Merge CouchDB cache compatibility changes into Journal recovery

test/e2e-cli/test-journal-chunk-recovery.ts

@@ -3,7 +3,7 @@ import assert from "node:assert/strict";
 import { mkdir, readFile, rename, writeFile } from "node:fs/promises";
 import { dirname, join } from "node:path";
 import { TempDir } from "./helpers/temp.ts";
-import { assertFilesEqual, runCliOrFail, sanitiseCatStdout } from "./helpers/cli.ts";
+import { assertFilesEqual, runCli, runCliOrFail, sanitiseCatStdout, type CliResult } from "./helpers/cli.ts";
 import { applyRemoteSyncSettings, initSettingsFile } from "./helpers/settings.ts";
 import { startMinio, stopMinio } from "./helpers/docker.ts";
 
@@ -34,6 +34,20 @@ function createJournalFixture(): string {
     ].join("");
 }
 
+async function assertFetchedVaultMatches(
+    sourceFile: string,
+    receiverFile: string,
+    result: CliResult,
+    message: string
+): Promise<void> {
+    assert.equal(result.code, 0, `${message}\nCLI exit code: ${result.code}\n${result.combined}`);
+    try {
+        await assertFilesEqual(sourceFile, receiverFile, message);
+    } catch (error) {
+        throw new Error(`${message}\nCLI output:\n${result.combined}`, { cause: error });
+    }
+}
+
 async function runScenario(encrypt: boolean): Promise<void> {
     const suffix = `${encrypt ? "enc1" : "enc0"}-${Date.now()}-${Math.floor(Math.random() * 100000)}`;
     const minioEndpoint = requireEnv("MINIO_ENDPOINT", "minioEndpoint").replace(/\/$/, "");
@@ -99,7 +113,7 @@ async function runScenario(encrypt: boolean): Promise<void> {
             "--force",
             "--write-settings"
         );
-        await runCliOrFail(
+        const initialFetch = await runCli(
             receiverDatabase,
             "--settings",
             receiverSettings,
@@ -110,7 +124,12 @@ async function runScenario(encrypt: boolean): Promise<void> {
             "--write-settings"
         );
 
-        await assertFilesEqual(sourceFile, receiverFile, "Fetched Vault file does not match the rebuild source");
+        await assertFetchedVaultMatches(
+            sourceFile,
+            receiverFile,
+            initialFetch,
+            "Initial fetch did not reproduce the rebuild source in the receiver Vault"
+        );
         const fetchedContent = sanitiseCatStdout(
             await runCliOrFail(receiverDatabase, "--settings", receiverSettings, "cat", targetPath)
         );
@@ -163,7 +182,7 @@ async function runScenario(encrypt: boolean): Promise<void> {
             "Fetch should retain both the intact remote and differing local contents without inferring their ancestry"
         );
         await rename(receiverFile, workDir.join("damaged-vault-backup.md"));
-        await runCliOrFail(
+        const restoreFetch = await runCli(
             receiverDatabase,
             "--settings",
             receiverSettings,
@@ -173,7 +192,12 @@ async function runScenario(encrypt: boolean): Promise<void> {
             "--force",
             "--write-settings"
         );
-        await assertFilesEqual(sourceFile, receiverFile, "Fetching into an empty Vault should restore the remote file");
+        await assertFetchedVaultMatches(
+            sourceFile,
+            receiverFile,
+            restoreFetch,
+            "Fetch did not restore the remote file after the damaged Vault copy was moved"
+        );
         assert.equal(await readFile(workDir.join("damaged-vault-backup.md"), "utf8"), damagedContent);
         const restoredContent = sanitiseCatStdout(
             await runCliOrFail(receiverDatabase, "--settings", receiverSettings, "cat", targetPath)

test/e2e-obsidian/README.md

@@ -172,9 +172,9 @@ The Harness also measures ID generation with fixed in-memory data on desktop and
 
 The same workflow checks the two remote-activity status boundaries. It first holds a real CouchDB request at the selected fetch implementation and confirms that `🌐N` is visible while `📲` is absent. It then holds the real one-shot replication immediately before its replicator call, confirms that `📲` is visible while no physical request is active, releases it, and requires the finite and bounded activity counts to return to zero, the request and response counts to balance, and both indicators to disappear. Finally, it creates a remote-only chunk, holds the real on-demand fetch immediately before its remote call, makes the same logical active and idle assertions, and verifies that the fetched chunk is written into the local database. These gates make the active states deterministic without replacing the remote request or operation.
 
