Merge pull request rubocop#2237 from rrosenblum/fix_format_parameter_mismatch

bbatsov · bbatsov · commit 94be910fdf0f · 2015-09-12T07:57:15.000+02:00
Fix format parameter mismatch
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -16,6 +16,8 @@
 * [#2213](https://github.com/bbatsov/rubocop/issues/2213): Write to cache with binary encoding to avoid transcoding exceptions in some locales. ([@jonas054][])
 * [#2218](https://github.com/bbatsov/rubocop/issues/2218): Fix loading config error when safe yaml is only partially loaded. ([@maxjacobson][])
 * [#2161](https://github.com/bbatsov/rubocop/issues/2161): Allow an explicit receiver (except `Kernel`) in `Style/SignalException`. ([@lumeet][])
+* [#2237](https://github.com/bbatsov/rubocop/pull/2237): Allow `Lint/FormatParameterMismatch` to be called using `Kernel.format` and `Kernel.sprintf`. ([@rrosenblum][])
+* [#2234](https://github.com/bbatsov/rubocop/issues/2234): Do not register an offense for `Lint/FormatParameterMismatch` when the format string is a variable. ([@rrosenblum][])
 
 ## 0.34.0 (05/09/2015)
 
diff --git a/lib/rubocop/cop/lint/format_parameter_mismatch.rb b/lib/rubocop/cop/lint/format_parameter_mismatch.rb
@@ -14,13 +14,14 @@ module Lint
       class FormatParameterMismatch < Cop
         # http://rubular.com/r/CvpbxkcTzy
         MSG = 'Number arguments (%i) to `%s` mismatches expected fields (%i).'
-        # rubocop:disable Metrics/LineLength
-        FIELD_REGEX = /(%(([\s#+-0\*])?(\d*)?(.\d+)?(\.)?[bBdiouxXeEfgGaAcps]|%))/
-        NAMED_FIELD_REGEX = /%\{[_a-zA-Z][_a-zA-Z]+\}/
-
-        def fields_regex
-          FIELD_REGEX
-        end
+        FIELD_REGEX = /(%(([\s#+-0\*])?(\d*)?(.\d+)?(\.)?[bBdiouxXeEfgGaAcps]|%))/.freeze # rubocop:disable Metrics/LineLength
+        NAMED_FIELD_REGEX = /%\{[_a-zA-Z][_a-zA-Z]+\}/.freeze
+        KERNEL = 'Kernel'.freeze
+        SHOVEL = '<<'.freeze
+        PERCENT = '%'.freeze
+        PERCENT_PERCENT = '%%'.freeze
+        SPLAT = '*'.freeze
+        STRING_TYPES = [:str, :dstr].freeze
 
         def on_send(node)
           add_offense(node, :selector) if offending_node?(node)
@@ -29,18 +30,29 @@ def on_send(node)
         private
 
         def offending_node?(node)
+          return false unless called_on_string?(node)
+
           if sprintf?(node) || format?(node) || percent?(node)
             if named_mode?(node) || node_with_splat_args?(node)
               false
             else
-              num_of_args_for_format, num_of_expected_fields = count_matches(node)
-              num_of_expected_fields != num_of_args_for_format
+              num_of_format_args, num_of_expected_fields = count_matches(node)
+              num_of_expected_fields != num_of_format_args
             end
           else
             false
           end
         end
 
+        def called_on_string?(node)
+          receiver_node, _method, format_string, = *node
+          if receiver_node.nil? || receiver_node.const_type?
+            format_string && format_string.str_type?
+          else
+            receiver_node.str_type?
+          end
+        end
+
         def named_mode?(node)
           receiver_node, _method_name, *args = *node
 
@@ -50,11 +62,7 @@ def named_mode?(node)
                             receiver_node
                           end
 
-          relevant_node
-            .loc
-            .expression
-            .source
-            .scan(NAMED_FIELD_REGEX).count > 0
+          relevant_node.loc.expression.source.scan(NAMED_FIELD_REGEX).size > 0
         end
 
         def node_with_splat_args?(node)
@@ -68,7 +76,7 @@ def node_with_splat_args?(node)
         def heredoc?(node)
           _receiver, _name, args = *node
 
