Post/update incremental coverage report on PRs. (#8186)

* Post/update incremental coverage report on PRs.

Author: granluo

scripts/code_coverage_report/post_incremental_coverage_in_pr.rb

@@ -0,0 +1,87 @@
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# USAGE: git diff -U0 [base_commit] HEAD | get_diff_lines.sh
+#
+# This will generate a JSON output of changed files and their newly added
+# lines.
+
+require 'octokit'
+require 'json'
+
+COMMENT_HEADER = "### Incremental code coverage report"
+REMOVE_PATTERN = /### Incremental code coverage report/
+REPO = ENV['GITHUB_REPOSITORY']
+GITHUB_WORKFLOW_URL = "https://github.com/#{REPO}/actions/runs/#{ENV['GITHUB_RUN_ID']}"
+UNCOVERED_LINE_FILE = ENV["UNCOVERED_LINE_FILE"]
+TESTING_COMMIT = ENV["TESTING_COMMIT"]
+PULL_REQUEST = ENV["PULL_REQUEST"].to_i
+
+client = Octokit::Client.new(access_token: ENV["INPUT_ACCESS_TOKEN"])
+uncovered_files = JSON.parse(File.read(UNCOVERED_LINE_FILE))
+
+# Clean comments matching REMOVE_PATTERN.
+def clean_coverage_comments(client)
+  comment_page = 0
+  loop do
+    comment_page += 1
+    cur_page_comment = client.pull_request_comments(REPO, PULL_REQUEST, { :per_page =>100, :page => comment_page })
+    if cur_page_comment.length == 0
+      break
+    end
+    for cmt in cur_page_comment do
+      # Remove comments when the comment body meets the REMOVE_PATTERN.
+      if cmt.body =~ REMOVE_PATTERN
+        client.delete_pull_request_comment(REPO,cmt.id)
+      end
+    end
+  end
+end
+
+def generate_comment(comment_header, xcresult_file)
+  body = "Tests for New code lines are not detected in [#{xcresult_file}](#{GITHUB_WORKFLOW_URL}), please add tests on highlighted lines."
+  return "#{comment_header} \n #{body}"
+end
+
+def add_coverage_comments(client, uncovered_files)
+  for changed_file in uncovered_files do
+    coverage_line = changed_file['coverage']
+    xcresult_file = changed_file['xcresultBundle'].split('/').last
+    start_line = -1
+    coverage_line.each_with_index do |line, idx|
+      # Init start_line to the first uncovered line of a file.
+      if start_line == -1
+        start_line = line
+      end
+      if idx < coverage_line.length() && line + 1 == coverage_line[idx+1]
+        next
+      else
+        comment = generate_comment(COMMENT_HEADER, xcresult_file)
+        if start_line == line
+          # One line code comment will only rely on the position param, which is
+          # 'line' here.
+          client.create_pull_request_comment(REPO,PULL_REQUEST, comment, TESTING_COMMIT,changed_file['fileName'], line, {:side=>"RIGHT"})
+        else
+          # multiple-line code block comment needs start_line and line options,
+          # which will override the position param.
+          client.create_pull_request_comment(REPO,PULL_REQUEST, comment, TESTING_COMMIT,changed_file['fileName'],0, {:side=>"RIGHT", :start_line=> start_line, :line=> line})
+        end
+        start_line = coverage_line[idx+1]
+      end
+    end
+  end
+end
+
+clean_coverage_comments(client)
+add_coverage_comments(client, uncovered_files)