VIRTUAL_ENV=/usr/local in dockerfile stopped working for uv 0.2 (error: No Python interpreters found in virtual environments)

[przecze]

this used to work:

FROM python:3.11-slim-bookworm

ENV VIRTUAL_ENV=/usr/local
RUN pip install --no-cache-dir uv && \
    uv pip install --no-cache-dir pandas

but now it results in

error: No Python interpreters found in virtual environments

I was able to pin it down to recent uv 0.2 release, namely:
this works

FROM python:3.11-slim-bookworm

ENV VIRTUAL_ENV=/usr/local
RUN pip install --no-cache-dir "uv<0.2" && \
    uv pip install --no-cache-dir pandas

but this throws the error:

FROM python:3.11-slim-bookworm

ENV VIRTUAL_ENV=/usr/local
RUN pip install --no-cache-dir "uv>=0.2" && \
    uv pip install --no-cache-dir pandas

Output with verbose:

Step 3/3 : RUN pip install --no-cache-dir "uv>=0.2" &&     uv pip install --verbose --no-cache-dir pandas
 ---> [Warning] The requested image's platform (linux/amd64) does not match the detected host platform (linux/arm64/v8) and no specific platform was requested
 ---> Running in f211bab5e4dc
Collecting uv>=0.2
  Downloading uv-0.2.2-py3-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl.metadata (32 kB)
Downloading uv-0.2.2-py3-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (13.0 MB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 13.0/13.0 MB 24.3 MB/s eta 0:00:00
Installing collected packages: uv
Successfully installed uv-0.2.2
WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv
<jemalloc>: MADV_DONTNEED does not work (memset will be used instead)
<jemalloc>: (This is the expected behaviour if you are running under QEMU)
DEBUG Searching for interpreter that fulfills Python @ default
DEBUG Searching for interpreter that fulfills Python @ default
INFO Found active virtual environment (via VIRTUAL_ENV) at: /usr/local
DEBUG Ignoring Python interpreter at `/usr/local/bin/python`: system intepreter not allowed
error: No Python interpreters found in virtual environments

Looks like system interpreter not allowed is the root cause in v0.2, how to work around it in Dockerfile?

[przecze]

note: seems to be fixed by adding the --system flag in uv pip install instead of VIRTUAL_ENV

[zanieb]

Hi! This is a duplicate of #3782 and #3765.

I think it's better to opt-in to system modification than to pretend you're in a virtual environment.