-          args.loc.expression.source[0, 2] == '<<'
+          args.loc.expression.source[0, 2] == SHOVEL
         end
 
         def count_matches(node)
@@ -80,7 +88,7 @@ def count_matches(node)
           elsif percent?(node)
             first_child_argument = args.first
 
-            if first_child_argument.type == :array
+            if first_child_argument.array_type?
               number_of_args_for_format = args.first.child_nodes.size
               number_of_expected_fields = expected_fields_count(receiver_node)
             else
@@ -95,10 +103,13 @@ def count_matches(node)
         def format_method?(name, node)
           receiver, method_name, *args = *node
 
-          # commands have no explicit receiver
-          return false unless !receiver && method_name == name
+          if receiver && receiver.const_type?
+            return false unless receiver.loc.name.is?(KERNEL)
+          end
+
+          return false unless method_name == name
 
-          args.size > 1 && :str == args.first.type
+          args.size > 1 && args.first.str_type?
         end
 
         def expected_fields_count(node)
@@ -107,8 +118,8 @@ def expected_fields_count(node)
             .expression
             .source
             .scan(FIELD_REGEX)
-            .select { |x| x.first != '%%' }
-            .reduce(0) { |a, e| a + (e[2] == '*' ? 2 : 1) }
+            .select { |x| x.first != PERCENT_PERCENT }
+            .reduce(0) { |a, e| a + (e[2] == SPLAT ? 2 : 1) }
         end
 
         def format?(node)
@@ -123,10 +134,10 @@ def percent?(node)
           receiver_node, method_name, *arg_nodes = *node
 
           percent = method_name == :% &&
-                    ([:str, :dstr].include?(receiver_node.type) ||
-                     arg_nodes[0].type == :array)
+                    (STRING_TYPES.include?(receiver_node.type) ||
+                     arg_nodes[0].array_type?)
 
-          if percent && [:str, :dstr].include?(receiver_node.type)
+          if percent && STRING_TYPES.include?(receiver_node.type)
             return false if heredoc?(node)
           end
 
@@ -137,7 +148,7 @@ def message(node)
           _receiver, method_name, *_args = *node
           num_args_for_format, num_expected_fields = count_matches(node)
 
-          method_name = 'String#%' if '%' == method_name.to_s
+          method_name = 'String#%' if PERCENT == method_name.to_s
           format(MSG, num_args_for_format, method_name, num_expected_fields)
         end
       end
diff --git a/spec/rubocop/cop/lint/format_parameter_mismatch_spec.rb b/spec/rubocop/cop/lint/format_parameter_mismatch_spec.rb
@@ -5,6 +5,53 @@
 describe RuboCop::Cop::Lint::FormatParameterMismatch do
   subject(:cop) { described_class.new }
 
+  shared_examples 'variables' do |variable|
+    it 'does not register an offense for % called on a variable' do
+      inspect_source(cop, ["#{variable} = '%s'",
+                           "#{variable} % [foo]"])
+
+      expect(cop.messages).to be_empty
+    end
+
+    it 'does not register an offense for format called on a variable' do
+      inspect_source(cop, ["#{variable} = '%s'",
+                           "format(#{variable}, foo)"])
+
+      expect(cop.messages).to be_empty
+    end
+
+    it 'does not register an offense for format called on a variable' do
+      inspect_source(cop, ["#{variable} = '%s'",
+                           "sprintf(#{variable}, foo)"])
+
+      expect(cop.messages).to be_empty
+    end
+  end
+
+  it_behaves_like 'variables', 'CONST'
+  it_behaves_like 'variables', 'var'
+  it_behaves_like 'variables', '@var'
+  it_behaves_like 'variables', '@@var'
+  it_behaves_like 'variables', '$var'
+
+  it 'registers an offense when calling Kernel.format ' \
+     'and the fields do not match' do
+    inspect_source(cop, 'Kernel.format("%s %s", 1)')
+    expect(cop.offenses.size).to eq(1)
+
+    msg = ['Number arguments (1) to `format` mismatches expected fields (2).']
+    expect(cop.messages).to eq(msg)
+  end
+
+  it 'registers an offense when calling Kernel.sprintf ' \
+     'and the fields do not match' do
+    inspect_source(cop, 'Kernel.sprintf("%s %s", 1)')
+    expect(cop.offenses.size).to eq(1)
+
+    msg = ['Number arguments (1) to `sprintf` mismatches expected fields (2).']
+    expect(cop.messages).to eq(msg)
+  end
+
   it 'registers an offense when there are less arguments than expected' do
     inspect_source(cop, 'format("%s %s", 1)')
     expect(cop.offenses.size).to eq(1)
@@ -38,15 +85,16 @@
   end
 