-`test:e2e:obsidian:couchdb-http-cache` checks replication after rebuilding an encrypted CouchDB remote while an earlier HTTP response remains cached. It enables internal Metadata encryption with Hidden File Sync and Customisation Sync, verifies that the Rebuild replaces the Security Seed and ciphertext while retaining the document revision, and requires the replication pre-check and subsequent sends to succeed without clearing the browser cache. It uses the CouchDB fixture variables, an isolated Vault and profile, and a unique remote database. The raw command uses the current built plug-in by default; `E2E_OBSIDIAN_ARTIFACT_ROOT` can select an exact earlier build for regression comparison.
+`test:e2e:obsidian:couchdb-http-cache` checks replication after rebuilding an encrypted CouchDB remote while an earlier HTTP response remains cached. It enables internal Metadata encryption with Hidden File Sync and Customisation Sync, verifies that the Rebuild replaces the Security Seed and ciphertext while retaining the document revision, and requires the replication pre-check and subsequent sends to succeed without clearing the browser cache. It uses the CouchDB fixture variables, an isolated Vault and profile, and a unique remote database. The raw command uses the current built plug-in by default; `E2E_OBSIDIAN_ARTIFACT_ROOT` can select an exact earlier build for regression comparison. It also verifies the combined startup-time/Seed hash, the default-off headers-only compatibility switch through the visible settings UI, its saved value after reopening, and the resulting request URLs and cache modes in both switch positions.
 
-Run `npm run test:e2e:obsidian:focused -- couchdb-http-cache --request-api` to warm Obsidian's Internal API cache and perform the same workflow with **Use Internal API** enabled. Both modes require an explicit `no-store` read to return the rebuilt ciphertext. The default mode also retains the stale browser-cache assertion; the Internal API mode permits reads during Rebuild to refresh that cache.
+Run `npm run test:e2e:obsidian:focused -- couchdb-http-cache --request-api` to warm Obsidian's Internal API cache and perform the same workflow with **Use Internal API** enabled. Both modes read decoded Metadata through owned Commonlib connections and observe the actual request URLs. They require the cache URL to change after Security Seed replacement and remain stable across new connections with an unchanged Seed, including after Standard Fetch. The ordinary Vault file must retain its expected contents. The final Standard Fetch phase includes Chunk bodies rather than leaving them for on-demand retrieval, so strict local reconciliation can read the file after database replacement. The default mode also retains the stale browser-cache assertion; the Internal API mode permits reads during Rebuild to refresh that cache. Native adapters may return a full body rather than 304 during revalidation.
 
 `npm run test:e2e:obsidian:focused -- chunk-fetch-retry` checks delayed Chunk availability through a real CouchDB service and Obsidian. It creates a Metadata-only remote fixture, starts ordinary one-shot replication with `readChunksOnline`, and inserts the missing Chunk only after a real fetch has returned an empty result. A pass-through observer records the replicator's call times and results without substituting responses or adding waits. The fixture sets the existing minimum request interval to 500 ms to keep the real retry status observable even if finite completion expedites the final probe. The actual status bar must show zero initial requests (`🛄`) and one retry (`🔁`), and both counts must return to zero after delivery ends. On-demand replication excludes Chunk documents from the ordinary pull, so the delayed Chunk must arrive through the observed fetch and produce the exact Vault content.
 

test/e2e-obsidian/scripts/couchdb-http-cache.ts

@@ -1,5 +1,5 @@
 import assert from "node:assert/strict";
-import { mkdir, writeFile } from "node:fs/promises";
+import { mkdir, readFile, writeFile } from "node:fs/promises";
 import { dirname, join, resolve } from "node:path";
 import { DoctorRegulation } from "@vrtmrz/livesync-commonlib/compat/common/configForDoc";
 import { DOCID_SYNC_PARAMETERS } from "@vrtmrz/livesync-commonlib/compat/common/types";
@@ -22,16 +22,47 @@ import {
     prepareRemote,
     pushLocalChanges,
     waitForLiveSyncCoreReady,
+    waitForLocalDatabaseEntry,
 } from "../runner/liveSyncWorkflow.ts";
 import { startObsidianLiveSyncSession, type ObsidianLiveSyncSession } from "../runner/session.ts";
 import { createTemporaryVault } from "../runner/vault.ts";
+import { obsidianRemoteDebuggingPort, openLiveSyncSettings, withObsidianPage } from "../runner/ui.ts";
 
 process.env.E2E_OBSIDIAN_CLI_TIMEOUT_MS ??= "60000";
 
