Add support for pattern matching in variables expressions

lib/gitlab/ci/pipeline/expression/lexeme/matches.rb

@@ -15,7 +15,7 @@ module Gitlab
               text = @left.evaluate(variables)
               regexp = @right.evaluate(variables)
 
-              regexp.scan(text).any?
+              regexp.scan(text.to_s).any?
             end
 
             def self.build(_value, behind, ahead)

lib/gitlab/ci/pipeline/expression/lexeme/pattern.rb

@@ -3,6 +3,8 @@ module Gitlab
     module Pipeline
       module Expression
         module Lexeme
+          require_dependency 're2'
+
           class Pattern < Lexeme::Value
             PATTERN = %r{/(?<regexp>.+)/}.freeze
 

lib/gitlab/ci/pipeline/expression/lexer.rb

@@ -10,8 +10,10 @@ module Gitlab
           LEXEMES = [
             Expression::Lexeme::Variable,
             Expression::Lexeme::String,
+            Expression::Lexeme::Pattern,
             Expression::Lexeme::Null,
-            Expression::Lexeme::Equals
+            Expression::Lexeme::Equals,
+            Expression::Lexeme::Matches
           ].freeze
 
           MAX_TOKENS = 100

lib/gitlab/ci/pipeline/expression/statement.rb

@@ -6,12 +6,14 @@ module Gitlab
           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],
+            %w[pattern matches variable]
           ].freeze
 
           def initialize(statement, variables = {})

spec/lib/gitlab/ci/pipeline/expression/lexeme/matches_spec.rb

@@ -39,6 +39,16 @@ describe Gitlab::Ci::Pipeline::Expression::Lexeme::Matches do
       expect(operator.evaluate).to eq true
     end
 
+    it 'supports matching against a nil value' do
+      allow(left).to receive(:evaluate).and_return(nil)
+      allow(right).to receive(:evaluate)
+        .and_return(Gitlab::UntrustedRegexp.new('pattern'))
+
+      operator = described_class.new(left, right)
+
+      expect(operator.evaluate).to eq false
+    end
+
     it 'supports multiline strings' do
       allow(left).to receive(:evaluate).and_return <<~TEXT
         My awesome contents

spec/lib/gitlab/ci/pipeline/expression/lexeme/pattern_spec.rb

 require 'fast_spec_helper'
-require_dependency 're2'
 
 describe Gitlab::Ci::Pipeline::Expression::Lexeme::Pattern do
   describe '.build' do

spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb

@@ -84,7 +84,6 @@ describe Gitlab::Ci::Pipeline::Expression::Statement do
   describe '#evaluate' do
     statements = [
       ['$PRESENT_VARIABLE == "my variable"', true],
-      ["$PRESENT_VARIABLE == 'my variable'", true],
       ['"my variable" == $PRESENT_VARIABLE', true],
       ['$PRESENT_VARIABLE == null', false],
       ['$EMPTY_VARIABLE == null', false],
@@ -93,7 +92,11 @@ describe Gitlab::Ci::Pipeline::Expression::Statement do
       ['$UNDEFINED_VARIABLE == null', true],
       ['null == $UNDEFINED_VARIABLE', true],
       ['$PRESENT_VARIABLE', 'my variable'],
-      ['$UNDEFINED_VARIABLE', nil]
+      ['$UNDEFINED_VARIABLE', nil],
+      ["$PRESENT_VARIABLE =~ /var.*e$/", true],
+      ["$PRESENT_VARIABLE =~ /^var.*/", false],
+      ["$EMPTY_VARIABLE =~ /var.*/", false],
+      ["$UNDEFINED_VARIABLE =~ /var.*/", false]
     ]
 
     statements.each do |expression, value|
@@ -115,7 +118,9 @@ describe Gitlab::Ci::Pipeline::Expression::Statement do
       ['$PRESENT_VARIABLE', true],
       ['$UNDEFINED_VARIABLE', false],
       ['$EMPTY_VARIABLE', false],
-      ['$INVALID = 1', false]
+      ['$INVALID = 1', false],
+      ["$PRESENT_VARIABLE =~ /var.*/", true],
+      ["$UNDEFINED_VARIABLE =~ /var.*/", false]
     ]
 
     statements.each do |expression, value|