add support for t-strings

src/flake8/_compat.py

@@ -9,3 +9,10 @@ if sys.version_info >= (3, 12):  # pragma: >=3.12 cover
     FSTRING_END = tokenize.FSTRING_END
 else:  # pragma: <3.12 cover
     FSTRING_START = FSTRING_MIDDLE = FSTRING_END = -1
+
+if sys.version_info >= (3, 14):  # pragma: >=3.14 cover
+    TSTRING_START = tokenize.TSTRING_START
+    TSTRING_MIDDLE = tokenize.TSTRING_MIDDLE
+    TSTRING_END = tokenize.TSTRING_END
+else:  # pragma: <3.14 cover
+    TSTRING_START = TSTRING_MIDDLE = TSTRING_END = -1

src/flake8/checker.py

@@ -19,6 +19,7 @@ from flake8 import exceptions
 from flake8 import processor
 from flake8 import utils
 from flake8._compat import FSTRING_START
+from flake8._compat import TSTRING_START
 from flake8.discover_files import expand_paths
 from flake8.options.parse_args import parse_args
 from flake8.plugins.finder import Checkers
@@ -554,6 +555,8 @@ class FileChecker:
         assert self.processor is not None
         if token.type == FSTRING_START:  # pragma: >=3.12 cover
             self.processor.fstring_start(token.start[0])
+        elif token.type == TSTRING_START:  # pragma: >=3.14 cover
+            self.processor.tstring_start(token.start[0])
         # a newline token ends a single physical line.
         elif processor.is_eol_token(token):
             # if the file does not end with a newline, the NEWLINE

src/flake8/processor.py

@@ -13,6 +13,8 @@ from flake8 import defaults
 from flake8 import utils
 from flake8._compat import FSTRING_END
 from flake8._compat import FSTRING_MIDDLE
+from flake8._compat import TSTRING_END
+from flake8._compat import TSTRING_MIDDLE
 from flake8.plugins.finder import LoadedPlugin
 
 LOG = logging.getLogger(__name__)
@@ -113,7 +115,7 @@ class FileProcessor:
         self.verbose = options.verbose
         #: Statistics dictionary
         self.statistics = {"logical lines": 0}
-        self._fstring_start = -1
+        self._fstring_start = self._tstring_start = -1
 
     @functools.cached_property
     def file_tokens(self) -> list[tokenize.TokenInfo]:
@@ -125,10 +127,16 @@ class FileProcessor:
         """Signal the beginning of an fstring."""
         self._fstring_start = lineno
 
+    def tstring_start(self, lineno: int) -> None:  # pragma: >=3.14 cover
+        """Signal the beginning of an tstring."""
+        self._tstring_start = lineno
+
     def multiline_string(self, token: tokenize.TokenInfo) -> Generator[str]:
         """Iterate through the lines of a multiline string."""
         if token.type == FSTRING_END:  # pragma: >=3.12 cover
             start = self._fstring_start
+        elif token.type == TSTRING_END:  # pragma: >=3.14 cover
+            start = self._tstring_start
         else:
             start = token.start[0]
 
@@ -198,7 +206,10 @@ class FileProcessor:
                 continue
             if token_type == tokenize.STRING:
                 text = mutate_string(text)
-            elif token_type == FSTRING_MIDDLE:  # pragma: >=3.12 cover
+            elif token_type in {
+                FSTRING_MIDDLE,
+                TSTRING_MIDDLE,
+            }:  # pragma: >=3.12 cover  # noqa: E501
                 # A curly brace in an FSTRING_MIDDLE token must be an escaped
                 # curly brace. Both 'text' and 'end' will account for the
                 # escaped version of the token (i.e. a single brace) rather
@@ -382,7 +393,7 @@ def is_eol_token(token: tokenize.TokenInfo) -> bool:
 
 def is_multiline_string(token: tokenize.TokenInfo) -> bool:
     """Check if this is a multiline string."""
-    return token.type == FSTRING_END or (
+    return token.type in {FSTRING_END, TSTRING_END} or (
         token.type == tokenize.STRING and "\n" in token.string
     )
 

tests/integration/test_plugins.py

@@ -296,3 +296,36 @@ t.py:1:1: T001 "f'xxxxxxxxxxxxxxxxxxxxxxxx'"
 """
     out, err = capsys.readouterr()
     assert out == expected
+
+
+@pytest.mark.xfail(sys.version_info < (3, 14), reason="3.14+")
+def test_tstring_logical_line(tmpdir, capsys):  # pragma: >=3.14 cover
+    cfg_s = f"""\
+[flake8]
+extend-ignore = F
+[flake8:local-plugins]
+extension =
+    T = {yields_logical_line.__module__}:{yields_logical_line.__name__}
+"""
+
+    cfg = tmpdir.join("tox.ini")
+    cfg.write(cfg_s)
+
+    src = """\
+t'''
+hello {world}
+'''
+t'{{"{hello}": "{world}"}}'
+"""
+    t_py = tmpdir.join("t.py")
+    t_py.write_binary(src.encode())
+
+    with tmpdir.as_cwd():
+        assert main(("t.py", "--config", str(cfg))) == 1
+
+    expected = """\
+t.py:1:1: T001 "t'''xxxxxxx{world}x'''"
+t.py:4:1: T001 "t'xxx{hello}xxxx{world}xxx'"
+"""
+    out, err = capsys.readouterr()
+    assert out == expected