 const useRequestAPI = process.argv.includes("--request-api");
+type ObservedRequest = { transport: string; method: string; url: string; cache?: RequestCache };
+type RestartState = {
+    settings: {
+        useCouchDBCacheControlHeadersOnly: boolean;
+        couchDB_DBNAME: string;
+        deviceAndVaultName: string;
+        encrypt: boolean;
+        encryptInternalMetadata: boolean;
+        usePathObfuscation: boolean;
+    };
+    localDatabaseName: string;
+    localMetadata: null | { id: string; revision: string; path: string; children: string[] };
+    nodeId: string;
+};
+
+async function waitForNextUnixSecond(previousUnixSecond: number): Promise<void> {
+    const timeoutMs = Number(process.env.E2E_OBSIDIAN_CORE_READY_TIMEOUT_MS ?? 20000);
+    const deadline = Date.now() + timeoutMs;
+    while (Math.floor(Date.now() / 1000) <= previousUnixSecond) {
+        if (Date.now() >= deadline) {
+            throw new Error("Timed out waiting for the next Unix second before restarting Obsidian.");
+        }
+        await new Promise((resolve) => setTimeout(resolve, 20));
+    }
+}
 
 const customPath = ".obsidian/snippets/http-cache.css";
 const nextCustomPath = ".obsidian/snippets/http-cache-new.css";
+const ordinaryPath = "example.md";
+const ordinaryContents = "/* HTTP cache fixture */\n";
+const restartNotePath = "restart-after-http-cache.md";
+const restartNoteContents = "Synchronised after restarting Obsidian.\n";
 const settings = {
     encrypt: true,
     passphrase: "couchdb-http-cache-fixture-secret",
@@ -48,6 +79,7 @@ const settings = {
     syncInternalFilesTargetPatterns: "^\\.http-cache(?:/|$)",
     watchInternalFileChanges: false,
     useRequestAPI,
+    usePowerUserMode: true,
     autoAcceptCompatibleTweak: false,
     doctorProcessedVersion: DoctorRegulation.version,
     deviceAndVaultName: "http-cache-source",
@@ -62,6 +94,7 @@ async function main(): Promise<void> {
     const connection = { ...couchDb, dbName };
     const vault = await createTemporaryVault();
     let session: ObsidianLiveSyncSession | undefined;
+    let observingRequests = false;
     const evaluate = async <T>(body: string): Promise<T> => {
         if (!session) throw new Error("No active Obsidian session.");
         return await evalObsidianJson<T>(
@@ -85,12 +118,118 @@ async function main(): Promise<void> {
             if(!response.ok)throw new Error('Fixture read failed: '+response.status);
             return JSON.stringify(await response.json());`);
     };
+    const observeCommonlibRequests = async (): Promise<void> => {
+        await evaluate(`return (() => {
+            const api=core.services.API;
+            const state={requests:[],originals:{},restore:undefined};
+            for(const name of ['webCompatFetch','nativeFetch']) {
+                state.originals[name]=api[name];
+                api[name]=function(request,options) {
+                    const url=typeof request==='string'?request:request.url;
+                    const method=options?.method??(typeof request==='string'?'GET':request.method);
+                    state.requests.push({transport:name,method,url,cache:options?.cache});
+                    return state.originals[name].call(this,request,options);
+                };
+            }
+            state.restore=()=>{for(const name of Object.keys(state.originals)) api[name]=state.originals[name];};
+            globalThis.couchDBHttpCacheObservations=state;
+            return JSON.stringify(true);
+        })()`);
+        observingRequests = true;
+    };
+    const restoreCommonlibRequests = async (): Promise<void> => {
+        await evaluate(`return (() => {
+            const state=globalThis.couchDBHttpCacheObservations;
+            if(state)state.restore();
+            delete globalThis.couchDBHttpCacheObservations;
+            return JSON.stringify(true);
+        })()`);
+        observingRequests = false;
+    };
+    const readCommonlibDocument = async (id: string) =>
+        await evaluate<{
+            document: CouchDbDocument;
+            requests: ObservedRequest[];
+        }>(`const state=globalThis.couchDBHttpCacheObservations;
+            if(!state)throw new Error('HTTP request observation is not active');
+            const firstRequest=state.requests.length;
+            const replicator=core.services.replicator.getActiveReplicator();
