fix(webview): send stable view-state id on launch and re-pin per-view state

[easonLiangWorldedtech]

Part of the vps2 durable per-view state series — tracked in easonLiangWorldedtech#41 (cross-repo: standalone a+d measured against the stack base; the displayed vs-main diff includes lower units until they merge).

Issue (created at PR-open time): #1551

What

Persists each webview's stable state identity at launch and makes launch-time per-view state re-pin correctly. The webview now carries a viewStateId (created and persisted via the webview state API, with an in-memory fallback) that is posted with webviewDidLaunch and persisted on the provider via setViewStateId, re-keying the pre-launch temporary state entry to the launching webview. When the view-local API profile is invalid at launch, the view is re-pinned to the still-valid shared global selection with a view-local write only — the shared global is repaired only when its own selection is also invalid. updateSettings is routed through provider.setValue so view-local buffer/pin sync stays consistent with the other mutation paths.

Design decisions

• The view-state id is owned by the webview (VSCodeAPIWrapper.getViewStateId): it reuses the id persisted in webview state, creates one (crypto.randomUUID, with a timestamp+random fallback) and persists it via setState; when storage is unavailable it falls back to an in-memory field. The id is best-effort — the launch message carries viewStateId: undefined when the helper is unavailable, and the provider degrades to the shared-global path.
• Re-pin is view-local: provider.saveViewState("currentApiConfigName", name) writes the view's buffer/pin without touching the shared global selection; the legacy global repair (global write + activateProviderProfile) runs only when the shared global selection is also invalid.
• Validation order on launch: merged (view-local) name first, then the shared global selection, then the first listed profile — matching the merged getState() semantics from F1b.
• updateSettings delegates to provider.setValue rather than contextProxy.setValue so the view-local buffer/pin sync path (_saveViewLocalStateFromMutation) runs for settings edits too.

Measurements

git diff --numstat 43b52aa11 (stack base, F1b head) — a+d total: 545 (528 insertions, 17 deletions):

file	+	−
src/core/webview/webviewMessageHandler.ts	32	8
src/core/webview/__tests__/webviewMessageHandler.spec.ts	117	1
webview-ui/src/utils/vscode.ts	62	7
webview-ui/src/utils/__tests__/vscode.spec.ts (new)	216	0
webview-ui/src/context/ExtensionStateContext.tsx	4	1
webview-ui/src/context/__tests__/ExtensionStateContext.spec.tsx	97	0

Composition note: 430 of the 528 inserted lines are tests (spec files 117 + 97 + 216); production additions are 98 lines. a+d is above the 400 soft budget because the unit ships both webview-side and extension-side behavior with unit + integration tests at each layer; it is well under the 1000 hard cap.

Changed executable lines (stryker-diff): 65 (32 extension + 33 webview changed lines) — cap ≤500.
Raw mutants (stryker-diff): 65 — cap ≤400.

Gates

• eslint: eslint --prune-suppressions --max-warnings=0 exit 0 per touched file (src: webviewMessageHandler.ts + spec; webview-ui: vscode.ts, vscode.spec.ts, ExtensionStateContext.tsx + spec). src/eslint-suppressions.json unchanged — suppression counts did not increase (a prune run that only re-indented the file with zero count change was reverted).
• check-types: src exit 0; webview-ui exit 0.
• vitest: webviewMessageHandler.spec.ts 85/85 pass (81 base + 4 new launch tests); vscode.spec.ts 9/9 (new spec); ExtensionStateContext.spec.tsx 24/24 (21 base + 3 new). ClineProvider.spec.ts not affected (no ClineProvider.ts changes in this unit).
• prettier: --check exit 0 on all six touched files (CRLF checkout normalized via --write).
• stryker-diff (base 43b52aa11, head 090d2c87e): 65 raw mutants — 59 Killed, 0 Survived, 0 NoCoverage (6 Ignored equivalent mutants, the documented CS Stryker disable comments in vscode.ts L91/L122). Caps: 0 Survived / 0 NoCoverage in changed code, 65 changed executable lines ≤ 500, 65 raw mutants ≤ 400.

Parked / documented

Observed in the CS diff but not ported (register items, to be tracked by the series ledger):

• Mojibake comment hunk in the WMH diff (—? corruption in the requestRouterModels opencode-go comment): base comment // Deliberately no opencodeGoApiKey — the endpoint is public. kept as-is.
• Unused defaultModeSlug import in the WMH spec: not ported (F3 re-adds it with its use).
• kimi-code OAuth try/catch hunk in requestRouterModels + its webviewMessageHandler.routerModels.spec.ts additions: not ported (review-hardening hunk outside F1c scope).
• ApiConfigManager.tsx className tweak: not ported (not part of the F1c row).
• ApiConfigManager.visual.tsx deletion + screenshot baselines: not ported (visual-suite churn outside F1c scope).
• providers/*, types, fetchers, e2e fixtures, and repo-config churn (.coderabbit.yaml, label-pr-review-state.yml, .gitignore, CONTRIBUTING.md, ClineProvider.ts changes, parallel-mode/sticky-mode specs, etc.): not ported (belong to the other series units).

Porting notes

Hand-ported from CS commit e9a44b2fa (base of record 0d937c050), hunk by hunk; no cherry-pick.

Ported:

• src/core/webview/webviewMessageHandler.ts: webviewDidLaunch handler — await provider.setViewStateId(message.viewStateId); launch-time re-pin block (validate merged view-local name, then shared global, re-pin the view via provider.saveViewState when the global is still valid, else legacy global repair); updateSettings routed through provider.setValue.
• webview-ui/src/utils/vscode.ts: VSCodeAPIWrapper fallback state, createViewStateId/getViewStateId, browser-fallback getState/setState with the CS Stryker disable comments.
• webview-ui/src/context/ExtensionStateContext.tsx: launch effect posts webviewDidLaunch with viewStateId.
• webview-ui/src/utils/__tests__/vscode.spec.ts: new spec, all 9 tests (id reuse, create+persist, in-memory fallback, id shape, stored-state edge cases).
• src/core/webview/__tests__/webviewMessageHandler.spec.ts: RooCodeSettings import, saveViewState mock, setValue mock delegating to contextProxy.setValue, and the webviewDidLaunch describe (CS verbatim, plus one CS deviation below).

CS deviation (mutation coverage): the CS launch tests as-is leave 2 mutants alive in the re-pin block — the StringLiteral on the getGlobalState("currentApiConfigName") key (the CS mock getValue returns the canned value for any key, so a mutated key is unobservable) and the ConditionalExpression on if (name) (every CS test leaves name truthy). To satisfy the 0-survived stryker-diff gate without an escape hatch, the getValue mock in the launch describe is key-aware ("currentApiConfigName" → "shared-profile", anything else → undefined), and one additional test covers the falsy-name legacy repair (selection recorded, no profile activation). This matches the CS commit's own "harden viewStateId mutation coverage" intent.

• webview-ui/src/context/__tests__/ExtensionStateContext.spec.tsx: @src/utils/vscode mock, ViewLocalStateTestComponent, and its 3 tests (launch post with/without id; view-local reseed contract).

Not ported (per the register above): the six parked items — verified by full-file diff against the CS final state: every ported file is byte-identical to the CS tree (modulo the intentionally skipped hunks).

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[codecov]

Codecov Report

❌ Patch coverage is 94.11765% with 13 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/core/webview/ClineProvider.ts	94.59%	3 Missing and 7 partials ⚠️
webview-ui/src/utils/vscode.ts	86.36%	1 Missing and 2 partials ⚠️

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