fix: Handle Python projects without pyproject.toml in a365 deploy

[pratapladhani]

Summary

Fixes #252 - a365 deploy overwrites requirements.txt for Python projects without pyproject.toml

Problem

When deploying Python projects that have only requirements.txt (no pyproject.toml or setup.py), the CLI overwrites the requirements file with -e ., which fails because pip cannot find a package to install.

Error from Azure Oryx:

ERROR: file:///tmp/8de6a0cc7ececaa (from -r requirements.txt (line 3)) does not appear to be a Python project: neither 'setup.py' nor 'pyproject.toml' found.

Solution

Modified CreateAzureRequirementsTxt() in PythonBuilder.cs to detect the project structure:

1. If pyproject.toml or setup.py exists: Use the existing -e . (editable install) approach
2. If only requirements.txt exists: Copy the existing file as-is to preserve dependencies
3. If neither exists: Create a minimal placeholder with a warning log

Changes

• PythonBuilder.cs: Updated CreateAzureRequirementsTxt() method with project structure detection
• Added projectDir parameter to access source requirements.txt
• Improved logging to indicate which approach is being used

Testing

• Build passes (dotnet build -c Release)
• All tests pass (945 passed, 0 failed)
• Manual test with Python project without pyproject.toml (was failing, now works)

Compatibility

This is a backward-compatible fix:

• Projects with pyproject.toml or setup.py continue to work as before
• Projects with only requirements.txt now work correctly

[Copilot]

Pull request overview

This PR fixes a bug where a365 deploy incorrectly overwrites requirements.txt with an editable install directive (-e .) for Python projects that lack pyproject.toml or setup.py, causing Azure Oryx deployment failures. The fix adds project structure detection to choose the appropriate requirements.txt generation strategy.

Changes:

• Modified CreateAzureRequirementsTxt() to detect project structure (pyproject.toml/setup.py presence)
• For projects with pyproject.toml/setup.py: uses editable install approach (existing behavior)
• For projects with only requirements.txt: copies the existing file to preserve dependencies (new behavior)
• For projects with no requirements file: creates a minimal placeholder (fallback)

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

[sellakumaran]

Thank you @pratapladhani for identifying issue #252 and providing the fix! You correctly identified that a365 deploy was overwriting requirements.txt for Python projects without pyproject.toml.

I've added some enhancements to your PR:

✅ Error handling - Added try-catch for File.Copy operations
✅ Edge case warning - Added warning when both pyproject.toml and requirements.txt exist
✅ Added tests - Created 5 test scenarios covering all code paths (all tests pass!)

Thanks again for the great contribution!