+            const connection=await replicator.connectRemoteCouchDBWithSetting(
+                core.services.setting.currentSettings(),false,false,true);
+            if(typeof connection==='string')throw new Error('Could not open the owned Commonlib connection: '+connection);
+            try {
+                const document=await connection.db.get(${JSON.stringify(id)});
+                return JSON.stringify({document,requests:state.requests.slice(firstRequest)});
+            } finally {
+                await connection.close();
+            }`);
+
+    const metadataRequest = (
+        read: Awaited<ReturnType<typeof readCommonlibDocument>>,
+        id: string
+    ): ObservedRequest => {
+        const request = read.requests
+            .filter((candidate) => {
+                const path = new URL(candidate.url).pathname;
+                return decodeURIComponent(path.slice(path.lastIndexOf("/") + 1)) === id;
+            })
+            .slice(-1)[0];
+        assert.ok(request, `The owned Commonlib read did not request Metadata ${id}.`);
+        assert.equal(request.transport, useRequestAPI ? "nativeFetch" : "webCompatFetch");
+        assert.equal(request.method.toUpperCase(), "GET");
+        return request;
+    };
+    const setHeadersOnlyThroughUI = async (enabled: boolean, expectedBefore: boolean): Promise<void> => {
+        await withObsidianPage(obsidianRemoteDebuggingPort(), async (page) => {
+            const navigator = await openLiveSyncSettings(page);
+            try {
+                const pane = await navigator.openPage("Power users");
+                const row = pane.locator(".setting-item").filter({
+                    hasText: "Use headers only for HTTP cache control (compatibility)",
+                });
+                await row.waitFor({ state: "visible" });
+                assert.equal(await row.locator(".checkbox-container.is-enabled").count(), Number(expectedBefore));
+                await row.locator(".checkbox-container").click();
+                await page.waitForFunction(
+                    `app.plugins.plugins['obsidian-livesync'].core.services.setting.currentSettings().useCouchDBCacheControlHeadersOnly === ${enabled}`
+                );
+            } finally {
+                await navigator.close();
+            }
+        });
+        const saved = JSON.parse(await readFile(join(vault.path, ".obsidian/plugins/obsidian-livesync/data.json"), "utf8"));
+        assert.equal(saved.useCouchDBCacheControlHeadersOnly, enabled, "The compatibility switch was not saved.");
+    };
+    const assertLogicalDocument = (document: CouchDbDocument, original: CouchDbDocument): void => {
+        assert.equal(document._id, original._id);
+        assert.equal(document._rev, original._rev, "The logical Metadata revision changed.");
+        assert.equal(document.path, ordinaryPath, "The owned connection did not return the logical file path.");
+        assert.equal(document.type, original.type);
+        assert.equal(document.size, Buffer.byteLength(ordinaryContents));
+        assert.ok(Array.isArray(document.children) && document.children.length > 0);
+    };
+    const readRestartState = async (): Promise<RestartState> =>
+        await evaluate<RestartState>([
+            "const settings=core.services.setting.currentSettings();",
+            "const database=core.localDatabase.localDatabase;",
+            "const databaseInfo=await database.info();",
+            "const nodeInfo=await database.get('_local/obsydian_livesync_nodeinfo').catch(()=>null);",
+            "const localMetadata=await core.localDatabase.getDBEntry('example.md',undefined,false,true).catch(()=>null);",
+            "return JSON.stringify({settings:{",
+            "useCouchDBCacheControlHeadersOnly:settings.useCouchDBCacheControlHeadersOnly===true,",
+            "couchDB_DBNAME:settings.couchDB_DBNAME,deviceAndVaultName:core.services.setting.getDeviceAndVaultName(),",
+            "encrypt:settings.encrypt,encryptInternalMetadata:settings.encryptInternalMetadata,",
+            "usePathObfuscation:settings.usePathObfuscation},",
+            "localDatabaseName:databaseInfo.db_name,",
+            "localMetadata:localMetadata?{id:localMetadata._id,revision:localMetadata._rev,path:localMetadata.path,children:localMetadata.children??[]}:null,",
+            "nodeId:nodeInfo?.nodeid??''});",
+        ].join(""));
 
