3 files changed, 19 insertions, 15 deletions
diff --git a/lib/gitlab/ci/pipeline/expression/lexer.rb b/lib/gitlab/ci/pipeline/expression/lexer.rb
index 26895174881..8432b36b066 100644
--- a/lib/gitlab/ci/pipeline/expression/lexer.rb
+++ b/lib/gitlab/ci/pipeline/expression/lexer.rb
@@ -2,32 +2,34 @@ module Gitlab
   module Ci
     module Pipeline
       module Expression
-        LEXEMES = [
-          Expression::Variable
-        ]
+        class Lexer
+          LEXEMES = [
+            Expression::Variable,
+            Expression::String
+          ]
 
-        MAX_CYCLES = 5
+          MAX_CYCLES = 5
+          SyntaxError = Class.new(StandardError)
 
-        class Lexer
           def initialize(statement)
             @scanner = StringScanner.new(statement)
             @tokens = []
           end
 
           def tokenize
-            @tokens.tap do
-              MAX_CYCLES.times do
-                LEXEMES.each do |lexeme|
-                  @scanner.scan(/\s+/) # ignore whitespace
-
-                  lexeme.scan(@scanner).tap do |token|
-                    @tokens.push(token) if token.present?
-                  end
+            MAX_CYCLES.times do
+              LEXEMES.each do |lexeme|
+                @scanner.scan(/\s+/) # ignore whitespace
 
-                  return @tokens if @scanner.eos?
+                lexeme.scan(@scanner).tap do |token|
+                  @tokens.push(token) if token.present?
                 end
+
+                return @tokens if @scanner.eos?
               end
             end
+
+            raise Lexer::SyntaxError unless @scanner.eos?
           end
         end
       end
diff --git a/lib/gitlab/ci/pipeline/expression/string.rb b/lib/gitlab/ci/pipeline/expression/string.rb
index a603ef6cf4c..e6cc50c56d8 100644
--- a/lib/gitlab/ci/pipeline/expression/string.rb
+++ b/lib/gitlab/ci/pipeline/expression/string.rb
@@ -3,7 +3,7 @@ module Gitlab
     module Pipeline
       module Expression
         class String < Expression::Lexeme
-          PATTERN = /("|')(?<value>.+)('|")/.freeze
+          PATTERN = /"(?<string>.+?)"/.freeze
 
           def initialize(value)
             @value = value
diff --git a/lib/gitlab/ci/pipeline/expression/token.rb b/lib/gitlab/ci/pipeline/expression/token.rb
index c800d1f0c08..03a47a17d40 100644
--- a/lib/gitlab/ci/pipeline/expression/token.rb
+++ b/lib/gitlab/ci/pipeline/expression/token.rb
@@ -3,6 +3,8 @@ module Gitlab
     module Pipeline
       module Expression
         class Token
+          attr_reader :value, :type
+
           def initialize(value, type)
             @value = value
             @type = type