Adding update PR elements in azure PR updater

common/lib/dependabot/clients/azure.rb

@@ -184,6 +184,28 @@ def create_pull_request(pr_name, source_branch, target_branch,
           "/pullrequests?api-version=5.0", content.to_json)
       end
 
+      def update_pull_request(pull_request_id:, status: nil, pr_name: nil, description: nil,
+                              completion_options: nil, merge_options: nil,
+                              auto_complete_setby_user_id: nil, target_branch: nil)
+        content = {
+          autoCompleteSetBy: ({ id: auto_complete_setby_user_id } unless
+                  auto_complete_setby_user_id.nil? || auto_complete_setby_user_id.strip.empty?),
+          title: pr_name,
+          description: truncate_pr_description(description),
+          status: status,
+          completionOptions: completion_options,
+          mergeOptions: merge_options,
+          targetRefName: ("refs/heads/" + target_branch unless target_branch.nil? || target_branch.strip.empty?)
+        }.compact
+
+        return if content.empty?
+
+        patch(source.api_endpoint +
+          source.organization + "/" + source.project +
+          "/_apis/git/repositories/" + source.unscoped_repo +
+          "/pullrequests/" + pull_request_id.to_s + "?api-version=5.0", content.to_json)
+      end
+
       def pull_request(pull_request_id)
         response = get(source.api_endpoint +
           source.organization + "/" + source.project +
@@ -251,6 +273,26 @@ def post(url, json)
         response
       end
 
+      def patch(url, json)
+        response = Excon.patch(
+          url,
+          body: json,
+          user: credentials&.fetch("username", nil),
+          password: credentials&.fetch("password", nil),
+          idempotent: true,
+          **SharedHelpers.excon_defaults(
+            headers: auth_header.merge(
+              {
+                "Content-Type" => "application/json"
+              }
+            )
+          )
+        )
+        raise NotFound if response.status == 404
+
+        response
+      end
+
       private
 
       def retry_connection_failures
@@ -279,6 +321,8 @@ def auth_header_for(token)
       end
 
       def truncate_pr_description(pr_description)
+        return if pr_description.nil? || pr_description.empty?
+
         # Azure DevOps only support descriptions up to 4000 characters in UTF-16
         # encoding.
         # https://developercommunity.visualstudio.com/content/problem/608770/remove-4000-character-limit-on-pull-request-descri.html

common/lib/dependabot/pull_request_updater/azure.rb

@@ -27,6 +27,21 @@ def update
         update_source_branch
       end
 
+      def update_pr_elements(elements = {})
+        return unless elements
+
+        azure_client_for_source.update_pull_request(
+          pull_request_id: pull_request_number,
+          status: elements[:status],
+          pr_name: elements[:pr_name],
+          description: elements[:description],
+          completion_options: elements[:completion_options],
+          merge_options: elements[:merge_options],
+          auto_complete_setby_user_id: elements[:auto_complete_setby_user_id],
+          target_branch: elements[:target_branch]
+        )
+      end
+
       private
 
       def azure_client_for_source

common/spec/dependabot/clients/azure_spec.rb

@@ -210,6 +210,60 @@
     end
   end
 
+  describe "#update_pull_request" do
+    subject(:update_pull_request) do
+      client.update_pull_request(
+        pull_request_id: pull_request_id,
+        auto_complete_setby_user_id: auto_complete_setby_user_id,
+        pr_name: pr_name
+      )
+    end
+
+    let(:pull_request_id) { 1 }
+    let(:auto_complete_setby_user_id) { "id" }
+    let(:pr_name) { "Test PR" }
+    let(:update_pull_request_url) { repo_url + "/pullrequests/" + pull_request_id.to_s + "?api-version=5.0" }
+
+    it "returns nil when there are no parameters to update" do
+      response = client.update_pull_request(pull_request_id: pull_request_id)
+
+      expect(response).to be_nil
+    end
+
+    context "sends update PR request with updated parameter values" do
+      it "successfully updates the PR" do
+        stub_request(:patch, update_pull_request_url).
+          with(basic_auth: [username, password]).
+          to_return(status: 200)
+
+        update_pull_request
+
+        expect(WebMock).
+          to(
+            have_requested(:patch, update_pull_request_url).
+              with do |req|
+                pr_update_details = JSON.parse(req.body)
+                expect(pr_update_details).
+                  to eq(
+                    {
+                      "title" => pr_name,
+                      "autoCompleteSetBy" => { "id" => auto_complete_setby_user_id }
+                    }
+                  )
+              end
+          )
+      end
+
+      it "raises helpful error when response is 404" do
+        stub_request(:patch, update_pull_request_url).
+          with(basic_auth: [username, password]).
+          to_return(status: 404)
+
+        expect { update_pull_request }.to raise_error(Dependabot::Clients::Azure::NotFound)
+      end
+    end
+  end
+
   describe "#get" do
     context "Using auth headers" do
       token = ":test_token"

common/spec/dependabot/pull_request_updater/azure_spec.rb

@@ -166,4 +166,39 @@
         )
     end
   end
+
+  describe "#update_pr_elements" do
+    let(:update_pull_request_url) { repo_url + "/pullrequests/" + pull_request_number.to_s + "?api-version=5.0" }
+
+    context "returns nil" do
+      it "when elements hash is empty" do
+        expect(updater.update_pr_elements).to be_nil
+      end
+
+      it "when elements hash does not contain expected parameters for update" do
+        elements = { test_parameter: "test" }
+
+        expect(updater.update_pr_elements(elements)).to be_nil
+      end
+    end
+
+    it "updates the given pr elements" do
+      elements = { pr_name: "Test PR", auto_complete_setby_user_id: "id" }
+
+      stub_request(:patch, update_pull_request_url).
+        to_return(status: 200)
+
+      updater.update_pr_elements(elements)
+
+      expect(WebMock).
+        to(
+          have_requested(:patch, update_pull_request_url).
+              with(body:
+                {
+                  title: elements[:pr_name],
+                  autoCompleteSetBy: { id: elements[:auto_complete_setby_user_id] }
+                })
+        )
+    end
+  end
 end