Fix moving issues API failing when text includes commit URLs

When a issue is moved from one project to another, all associated
Markdown text is rewritten in the context of the new project. If the
note contained a link to a commit URL, `CommitRewriter#rewrite` would
fail because `Commit#link_reference_pattern` would match `nil` `commit`
values in the HTML generated from the Markdown. These `nil` values were
passed along to `Project#commits_by` because `Commit#reference_valid?`
was always returning `true`.

To prevent this issue from happening, we tighten up the check for
`Commit#reference_valid?` to look for valid SHA values.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/66666

app/models/commit.rb

@@ -35,6 +35,7 @@ class Commit
 
   MIN_SHA_LENGTH = Gitlab::Git::Commit::MIN_SHA_LENGTH
   COMMIT_SHA_PATTERN = /\h{#{MIN_SHA_LENGTH},40}/.freeze
+  EXACT_COMMIT_SHA_PATTERN = /\A#{COMMIT_SHA_PATTERN}\z/.freeze
   # Used by GFM to match and present link extensions on node texts and hrefs.
   LINK_EXTENSION_PATTERN = /(patch)/.freeze
 
@@ -90,7 +91,7 @@ class Commit
     end
 
     def valid_hash?(key)
-      !!(/\A#{COMMIT_SHA_PATTERN}\z/ =~ key)
+      !!(EXACT_COMMIT_SHA_PATTERN =~ key)
     end
 
     def lazy(project, oid)
@@ -139,6 +140,10 @@ class Commit
     '@'
   end
 
+  def self.reference_valid?(reference)
+    !!(reference =~ EXACT_COMMIT_SHA_PATTERN)
+  end
+
   # Pattern used to extract commit references from text
   #
   # This pattern supports cross-project references.

changelogs/unreleased/sh-fix-issue-move-api.yml

+---
+title: Fix moving issues API failing when text includes commit URLs
+merge_request: 32317
+author:
+type: fixed

spec/lib/gitlab/gfm/reference_rewriter_spec.rb

@@ -102,6 +102,23 @@ describe Gitlab::Gfm::ReferenceRewriter do
       end
     end
 
+    context 'with a commit' do
+      let(:old_project) { create(:project, :repository, name: 'old-project', group: group) }
+      let(:commit) { old_project.commit }
+
+      context 'reference to an absolute URL to a commit' do
+        let(:text) { Gitlab::UrlBuilder.build(commit) }
+
+        it { is_expected.to eq(text) }
+      end
+
+      context 'reference to a commit' do
+        let(:text) { commit.id }
+
+        it { is_expected.to eq("#{old_project_ref}@#{text}") }
+      end
+    end
+
     context 'reference contains project milestone' do
       let!(:milestone) do
         create(:milestone, title: '9.0', project: old_project)

spec/models/commit_spec.rb

@@ -192,6 +192,24 @@ describe Commit do
     end
   end
 
+  describe '.reference_valid?' do
+    using RSpec::Parameterized::TableSyntax
+
+    where(:ref, :result) do
+      '1234567' | true
+      '123456' | false
+      '1' | false
+      '0' * 40 | true
+      'c1acaa58bbcbc3eafe538cb8274ba387047b69f8' | true
+      'H1acaa58bbcbc3eafe538cb8274ba387047b69f8' | false
+      nil | false
+    end
+
+    with_them do
+      it { expect(described_class.reference_valid?(ref)).to eq(result) }
+    end
+  end
+
   describe '#reference_link_text' do
     let(:project) { create(:project, :repository, path: 'sample-project') }