Default dependency job stage index to Infinity, and correctly report it as undefined in prior stages

3 files changed, 34 insertions, 1 deletions

diff --git a/changelogs/unreleased/report-missing-job-dependency.yml b/changelogs/unreleased/report-missing-job-dependency.yml
new file mode 100644
index 00000000000..660cdfc856e
--- /dev/null
+++ b/changelogs/unreleased/report-missing-job-dependency.yml
@@ -0,0 +1,6 @@
+---
+title: Default dependency job stage index to Infinity, and correctly report it as
+  undefined in prior stages
+merge_request: 31116
+author:
+type: fixed
diff --git a/lib/gitlab/ci/yaml_processor.rb b/lib/gitlab/ci/yaml_processor.rb
index a5693dc4f81..a0bbf3c23a2 100644
--- a/lib/gitlab/ci/yaml_processor.rb
+++ b/lib/gitlab/ci/yaml_processor.rb
@@ -144,7 +144,9 @@ module Gitlab
         job[:dependencies].each do |dependency|
           raise ValidationError, "#{name} job: undefined dependency: #{dependency}" unless @jobs[dependency.to_sym]
 
-          unless @stages.index(@jobs[dependency.to_sym][:stage]) < stage_index
+          dependency_stage_index = @stages.index(@jobs[dependency.to_sym][:stage])
+
+          unless dependency_stage_index.present? && dependency_stage_index < stage_index
             raise ValidationError, "#{name} job: dependency #{dependency} is not defined in prior stages"
           end
         end
diff --git a/spec/lib/gitlab/ci/yaml_processor_spec.rb b/spec/lib/gitlab/ci/yaml_processor_spec.rb
index fc9d4f97bda..d3676ee03bf 100644
--- a/spec/lib/gitlab/ci/yaml_processor_spec.rb
+++ b/spec/lib/gitlab/ci/yaml_processor_spec.rb
@@ -1085,6 +1085,31 @@ module Gitlab
 
           it { expect { subject }.to raise_error(Gitlab::Ci::YamlProcessor::ValidationError, 'test1 job: dependency deploy is not defined in prior stages') }
         end
+
+        context 'when a job depends on another job that references a not-yet defined stage' do
+          let(:config) do
+            {
+              "stages" => [
+                "version"
+              ],
+              "version" => {
+                "stage" => "version",
+                "dependencies" => ["release:components:versioning"],
+                "script" => ["./versioning/versioning"]
+              },
+              ".release_go" => {
+                "stage" => "build",
+                "script" => ["cd versioning"]
+              },
+              "release:components:versioning" => {
+                "stage" => "build",
+                "script" => ["cd versioning"]
+              }
+            }
+          end
+
+          it { expect { subject }.to raise_error(Gitlab::Ci::YamlProcessor::ValidationError, /is not defined in prior stages/) }
+        end
       end
 
       describe "Hidden jobs" do