Improve Danger files after first review

Signed-off-by: Rémy Coutable <remy@rymai.me>

6 files changed, 111 insertions, 47 deletions

diff --git a/danger/changelog/Dangerfile b/danger/changelog/Dangerfile
index 773ffa15a0f..b4a2f7b964c 100644
--- a/danger/changelog/Dangerfile
+++ b/danger/changelog/Dangerfile
@@ -2,23 +2,55 @@
 
 require 'yaml'
 
+NO_CHANGELOG_LABELS = %w[backstage QA test]
+SEE_DOC = "See [the documentation](https://docs.gitlab.com/ce/development/changelog.html)."
+MISSING_CHANGELOG_MESSAGE = <<~MSG
+**[CHANGELOG missing](https://docs.gitlab.com/ce/development/changelog.html).**
+
+You can create one with:
+
+```
+bin/changelog -m %<mr_iid>s
+```
+
+If your merge request doesn't warrant a CHANGELOG entry,
+consider adding any of the %<labels>s labels.
+#{SEE_DOC}
+MSG
+
+def ee?
+  ENV['CI_PROJECT_NAME'] == 'gitlab-ee' || File.exist?('../../CHANGELOG-EE.md')
+end
+
+def ee_changelog?(changelog_path)
+  changelog_path =~ /unreleased-ee/
+end
+
+def ce_port_changelog?(changelog_path)
+  ee? && !ee_changelog?(changelog_path)
+end
+
 def check_changelog(path)
   yaml = YAML.safe_load(File.read(path))
 
-  fail "`title` should be set, in #{gitlab.html_link(path)}." if yaml["title"].nil?
-  fail "`type` should be set, in #{gitlab.html_link(path)}." if yaml["type"].nil?
+  fail "`title` should be set, in #{gitlab.html_link(path)}! #{SEE_DOC}" if yaml["title"].nil?
+  fail "`type` should be set, in #{gitlab.html_link(path)}! #{SEE_DOC}" if yaml["type"].nil?
 
   if yaml["merge_request"].nil?
-    message "Consider setting `merge_request` to #{gitlab.mr_json["iid"]} in #{gitlab.html_link(path)}."
-  elsif yaml["merge_request"] != gitlab.mr_json["iid"]
-    fail "Merge request IID was not set to #{gitlab.mr_json["iid"]}!"
+    message "Consider setting `merge_request` to #{gitlab.mr_json["iid"]} in #{gitlab.html_link(path)}. #{SEE_DOC}"
+  elsif yaml["merge_request"] != gitlab.mr_json["iid"] && !ce_port_changelog?(changelog_path)
+    fail "Merge request ID was not set to #{gitlab.mr_json["iid"]}! #{SEE_DOC}"
   end
 rescue StandardError
   # YAML could not be parsed, fail the build.
-  fail "#{gitlab.html_link(path)} isn't valid YAML!"
+  fail "#{gitlab.html_link(path)} isn't valid YAML! #{SEE_DOC}"
 end
 
-changelog_needed = !gitlab.mr_labels.include?("backstage")
+def presented_no_changelog_labels
+  NO_CHANGELOG_LABELS.map { |label| "~#{label}" }.join(', ')
+end
+
+changelog_needed = (gitlab.mr_labels & NO_CHANGELOG_LABELS).empty?
 changelog_found = git.added_files.find { |path| path =~ %r{\A(ee/)?(changelogs/unreleased)(-ee)?/} }
 
 if git.modified_files.include?("CHANGELOG.md")
@@ -29,11 +61,6 @@ if changelog_needed
   if changelog_found
     check_changelog(path)
   else
-    msg = [
-      "This merge request is missing a CHANGELOG entry, you can create one with `bin/changelog -m #{gitlab.mr_json["iid"]}`.",
-      "If your merge request doesn't warrant a CHANGELOG entry, consider adding the ~backstage label."
-    ]
-
-    warn msg.join(" ")
+    warn format(MISSING_CHANGELOG_MESSAGE, mr_iid: gitlab.mr_json["iid"], labels: presented_no_changelog_labels)
   end
 end
diff --git a/danger/changes_size/Dangerfile b/danger/changes_size/Dangerfile
index 4471e1926c9..597073e6029 100644
--- a/danger/changes_size/Dangerfile
+++ b/danger/changes_size/Dangerfile
@@ -1,9 +1,19 @@
 # rubocop:disable Style/SignalException
 
