Merge branch 'feature/gb/add-regexp-variables-expression' into 'master'

Add support for variables expression regexp syntax

Closes #43601

See merge request gitlab-org/gitlab-ce!18902

5 files changed, 83 insertions, 6 deletions

diff --git a/lib/gitlab/ci/pipeline/expression.rb b/lib/gitlab/ci/pipeline/expression.rb
new file mode 100644
index 00000000000..f57df7c5637
--- /dev/null
+++ b/lib/gitlab/ci/pipeline/expression.rb
@@ -0,0 +1,10 @@
+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        ExpressionError = Class.new(StandardError)
+        RuntimeError = Class.new(ExpressionError)
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/pipeline/expression/lexeme/matches.rb b/lib/gitlab/ci/pipeline/expression/lexeme/matches.rb
new file mode 100644
index 00000000000..10957598f76
--- /dev/null
+++ b/lib/gitlab/ci/pipeline/expression/lexeme/matches.rb
@@ -0,0 +1,29 @@
+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        module Lexeme
+          class Matches < Lexeme::Operator
+            PATTERN = /=~/.freeze
+
+            def initialize(left, right)
+              @left = left
+              @right = right
+            end
+
+            def evaluate(variables = {})
+              text = @left.evaluate(variables)
+              regexp = @right.evaluate(variables)
+
+              regexp.scan(text.to_s).any?
+            end
+
+            def self.build(_value, behind, ahead)
+              new(behind, ahead)
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/pipeline/expression/lexeme/pattern.rb b/lib/gitlab/ci/pipeline/expression/lexeme/pattern.rb
new file mode 100644
index 00000000000..9b239c29ea4
--- /dev/null
+++ b/lib/gitlab/ci/pipeline/expression/lexeme/pattern.rb
@@ -0,0 +1,33 @@
+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        module Lexeme
+          require_dependency 're2'
+
+          class Pattern < Lexeme::Value
+            PATTERN = %r{^/.+/[ismU]*$}.freeze
+
+            def initialize(regexp)
+              @value = regexp
+
+              unless Gitlab::UntrustedRegexp.valid?(@value)
+                raise Lexer::SyntaxError, 'Invalid regular expression!'
+              end
+            end
+
+            def evaluate(variables = {})
+              Gitlab::UntrustedRegexp.fabricate(@value)
+            rescue RegexpError
+              raise Expression::RuntimeError, 'Invalid regular expression!'
+            end
+
+            def self.build(string)
+              new(string)
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/pipeline/expression/lexer.rb b/lib/gitlab/ci/pipeline/expression/lexer.rb
index e1c68b7c3c2..4cacb1e62c9 100644
--- a/lib/gitlab/ci/pipeline/expression/lexer.rb
+++ b/lib/gitlab/ci/pipeline/expression/lexer.rb
@@ -5,15 +5,17 @@ module Gitlab
         class Lexer
           include ::Gitlab::Utils::StrongMemoize
 
+          SyntaxError = Class.new(Expression::ExpressionError)
+
           LEXEMES = [
             Expression::Lexeme::Variable,
             Expression::Lexeme::String,
+            Expression::Lexeme::Pattern,
             Expression::Lexeme::Null,
-            Expression::Lexeme::Equals
+            Expression::Lexeme::Equals,
+            Expression::Lexeme::Matches
           ].freeze
 
-          SyntaxError = Class.new(Statement::StatementError)
-
           MAX_TOKENS = 100
 
           def initialize(statement, max_tokens: MAX_TOKENS)
diff --git a/lib/gitlab/ci/pipeline/expression/statement.rb b/lib/gitlab/ci/pipeline/expression/statement.rb
index 09a7c98464b..b36f1e0f865 100644
--- a/lib/gitlab/ci/pipeline/expression/statement.rb
+++ b/lib/gitlab/ci/pipeline/expression/statement.rb
@@ -3,15 +3,16 @@ module Gitlab
     module Pipeline
       module Expression
         class Statement
-          StatementError = Class.new(StandardError)
+          StatementError = Class.new(Expression::ExpressionError)
 
           GRAMMAR = [
+            %w[variable],
             %w[variable equals string],
             %w[variable equals variable],
             %w[variable equals null],
             %w[string equals variable],
             %w[null equals variable],
-            %w[variable]
+            %w[variable matches pattern]
           ].freeze
 
           def initialize(statement, variables = {})
@@ -35,11 +36,13 @@ module Gitlab
 
           def truthful?
             evaluate.present?
+          rescue Expression::ExpressionError
+            false
           end
 
           def valid?
             parse_tree.is_a?(Lexeme::Base)
-          rescue StatementError
+          rescue Expression::ExpressionError
             false
           end
         end