feat(linear): Support refresh tokens and migrate legacy OAuth tokens (#13721)

Linear is deprecating long-lived OAuth2 access tokens (valid for 10
years) in favor of short-lived access tokens with refresh tokens.
Starting October 1, 2025, all new OAuth2 apps will default to refresh
tokens. Linear will no longer issue long-lived access tokens. Please
read more details
[here](https://linear.app/developers/oauth-2-0-authentication#migrate-to-using-refresh-tokens)
We currently use long-lived tokens in our Linear integration (valid for
up to 10 years). To remain compatible, this PR ensures compatibility by
supporting refresh-token-based auth and migrating existing legacy
tokens.

Fixes
https://linear.app/chatwoot/issue/CW-5541/migrate-linear-oauth2-integration-to-support-refresh-tokens

app/controllers/api/v1/accounts/integrations/linear_controller.rb

@@ -126,7 +126,7 @@ class Api::V1::Accounts::Integrations::LinearController < Api::V1::Accounts::Bas
     return unless @hook&.access_token
 
     begin
-      linear_client = Linear.new(@hook.access_token)
+      linear_client = Linear.new(@hook.access_token, refresh_token: @hook.settings&.[]('refresh_token'))
       linear_client.revoke_token
     rescue StandardError => e
       Rails.logger.error "Failed to revoke Linear token: #{e.message}"

app/controllers/linear/callbacks_controller.rb

@@ -2,6 +2,8 @@ class Linear::CallbacksController < ApplicationController
   include Linear::IntegrationHelper
 
   def show
+    return redirect_to(safe_linear_redirect_uri) if params[:code].blank? || account_id.blank?
+
     @response = oauth_client.auth_code.get_token(
       params[:code],
       redirect_uri: "#{base_url}/linear/callback"
@@ -10,7 +12,7 @@ class Linear::CallbacksController < ApplicationController
     handle_response
   rescue StandardError => e
     Rails.logger.error("Linear callback error: #{e.message}")
-    redirect_to linear_redirect_uri
+    redirect_to safe_linear_redirect_uri
   end
 
   private
@@ -31,22 +33,19 @@ class Linear::CallbacksController < ApplicationController
   end
 
   def handle_response
-    hook = account.hooks.new(
+    raise ArgumentError, 'Missing access token in Linear OAuth response' if parsed_body['access_token'].blank?
+
+    hook = account.hooks.find_or_initialize_by(app_id: 'linear')
+    hook.assign_attributes(
       access_token: parsed_body['access_token'],
       status: 'enabled',
-      app_id: 'linear',
-      settings: {
-        token_type: parsed_body['token_type'],
-        expires_in: parsed_body['expires_in'],
-        scope: parsed_body['scope']
-      }
+      settings: merged_integration_settings(hook.settings)
     )
-    # You may wonder why we're not handling the refresh token update, since the token will expire only after 10 years, https://github.com/linear/linear/issues/251
     hook.save!
     redirect_to linear_redirect_uri
   rescue StandardError => e
     Rails.logger.error("Linear callback error: #{e.message}")
-    redirect_to linear_redirect_uri
+    redirect_to safe_linear_redirect_uri
   end
 
   def account
@@ -54,19 +53,47 @@ class Linear::CallbacksController < ApplicationController
   end
 
   def account_id
-    return unless params[:state]
+    return @account_id if instance_variable_defined?(:@account_id)
 
-    verify_linear_token(params[:state])
+    @account_id = params[:state].present? ? verify_linear_token(params[:state]) : nil
   end
 
   def linear_redirect_uri
     "#{ENV.fetch('FRONTEND_URL', nil)}/app/accounts/#{account.id}/settings/integrations/linear"
   end
 
+  def safe_linear_redirect_uri
+    return base_url if account_id.blank?
+
+    linear_redirect_uri
+  rescue StandardError
+    base_url
+  end
+
   def parsed_body
     @parsed_body ||= @response.response.parsed
   end
 
