Version 0.8.0 introduced bug in python discovery on Windows #16077
Description
Summary
There seems to be a bug with python discovery in uv versions 0.8+.
Using uv python list on uv versions starting with 0.8.0 does not show anything:
> uv self version
uv 0.8.22 (ade2bdbd2 2025-09-23)
> uv python list --verbose
DEBUG uv 0.8.22 (ade2bdbd2 2025-09-23)
DEBUG Acquired shared lock for `E:\cache\uv`
DEBUG Searching for any Python interpreter in registry or search path
WARN Broken interpreter cache entry at E:\cache\uv\interpreter-v4\79d66dac82fc70e0\b9f0db740e5eaade.msgpack, removing: invalid type: string "D:\\Python\\Python313\\Lib", expected a sequence
DEBUG Found `cpython-3.13.7-windows-x86_64-none` at `C:\Python\Python313\python.exe` (first executable in the search path)
DEBUG Ignoring Python interpreter at `C:\Python\Python313\python.exe`: only system interpreters allowed
WARN Broken interpreter cache entry at E:\cache\uv\interpreter-v4\79d66dac82fc70e0\bda971ee0901f517.msgpack, removing: invalid type: string "D:\\Python\\Python312\\Lib", expected a sequence
DEBUG Found `cpython-3.12.10-windows-x86_64-none` at `C:\Python\Python312\python.exe` (search path)
DEBUG Ignoring Python interpreter at `C:\Python\Python312\python.exe`: only system interpreters allowed
WARN Broken interpreter cache entry at E:\cache\uv\interpreter-v4\79d66dac82fc70e0\b85ea2b953b5aa48.msgpack, removing: invalid type: string "D:\\Python\\Python310\\Lib", expected a sequence
DEBUG Found `cpython-3.10.11-windows-x86_64-none` at `C:\Python\Python310\python.exe` (search path)
DEBUG Ignoring Python interpreter at `C:\Python\Python310\python.exe`: only system interpreters allowed
DEBUG Found `cpython-3.13.7-windows-x86_64-none` at `C:\Python\Python313\python.exe` (registry)
DEBUG Ignoring Python interpreter at `C:\Python\Python313\python.exe`: only system interpreters allowed
DEBUG Found `cpython-3.12.10-windows-x86_64-none` at `C:\Python\Python312\python.exe` (registry)
DEBUG Ignoring Python interpreter at `C:\Python\Python312\python.exe`: only system interpreters allowed
DEBUG Found `cpython-3.10.11-windows-x86_64-none` at `C:\Python\Python310\python.exe` (registry)
DEBUG Ignoring Python interpreter at `C:\Python\Python310\python.exe`: only system interpreters allowed
DEBUG Released lock at `E:\cache\uv\.lock`Below are results of bisecting the recent versions history.
So it appears the bug was introduced in uv version 0.8.0.
0.8.22 <- Bug
0.8.21 <- Bug
... <- Unchecked
0.8.9 <- Bug
... <- Unchecked
0.8.0 <- Bug
0.7.22 <- OK
Last version producing correct results is 0.7.22:
> uv self version
uv 0.7.22 (78d6d1134 2025-07-17)
> uv python list --verbose
DEBUG uv 0.7.22 (78d6d1134 2025-07-17)
DEBUG Searching for any Python interpreter in registry or search path
WARN Broken interpreter cache entry at E:\cache\uv\interpreter-v4\79d66dac82fc70e0\b9f0db740e5eaade.msgpack, removing: invalid type: sequence, expected path string
DEBUG Found `cpython-3.13.7-windows-x86_64-none` at `C:\Python\Python313\python.exe` (first executable in the search path)
WARN Broken interpreter cache entry at E:\cache\uv\interpreter-v4\79d66dac82fc70e0\bda971ee0901f517.msgpack, removing: invalid type: sequence, expected path string
DEBUG Found `cpython-3.12.10-windows-x86_64-none` at `C:\Python\Python312\python.exe` (search path)
WARN Broken interpreter cache entry at E:\cache\uv\interpreter-v4\79d66dac82fc70e0\b85ea2b953b5aa48.msgpack, removing: invalid type: sequence, expected path string
DEBUG Found `cpython-3.10.11-windows-x86_64-none` at `C:\Python\Python310\python.exe` (search path)
DEBUG Found `cpython-3.13.7-windows-x86_64-none` at `C:\Python\Python313\python.exe` (registry)
DEBUG Found `cpython-3.12.10-windows-x86_64-none` at `C:\Python\Python312\python.exe` (registry)
DEBUG Found `cpython-3.10.11-windows-x86_64-none` at `C:\Python\Python310\python.exe` (registry)
cpython-3.13.7-windows-x86_64-none C:\Python\Python313\python.exe
cpython-3.12.10-windows-x86_64-none C:\Python\Python312\python.exe
cpython-3.10.11-windows-x86_64-none C:\Python\Python310\python.exePlatform
Windows 11 x64
Version
0.8.22
Python version
Python 3.13