     try {
         await createCouchDbDatabase(couchDb, dbName);
-        for (const path of ["example.md", ".http-cache/example.json", customPath]) {
+        for (const path of [ordinaryPath, ".http-cache/example.json", customPath]) {
             await mkdir(dirname(join(vault.path, path)), { recursive: true });
-            await writeFile(join(vault.path, path), "/* HTTP cache fixture */\n");
+            await writeFile(join(vault.path, path), ordinaryContents);
         }
         session = await startObsidianLiveSyncSession({
             binary,
@@ -114,6 +253,27 @@ async function main(): Promise<void> {
         const initialParameters = await fetchCouchDbDocument(couchDb, dbName, DOCID_SYNC_PARAMETERS);
         // Populate the HTTP cache as an earlier plug-in version would have done.
         assert.deepEqual(await readCachedDocument(original._id, "reload"), original);
+        await observeCommonlibRequests();
+        const initialRead = await readCommonlibDocument(original._id);
+        assertLogicalDocument(initialRead.document, original);
+        const initialMetadataRequest = metadataRequest(initialRead, original._id);
+        const initialEpoch = new URL(initialMetadataRequest.url).searchParams.get("_livesync_epoch");
+        assert.ok(initialEpoch, "The ordinary Metadata read did not include a Seed cache namespace.");
+        assert.match(initialEpoch, /^[0-9a-f]{64}$/, "The URL must contain only the combined hash.");
+
+        await setHeadersOnlyThroughUI(true, false);
+        const compatibilityRead = await readCommonlibDocument(original._id);
+        assertLogicalDocument(compatibilityRead.document, original);
+        const compatibilityRequest = metadataRequest(compatibilityRead, original._id);
+        assert.equal(new URL(compatibilityRequest.url).searchParams.has("_livesync_epoch"), false);
+        assert.equal(compatibilityRequest.cache, "no-store");
+
+        await setHeadersOnlyThroughUI(false, true);
+        const restoredRead = await readCommonlibDocument(original._id);
+        assertLogicalDocument(restoredRead.document, original);
+        const restoredRequest = metadataRequest(restoredRead, original._id);
+        assert.equal(new URL(restoredRequest.url).searchParams.get("_livesync_epoch"), initialEpoch);
+        assert.equal(restoredRequest.cache, "no-cache");
 
         await evaluate(`await core.services.setting.applyPartial({encryptInternalMetadata:true},true);
             await core.services.control.applySettings();
@@ -138,6 +298,17 @@ async function main(): Promise<void> {
                 "The stale browser HTTP cache fixture is no longer present."
             );
         }
+        const rebuiltRead = await readCommonlibDocument(original._id);
+        assertLogicalDocument(rebuiltRead.document, original);
+        assert.deepEqual(
+            rebuiltRead.document.children,
+            initialRead.document.children,
+            "The logical file content references changed during Rebuild."
+        );
+        const rebuiltMetadataRequest = metadataRequest(rebuiltRead, original._id);
+        const rebuiltEpoch = new URL(rebuiltMetadataRequest.url).searchParams.get("_livesync_epoch");
+        assert.ok(rebuiltEpoch, "The post-Rebuild Metadata read did not include a Seed cache namespace.");
+        assert.notEqual(rebuiltEpoch, initialEpoch, "The cache namespace did not change with the Security Seed.");
 