+  def integration_settings
+    {
+      token_type: parsed_body['token_type'],
+      expires_in: parsed_body['expires_in'],
+      expires_on: expires_on,
+      scope: parsed_body['scope'],
+      refresh_token: parsed_body['refresh_token']
+    }.compact
+  end
+
+  def merged_integration_settings(existing_settings)
+    existing_settings.to_h.with_indifferent_access.merge(integration_settings)
+  end
+
+  def expires_on
+    return if parsed_body['expires_in'].blank?
+
+    (Time.current.utc + parsed_body['expires_in'].to_i.seconds).to_s
+  end
+
   def base_url
     ENV.fetch('FRONTEND_URL', 'http://localhost:3000')
   end

lib/integrations/linear/access_token_service.rb

@@ -0,0 +1,121 @@
+class Integrations::Linear::AccessTokenService
+  TOKEN_URL = 'https://api.linear.app/oauth/token'.freeze
+  MIGRATE_OLD_TOKEN_URL = 'https://api.linear.app/oauth/migrate_old_token'.freeze
+  TOKEN_EXPIRY_BUFFER = 1.minute
+
+  pattr_initialize [:hook!]
+
+  def access_token
+    return hook.access_token if token_valid?
+    return refresh_access_token if refresh_token.present?
+    return migrate_legacy_token if migration_applicable?
+
+    hook.access_token
+  end
+
+  private
+
+  def refresh_access_token
+    response = HTTParty.post(
+      TOKEN_URL,
+      headers: url_encoded_headers,
+      body: {
+        grant_type: 'refresh_token',
+        refresh_token: refresh_token,
+        client_id: client_id,
+        client_secret: client_secret
+      }
+    )
+
+    return fallback_access_token unless response.success?
+
+    persist_tokens(response.parsed_response)
+    hook.access_token
+  rescue StandardError => e
+    Rails.logger.error("Linear token refresh failed for hook #{hook.id}: #{e.message}")
+    fallback_access_token
+  end
+
+  def migrate_legacy_token
+    response = HTTParty.post(
+      MIGRATE_OLD_TOKEN_URL,
+      headers: url_encoded_headers,
+      body: {
+        access_token: hook.access_token,
+        client_id: client_id,
+        client_secret: client_secret
+      }
+    )
+
+    return fallback_access_token unless response.success?
+
+    persist_tokens(response.parsed_response)
+    hook.access_token
+  rescue StandardError => e
+    Rails.logger.error("Linear legacy token migration failed for hook #{hook.id}: #{e.message}")
+    fallback_access_token
+  end
+
+  def persist_tokens(token_data)
+    raise ArgumentError, 'Missing access token in Linear token response' if token_data['access_token'].blank?
+
+    current_settings = hook_settings
+    updated_settings = current_settings.merge(
+      token_type: token_data['token_type'] || current_settings[:token_type],
+      expires_in: token_data['expires_in'] || current_settings[:expires_in],
+      expires_on: expires_on(token_data['expires_in']),
+      scope: token_data['scope'] || current_settings[:scope],
+      refresh_token: token_data['refresh_token'] || current_settings[:refresh_token]
+    ).compact
+
+    hook.update!(
+      access_token: token_data['access_token'],
+      settings: updated_settings
+    )
+  end
+
+  def token_valid?
+    expiry = hook_settings[:expires_on]
+    return false if expiry.blank?
+
+    Time.zone.parse(expiry).utc > (Time.current.utc + TOKEN_EXPIRY_BUFFER)
+  rescue StandardError
+    false
+  end
+
+  def migration_applicable?
+    hook_settings[:token_type].present?
+  end
+
+  def refresh_token
+    hook_settings[:refresh_token]
+  end
+
+  def hook_settings
+    hook.settings.to_h.with_indifferent_access
+  end
+
+  def expires_on(expires_in)
+    return hook_settings[:expires_on] if expires_in.blank?
+
+    (Time.current.utc + expires_in.to_i.seconds).to_s
+  end
+
+  def url_encoded_headers
+    { 'Content-Type' => 'application/x-www-form-urlencoded' }
+  end
+
+  def client_id
+    GlobalConfigService.load('LINEAR_CLIENT_ID', nil)
+  end
+
+  def client_secret
+    GlobalConfigService.load('LINEAR_CLIENT_SECRET', nil)
+  end
+
+  def fallback_access_token
+    hook.reload.access_token
+  rescue StandardError
+    hook.access_token
+  end
+end

lib/integrations/linear/processor_service.rb

@@ -77,6 +77,10 @@ class Integrations::Linear::ProcessorService
   end
 
   def linear_client
-    @linear_client ||= Linear.new(linear_hook.access_token)
+    @linear_client ||= Linear.new(linear_access_token)
+  end
+
+  def linear_access_token
+    @linear_access_token ||= Integrations::Linear::AccessTokenService.new(hook: linear_hook).access_token
   end
 end

lib/linear.rb

@@ -3,8 +3,9 @@ class Linear
   REVOKE_URL = 'https://api.linear.app/oauth/revoke'.freeze
   PRIORITY_LEVELS = (0..4).to_a
 
