[1/4] Load chat preferences without blocking Eclipse

[Sheng Chen (jdneo)]

Opening chat can block Eclipse's SWT thread while the Copilot Language Server resolves the preference path or saved preferences are read. This first layer addresses initial-loading responsiveness from #408 without changing the preference file location, representation, account association, or CLS persistence contract.

Scope and approach

• Give ChatServiceManager one authoritative, lifecycle-owned PreferenceStorage, shared by actual mode/model preference consumers. Constructors and synchronous getters no longer wait for preference RPCs or file reads.
• Restore preferences asynchronously with a 15-second logical deadline covering path resolution and reading. Publish successful restoration through the correct observable Realm; show localized loading, failure, and retry states while disabling only dependent controls.
• Treat a definitely missing file as first-run defaults. Reject unreadable files, malformed/null JSON, invalid persistence responses, and RPC failures without overwriting existing files. Reject legacy Gson syntax extensions on older supported Eclipse targets.
• Coalesce initialization/retry requests and reject obsolete results after timeout, account changes, or disposal. Preserve restored mode, model, history, confirmation, reasoning-effort, and context-window choices and existing policy behavior.
• Remove a cold built-in-mode discovery wait that otherwise still blocked initialization. Preserve unresolved mode identity instead of silently sending Plan as Agent, refresh dependent controls after discovery, and provide independent manual mode-discovery failure/retry without reloading ready preferences.
• Keep vision bindings observable during loading and handle unavailable/disposed models safely, including image-reference tooltips.

Review and regression coverage

Parallel Standards and Spec reviews were performed against b138f1a7cfec6aa293b6834bbe9fb5bf8e1f0235, including follow-up changes before commit. All in-scope findings were resolved. The known synchronous-saving limitation is intentionally assigned to layer 02.

Tests exercise real first-initialization entry points and the public storage lifecycle: incomplete authenticated RPCs with separately queued SWT actions, readiness/control states, controlled deadlines, restoration and file/RPC failures, coalesced retries, stale/account/disposal protection, both preference/mode-discovery completion orders, and manual discovery recovery preserving loaded choices. UI tests propagate SWT-thread failures back to JUnit rather than relying on workbench exception handling. Red-to-green failures were demonstrated for lost vision observation, unavailable-image-model dereference, and disposed-observable access.

Validation

Final committed code was validated on Windows using installed Java 21 (JAVA_HOME=C:\Users\sheche\.jdks\ms-21.0.11):

.\mvnw.cmd -B '-Dtycho.disableP2Mirrors=true' clean verify
.\mvnw.cmd -B '-Dtycho.disableP2Mirrors=true' checkstyle:check
.\mvnw.cmd -B '-Dtycho.disableP2Mirrors=true' test

All three commands passed. The final clean build passed all 19 reactor modules and 10,767 tests: core 10,210, UI 553, and jobs 4, with zero failures, errors, or skipped tests in those suites. The targeted preference/initialization/image selection passed 87 tests. Tycho's executed suite evidence comes from verify; the test phase also completed successfully. git diff --check passed.

The SWTBot JSON-probe module skips execution by default. No JSON probe was authored or executed, and no probe coverage is claimed.

Bootstrap issues were resolved without tracked build changes: npm install --force --no-audit --no-fund in com.microsoft.copilot.eclipse.core\copilot-agent restored pinned CLS 1.541.0 assets; disabling Eclipse P2 mirrors avoided a stalled download; installed Java 21 avoided the pinned Mockito/Byte Buddy incompatibility with the default Java 25. No validation blocker remains.

Stack boundaries and follow-ups

This is layer 01 of 04, based on main. It delivers nonblocking loading, not the whole nonblocking-preferences specification.

• 02: Immediate updates and serialized, atomic, retryable background saving. This layer preserves existing saving through shared state; synchronous mode/confirmation/sign-out/disposal saves and save-lock contention remain for that follow-up.
• 03: Automatic preference recovery on authentication and actual CLS reconnection, preserving dirty choices and account isolation. This layer adds basic invalidation and manual recovery only.
• 04: Best-effort asynchronous shutdown flush within a two-second budget.

No CLS CPU investigation, preference-format migration, cross-instance merging, or protocol change is included.