Improve extended CI/CD config error messages

lib/gitlab/ci/config/extendable/entry.rb

@@ -3,12 +3,12 @@ module Gitlab
     class Config
       class Extendable
         class Entry
-          MAX_NESTING_LEVELS = 10
-
           InvalidExtensionError = Class.new(Extendable::ExtensionError)
           CircularDependencyError = Class.new(Extendable::ExtensionError)
           NestingTooDeepError = Class.new(Extendable::ExtensionError)
 
+          MAX_NESTING_LEVELS = 10
+
           attr_reader :key
 
           def initialize(key, context, parent = nil)
@@ -48,22 +48,22 @@ module Gitlab
 
             if unknown_extension?
               raise Entry::InvalidExtensionError,
-                    "Unknown extends key in extended `#{key}`!"
+                    "#{key}: unknown `extends` key"
             end
 
             if invalid_base?
               raise Entry::InvalidExtensionError,
-                    "Invalid base hash in extended `#{key}`!"
+                    "#{key}: invalid base hash in `extends`"
             end
 
             if nesting_too_deep?
               raise Entry::NestingTooDeepError,
-                    "`extends` nesting too deep in `#{key}`!"
+                    "#{key}: `extends` nesting too deep"
             end
 
             if circular_dependency?
               raise Entry::CircularDependencyError,
-                    "Circular dependency detected in extended `#{key}`!"
+                    "#{key}: circular dependency detected in `extends`"
             end
 
             @context[key] = base_hash!.deep_merge(value)

spec/lib/gitlab/ci/config/extendable/entry_spec.rb

@@ -126,7 +126,8 @@ describe Gitlab::Ci::Config::Extendable::Entry do
 
       it 'raises an error' do
         expect { subject.extend! }
-          .to raise_error(StandardError, /Invalid base hash/)
+          .to raise_error(described_class::InvalidExtensionError,
+                          /invalid base hash/)
       end
     end
 
@@ -137,7 +138,8 @@ describe Gitlab::Ci::Config::Extendable::Entry do
 
       it 'raises an error' do
         expect { subject.extend! }
-          .to raise_error(StandardError, /Unknown extends key/)
+          .to raise_error(described_class::InvalidExtensionError,
+                          /unknown `extends` key/)
       end
     end
 
@@ -199,7 +201,7 @@ describe Gitlab::Ci::Config::Extendable::Entry do
       it 'raises an error' do
         expect { subject.extend! }
           .to raise_error(described_class::CircularDependencyError,
-                          /Circular dependency detected/)
+                          /circular dependency detected/)
       end
     end
 

spec/lib/gitlab/ci/config_spec.rb

@@ -119,7 +119,7 @@ describe Gitlab::Ci::Config do
 
       it 'raises an error' do
         expect { config }.to raise_error(
-          described_class::ConfigError, /Circular dependency detected/
+          described_class::ConfigError, /circular dependency detected/
         )
       end
     end

spec/lib/gitlab/ci/yaml_processor_spec.rb

@@ -1367,7 +1367,7 @@ module Gitlab
 
           expect { Gitlab::Ci::YamlProcessor.new(config) }
             .to raise_error(Gitlab::Ci::YamlProcessor::ValidationError,
-                            'Unknown extends key in extended `rspec`!')
+                            'rspec: unknown `extends` key')
         end
       end