/errors /poetry/no-dev-option-does-not-exist

Poetry: The option "--no-dev" does not exist

updated 2026-10-21

tool: Poetry
exit code: 1
versions: Poetry 2.x
os: any

The option "--no-dev" does not exist means the installed Poetry is 2.x, where the --no-dev flag no longer exists. Since Poetry 1.2, development dependencies live in dependency groups; --no-dev was deprecated then and Poetry 2 no longer accepts it. Replace poetry install --no-dev with poetry install --without dev (skip the dev group) or poetry install --only main (main dependencies only).

Reproduce it

bash

cat > pyproject.toml <<'EOF'
[project]
name = "demo"
version = "0.1.0"
requires-python = ">=3.10"
dependencies = []

[tool.poetry]
package-mode = false
EOF
uvx -q poetry@2.5.1 config virtualenvs.in-project true --local
uvx -q poetry@2.5.1 install --no-dev

Output · exit 1

Creating virtualenv demo in /tmp/work/.venv

The option "--no-dev" does not exist

Poetry rejects the option before it resolves or installs anything.

Fix

bash

cat > pyproject.toml <<'EOF'
[project]
name = "demo"
version = "0.1.0"
requires-python = ">=3.10"
dependencies = []

[tool.poetry]
package-mode = false

[tool.poetry.group.dev.dependencies]
six = "1.16.0"
EOF
uvx -q poetry@2.5.1 config virtualenvs.in-project true --local
uvx -q poetry@2.5.1 install --without dev

Output

Creating virtualenv demo in /tmp/work/.venv
Updating dependencies
Resolving dependencies...

Writing lock file

The group passed to --without must exist: Poetry 2 stops with Group(s) not found: dev (via --without) when pyproject.toml has no dev group, so drop the option for projects without dev dependencies.

Poetry 1.x	Poetry 2.x
poetry install --no-dev	poetry install --without dev
poetry install --no-dev (main only, no other groups)	poetry install --only main

--without dev still installs any other non-optional group (for example a test group); --only main installs nothing but the main dependencies. poetry add -D PKG is still accepted in Poetry 2 as a shortcut for --group dev.

Sources

commands · poetrypoetry add --group dev pytest: add a development dependencypoetry add --group dev pytest records a development-only dependency; Poetry 2 writes it to [dependency-groups]. poetry install --without dev leaves it out.errors · poetrypyproject.toml changed significantly since poetry.lock was last generated. Run `poetry lock`poetry install stops when pyproject.toml dependencies changed after poetry.lock was written. Run poetry lock, commit poetry.lock, verify with check --lock.errors · poetryPoetry could not find a pyproject.toml file in /path or its parentsPoetry commands need a pyproject.toml in the current folder or a parent, or fail with Poetry could not find a pyproject.toml file. Use poetry init, cd or -C.flags · poetrypoetry install --only main: skip dev dependencies (replaces --no-dev)poetry install --only main skips dev and other groups and replaces the removed --no-dev. --without, --with, optional groups, poetry sync, production installs.

Reproduce it

Fix

Sources

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