FURB101 and FURB103 shouldn’t apply when the I/O variable is used later #21483
Description
Summary
read-whole-file (FURB101) and write-whole-file (FURB103) should be suppressed when the I/O variable is used after the with block (unless the variable is unconditionally rebound). There is no straightforward way to get the same behavior by using the suggested pathlib methods. Examples:
$ cat >furb10.py <<'# EOF'
with open("furb10.py", encoding="utf-8") as f1:
_ = f1.read()
try:
print(f1.mode)
except NameError as e:
print(e)
with open("furb10.txt", "w") as f2:
f2.write("\n")
try:
print(f2.encoding)
except NameError as e:
print(e)
# EOF
$ python furb10.py
r
UTF-8
$ ruff --isolated check furb10.py --select FURB101,FURB103 --preview --fix
Found 2 errors (2 fixed, 0 remaining).
$ cat furb10.py
import pathlib
_ = pathlib.Path("furb10.py").read_text(encoding="utf-8")
try:
print(f1.mode)
except NameError as e:
print(e)
pathlib.Path("furb10.txt").write_text("\n")
try:
print(f2.encoding)
except NameError as e:
print(e)
$ python furb10.py
name 'f1' is not defined
name 'f2' is not definedVersion
ruff 0.14.5 (87dafb8 2025-11-13)