-  def initialize(access_token)
+  def initialize(access_token, refresh_token: nil)
     @access_token = access_token
+    @refresh_token = refresh_token
     raise ArgumentError, 'Missing Credentials' if access_token.blank?
   end
 
@@ -79,9 +80,13 @@ class Linear
   end
 
   def revoke_token
+    token = @refresh_token.presence || @access_token
+    token_type_hint = @refresh_token.present? ? 'refresh_token' : 'access_token'
+
     response = HTTParty.post(
       REVOKE_URL,
-      headers: { 'Authorization' => "Bearer #{@access_token}", 'Content-Type' => 'application/json' }
+      headers: { 'Content-Type' => 'application/x-www-form-urlencoded' },
+      body: { token: token, token_type_hint: token_type_hint }
     )
     response.success?
   end

spec/controllers/linear/callbacks_controller_spec.rb

@@ -9,9 +9,11 @@ RSpec.describe Linear::CallbacksController, type: :request do
 
   describe 'GET /linear/callback' do
     let(:access_token) { SecureRandom.hex(10) }
+    let(:refresh_token) { SecureRandom.hex(10) }
     let(:response_body) do
       {
         'access_token' => access_token,
+        'refresh_token' => refresh_token,
         'token_type' => 'Bearer',
         'expires_in' => 7200,
         'scope' => 'read,write'
@@ -35,7 +37,7 @@ RSpec.describe Linear::CallbacksController, type: :request do
           )
       end
 
-      it 'creates a new integration hook' do
+      it 'creates a new integration hook', :aggregate_failures do
         expect do
           get linear_callback_path, params: { code: code, state: state }
         end.to change(Integrations::Hook, :count).by(1)
@@ -44,11 +46,11 @@ RSpec.describe Linear::CallbacksController, type: :request do
         expect(hook.access_token).to eq(access_token)
         expect(hook.app_id).to eq('linear')
         expect(hook.status).to eq('enabled')
-        expect(hook.settings).to eq(
-          'token_type' => 'Bearer',
-          'expires_in' => 7200,
-          'scope' => 'read,write'
-        )
+        expect(hook.settings['token_type']).to eq('Bearer')
+        expect(hook.settings['expires_in']).to eq(7200)
+        expect(hook.settings['scope']).to eq('read,write')
+        expect(hook.settings['refresh_token']).to eq(refresh_token)
+        expect(hook.settings['expires_on']).to be_present
         expect(response).to redirect_to(linear_redirect_uri)
       end
     end
@@ -69,6 +71,106 @@ RSpec.describe Linear::CallbacksController, type: :request do
       end
     end
 
+    context 'when state is missing' do
+      it 'redirects to frontend root' do
+        get linear_callback_path, params: { code: code }
+        expect(response).to redirect_to('http://www.example.com')
+      end
+    end
+
+    context 'when state is invalid' do
+      it 'redirects to frontend root' do
+        get linear_callback_path, params: { code: code, state: 'invalid-state' }
+        expect(response).to redirect_to('http://www.example.com')
+      end
+    end
+
+    context 'when hook exists and response omits refresh_token' do
+      let!(:existing_hook) do
+        create(
+          :integrations_hook,
+          :linear,
+          account: account,
+          settings: {
+            'refresh_token' => 'existing_refresh_token',
+            'token_type' => 'Bearer',
+            'scope' => 'read,write',
+            'expires_on' => 1.day.from_now.utc.to_s
+          }
+        )
+      end
+      let(:response_body) do
+        {
+          'access_token' => access_token,
+          'token_type' => 'Bearer',
+          'expires_in' => 7200,
+          'scope' => 'read,write'
+        }
+      end
+
+      before do
+        stub_request(:post, 'https://api.linear.app/oauth/token')
+          .to_return(
+            status: 200,
+            body: response_body.to_json,
+            headers: { 'Content-Type' => 'application/json' }
+          )
+      end
+
+      it 'preserves existing refresh token', :aggregate_failures do
+        get linear_callback_path, params: { code: code, state: state }
+
+        existing_hook.reload
+        expect(existing_hook.access_token).to eq(access_token)
+        expect(existing_hook.settings['refresh_token']).to eq('existing_refresh_token')
+      end
+    end
+
+    context 'when hook exists and response omits access_token' do
+      let!(:existing_hook) do
+        create(
+          :integrations_hook,
+          :linear,
+          account: account,
+          access_token: 'existing_access_token',
+          settings: {
+            'refresh_token' => 'existing_refresh_token',
+            'token_type' => 'Bearer',
+            'scope' => 'read,write',
+            'expires_on' => 1.day.from_now.utc.to_s
+          }
+        )
+      end
+      let(:response_body) do
+        {
+          'refresh_token' => refresh_token,
+          'token_type' => 'Bearer',
+          'expires_in' => 7200,
+          'scope' => 'read,write'
+        }
+      end
+
+      before do
+        stub_request(:post, 'https://api.linear.app/oauth/token')
+          .to_return(
+            status: 200,
+            body: response_body.to_json,
+            headers: { 'Content-Type' => 'application/json' }
+          )
+      end
+
+      it 'does not overwrite the existing hook', :aggregate_failures do
+        expect do
+          get linear_callback_path, params: { code: code, state: state }
+        end.not_to change(Integrations::Hook, :count)
+
+        existing_hook.reload
+        expect(existing_hook.access_token).to eq('existing_access_token')
+        expect(existing_hook.settings['refresh_token']).to eq('existing_refresh_token')
+        expect(response).to redirect_to(linear_redirect_uri)
+      end
+    end
+
     context 'when the token is invalid' do
       before do
         stub_request(:post, 'https://api.linear.app/oauth/token')

