Auto merge of #17749 - SergeevPavel:extra-space-check, r=jdm

Extra space check

<!-- Please describe your changes on the following line: -->
Add tidy check for keywords with more than one space afterwards.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #17700 (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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python/tidy/servo_tidy/tidy.py

@@ -584,6 +584,12 @@ def check_rust(file_name, lines):
             # -> () is unnecessary
             (r"-> \(\)", "encountered function signature with -> ()", no_filter),
         ]
+        keywords = ["if", "let", "mut", "extern", "as", "impl", "fn", "struct", "enum", "pub", "mod",
+                    "use", "in", "ref", "type", "where", "trait"]
+        extra_space_after = lambda key: (r"(?<![A-Za-z0-9\-_]){key}  ".format(key=key),
+                                         "extra space after {key}".format(key=key),
+                                         lambda match, line: not is_attribute)
+        regex_rules.extend(map(extra_space_after, keywords))
 
         for pattern, message, filter_func in regex_rules:
             for match in re.finditer(pattern, line):

python/tidy/servo_tidy_tests/rust_tidy.rs

@@ -72,4 +72,10 @@ impl test {
       } else { // Should not trigger
           "false"
       } // Should not trigger
+
+    if  true { // Double space after keyword
+        42
+    } else {
+        let xif = 42 in {  xif  } // Should not trigger
+    }
 }

python/tidy/servo_tidy_tests/test_tidy.py

@@ -95,6 +95,7 @@ class CheckTidiness(unittest.TestCase):
 
     def test_rust(self):
         errors = tidy.collect_errors_for_files(iterFile('rust_tidy.rs'), [], [tidy.check_rust], print_text=False)
+        self.assertEqual('extra space after use', errors.next()[2])
         self.assertEqual('extra space after {', errors.next()[2])
         self.assertEqual('extra space before }', errors.next()[2])
         self.assertEqual('use statement spans multiple lines', errors.next()[2])
@@ -133,6 +134,7 @@ class CheckTidiness(unittest.TestCase):
         self.assertEqual('no = in the beginning of line', errors.next()[2])
         self.assertEqual('space before { is not a multiple of 4', errors.next()[2])
         self.assertEqual('space before } is not a multiple of 4', errors.next()[2])
+        self.assertEqual('extra space after if', errors.next()[2])
         self.assertNoMoreErrors(errors)
 
         feature_errors = tidy.collect_errors_for_files(iterFile('lib.rs'), [], [tidy.check_rust], print_text=False)