feat: Type failures now raise a Delivered::ArgumentError exception

fixes #1

Author: joelmoss

README.md

@@ -1,5 +1,7 @@
 # Delivered: Simple runtime type checking for Ruby method signatures
 
+> Signed, Sealed, Delivered 🎹
+
 Delivered gives you the ability to define method signatures in Ruby, and have them checked at
 runtime. This is useful for ensuring that your methods are being called with the correct arguments,
 and for providing better error messages when they are not. It also serves as a nice way of
@@ -22,7 +24,7 @@ end
 ```
 
 If an invalid argument is given to `User#create`, for example, if `age` is a `String` instead of
-the required `Integer`, a `NoMatchingPatternError` exception will be raised.
+the required `Integer`, a `Delivered::ArgumentError` exception will be raised.
 
 ### Return Types
 

lib/delivered.rb

@@ -1,6 +1,9 @@
 # frozen_string_literal: true
 
 module Delivered
+  class ArgumentError < ArgumentError
+  end
+
   autoload :Signature, 'delivered/signature'
   autoload :Types, 'delivered/types'
 end

lib/delivered/signature.rb

@@ -11,26 +11,41 @@ def sig(*sig_args, **sig_kwargs, &return_blk)
       # Hashrocket return
       if sig_kwargs.keys[0].is_a?(Array)
         unless returns.nil?
-          raise ArgumentError, 'Cannot mix block and hash for return type. Use one or the other.'
+          raise Delivered::ArgumentError,
+                'Cannot mix block and hash for return type. Use one or the other.', caller
         end
 
         returns = sig_kwargs.values[0]
         sig_args = sig_kwargs.keys[0]
-        sig_kwargs = sig_args.pop
+        sig_kwargs = sig_args.pop if sig_args.last.is_a?(Hash)
       end
 
-      # ap sig_args
-      # ap sig_kwargs
-      # ap returns
+      # ap [sig_args, sig_kwargs, returns]
 
       meta = class << self; self; end
-      sig_check = lambda do |klass, name, *args, **kwargs, &block|
+      sig_check = lambda do |klass, class_method, name, *args, **kwargs, &block|
+        cname = if class_method
+                  "#{klass.name}.#{name}"
+                else
+                  "#{klass.class.name}##{name}"
+                end
+
         sig_args.each.with_index do |arg, i|
           args[i] => ^arg
+        rescue NoMatchingPatternError => e
+          raise Delivered::ArgumentError,
+                "`#{cname}` expected `#{arg}` as positional arg #{i}, but received " \
+                "`#{args[i].inspect}`",
+                caller, cause: e
         end
 
         kwargs.each do |key, value|
           value => ^(sig_kwargs[key])
+        rescue NoMatchingPatternError => e
+          raise Delivered::ArgumentError,
+                "`#{cname}` expected `#{sig_kwargs[key]}` as keyword arg :#{key}, but received " \
+                "`#{value.inspect}`",
+                caller, cause: e
         end
 
         result = if block
@@ -39,7 +54,13 @@ def sig(*sig_args, **sig_kwargs, &return_blk)
                    klass.send(:"__#{name}", *args, **kwargs)
                  end
 
-        result => ^returns unless returns.nil?
+        begin
+          result => ^returns unless returns.nil?
+        rescue NoMatchingPatternError => e
+          raise Delivered::ArgumentError,
+                "`#{cname}` expected to return `#{returns}`, but returned `#{result.inspect}`",
+                caller, cause: e
+        end
 
         result
       end
@@ -50,7 +71,7 @@ def sig(*sig_args, **sig_kwargs, &return_blk)
 
         alias_method :"__#{name}", name
         define_method name do |*args, **kwargs, &block|
-          sig_check.call(self, name, *args, **kwargs, &block)
+          sig_check.call(self, false, name, *args, **kwargs, &block)
         end
       end
 
@@ -62,7 +83,7 @@ def sig(*sig_args, **sig_kwargs, &return_blk)
 
         meta.alias_method :"__#{name}", name