         await evaluate(`await core.services.setting.applyPartial({usePluginSync:true,syncInternalFiles:true},true);
             await core.services.control.applySettings();return JSON.stringify(true);`);
@@ -148,13 +319,229 @@ async function main(): Promise<void> {
             if(opened)await opened.close();return JSON.stringify({admitted:!!opened});
             }catch(error){return JSON.stringify({admitted:false,error:error.name});}`);
         assert.ok(admission.admitted, `Replication admission failed: ${JSON.stringify(admission)}`);
-        assert.equal((await readCachedDocument(original._id, "no-store")).path, rebuilt.path);
+        const repeatedRead = await readCommonlibDocument(original._id);
+        assertLogicalDocument(repeatedRead.document, original);
+        assert.deepEqual(
+            repeatedRead.document.children,
+            initialRead.document.children,
+            "The logical file content references changed after replication admission."
+        );
+        const repeatedMetadataRequest = metadataRequest(repeatedRead, original._id);
+        const repeatedEpoch = new URL(repeatedMetadataRequest.url).searchParams.get("_livesync_epoch");
+        assert.equal(
+            repeatedEpoch,
+            rebuiltEpoch,
+            "A new connection at the same Seed did not reuse its cache namespace."
+        );
         await pushLocalChanges(cliBinary, session.cliEnv);
         await pushLocalChanges(cliBinary, session.cliEnv);
+        // Include Chunk bodies for strict reconciliation after replacing the local database.
+        await evaluate(
+            `await core.services.setting.applyPartial({readChunksOnline:false},true);return JSON.stringify(true);`
+        );
+        const fetchAttempt = await evaluate<{ succeeded: boolean; error?: string; diagnostics?: unknown }>(`try {
+            await core.rebuilder.fetchLocal(false,true);return JSON.stringify({succeeded:true});
+            } catch(error) {
+                await core.services.API.showWindow('log-log');
+                await new Promise(resolve=>setTimeout(resolve,100));
+                const log=Array.from(document.querySelectorAll('.logpane .log pre')).map(e=>e.textContent??'').join('\\n').slice(-16000);
+                return JSON.stringify({succeeded:false,error:String(error),diagnostics:{
+                    databaseReady:core.services.database.isDatabaseReady(),appReady:core.services.appLifecycle.isReady(),
+                    unresolvedMessages:(await core.services.appLifecycle.getUnresolvedMessages()).flat(),log}});
+            }`);
+        assert.ok(fetchAttempt.succeeded, `Standard Fetch failed: ${JSON.stringify(fetchAttempt)}`);
+        await waitForLiveSyncCoreReady(cliBinary, session.cliEnv);
+        const fetchedRead = await readCommonlibDocument(original._id);
+        assertLogicalDocument(fetchedRead.document, original);
+        assert.deepEqual(fetchedRead.document.children, initialRead.document.children);
+        assert.equal(
+            new URL(metadataRequest(fetchedRead, original._id).url).searchParams.get("_livesync_epoch"),
+            rebuiltEpoch
+        );
+        assert.equal(await readFile(join(vault.path, ordinaryPath), "utf8"), ordinaryContents);
+        await pushLocalChanges(cliBinary, session.cliEnv);
+
+        const remoteBeforeRestart = await fetchCouchDbDocument(couchDb, dbName, original._id);
+        const seedBeforeRestart = await fetchCouchDbDocument(couchDb, dbName, DOCID_SYNC_PARAMETERS);
+        assert.equal(remoteBeforeRestart._rev, rebuilt._rev, "The Metadata revision changed before restart.");
+        assert.equal(remoteBeforeRestart.path, rebuilt.path, "The remote Metadata ciphertext changed before restart.");
+        assert.equal(
+            seedBeforeRestart.pbkdf2salt,
+            rebuiltParameters.pbkdf2salt,
+            "The Security Seed changed before restart."
+        );
+        const stateBeforeRestart = await readRestartState();
+        assert.equal(stateBeforeRestart.settings.useCouchDBCacheControlHeadersOnly, false);
+        assert.equal(stateBeforeRestart.settings.couchDB_DBNAME, dbName);
+        assert.equal(stateBeforeRestart.settings.deviceAndVaultName, "http-cache-source");
+        assert.equal(stateBeforeRestart.settings.encrypt, true);
+        assert.equal(stateBeforeRestart.settings.encryptInternalMetadata, true);
+        assert.equal(stateBeforeRestart.settings.usePathObfuscation, true);
+        assert.equal(stateBeforeRestart.localMetadata?.path, ordinaryPath);
+        assert.ok(stateBeforeRestart.nodeId, "The device identity was not persisted before restart.");
+
+        const previousUnixSecond = Math.floor(Date.now() / 1000);
+        await restoreCommonlibRequests();
+        if (!session) throw new Error("No active Obsidian session to stop.");
+        await session.app.stop();
+        session = undefined;
+        await waitForNextUnixSecond(previousUnixSecond);
+
+        // Reuse the same Vault and isolated profile. Do not reseed settings or local device state.
+        session = await startObsidianLiveSyncSession({
