Omit Git SHA from MemoryChangesets

When a MemoryChangeset is created, it's usually for some change mono
itself made, like updating dependency versions or releasing the final
version of a package (when it's a prerelease).

When it creates changelog entries for these changes, the Git SHA points
to the last commit, any commit, which is inaccurate.

The commit in which this change is actually stored is not made yet, so
omit it from the changelog. This creates less noise in the changelog.

.changesets/changelog-entries-without-commit.md

@@ -0,0 +1,5 @@
+---
+bump: "patch"
+---
+
+Remove commit info from some changeset entries made by mono. Changeset entries made by mono for dependency bumps do not have a commit, as they are part of the "publish" commit, which doesn't exist at time of changelog generation, so omit the information to reduce noise.

lib/mono/changeset.rb

@@ -58,6 +58,10 @@ def bump
       @metadata["bump"]
     end
 
+    def date
+      commit[:date]
+    end
+
     def commit
       @commit ||=
         begin
@@ -81,6 +85,14 @@ def initialize(metadata, message)
       super(nil, metadata, message)
     end
 
+    def date
+      @date ||= Time.now
+    end
+
+    def commit
+      # noop
+    end
+
     def remove
       # noop
     end

lib/mono/changeset_collection.rb

@@ -24,12 +24,9 @@ def changesets
 
     def write_changesets_to_changelog
       new_messages = []
-      sets = changesets.sort_by { |set| [set.bump, set.commit[:date]] }
+      sets = changesets.sort_by { |set| [set.bump, set.date] }
       sets.each do |changeset|
-        commit = changeset.commit
-        url = "#{config.repo}/commit/#{commit[:long]}"
-        new_messages << "- [#{commit[:short]}](#{url}) #{changeset.bump} - " \
-          "#{changeset.message.lines.join("  ")}\n"
+        new_messages << build_changelog_entry(changeset)
       end
       changelog_path = File.join(package.path, "CHANGELOG.md")
       FileUtils.touch(changelog_path)
@@ -59,5 +56,19 @@ def next_bump
         "patch"
       end
     end
+
+    private
+
+    def build_changelog_entry(changeset)
+      message = ["- "]
+      commit = changeset.commit
+      if commit
+        url = "#{config.repo}/commit/#{commit[:long]}"
+        message << "[#{commit[:short]}](#{url}) "
+      end
+      message << changeset.bump
+      message << " - #{changeset.message.lines.join("  ")}\n"
+      message.join
+    end
   end
 end

spec/lib/mono/cli/publish/base_spec.rb

@@ -392,7 +392,7 @@
 
         changelog = File.read("CHANGELOG.md")
         expect_changelog_to_include_version_header(changelog, next_version)
-        expect_changelog_to_include_release_notes(changelog, :patch, "Package release.")
+        expect_changelog_to_include_message(changelog, :patch, "Package release.")
 
         expect(local_changes?).to be_falsy, local_changes.inspect
         expect(commited_files).to eql([

spec/support/helpers/publish_helper.rb

@@ -12,11 +12,13 @@ def expect_changelog_to_include_release_notes(changelog, bump, message = nil)
       .to match(%r{- \[[a-z0-9]{7}\]\(#{url}/commit/[a-z0-9]{40}\) #{bump} - #{message}})
   end
 
+  def expect_changelog_to_include_message(changelog, bump, message)
+    expect(changelog).to match(/- #{bump} - #{message}/)
+  end
+
   def expect_changelog_to_include_package_bump(changelog, package, version)
-    url = "https://github.com/appsignal/#{current_project}"
     message = "Update #{package} dependency to #{version}"
-    expect(changelog)
-      .to match(%r{- \[[a-z0-9]{7}\]\(#{url}/commit/[a-z0-9]{40}\) patch - #{message}})
+    expect_changelog_to_include_message(changelog, "patch", message)
   end
 
   def do_not_publish_package