An application created as a member of a uv workspace would fail to build if they depended on other workspace
members.
The following shows the problematic workspace structure.
workspace root
├── lib
│ ├── pyproject.toml
│ └── src
├── pyproject.toml
├── sam-app
│ ├── __init__.py
│ ├── app.py
│ ├── pyproject.toml
│ ├── samconfig.toml
│ └── template.yaml
└── uv.lock
The following shows the problematic workspace structure and the error message.
2026-07-15 13:49:33,345 | Building from UV lock file
2026-07-15 13:49:33,346 | Executing UV command: /Users/me/.cargo/bin/uv export --format requirements.txt --no-emit-project --no-hashes --no-default-groups --output-file
/var/folders/8s/g1znx0c90vx3tz81t_rqqgyr0000gn/T/tmptz94ffbg/lock_requirements.txt --python 3.14
2026-07-15 13:49:33,499 | UV command return code: 0
2026-07-15 13:49:33,500 | UV stdout: # This file was autogenerated by uv via the following command:
# uv export --format requirements.txt --no-emit-project --no-hashes --no-default-groups --output-file /var/folders/8s/g1znx0c90vx3tz81t_rqqgyr0000gn/T/tmptz94ffbg/lock_requirements.txt --python 3.14
-e ./lib
# via sam-app
2026-07-15 13:49:33,500 | UV stderr: Using CPython 3.14.6 interpreter at: /opt/homebrew/opt/python@3.14/bin/python3.14
Resolved 3 packages in 8ms
2026-07-15 13:49:33,501 | Executing UV command: /Users/me/.cargo/bin/uv pip install -r /var/folders/8s/g1znx0c90vx3tz81t_rqqgyr0000gn/T/tmptz94ffbg/lock_requirements.txt --target
/Users/me/workspace/sam-app/.aws-sam/deps/351538c7-a05e-4aad-b5c5-928f241070b6 --cache-dir /var/folders/8s/g1znx0c90vx3tz81t_rqqgyr0000gn/T/tmptz94ffbg/uv-cache
--python-version 3.14 --python-platform aarch64-unknown-linux-gnu
2026-07-15 13:49:33,653 | UV command return code: 2
2026-07-15 13:49:33,655 | UV stdout:
2026-07-15 13:49:33,656 | UV stderr: Using CPython 3.13.0 interpreter at: /Users/me/workspace/.venv/bin/python3
error: Distribution not found at: file:///Users/me/workspace/sam-app/lib
2026-07-15 13:49:33,657 | Failed to build dependencies: UV package build failed: Failed to build from pyproject.toml: Lock file operation failed: Failed to install dependencies using uv: UV pip install
failed: Using CPython 3.13.0 interpreter at: /Users/me/workspace/.venv/bin/python3
error: Distribution not found at: file:///Users/me/workspace/sam-app/lib
2026-07-15 13:49:33,662 | PythonUvBuilder:ResolveDependencies failed
Traceback (most recent call last):
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/packager.py", line 348, in _build_from_lock_file
self._uv_runner.install_requirements(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
requirements_path=temp_requirements,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...<6 lines>...
architecture=architecture,
^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/packager.py", line 167, in install_requirements
raise UvInstallationError(reason=f"UV pip install failed: {stderr}")
aws_lambda_builders.workflows.python_uv.exceptions.UvInstallationError: Failed to install dependencies using uv: UV pip install failed: Using CPython 3.13.0 interpreter at:
/Users/me/workspace/.venv/bin/python3
error: Distribution not found at: file:///Users/me/workspace/sam-app/lib
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/packager.py", line 389, in _build_from_pyproject
self._build_from_lock_file(lock_path, target_dir, scratch_dir, python_version, architecture, config)
~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/packager.py", line 361, in _build_from_lock_file
raise LockFileError(reason=str(e))
aws_lambda_builders.workflows.python_uv.exceptions.LockFileError: Lock file operation failed: Failed to install dependencies using uv: UV pip install failed: Using CPython 3.13.0 interpreter at:
/Users/me/workspace/.venv/bin/python3
error: Distribution not found at: file:///Users/me/workspace/sam-app/lib
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/actions.py", line 68, in execute
package_builder.build_dependencies(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
artifacts_dir_path=target_artifact_dir,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...<3 lines>...
config=self.config,
^^^^^^^^^^^^^^^^^^^
)
^
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/packager.py", line 229, in build_dependencies
handler(manifest_path, artifacts_dir_path, scratch_dir_path, python_version, architecture, config)
~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/packager.py", line 282, in _handle_pyproject_build
self._build_from_pyproject(manifest_path, target_dir, scratch_dir, python_version, architecture, config)
~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/packager.py", line 392, in _build_from_pyproject
raise UvBuildError(reason=f"Failed to build from pyproject.toml: {str(e)}")
aws_lambda_builders.workflows.python_uv.exceptions.UvBuildError: UV package build failed: Failed to build from pyproject.toml: Lock file operation failed: Failed to install dependencies using uv: UV pip
install failed: Using CPython 3.13.0 interpreter at: /Users/me/workspace/.venv/bin/python3
error: Distribution not found at: file:///Users/me/workspace/sam-app/lib
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflow.py", line 374, in run
action.execute()
~~~~~~~~~~~~~~^^
File "/opt/homebrew/Cellar/aws-sam-cli/1.162.1/libexec/lib/python3.14/site-packages/aws_lambda_builders/workflows/python_uv/actions.py", line 76, in execute
raise ActionFailedError(str(ex))
aws_lambda_builders.actions.ActionFailedError: UV package build failed: Failed to build from pyproject.toml: Lock file operation failed: Failed to install dependencies using uv: UV pip install failed:
Using CPython 3.13.0 interpreter at: /Users/me/workspace/.venv/bin/python3
error: Distribution not found at: file:///Users/me/workspace/sam-app/lib
2026-07-15 13:49:33,711 | Exception raised during the execution
Build Failed
Successful build is expected.
Description:
An application created as a member of a uv workspace would fail to build if they depended on other workspace
members.
The following shows the problematic workspace structure.
Steps to reproduce:
uv init --bare uv init --lib lib sam init --name sam-app --runtime python3.14 --architecture arm64 \ --dependency-manager pip --package-type Zip \ --app-template hello-world cd sam-app uv init uv add lib@../lib # remove requirements.txt and edit the app # edit template.yaml to configure `BuildMethod: python-uv` and `CodeUri: .` sam build --beta-featuresObserved result:
The following shows the problematic workspace structure and the error message.
Even though
libandsam-appare in the same directory level in the workspace, the workflow attempts to installlibundersam-app.Expected result:
Successful build is expected.
Notes
I've submitted PR #887 to fix for this issue.
Additional environment details (Ex: Windows, Mac, Amazon Linux etc)
sam --version: version 1.162.1Add --debug flag to any SAM CLI commands you are running