Rework error reporting, and fix pretty print of SPEC parse error

src/errors.cr

@@ -35,15 +35,15 @@ module Shards
  end
 
  def to_s(io)
- io.puts "in #{ filename }:#{ line_number }: #{ self.class.name }: #{ message }"
+ io.puts "in #{ filename }: #{ message }"
  io.puts
 
  lines = input.split('\n')
- from = line_number - 2
+ from = line_number - 3
  from = 0 if from < 0
 
- lines[from .. line_number].each_with_index do |line, i|
- io.puts " #{ i + 1 }. #{ line }"
+ lines[from ... line_number].each_with_index do |line, i|
+ io.puts " #{ from + i + 1 }. #{ line }"
  end
 
  arrow = String.build do |s|

src/lock.cr

@@ -27,7 +27,7 @@ module Shards
  dependencies << Dependency.new(pull)
  end
  else
- pull.raise "no such attribute #{key} in lock version 1.0"
+ pull.raise "No such attribute #{key} in lock version 1.0"
  end
  end
  end

src/resolvers/git.cr

@@ -214,7 +214,7 @@ module Shards
 
  private def run(command, path = local_path, capture = false)
  unless GitResolver.has_git_command?
- raise Error.new("Error: missing git command line tool. Please install Git first!")
+ raise Error.new("Error missing git command line tool. Please install Git first!")
  end
 
  # Shards.logger.debug { "cd #{path}" }
@@ -233,7 +233,7 @@ module Shards
  if str.starts_with?("error: ") && (idx = str.index('\n'))
  message = str[7 ... idx]
  end
- raise Error.new("git command failed: #{ command } (#{ message }). Maybe a commit, branch or file doesn't exist?")
+ raise Error.new("Failed #{ command } (#{ message }). Maybe a commit, branch or file doesn't exist?")
  end
  end
  end

src/resolvers/resolver.cr

@@ -92,7 +92,7 @@ module Shards
  def self.find_resolver(dependency, update_cache = true)
  @@resolvers[dependency.name] ||= begin
  klass = get_resolver_class(dependency.keys)
- raise Error.new("can't resolve dependency #{dependency.name} (unsupported resolver)") unless klass
+ raise Error.new("Failed can't resolve dependency #{dependency.name} (unsupported resolver)") unless klass
  klass.new(dependency, update_cache: update_cache)
  end
  end

src/spec.cr

@@ -30,13 +30,15 @@ module Shards
 
  def self.new(pull : YAML::PullParser)
  name = pull.read_scalar
+
+ line, column = pull.location
  version = pull.read_scalar.strip if pull.kind.scalar?
 
- if version && !version.empty?
- new(name, version)
- else
- raise Error.new("library version of #{name} can't be empty, use * for any version.")
+ if !version || version.try(&.empty?)
+ pull.raise "library version for #{name} can't be empty, use * for any version", line, column
  end
+
+ new(name, version)
  end
 
  def initialize(@soname, @version)
@@ -71,6 +73,8 @@ module Shards
  # :nodoc:
  def initialize(pull : YAML::PullParser, validate = false)
  pull.each_in_mapping do
+ line, column = pull.location
+
  case key = pull.read_scalar
  when "name"
  @name = pull.read_scalar
@@ -108,7 +112,7 @@ module Shards
  end
  else
  if validate
- pull.raise "unknown attribute: #{key}"
+ pull.raise "unknown attribute: #{key}", line, column
  else
  pull.skip
  end