spec/lib/integrations/linear/access_token_service_spec.rb

@@ -0,0 +1,178 @@
+require 'rails_helper'
+
+describe Integrations::Linear::AccessTokenService do
+  let(:account) { create(:account) }
+  let(:client_id) { 'linear_client_id' }
+  let(:client_secret) { 'linear_client_secret' }
+
+  before do
+    allow(GlobalConfigService).to receive(:load).and_call_original
+    allow(GlobalConfigService).to receive(:load).with('LINEAR_CLIENT_ID', nil).and_return(client_id)
+    allow(GlobalConfigService).to receive(:load).with('LINEAR_CLIENT_SECRET', nil).and_return(client_secret)
+  end
+
+  describe '#access_token' do
+    context 'when access token is still valid' do
+      let(:hook) do
+        create(
+          :integrations_hook,
+          :linear,
+          account: account,
+          access_token: 'valid_access_token',
+          settings: {
+            refresh_token: 'refresh_token',
+            token_type: 'Bearer',
+            scope: 'read,write',
+            expires_on: 30.minutes.from_now.utc.to_s
+          }
+        )
+      end
+
+      it 'returns the current access token' do
+        stub_request(:post, 'https://api.linear.app/oauth/token')
+          .to_return(status: 200, body: {}.to_json, headers: { 'Content-Type' => 'application/json' })
+        stub_request(:post, 'https://api.linear.app/oauth/migrate_old_token')
+          .to_return(status: 200, body: {}.to_json, headers: { 'Content-Type' => 'application/json' })
+
+        service = described_class.new(hook: hook)
+
+        expect(service.access_token).to eq('valid_access_token')
+        expect(WebMock).not_to have_requested(:post, 'https://api.linear.app/oauth/token')
+        expect(WebMock).not_to have_requested(:post, 'https://api.linear.app/oauth/migrate_old_token')
+      end
+    end
+
+    context 'when access token is expired and refresh token is present' do
+      let(:hook) do
+        create(
+          :integrations_hook,
+          :linear,
+          account: account,
+          access_token: 'expired_access_token',
+          settings: {
+            refresh_token: 'old_refresh_token',
+            token_type: 'Bearer',
+            scope: 'read,write',
+            expires_on: 1.hour.ago.utc.to_s
+          }
+        )
+      end
+
+      it 'refreshes the token and persists new values' do
+        stub_request(:post, 'https://api.linear.app/oauth/token')
+          .to_return(
+            status: 200,
+            body: {
+              access_token: 'new_access_token',
+              refresh_token: 'new_refresh_token',
+              token_type: 'Bearer',
+              expires_in: 7200,
+              scope: 'read,write'
+            }.to_json,
+            headers: { 'Content-Type' => 'application/json' }
+          )
+
+        service = described_class.new(hook: hook)
+
+        expect(service.access_token).to eq('new_access_token')
+        hook.reload
+        expect(hook.access_token).to eq('new_access_token')
+        expect(hook.settings['refresh_token']).to eq('new_refresh_token')
+        expect(hook.settings['expires_in']).to eq(7200)
+        expect(hook.settings['expires_on']).to be_present
+      end
+
+      it 'falls back to latest persisted token on refresh failure' do
+        stub_request(:post, 'https://api.linear.app/oauth/token')
+          .to_return(status: 401, body: { error: 'invalid_grant' }.to_json, headers: { 'Content-Type' => 'application/json' })
+
+        Integrations::Hook.find(hook.id).update!(access_token: 'rotated_access_token')
+
+        service = described_class.new(hook: hook)
+
+        expect(service.access_token).to eq('rotated_access_token')
+      end
+
+      it 'does not overwrite the existing token on malformed success response' do
+        stub_request(:post, 'https://api.linear.app/oauth/token')
+          .to_return(
+            status: 200,
+            body: {
+              refresh_token: 'new_refresh_token',
+              token_type: 'Bearer',
+              expires_in: 7200,
+              scope: 'read,write'
+            }.to_json,
+            headers: { 'Content-Type' => 'application/json' }
+          )
+
+        service = described_class.new(hook: hook)
+
+        expect(service.access_token).to eq('expired_access_token')
+        hook.reload
+        expect(hook.access_token).to eq('expired_access_token')
+        expect(hook.settings['refresh_token']).to eq('old_refresh_token')
+      end
+    end
+
+    context 'when refresh token is missing and legacy migration is applicable' do
+      let(:hook) do
+        create(
+          :integrations_hook,
+          :linear,
+          account: account,
+          access_token: 'legacy_access_token',
+          settings: {
+            token_type: 'Bearer',
+            scope: 'read,write'
+          }
+        )
+      end
+
+      it 'migrates the legacy token and persists refresh token data' do
+        stub_request(:post, 'https://api.linear.app/oauth/migrate_old_token')
+          .to_return(
+            status: 200,
+            body: {
+              access_token: 'migrated_access_token',
+              refresh_token: 'migrated_refresh_token',
+              token_type: 'Bearer',
+              expires_in: 7200,
+              scope: 'read,write'
+            }.to_json,
+            headers: { 'Content-Type' => 'application/json' }
+          )
+
+        service = described_class.new(hook: hook)
+
+        expect(service.access_token).to eq('migrated_access_token')
+        hook.reload
+        expect(hook.access_token).to eq('migrated_access_token')
+        expect(hook.settings['refresh_token']).to eq('migrated_refresh_token')
+        expect(hook.settings['expires_in']).to eq(7200)
+        expect(hook.settings['expires_on']).to be_present
+      end
+
+      it 'does not overwrite the existing token on malformed migration success response' do
+        stub_request(:post, 'https://api.linear.app/oauth/migrate_old_token')
+          .to_return(
+            status: 200,
+            body: {
+              refresh_token: 'migrated_refresh_token',
+              token_type: 'Bearer',
+              expires_in: 7200,
+              scope: 'read,write'
+            }.to_json,
+            headers: { 'Content-Type' => 'application/json' }
+          )
+
+        service = described_class.new(hook: hook)
+
+        expect(service.access_token).to eq('legacy_access_token')
+        hook.reload
+        expect(hook.access_token).to eq('legacy_access_token')
+        expect(hook.settings['token_type']).to eq('Bearer')
+      end
+    end
+  end
+end

