[smshagor-dev]

Background

PR #438 merged green as 7a9914c6daa474a86f28a2e850b407d3176f8592, protecting two views sharing the same manager instance from concurrent download status and cancellation corruption. A separate desktop process with its own manager could still install models into the same portable root simultaneously, racing the checkpoint, voice/config and manifest writes.

Changes

• Add a persistent <portable-root>/.openmindai-model-install.lock, opened read/write and guarded with Rust standard-library exclusive OS File::try_lock (no extra dependencies). The OS releases the lock automatically when its file handle is dropped or its owner exits.
• Acquire it before changing status, cancellation token or model files, after the existing in-memory permit. Hold it through the complete model/dependency/manifest installation and final status recording. Reject an overlapping process immediately with a readable error; never steal its progress or cancel it.
• Reject symlink/non-regular lock destinations and check root containment; fail closed on unsupported or failed locks. Keep the lock file persistent rather than deleting a possibly locked inode.
• Add no-network Rust regression tests for two independently instantiated managers targeting one root, a separate unaffected root, lock reacquisition after release, unsafe lock destination rejection, and preserving status on refused install.
• Document advisory-lock semantics, crash recovery, and filesystem limitations.

Review gates

Keep draft until all current-head Windows/macOS/Linux CI, Security/CodeQL, Release Readiness, and real Kokoro cross-platform + production Model Download Manager install-and-speak checks pass. This protects cooperating OpenMindAI processes; it does not claim unrelated software respects advisory locks or that removable/network disks guarantee identical behavior.

[smshagor-dev]

CI investigation (2026-10-20): On head 26d062dc733e3cd3312df5cc37a9f4542d26e6c7, all four authentic Kokoro tests, Security/CodeQL, Release Readiness, Frontend validation, Cargo lockfile and Windows Tauri build passed. Windows, macOS and Linux Rust validation failed at the same cargo fmt --check gate, with three formatting diffs in src-tauri/src/model_download.rs: the TryLockError match arms, the rejected-lock assertion, and the error-message assertion. Applied exactly those rustfmt adjustments in commit f200ddef180bd09c79b5612eb11e9c67721f9b76. Fresh head workflows: CI #39461831089, Security #39461831025, Release Readiness #39461831187, and Kokoro Real Voice Inference #39461831771. The PR remains draft and unmerged pending all current-head checks green.