fix the commit reference pattern from matching other entities

app/models/commit.rb

@@ -26,7 +26,7 @@ class Commit
   DIFF_HARD_LIMIT_LINES = 50000
 
   MIN_SHA_LENGTH = 7
-  COMMIT_SHA_PATTERN = /\h{#{MIN_SHA_LENGTH},40}/.freeze
+  COMMIT_SHA_PATTERN = /\b(?<![~#!@:])\h{#{MIN_SHA_LENGTH},40}/.freeze
 
   def banzai_render_context(field)
     context = { pipeline: :single_line, project: self.project }

changelogs/unreleased/39461-notes-api-for-issues-no-longer-returns-label-additions-removals.yml

+---
+title: Label addition/removal are not going to be redacted wrongfully in the API.
+merge_request: 15080
+author:
+type: fixed

spec/models/commit_spec.rb

@@ -468,4 +468,27 @@ eos
       expect(described_class.valid_hash?('a' * 41)).to be false
     end
   end
+
+  describe '.reference_pattern' do
+    where(:ref, :matches?) do
+      sha = Digest::SHA1.hexdigest 'thisisacommitid'
+
+      [
+        [sha.first(Commit::MIN_SHA_LENGTH - 1), false],
+        [sha.first(Commit::MIN_SHA_LENGTH), true],
+        [sha, true],
+        ['~' << sha, false], # labels
+        ['!' << sha, false], # merge_request
+        [':' << sha, false], # emoji
+        ['#' << sha, false], # issue
+        ['@' << sha, false], # user
+      ]
+    end
+
+    with_them do
+      it "should match only on commit references" do
+        expect(Commit.reference_pattern.match(ref).present?).to eq(matches?)
+      end
+    end
+  end
 end