branch = @project.repository.find_branch(@ref)
+      if branch
+        redirect_to project_tree_path(@project, branch.target)
+        return
+      end
+    end
+
     if tree.entries.empty?
       if @repository.blob_at(@commit.id, @path)
         redirect_to project_blob_path(@project, File.join(@ref, @path))
diff --git a/app/controllers/projects_controller.rb b/app/controllers/projects_controller.rb
index 71ad747b6b1..d71b782c62b 100644
--- a/app/controllers/projects_controller.rb
+++ b/app/controllers/projects_controller.rb
@@ -171,11 +171,19 @@ class ProjectsController < Projects::ApplicationController
       flash.now[:alert] = _("Project '%{project_name}' queued for deletion.") % { project_name: @project.name }
     end
 
+    if ambiguous_ref?(@project, @ref)
+      branch = @project.repository.find_branch(@ref)
+
+      # The files view would render a ref other than the default branch
+      # This redirect can be removed once the view is fixed
+      redirect_to(project_tree_path(@project, branch.target), alert: _("The default branch of this project clashes with another ref"))
+      return
+    end
+
     respond_to do |format|
       format.html do
         @notification_setting = current_user.notification_settings_for(@project) if current_user
         @project = @project.present(current_user: current_user)
-
         render_landing_page
       end