1.2.x version regression: when `install` called multiple times with different "extras", then "extras" from previous step are removed

Steps to reproduce (1.2.x version)

1. poetry install -E foobar
2. poetry install -E spameggs

After calling -E spameggs, all extras from “foobar” will be removed.

Old behavior (1.1.x version)

1. poetry install -E foobar
2. poetry install -E spameggs

After calling -E spameggs, all extras from “foobar” are kept. In result, I have all “foobar” and “spameggs” dependencies.

Problems

• This change is not mentioned in the changelog https://python-poetry.org/history/
• This change is Poetry regression / degradation.

Rationale

In the past, I was able to use Docker multi-stage builds:

FROM python:3.10-slim-bullseye as base
# Install only main dependencies
RUN poetry install --no-interaction --no-ansi --no-root --no-dev


FROM base as testing
# We have runtime dependencies, now add only "dev" dependencies
RUN poetry install --no-interaction --no-ansi --no-root


FROM base as deploy
# We have runtime dependencies, now add only cloud dependencies
RUN poetry install --no-interaction --no-ansi --no-root --no-dev -E cloud_deploy

In other words, I was able to add more and more “extras” on every CI/CD step. Since 1.2.x version such behavior is broken and I see no workarounds.

[dimbleby]

An MR updating the docs would be welcome I’m sure. I’ve been trying to help you with

and I see no workarounds

… and I think we’re done.

[dimbleby]

The 1.2 behaviour seems like an improvement to me. If you want to install more than one set of extras then, per the help

  -E (--extras)          Extra sets of dependencies to install. (multiple values allowed)

multiple values are allowed