Question
ERROR: Cannot open file: Permission denied – File Opening Component
Rey Maple
0 reputation · 12 Jul 2024, 17:36 UTC
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0 reputation · 12 Jul 2024, 17:36 UTC
When Blender attempts to open a file located in a protected directory, the console emits the message ERROR: Cannot open file: Permission denied and aborts the operation. The current implementation provides no graphical feedback, leaving the user unaware of possible remedies.
Key constraints include the lack of a GUI dialog, absence of automated permission escalation, and the potential for cross‑platform inconsistencies. Users report frustration due to the abrupt halt and lack of guidance on how to resolve the issue.
Unresolved decisions revolve around whether Blender should (1) present a dialog offering to retry or request elevated privileges, (2) suggest alternative file locations, or (3) provide a fallback mechanism for read‑only files. What design pattern should govern the permission‑escalation workflow across Windows, macOS, and Linux?
33775 reputation · 13 Jul 2024, 02:09 UTC
Use an explicit, per-file elevation workflow: separate file access from the UI, then show a platform-native dialog offering Retry, Choose another location, Open read-only, Request elevation for this file, and Cancel. Do not silently run Blender as administrator or root.
Likely explanation: Blender's file-open call fails because the process lacks permission for the protected path, and the current code aborts before presenting graphical feedback. This is most likely on desktop builds when opening files under system directories such as C:\Windows\System32, /etc, or /System/Library.
| Statement | Status |
|---|---|
| Console error precedes abort; no GUI dialog appears | Described in the issue report |
| OS-native elevation mechanisms exist for Windows, macOS, and Linux | Well-established platform behavior |
| Read-only opening can remove the need for elevation | Depends on user intent; unconfirmed |
| Behavior across Blender builds and Python API versions | Unverified; test against the installed release |
Reproduce with a non-admin Blender process opening a file under a protected path and observe whether a dialog appears. Identify the build variant (installer, Flatpak, Snap, AppImage, console/headless) because sandboxing and GUI availability change what is feasible. Test each adapter with a writable temp file first, then a protected file.
Missing diagnostic: does the user require write access to the file, or is opening it read-only acceptable? This determines whether elevation is necessary or whether a read-only fallback is sufficient.
Assumption: this concerns an interactive desktop GUI build of Blender. Headless or console builds cannot show dialogs and should log the error with exit guidance instead.
Use comments to ask for clarification. Post a solution as an answer.
33,775 reputation · 12 Jul 2024, 22:36 UTC
By defining a PermissionEscalator interface, the UI can remain agnostic of OS specifics. Each concrete class—WindowsEscalator, macOSEscalator, LinuxEscalator—implements boolean requestElevation(Path file) and calls the native elevation API (UAC, Authorization Services, polkit). The file‑open workflow simply escalator.requestElevation(file) and retries if true.
blenderSystem.getProperty("os.name") at runtime.EscalatorRegistry.This pattern keeps dialog logic uniform while delegating platform‑specific permission handling to interchangeable handlers, satisfying cross‑platform consistency and testability.