-if git.lines_of_code > 500
-  warn "This merge request is quite big, please consider splitting it into multiple merge requests."
-end
+# FIXME: git.info_for_file raises the following error
+# /usr/local/bundle/gems/git-1.4.0/lib/git/lib.rb:956:in `command':  (Danger::DSLError)
+# [!] Invalid `Dangerfile` file:
+# [!] Invalid `Dangerfile` file: git '--git-dir=/builds/gitlab-org/gitlab-ce/.git' '--work-tree=/builds/gitlab-org/gitlab-ce' cat-file '-t' ''  2>&1:fatal: Not a valid object name
+# This seems to be the same as https://github.com/danger/danger/issues/535.
+
+# locale_files_updated = git.modified_files.select { |path| path.start_with?('locale') }
+# locale_files_updated.each do |locale_file_updated|
+#   git_stats = git.info_for_file(locale_file_updated)
+#   message "Git stats for #{locale_file_updated}: #{git_stats[:insertions]} insertions, #{git_stats[:deletions]} insertions"
+# end
 
-if git.lines_of_code > 5_000
-  fail "This merge request is definitely too big, please split it into multiple merge requests."
+if git.lines_of_code > 2_000
+  warn "This merge request is definitely too big (more than #{git.lines_of_code} lines changed), please split it into multiple merge requests."
+elsif git.lines_of_code > 500
+  warn "This merge request is quite big  (more than #{git.lines_of_code} lines changed), please consider splitting it into multiple merge requests."
 end
diff --git a/danger/database/Dangerfile b/danger/database/Dangerfile
index 136dcef7972..4759ceb7eb4 100644
--- a/danger/database/Dangerfile
+++ b/danger/database/Dangerfile
@@ -1,16 +1,31 @@
 # rubocop:disable Style/SignalException
 
-db_schema_updated = !git.modified_files.grep(%r{\A(ee/)?(db/(geo/)?(post_)?migrate)/}).empty?
-migration_created = !git.added_files.grep(%r{\A(db/(post_)?migrate)/}).empty?
-geo_migration_created = !git.added_files.grep(%r{\Aee/(db/geo/(post_)?migrate)/}).empty?
-
-if (migration_created || geo_migration_created) && !db_schema_updated
-  msg = ["New migrations were added but #{gitlab.html_link("db/schema.rb")}"]
-  msg << "(nor #{gitlab.html_link("ee/db/geo/schema.rb")})" if geo_migration_created
-  msg << "wasn't. Usually, when adding new migrations, #{gitlab.html_link("db/schema.rb")}"
-  msg << "(and #{gitlab.html_link("ee/db/geo/schema.rb")})" if geo_migration_created
-  msg << "should be updated too (unless your migrations are data migrations and your"
-  msg << "migration isn't the most recent one)."
-
-  warn msg.join(" ")
+ANY_MIGRATIONS_REGEX = %r{\A(ee/)?(db/(geo/)?(post_)?migrate)/}
+SCHEMA_NOT_UPDATED_MESSAGE = <<~MSG
+**New %<migrations>s added but %<schema>s wasn't updated.**
+
+Usually, when adding new %<migrations>s, %<schema>s should be
+updated too (unless the migration isn't changing the DB schema
+and isn't the most recent one).
+MSG
+
+non_geo_db_schema_updated = !git.modified_files.grep(%r{\Adb/schema\.rb/}).empty?
+geo_db_schema_updated = !git.modified_files.grep(%r{\Aee/db/geo/schema\.rb/}).empty?
+
+any_migration_created = !git.added_files.grep(ANY_MIGRATIONS_REGEX).empty?
+any_migration_updated = !git.modified_files.grep(ANY_MIGRATIONS_REGEX).empty?
+
+non_geo_migration_created = !git.added_files.grep(%r{\A(db/(post_)?migrate)/}).empty?
+geo_migration_created = !git.added_files.grep(%r{\Aee/db/geo/(post_)?migrate/}).empty?
+
+if any_migration_created || any_migration_updated || non_geo_db_schema_updated || geo_db_schema_updated
+  message "Please make sure to ask a Database engineer for a review."
+end
+
+if non_geo_migration_created && !non_geo_db_schema_updated
+  warn format(SCHEMA_NOT_UPDATED_MESSAGE, migrations: 'migrations', schema: gitlab.html_link("db/schema.rb"))
+end
+
+if geo_migration_created && !geo_db_schema_updated
+  warn format(SCHEMA_NOT_UPDATED_MESSAGE, migrations: 'Geo migrations', schema: gitlab.html_link("ee/db/geo/schema.rb"))
 end
diff --git a/danger/gemfile/Dangerfile b/danger/gemfile/Dangerfile
index 3d38959a9d0..b9f59d95815 100644
--- a/danger/gemfile/Dangerfile
+++ b/danger/gemfile/Dangerfile
@@ -1,15 +1,26 @@
 # rubocop:disable Style/SignalException
 
