* ext/psych/lib/psych.rb (module Psych): parse and load methods take

  an optional file name that is used when raising Psych::SyntaxError
  exceptions
* ext/psych/lib/psych/syntax_error.rb (module Psych): allow nil file
  names and handle nil file names in the exception message
* test/psych/test_exception.rb (module Psych): Tests for changes.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33965 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 50 insertions, 14 deletions

diff --git a/ext/psych/lib/psych.rb b/ext/psych/lib/psych.rb
index ebf2b35d14..3b7f9a34f2 100644
--- a/ext/psych/lib/psych.rb
+++ b/ext/psych/lib/psych.rb
@@ -106,34 +106,58 @@ module Psych
   ###
   # Load +yaml+ in to a Ruby data structure.  If multiple documents are
   # provided, the object contained in the first document will be returned.
+  # +filename+ will be used in the exception message if any exception is raised
+  # while parsing.
+  #
+  # Raises a Psych::SyntaxError when a YAML syntax error is detected.
   #
   # Example:
   #
-  #   Psych.load("--- a")           # => 'a'
-  #   Psych.load("---\n - a\n - b") # => ['a', 'b']
-  def self.load yaml
-    result = parse(yaml)
+  #   Psych.load("--- a")             # => 'a'
+  #   Psych.load("---\n - a\n - b")   # => ['a', 'b']
+  #
+  #   begin
+  #     Psych.load("--- `", "file.txt")
+  #   rescue Psych::SyntaxError => ex
+  #     ex.file    # => 'file.txt'
+  #     ex.message # => "(foo.txt): found character that cannot start any token"
+  #   end
+  def self.load yaml, filename = nil
+    result = parse(yaml, filename)
     result ? result.to_ruby : result
   end
 
   ###
   # Parse a YAML string in +yaml+.  Returns the first object of a YAML AST.
+  # +filename+ is used in the exception message if a Psych::SyntaxError is
+  # raised.
+  #
+  # Raises a Psych::SyntaxError when a YAML syntax error is detected.
   #
   # Example:
   #
   #   Psych.parse("---\n - a\n - b") # => #<Psych::Nodes::Sequence:0x00>
   #
+  #   begin
+  #     Psych.parse("--- `", "file.txt")
+  #   rescue Psych::SyntaxError => ex
+  #     ex.file    # => 'file.txt'
+  #     ex.message # => "(foo.txt): found character that cannot start any token"
+  #   end
+  #
   # See Psych::Nodes for more information about YAML AST.
-  def self.parse yaml
-    children = parse_stream(yaml).children
+  def self.parse yaml, filename = nil
+    children = parse_stream(yaml, filename).children
     children.empty? ? false : children.first.children.first
   end
 
   ###
   # Parse a file at +filename+. Returns the YAML AST.
+  #
+  # Raises a Psych::SyntaxError when a YAML syntax error is detected.
   def self.parse_file filename
     File.open filename do |f|
-      parse f
+      parse f, filename
     end
   end
 
@@ -146,15 +170,26 @@ module Psych
   ###
   # Parse a YAML string in +yaml+.  Returns the full AST for the YAML document.
   # This method can handle multiple YAML documents contained in +yaml+.
+  # +filename+ is used in the exception message if a Psych::SyntaxError is
+  # raised.
+  #
+  # Raises a Psych::SyntaxError when a YAML syntax error is detected.
   #
   # Example:
   #
   #   Psych.parse_stream("---\n - a\n - b") # => #<Psych::Nodes::Stream:0x00>
   #
+  #   begin
+  #     Psych.parse_stream("--- `", "file.txt")
+  #   rescue Psych::SyntaxError => ex
+  #     ex.file    # => 'file.txt'
+  #     ex.message # => "(foo.txt): found character that cannot start any token"
+  #   end
+  #
   # See Psych::Nodes for more information about YAML AST.
-  def self.parse_stream yaml
+  def self.parse_stream yaml, filename = nil
     parser = self.parser
-    parser.parse yaml
+    parser.parse yaml, filename
     parser.handler.root
   end
 
@@ -221,15 +256,15 @@ module Psych
   #
   #   Psych.load_stream("--- foo\n...\n--- bar\n...") # => ['foo', 'bar']
   #
-  def self.load_stream yaml
-    parse_stream(yaml).children.map { |child| child.to_ruby }
+  def self.load_stream yaml, filename = nil
+    parse_stream(yaml, filename).children.map { |child| child.to_ruby }
   end
 
   ###
   # Load the document contained in +filename+.  Returns the yaml contained in
   # +filename+ as a ruby object
   def self.load_file filename
-    File.open(filename) { |f| self.load f }
+    File.open(filename) { |f| self.load f, filename }
   end
 
   # :stopdoc:
diff --git a/ext/psych/lib/psych/syntax_error.rb b/ext/psych/lib/psych/syntax_error.rb
index 9fe3e0da30..f79743dba4 100644
--- a/ext/psych/lib/psych/syntax_error.rb
+++ b/ext/psych/lib/psych/syntax_error.rb
@@ -3,8 +3,9 @@ module Psych
     attr_reader :file, :line, :column, :offset, :problem, :context
 
     def initialize file, line, col, offset, problem, context
-      err     = [problem, context].compact.join ' '
-      message = "(%s): %s at line %d column %d" % [file, err, line, col]
+      err      = [problem, context].compact.join ' '
+      filename = file || '<unknown>'
+      message  = "(%s): %s at line %d column %d" % [filename, err, line, col]
 
       @file    = file
       @line    = line