   it 'registers offense with sprintf' do
-    inspect_source(cop, 'format("%s %s", 1, 2, 3)')
+    inspect_source(cop, 'sprintf("%s %s", 1, 2, 3)')
     expect(cop.offenses.size).to eq(1)
 
-    msg = ['Number arguments (3) to `format` mismatches expected fields (2).']
+    msg = ['Number arguments (3) to `sprintf` mismatches expected fields (2).']
     expect(cop.messages).to eq(msg)
   end
 
   it 'correctly parses different sprintf formats' do
-    inspect_source(cop, 'format("%020x%+g:% g %%%#20.8x %#.0e", 1, 2, 3, 4, 5)')
+    inspect_source(cop,
+                   'sprintf("%020x%+g:% g %%%#20.8x %#.0e", 1, 2, 3, 4, 5)')
     expect(cop.offenses).to be_empty
   end
 
@@ -130,53 +178,53 @@
   end
 
   it 'finds the correct number of fields' do
-    expect(''.scan(cop.fields_regex).size)
+    expect(''.scan(described_class::FIELD_REGEX).size)
       .to eq(0)
-    expect('%s'.scan(cop.fields_regex).size)
+    expect('%s'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%s %s'.scan(cop.fields_regex).size)
+    expect('%s %s'.scan(described_class::FIELD_REGEX).size)
       .to eq(2)
-    expect('%s %s %%'.scan(cop.fields_regex).size)
+    expect('%s %s %%'.scan(described_class::FIELD_REGEX).size)
       .to eq(3)
-    expect('%s %s %%'.scan(cop.fields_regex).size)
+    expect('%s %s %%'.scan(described_class::FIELD_REGEX).size)
       .to eq(3)
-    expect('% d'.scan(cop.fields_regex).size)
+    expect('% d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%+d'.scan(cop.fields_regex).size)
+    expect('%+d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%d'.scan(cop.fields_regex).size)
+    expect('%d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%+o'.scan(cop.fields_regex).size)
+    expect('%+o'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%#o'.scan(cop.fields_regex).size)
+    expect('%#o'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%.0e'.scan(cop.fields_regex).size)
+    expect('%.0e'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%#.0e'.scan(cop.fields_regex).size)
+    expect('%#.0e'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('% 020d'.scan(cop.fields_regex).size)
+    expect('% 020d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%20d'.scan(cop.fields_regex).size)
+    expect('%20d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%+20d'.scan(cop.fields_regex).size)
+    expect('%+20d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%020d'.scan(cop.fields_regex).size)
+    expect('%020d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%+020d'.scan(cop.fields_regex).size)
+    expect('%+020d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('% 020d'.scan(cop.fields_regex).size)
+    expect('% 020d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%-20d'.scan(cop.fields_regex).size)
+    expect('%-20d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%-+20d'.scan(cop.fields_regex).size)
+    expect('%-+20d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%- 20d'.scan(cop.fields_regex).size)
+    expect('%- 20d'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%020x'.scan(cop.fields_regex).size)
+    expect('%020x'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%#20.8x'.scan(cop.fields_regex).size)
+    expect('%#20.8x'.scan(described_class::FIELD_REGEX).size)
       .to eq(1)
-    expect('%+g:% g:%-g'.scan(cop.fields_regex).size)
+    expect('%+g:% g:%-g'.scan(described_class::FIELD_REGEX).size)
       .to eq(3)
   end
 end