+            binary,
+            cliBinary,
+            vault,
+            artifactRoot: resolve(process.env.E2E_OBSIDIAN_ARTIFACT_ROOT ?? "."),
+            pluginStartup: "natural",
+        });
+        await waitForLiveSyncCoreReady(cliBinary, session.cliEnv);
+        const stateAfterRestart = await readRestartState();
+        assert.deepEqual(stateAfterRestart.settings, stateBeforeRestart.settings);
+        assert.equal(stateAfterRestart.localDatabaseName, stateBeforeRestart.localDatabaseName);
+        assert.deepEqual(stateAfterRestart.localMetadata, stateBeforeRestart.localMetadata);
+        assert.equal(stateAfterRestart.nodeId, stateBeforeRestart.nodeId, "Restart changed the persisted device identity.");
+
+        const remoteAfterRestart = await fetchCouchDbDocument(couchDb, dbName, original._id);
+        const seedAfterRestart = await fetchCouchDbDocument(couchDb, dbName, DOCID_SYNC_PARAMETERS);
+        assert.equal(remoteAfterRestart._rev, remoteBeforeRestart._rev, "Restart changed the remote Metadata revision.");
+        assert.equal(
+            remoteAfterRestart.path,
+            remoteBeforeRestart.path,
+            "Restart changed the remote Metadata ciphertext."
+        );
+        assert.equal(seedAfterRestart.pbkdf2salt, seedBeforeRestart.pbkdf2salt, "Restart changed the Security Seed.");
+        assert.equal(await readFile(join(vault.path, ordinaryPath), "utf8"), ordinaryContents);
+        if (!useRequestAPI) {
+            assert.equal(
+                (await readCachedDocument(original._id, "default")).path,
+                original.path,
+                "The isolated browser HTTP cache did not survive the application restart."
+            );
+        }
+
+        await observeCommonlibRequests();
+        const restartedRead = await readCommonlibDocument(original._id);
+        assertLogicalDocument(restartedRead.document, original);
+        assert.deepEqual(restartedRead.document.children, initialRead.document.children);
+        const restartedMetadataRequest = metadataRequest(restartedRead, original._id);
+        const restartedEpoch = new URL(restartedMetadataRequest.url).searchParams.get("_livesync_epoch");
+        assert.ok(restartedEpoch, "The restarted Metadata read did not include a cache namespace.");
+        assert.match(restartedEpoch, /^[0-9a-f]{64}$/, "The restarted URL must contain only the combined hash.");
+        assert.notEqual(
+            restartedEpoch,
+            rebuiltEpoch,
+            "A full application restart reused its earlier non-compatibility cache namespace."
+        );
+        assert.equal(restartedMetadataRequest.cache, "no-cache");
+
+        await evaluate("await core.services.setting.applyPartial({readChunksOnline:false},true);return JSON.stringify(true);");
+        const restartedFetchAttempt = await evaluate<{ succeeded: boolean; error?: string }>([
+            "try{await core.rebuilder.fetchLocal(false,true);return JSON.stringify({succeeded:true});}",
+            "catch(error){return JSON.stringify({succeeded:false,error:String(error)});}",
+        ].join(""));
+        assert.ok(
+            restartedFetchAttempt.succeeded,
+            `Standard Fetch after restart failed: ${JSON.stringify(restartedFetchAttempt)}`
+        );
+        await waitForLiveSyncCoreReady(cliBinary, session.cliEnv);
+        const afterRestartFetch = await readCommonlibDocument(original._id);
+        assertLogicalDocument(afterRestartFetch.document, original);
+        assert.deepEqual(afterRestartFetch.document.children, initialRead.document.children);
+        assert.equal(
+            new URL(metadataRequest(afterRestartFetch, original._id).url).searchParams.get("_livesync_epoch"),
+            restartedEpoch,
+            "Standard Fetch changed the restarted cache namespace."
+        );
+        assert.equal(await readFile(join(vault.path, ordinaryPath), "utf8"), ordinaryContents);
+        const remoteAfterRestartFetch = await fetchCouchDbDocument(couchDb, dbName, original._id);
+        const seedAfterRestartFetch = await fetchCouchDbDocument(couchDb, dbName, DOCID_SYNC_PARAMETERS);
+        assert.equal(remoteAfterRestartFetch._rev, remoteBeforeRestart._rev);
+        assert.equal(remoteAfterRestartFetch.path, remoteBeforeRestart.path);
+        assert.equal(seedAfterRestartFetch.pbkdf2salt, seedBeforeRestart.pbkdf2salt);
+
+        await writeFile(join(vault.path, restartNotePath), restartNoteContents);
+        const restartNoteEntry = await waitForLocalDatabaseEntry(cliBinary, session.cliEnv, restartNotePath);
+        assert.equal(restartNoteEntry.path, restartNotePath);
+        await pushLocalChanges(cliBinary, session.cliEnv);
+        const uploadedRestartNote = await readCommonlibDocument(restartNoteEntry.id);
+        assert.equal(uploadedRestartNote.document.path, restartNotePath);
+        assert.equal(uploadedRestartNote.document.size, Buffer.byteLength(restartNoteContents));
+        assert.ok(
+            Array.isArray(uploadedRestartNote.document.children) && uploadedRestartNote.document.children.length > 0
+        );
