From 584b492e706122ddd6eabb3aeba9cd4a8efb7549 Mon Sep 17 00:00:00 2001
From: Florian Weingarten <flo@hackvalue.de>
Date: Fri, 3 Oct 2014 21:00:31 +0000
Subject: [PATCH] Line numbers for all parse errors

---
 lib/liquid/block.rb                     | 63 +++++++++++++------------
 lib/liquid/errors.rb                    |  1 +
 test/integration/error_handling_test.rb | 49 +++++++++++++++++++
 3 files changed, 84 insertions(+), 29 deletions(-)

diff --git a/lib/liquid/block.rb b/lib/liquid/block.rb
index b2d5913..2e0ef9a 100644
--- a/lib/liquid/block.rb
+++ b/lib/liquid/block.rb
@@ -15,42 +15,47 @@ module Liquid
       @nodelist.clear
 
       while token = tokens.shift
-        unless token.empty?
-          case
-          when token.start_with?(TAGSTART)
-            if token =~ FullToken
+        begin
+          unless token.empty?
+            case
+            when token.start_with?(TAGSTART)
+              if token =~ FullToken
 
-              # if we found the proper block delimiter just end parsing here and let the outer block
-              # proceed
-              if block_delimiter == $1
-                end_tag
-                return
-              end
+                # if we found the proper block delimiter just end parsing here and let the outer block
+                # proceed
+                if block_delimiter == $1
+                  end_tag
+                  return
+                end
 
-              # fetch the tag from registered blocks
-              if tag = Template.tags[$1]
-                markup = token.is_a?(Token) ? token.child($2) : $2
-                new_tag = tag.parse($1, markup, tokens, @options)
-                new_tag.line_number = token.line_number if token.is_a?(Token)
-                @blank &&= new_tag.blank?
-                @nodelist << new_tag
+                # fetch the tag from registered blocks
+                if tag = Template.tags[$1]
+                  markup = token.is_a?(Token) ? token.child($2) : $2
+                  new_tag = tag.parse($1, markup, tokens, @options)
+                  new_tag.line_number = token.line_number if token.is_a?(Token)
+                  @blank &&= new_tag.blank?
+                  @nodelist << new_tag
+                else
+                  # this tag is not registered with the system
+                  # pass it to the current block for special handling or error reporting
+                  unknown_tag($1, $2, tokens)
+                end
               else
-                # this tag is not registered with the system
-                # pass it to the current block for special handling or error reporting
-                unknown_tag($1, $2, tokens)
+                raise SyntaxError.new(options[:locale].t("errors.syntax.tag_termination".freeze, :token => token, :tag_end => TagEnd.inspect))
               end
+            when token.start_with?(VARSTART)
+              new_var = create_variable(token)
+              new_var.line_number = token.line_number if token.is_a?(Token)
+              @nodelist << new_var
+              @blank = false
             else
-              raise SyntaxError.new(options[:locale].t("errors.syntax.tag_termination".freeze, :token => token, :tag_end => TagEnd.inspect))
+              @nodelist << token
+              @blank &&= (token =~ /\A\s*\z/)
             end
-          when token.start_with?(VARSTART)
-            new_var = create_variable(token)
-            new_var.line_number = token.line_number if token.is_a?(Token)
-            @nodelist << new_var
-            @blank = false
-          else
-            @nodelist << token
-            @blank &&= (token =~ /\A\s*\z/)
           end
+        rescue SyntaxError => e
+          e.set_line_number_from_token(token)
+          raise
         end
       end
 
diff --git a/lib/liquid/errors.rb b/lib/liquid/errors.rb
index bb9132d..6de9d00 100644
--- a/lib/liquid/errors.rb
+++ b/lib/liquid/errors.rb
@@ -18,6 +18,7 @@ module Liquid
 
     def set_line_number_from_token(token)
       return unless token.respond_to?(:line_number)
+      return if self.line_number
       self.line_number = token.line_number
     end
 
diff --git a/test/integration/error_handling_test.rb b/test/integration/error_handling_test.rb
index ee07204..7334402 100644
--- a/test/integration/error_handling_test.rb
+++ b/test/integration/error_handling_test.rb
@@ -100,6 +100,55 @@ class ErrorHandlingTest < Minitest::Test
     assert_equal Liquid::ArgumentError, template.errors.first.class
   end
 
+  def test_with_line_numbers_adds_numbers_to_parser_errors
+    err = assert_raises(SyntaxError) do
+      template = Liquid::Template.parse(%q{
+          foobar
+
+          {% "cat" | foobar %}
+
+          bla
+        },
+        :line_numbers => true
+      )
+    end
+
+    assert_match /Liquid syntax error \(line 4\)/, err.message
+  end
+
+  def test_parsing_warn_with_line_numbers_adds_numbers_to_lexer_errors
+    template = Liquid::Template.parse(%q{
+        foobar
+
+        {% if 1 =! 2 %}ok{% endif %}
+
+        bla
+      },
+      :error_mode => :warn,
+      :line_numbers => true
+    )
+
+    assert_equal ['Liquid syntax error (line 4): Unexpected character = in "1 =! 2"'],
+      template.warnings.map(&:message)
+  end
+
+  def test_parsing_strict_with_line_numbers_adds_numbers_to_lexer_errors
+    err = assert_raises(SyntaxError) do
+      Liquid::Template.parse(%q{
+          foobar
+
+          {% if 1 =! 2 %}ok{% endif %}
+
+          bla
+        },
+        :error_mode => :strict,
+        :line_numbers => true
+      )
+    end
+
+    assert_equal 'Liquid syntax error (line 4): Unexpected character = in "1 =! 2"', err.message
+  end
+
   def test_strict_error_messages
     err = assert_raises(SyntaxError) do
       Liquid::Template.parse(' {% if 1 =! 2 %}ok{% endif %} ', :error_mode => :strict)