+GEMFILE_LOCK_NOT_UPDATED_MESSAGE = <<~MSG
+**%<gemfile>s was updated but %<gemfile_lock>s wasn't updated.**
+
+Usually, when %<gemfile>s is updated, you should run
+```
+bundle install && \
+  BUNDLE_GEMFILE=Gemfile.rails5 bundle install
+```
+
+or
+
+```
+bundle update <the-added-or-updated-gem>
+```
+
+and commit the %<gemfile_lock>s changes.
+MSG
+
 gemfile_modified = git.modified_files.include?("Gemfile")
 gemfile_lock_modified = git.modified_files.include?("Gemfile.lock")
 
 if gemfile_modified && !gemfile_lock_modified
-  msg = [
-    "#{gitlab.html_link("Gemfile")} was edited but #{gitlab.html_link("Gemfile.lock")} wasn't.",
-    "Usually, when #{gitlab.html_link("Gemfile")} is updated, you should run",
-    "`bundle install && BUNDLE_GEMFILE=Gemfile.rails5 bundle install` or",
-    "`bundle update <the-added-or-updated-gem>` and commit the #{gitlab.html_link("Gemfile.lock")} changes."
-  ]
-
-  warn msg.join(" ")
+  warn format(GEMFILE_LOCK_NOT_UPDATED_MESSAGE, gemfile: gitlab.html_link("Gemfile"), gemfile_lock: gitlab.html_link("Gemfile.lock"))
 end
diff --git a/danger/metadata/Dangerfile b/danger/metadata/Dangerfile
index 033a84d6ecd..3cfaa04e01b 100644
--- a/danger/metadata/Dangerfile
+++ b/danger/metadata/Dangerfile
@@ -1,7 +1,7 @@
 # rubocop:disable Style/SignalException
 
 if gitlab.mr_body.size < 5
-  fail "Please provide a merge request description."
+  fail "Please provide a proper merge request description."
 end
 
 if gitlab.mr_labels.empty?
@@ -21,5 +21,5 @@ end
 has_pick_into_stable_label = gitlab.mr_labels.find { |label| label.start_with?('Pick into') }
 
 if gitlab.branch_for_base != "master" && !has_pick_into_stable_label
-  fail "All merge requests should target `master`. Otherwise, please set the relevant `Pick into X.Y` label."
+  warn "Most of the time, all merge requests should target `master`. Otherwise, please set the relevant `Pick into X.Y` label."
 end
diff --git a/danger/specs/Dangerfile b/danger/specs/Dangerfile
index 88e64c57a4b..0ed5235ec02 100644
--- a/danger/specs/Dangerfile
+++ b/danger/specs/Dangerfile
@@ -1,13 +1,14 @@
 # rubocop:disable Style/SignalException
 
+NO_NEW_SPEC_MESSAGE = <<~MSG
+You've made some app changes, but didn't add any tests.
+That's OK as long as you're refactoring existing code,
+but please consider adding the ~backstage label in that case.
+MSG
+
 has_app_changes = !git.modified_files.grep(%r{\A(ee/)?(app|lib|db/(geo/)?(post_)?migrate)/}).empty?
 has_spec_changes = !git.modified_files.grep(/spec/).empty?
 
 if has_app_changes && !has_spec_changes
-  msg = [
-    "You've made some app changes, but didn't add any tests.",
-    "That's OK as long as you're refactoring existing code (please consider adding the ~backstage label in that case)."
-  ]
-
-  warn msg.join(" "), sticky: false
+  warn NO_NEW_SPEC_MESSAGE, sticky: false
 end