         define_singleton_method name do |*args, **kwargs, &block|
-          sig_check.call(self, name, *args, **kwargs, &block)
+          sig_check.call(self, true, name, *args, **kwargs, &block)
         end
       end
     end

test/delivered/signature.rb

@@ -53,12 +53,12 @@ def self.find_by_name(name) = User.new(name)
 
     it 'raises on incorrect types' do
       user = User.new('Joel')
-      expect { user.with_hash_return }.to raise_exception NoMatchingPatternError
+      expect { user.with_hash_return }.to raise_exception Delivered::ArgumentError
     end
 
     it 'raises on incorrect return type' do
       user = User.new('Joel')
-      expect { user.with_incorrect_hash_return }.to raise_exception NoMatchingPatternError
+      expect { user.with_incorrect_hash_return }.to raise_exception Delivered::ArgumentError
     end
   end
 
@@ -70,12 +70,12 @@ def self.find_by_name(name) = User.new(name)
 
     it 'raises on incorrect types' do
       user = User.new('Joel')
-      expect { user.with_block_return }.to raise_exception NoMatchingPatternError
+      expect { user.with_block_return }.to raise_exception Delivered::ArgumentError
     end
 
     it 'raises on incorrect return type' do
       user = User.new('Joel')
-      expect { user.with_incorrect_block_return }.to raise_exception NoMatchingPatternError
+      expect { user.with_incorrect_block_return }.to raise_exception Delivered::ArgumentError
     end
   end
 
@@ -105,29 +105,29 @@ def self.find_by_name(name) = User.new(name)
 
     it 'raise on incorrect type' do
       user = User.new('Joel', 47)
-      expect { user.age = '47' }.to raise_exception NoMatchingPatternError
+      expect { user.age = '47' }.to raise_exception Delivered::ArgumentError
     end
   end
 
   it 'raises on incorrect Delivered type' do
     user = User.new('Joel')
-    expect { user.active = 1 }.to raise_exception NoMatchingPatternError
+    expect { user.active = 1 }.to raise_exception Delivered::ArgumentError
   end
 
   it 'raises on missing args' do
-    expect { User.new }.to raise_exception NoMatchingPatternError
+    expect { User.new }.to raise_exception Delivered::ArgumentError
   end
 
   it 'raises on incorrect arg type' do
-    expect { User.new 1 }.to raise_exception NoMatchingPatternError
+    expect { User.new 1 }.to raise_exception Delivered::ArgumentError
   end
 
   it 'supports keyword args' do
     expect(User.new('Joel', 47, town: 'Chorley').town).to be == 'Chorley'
   end
 
   it 'raises on incorrect kwarg type' do
-    expect { User.new('Joel', town: 1) }.to raise_exception NoMatchingPatternError
+    expect { User.new('Joel', town: 1) }.to raise_exception Delivered::ArgumentError
   end
 
   with 'class methods' do
@@ -136,23 +136,23 @@ def self.find_by_name(name) = User.new(name)
     end
 
     it 'raises on incorrect return type' do
-      expect { User.find_by_name('Hugo') }.to raise_exception NoMatchingPatternError
+      expect { User.find_by_name('Hugo') }.to raise_exception Delivered::ArgumentError
     end
 
     it 'raises on missing args' do
-      expect { User.where }.to raise_exception NoMatchingPatternError
+      expect { User.where }.to raise_exception Delivered::ArgumentError
     end
 
     it 'raises on incorrect arg type' do
-      expect { User.where(1) }.to raise_exception NoMatchingPatternError
+      expect { User.where(1) }.to raise_exception Delivered::ArgumentError
     end
 
     it 'supports keyword args' do
       expect(User.where('hugo', _age: 27)).to be == []
     end
 
     it 'raises on incorrect kwarg type' do
-      expect { User.where(1, _age: 'twentyseven') }.to raise_exception NoMatchingPatternError
+      expect { User.where(1, _age: 'twentyseven') }.to raise_exception Delivered::ArgumentError
     end
   end
 end