Strip whitespace around GitHub personal access tokens

Some browsers insert a trailing whitespace after pasting the
token into the field. This should help reduce confusion.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/46588

app/controllers/import/github_controller.rb

@@ -20,7 +20,7 @@ class Import::GithubController < Import::BaseController
   end
 
   def personal_access_token
-    session[access_token_key] = params[:personal_access_token]
+    session[access_token_key] = params[:personal_access_token]&.strip
     redirect_to status_import_url
   end
 

changelogs/unreleased/sh-strip-github-pat-whitespace.yml

+---
+title: Strip whitespace around GitHub personal access tokens
+merge_request: 22432
+author:
+type: fixed

spec/support/controllers/githubish_import_controller_shared_examples.rb

@@ -22,6 +22,18 @@ shared_examples 'a GitHub-ish import controller: POST personal_access_token' do
     expect(session[:"#{provider}_access_token"]).to eq(token)
     expect(controller).to redirect_to(status_import_url)
   end
+
+  it "strips access token with spaces" do
+    token = 'asdfasdf9876'
+
+    allow_any_instance_of(Gitlab::LegacyGithubImport::Client)
+      .to receive(:user).and_return(true)
+
+    post :personal_access_token, personal_access_token: "  #{token} "
+
+    expect(session[:"#{provider}_access_token"]).to eq(token)
+    expect(controller).to redirect_to(status_import_url)
+  end
 end
 
 shared_examples 'a GitHub-ish import controller: GET new' do