[CapThunder19]

What type of PR is this?

/kind bug

What this PR does / why we need it

UploadFileRequest.Content had binding:"required" on a plain string. Gin treats an empty string as missing, so a JSON upload with "content": "" was rejected with a 400. Since the base64 of an empty file is an empty string, there was no way to create an empty file this way. That breaks write_file("", ...) in the Python SDK, run_code with empty code, and the MCP server's write_file tool. Multipart upload of the same empty file already worked.

This changes Content to *string and keeps binding:"required", so:

• "content": "" creates a zero-byte file
• a request with no content field is still rejected with 400

Which issue(s) this PR fixes

Fixes #476

Special notes for your reviewer

Added TestHandleJSONBase64Upload_Content, which covers empty content, missing content and normal content. The empty-content case fails on main and passes with this change. I also checked it end to end with the Python SDK against a local PicoD build: write_file("", "pkg/__init__.py") returned 400 before and succeeds now.

Does this PR introduce a user-facing change?

PicoD now accepts empty content in JSON file uploads, so empty files can be created with the SDK's write_file.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[acsoto]

/lgtm
/approve

[volcano-sh-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: acsoto

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• pkg/picod/OWNERS [acsoto]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 60.42%. Comparing base (5903457) to head (828fb12).
⚠️ Report is 18 commits behind head on main.
❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #481      +/-   ##
==========================================
+ Coverage   59.98%   60.42%   +0.43%     
==========================================
  Files          36       35       -1     
  Lines        3589     3618      +29     
==========================================
+ Hits         2153     2186      +33     
+ Misses       1216     1212       -4     
  Partials      220      220              

Flag	Coverage Δ
unittests	60.42% <100.00%> (+0.43%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.