hrw4u: Fix u4wrh emitting quoted header names in Prism output

tools/hrw4u/src/common.py

@@ -50,6 +50,9 @@ class RegexPatterns:
         re.VERBOSE | re.DOTALL,
     )
 
+    # Grammar IDENT rule from hrw4u.g4 (header names, qualifiers)
+    GRAMMAR_IDENT: Final = re.compile(r'^[a-zA-Z_][a-zA-Z0-9_@.-]*$')
+
     # Additional performance patterns
     IDENTIFIER: Final = re.compile(r'^[a-zA-Z_][a-zA-Z0-9_]*$')
     WHITESPACE: Final = re.compile(r'\s+')

tools/hrw4u/src/hrw_symbols.py

@@ -233,6 +233,7 @@ def repl(match: re.Match) -> str:
 
     def _handle_set_rm_operation(
             self, cmd: str, toks: list[str], prefix: str, qualifier: str, section: SectionType | None = None) -> str:
+        qualifier = Validator.unquote_if_ident(qualifier)
         if cmd.startswith("rm-"):
             return f'{prefix}{qualifier} = ""'
         if len(toks) < 3:
@@ -289,7 +290,7 @@ def _handle_statement_function(self, name: str, args: list[str], section: Sectio
             qargs = [status_code, self._rewrite_inline_percents(f'"{url_arg}"', section)]
         elif name == "add-header" and args:
             # Convert add-header command to += syntax for reverse mapping
-            header_name = args[0]
+            header_name = Validator.unquote_if_ident(args[0])
             prefix = self.get_prefix_for_context("header_ops", section)
             prefixed_header = f"{prefix}{header_name}"
 

tools/hrw4u/src/validation.py

@@ -228,6 +228,18 @@ def needs_quotes(value: str) -> bool:
     def quote_if_needed(value: str) -> str:
         return f'"{value}"' if Validator.needs_quotes(value) else value
 
+    @staticmethod
+    def unquote_if_ident(value: str) -> str:
+        """Strip surrounding quotes when the unquoted form is a valid grammar IDENT.
+
+        See grammar/hrw4u.g4:72 (IDENT rule); regex at common.py:52 must stay in sync.
+        """
+        if len(value) >= 2 and value.startswith('"') and value.endswith('"'):
+            inner = value[1:-1]
+            if RegexPatterns.GRAMMAR_IDENT.fullmatch(inner):
+                return inner
+        return value
+
     @staticmethod
     def percent_block() -> Callable[[str], None]:
 

tools/hrw4u/tests/data/vars/exceptions.txt

@@ -3,3 +3,6 @@
 #
 # Explicit slot assignment syntax cannot be reversed
 explicit_slots.input: hrw4u
+
+# HRW accepts quoted header names but hrw4u emits them bare when IDENT-safe
+hyphen_header.input: u4wrh

tools/hrw4u/tests/data/vars/hyphen_header.input.txt

@@ -0,0 +1,5 @@
+REMAP {
+    if inbound.method == HEAD {
+        inbound.req.X-Blobstore-Authproxy-Head-Request = "true";
+    }
+}

tools/hrw4u/tests/data/vars/hyphen_header.output.txt

@@ -0,0 +1,2 @@
+cond %{METHOD} =HEAD [AND]
+    set-header "X-Blobstore-Authproxy-Head-Request" "true"

tools/hrw4u/tests/test_errors.py

@@ -324,6 +324,20 @@ def test_quote_if_needed(self):
         assert Validator.quote_if_needed("simple") == "simple"
         assert Validator.quote_if_needed("has space") == '"has space"'
 
+    @pytest.mark.parametrize(
+        "value,expected",
+        [
+            ('"X-Foo"', "X-Foo"),
+            ('"X Foo"', '"X Foo"'),
+            ("X-Foo", "X-Foo"),
+            ('""', '""'),
+            ('"@internal"', '"@internal"'),
+            ('"1foo"', '"1foo"'),
+        ],
+    )
+    def test_unquote_if_ident(self, value, expected):
+        assert Validator.unquote_if_ident(value) == expected
+
 
 class TestPlainTextFormatterParity:
     """The plain formatter must preserve current CLI output byte-for-byte."""