File Type Restriction Bypass via Rename

p5.js version

No response

What is your operating system?

None

Web browser and version

No response

Actual Behavior

User attempts to create a new file with a .obj extension (e.g., demo.obj) in the p5.js web editor
The editor correctly blocks the creation and displays an error:
"Invalid file type. Valid extensions are .js, .css, .json, .xml, .stl, .txt, .csv, .tsv, .mtl, .frag, and .vert."
User creates a file with a valid extension (e.g., demo.js) — this succeeds
User then renames demo.js to demo.obj
The editor allows the rename without any validation, successfully creating a .obj file — bypassing the restriction entirely

Expected Behavior

When a user attempts to rename a file to an invalid extension (e.g., .obj), the editor should trigger the same validation as it does during file creation
The rename action should be blocked and display the same error message:
"Invalid file type. Valid extensions are .js, .css, .json, .xml, .stl, .txt, .csv, .tsv, .mtl, .frag, and .vert."
The filename should revert back to its previous valid name
File type restrictions should be consistently enforced across all entry points — both creation and rename — so there is no way to bypass the whitelist

Steps to reproduce

Steps:

Step 1: Open the p5.js web editor and log in to your account

Step 2: In the Sketch Files panel on the left side, click the "+" button to create a new file

Step 3: In the "Create File" dialog, type demo.obj and click "Add File"

✅ Confirm that the editor blocks this and shows the error:
"Invalid file type. Valid extensions are .js, .css, .json, .xml, .stl, .txt, .csv, .tsv, .mtl, .frag, and .vert."

Step 4: Again click the "+" button and this time type demo.txt and click "Add File"

✅ Confirm that the file demo.txt is created successfully and appears in the Sketch Files panel

Step 5: In the Sketch Files panel, double-click on demo.txt to rename it

Step 6: Clear the filename and type demo.obj, then press Enter to confirm the rename

// Paste your code here :)

Reproduce the issue in the p5.js web editor through the Sketch Files panel, comparing the Create File flow with the double-click rename entry point. Trace where the invalid-extension error is enforced during creation and where rename is confirmed. Done means renaming to an unsupported extension is blocked, the existing valid name is restored, and the same error message is shown.