+        assert.equal(
+            new URL(metadataRequest(uploadedRestartNote, restartNoteEntry.id).url).searchParams.get("_livesync_epoch"),
+            restartedEpoch,
+            "Subsequent synchronisation did not use the restarted cache namespace."
+        );
+        assert.equal(await readFile(join(vault.path, restartNotePath), "utf8"), restartNoteContents);
+        const originalAfterRestartSync = await fetchCouchDbDocument(couchDb, dbName, original._id);
+        assert.equal(originalAfterRestartSync._rev, remoteBeforeRestart._rev);
+        assert.equal(originalAfterRestartSync.path, remoteBeforeRestart.path);
+        const uploadedRestartNoteRemote = await fetchCouchDbDocument(couchDb, dbName, restartNoteEntry.id);
+
+        await evaluate("await core.services.setting.applyPartial({readChunksOnline:false},true);return JSON.stringify(true);");
+        const uploadVerificationFetch = await evaluate<{ succeeded: boolean; error?: string }>([
+            "try{await core.rebuilder.fetchLocal(false,true);return JSON.stringify({succeeded:true});}",
+            "catch(error){return JSON.stringify({succeeded:false,error:String(error)});}",
+        ].join(""));
+        assert.ok(
+            uploadVerificationFetch.succeeded,
+            `Standard Fetch after the upload failed: ${JSON.stringify(uploadVerificationFetch)}`
+        );
+        await waitForLiveSyncCoreReady(cliBinary, session.cliEnv);
+        const fetchedRestartNoteEntry = await waitForLocalDatabaseEntry(cliBinary, session.cliEnv, restartNotePath);
+        assert.equal(fetchedRestartNoteEntry.id, restartNoteEntry.id);
+        assert.equal(fetchedRestartNoteEntry.rev, uploadedRestartNote.document._rev);
+        assert.deepEqual(fetchedRestartNoteEntry.children, uploadedRestartNote.document.children);
+        const fetchedRestartNoteBody = await evaluate<string>([
+            "const file=await core.serviceModules.databaseFileAccess.fetch(" + JSON.stringify(restartNotePath) + ");",
+            "if(!file||file.deleted||!file.body)throw new Error('The uploaded note was not readable from the replaced local database.');",
+            "return JSON.stringify(await file.body.text());",
+        ].join(""));
+        assert.equal(
+            fetchedRestartNoteBody,
+            restartNoteContents,
+            "The replaced local database did not return the exact uploaded Chunk content."
+        );
+        const fetchedRestartNote = await readCommonlibDocument(restartNoteEntry.id);
+        assert.equal(fetchedRestartNote.document.path, restartNotePath);
+        assert.equal(fetchedRestartNote.document.size, Buffer.byteLength(restartNoteContents));
+        assert.equal(fetchedRestartNote.document._rev, uploadedRestartNote.document._rev);
+        assert.deepEqual(fetchedRestartNote.document.children, uploadedRestartNote.document.children);
+        assert.equal(
+            new URL(metadataRequest(fetchedRestartNote, restartNoteEntry.id).url).searchParams.get("_livesync_epoch"),
+            restartedEpoch,
+            "Standard Fetch after the upload changed the restarted cache namespace."
+        );
+        assert.equal(await readFile(join(vault.path, restartNotePath), "utf8"), restartNoteContents);
+        assert.equal(await readFile(join(vault.path, ordinaryPath), "utf8"), ordinaryContents);
+        const restartNoteAfterFetch = await fetchCouchDbDocument(couchDb, dbName, restartNoteEntry.id);
+        assert.equal(restartNoteAfterFetch._rev, uploadedRestartNoteRemote._rev);
+        assert.equal(restartNoteAfterFetch.path, uploadedRestartNoteRemote.path);
+        const originalAfterUploadFetch = await fetchCouchDbDocument(couchDb, dbName, original._id);
+        const seedAfterUploadFetch = await fetchCouchDbDocument(couchDb, dbName, DOCID_SYNC_PARAMETERS);
+        assert.equal(originalAfterUploadFetch._rev, remoteBeforeRestart._rev);
+        assert.equal(originalAfterUploadFetch.path, remoteBeforeRestart.path);
+        assert.equal(seedAfterUploadFetch.pbkdf2salt, seedBeforeRestart.pbkdf2salt);
+
+        await restoreCommonlibRequests();
         console.log(
-            `Rebuild and subsequent replication succeeded after warming the ${useRequestAPI ? "Internal API" : "browser"} HTTP cache.`
+            `Cache compatibility switch persistence, Rebuild, Standard Fetch, and subsequent replication succeeded with the ${useRequestAPI ? "Internal API" : "browser"} HTTP cache.`
+        );
+        console.log(
+            `Full application restart on the same Vault and profile retained device identity, ` +
+                `changed the cache namespace, and passed post-restart Fetch and upload (${useRequestAPI ? "Internal API" : "browser"}).`
         );
     } finally {
+        if (observingRequests && session) {
+            try {
+                await restoreCommonlibRequests();
+            } catch {
+                // The isolated Obsidian process is stopped immediately below.
+            }
+        }
         await session?.app.stop();
         await vault.dispose();
         await deleteCouchDbDatabase(couchDb, dbName);