Describe the bug

Running pdm export command results in an empty requirements.txt file.

pdm export -f requirements -o requirements.txt --lockfile pylock.toml 

Output of the requirements.txt file:

# This file is @generated by PDM.
# Please do not edit it manually.

To reproduce

Run pdm export -f requirements -o requirements.txt --lockfile pylock.toml on a project with pylock.toml file

Expected Behavior

Requirements file should have generated with libraries and their versions

Environment Information

PDM version:
2.25.4
Python Interpreter:
/Users/raczeq/dev/quackosm/.venv/bin/python (3.12)
Project Root:
/Users/raczeq/dev/quackosm
Local Packages:

{
"implementation_name": "cpython",
"implementation_version": "3.12.9",
"os_name": "posix",
"platform_machine": "arm64",
"platform_release": "24.5.0",
"platform_system": "Darwin",
"platform_version": "Darwin Kernel Version 24.5.0: Tue Apr 22 19:54:29 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T6030",
"python_full_version": "3.12.9",
"platform_python_implementation": "CPython",
"python_version": "3.12",
"sys_platform": "darwin"
}

Verbose Command Output

No response

Additional Context

No response

Are you willing to submit a PR to fix this bug?

• Yes, I would like to submit a PR.