spec/lib/linear_spec.rb

@@ -2,7 +2,9 @@ require 'rails_helper'
 
 describe Linear do
   let(:access_token) { 'valid_access_token' }
+  let(:refresh_token) { 'valid_refresh_token' }
   let(:url) { 'https://api.linear.app/graphql' }
+  let(:revoke_url) { 'https://api.linear.app/oauth/revoke' }
   let(:linear_client) { described_class.new(access_token) }
   let(:headers) { { 'Content-Type' => 'application/json', 'Authorization' => "Bearer #{access_token}" } }
 
@@ -433,4 +435,30 @@ describe Linear do
       end
     end
   end
+
+  context 'when revoking a token' do
+    it 'uses the refresh token when present' do
+      client = described_class.new(access_token, refresh_token: refresh_token)
+
+      stub_request(:post, revoke_url)
+        .with(
+          headers: { 'Content-Type' => 'application/x-www-form-urlencoded' },
+          body: { token: refresh_token, token_type_hint: 'refresh_token' }
+        )
+        .to_return(status: 200, body: '', headers: {})
+
+      expect(client.revoke_token).to be(true)
+    end
+
+    it 'falls back to the access token when refresh token is absent' do
+      stub_request(:post, revoke_url)
+        .with(
+          headers: { 'Content-Type' => 'application/x-www-form-urlencoded' },
+          body: { token: access_token, token_type_hint: 'access_token' }
+        )
+        .to_return(status: 200, body: '', headers: {})
+
+      expect(linear_client.revoke_token).to be(true)
+    end
+  end
 end