address review

Author: lpyu001

Lib/test/test_fstring.py

@@ -1678,6 +1678,14 @@ def __repr__(self):
         self.assertEqual(f'{" # nooo "=}', '" # nooo "=\' # nooo \'')
         self.assertEqual(f'{" \" # nooo \" "=}', '" \\" # nooo \\" "=\' " # nooo " \'')
 
+        result = f'''{(
+            1,  # Force lexer metadata reconstruction.
+            "\"#")=}'''
+        self.assertEqual(
+            result,
+            '(\n            1,  \n            "\\"#")=(1, \'"#\')',
+        )
+
         self.assertEqual(f'{ # some comment goes here
   """hello"""=}',  ' \n  """hello"""=\'hello\'')
         self.assertEqual(f'{"""# this is not a comment

Lib/test/test_tstring.py

@@ -140,6 +140,43 @@ def test_debug_specifier(self):
         )
         self.assertEqual(fstring(t), "Value: value = 42")
 
+        # Explicit line continuations after the debug marker are part of
+        # the debug text, not the interpolation expression.
+        for template, strings, interpolation, rendered in (
+            (
+                t"""Value: {value =\
+}""",
+                ("Value: value =\\\n", ""),
+                (value, "value ", "r"),
+                "Value: value =\\\n42",
+            ),
+            (
+                t"""Value: {value =\
+!r}""",
+                ("Value: value =\\\n", ""),
+                (value, "value ", "r"),
+                "Value: value =\\\n42",
+            ),
+            (
+                t"""Value: {value =\
+:04}""",
+                ("Value: value =\\\n", ""),
+                (value, "value ", None, "04"),
+                "Value: value =\\\n0042",
+            ),
+            (
+                t"""Value: {value =\
+\
+}""",
+                ("Value: value =\\\n\\\n", ""),
+                (value, "value ", "r"),
+                "Value: value =\\\n\\\n42",
+            ),
+        ):
+            with self.subTest(template=template):
+                self.assertTStringEqual(template, strings, [interpolation])
+                self.assertEqual(fstring(template), rendered)
+
     def test_interpolation_expression_whitespace(self):
         x = 42
         for template, expected in (

Lib/test/test_unparse.py

@@ -221,6 +221,10 @@ def test_tstrings(self):
                 1,  # Force lexer metadata reconstruction.
                 "\"#")}'''"""
         )
+        self.check_ast_roundtrip(
+            r'''t"""Value: {value =\
+}"""'''
+        )
 
     def test_tstring_with_nonsensical_str_field(self):
         # `value` suggests that the original code is `t'{test1}`, but `str` suggests otherwise

Misc/NEWS.d/next/Core_and_Builtins/2026-07-27-17-20-49.gh-issue-154719.eI88Gs.rst

@@ -1,4 +1,5 @@
 Whitespace immediately before ``}``, ``!``, ``:``, or ``=`` is now included
 in :attr:`string.templatelib.Interpolation.expression` for interpolations
-created from t-string literals.  Preserve escaped quotes while reconstructing
-interpolation expression metadata containing comments.
+created from t-string literals. Preserve escaped quotes while reconstructing
+t-string interpolation metadata and f-string debug expression text containing
+comments.

Parser/action_helpers.c

@@ -1544,15 +1544,29 @@ _strip_interpolation_debug_expr(PyObject *exprstr)
 {
     Py_ssize_t len = PyUnicode_GET_LENGTH(exprstr);
 
-    /* Discard whitespace after the debug "=" but preserve whitespace before it. */
+    /* Discard whitespace and explicit line continuations after the debug "="
+       but preserve whitespace before it. */
     while (len > 0) {
-        Py_UCS4 c = PyUnicode_READ_CHAR(exprstr, len - 1);
-        if (!_PyUnicode_IsWhitespace(c)) {
+        int has_newline = 0;
+        while (len > 0) {
+            Py_UCS4 c = PyUnicode_READ_CHAR(exprstr, len - 1);
+            if (!_PyUnicode_IsWhitespace(c)) {
+                break;
+            }
+            if (c == '\r' || c == '\n') {
+                has_newline = 1;
+            }
+            len--;
+        }
+        if (!has_newline || len == 0 ||
+            PyUnicode_READ_CHAR(exprstr, len - 1) != '\\')
+        {
             break;
         }
         len--;
     }
-    /* The debug marker may be absent from reconstructed lexer metadata. */
+
+    /* Preserve unexpected metadata instead of dropping source text. */
     if (len == 0 || PyUnicode_READ_CHAR(exprstr, len - 1) != '=') {
         return Py_NewRef(exprstr);
     }