rewrite transforms, implement unified transform layer

docs/ARCHITECTURE.md

@@ -51,6 +51,16 @@ Writes go through a server-side write coalescer (`server/write-coalescer.js`) de
 
 Sync calls use synchronous XHR to ensure blocking behavior. Async calls use fetch. Everything goes through a transport layer that handles vault ID injection, base64 encoding for binary files, and mapping HTTP error codes back to Node errno values.
 
+### Translation registry
+
+The shim has a registry (`src/shims/fs/transforms.js`) for hooks applied at the public shim surface, before caches or transport see the path. Three hook types:
+
+- **Path resolvers** map a logical path to a physical path. Used by the workspaces shim to redirect reads and writes of `.obsidian/workspace.json` to `.obsidian/workspace.<name>.json` based on the `?workspace=` URL parameter, so each browser tab can hold a separate layout.
+- **Read transforms** post-process bytes returned by a read (cache hit or transport miss). Used to mask the Obsidian Sync setting in `core-plugins.json` when headless-sync is active for the vault, and to override the `active` field on reads of `workspaces.json` so each tab sees its own workspace as selected.
+- **Write transforms** pre-process bytes before a write hits the cache or transport. Used to override the `active` field on writes to `workspaces.json` so cross-tab disk state stays canonical.
+
+All hooks are synchronous and registered at module load. Translation happens once at the shim entry; downstream layers (content cache, metadata cache, transport) operate only on resolved physical paths and as-stored bytes. This keeps cache keys coherent with what transport actually reads and writes, so prefetch and on-demand fetches share the same cache slot.
+
 ### IPC
 
 IPC is implemented as a synchronous dispatcher that maps channel names to handlers.

src/shims/fs/fd.js

@@ -3,6 +3,7 @@
 // around files without loading them via readFileSync upfront.
 
 import { isInputCachePath, inputCacheGet } from "./input-cache.js";
+import { resolvePath } from "./transforms.js";
 
 let nextFd = 100;
 const openFiles = new Map();
@@ -22,7 +23,8 @@ export function createFdOps(metadataCache, contentCache, transport) {
       }
     }
 
-    const cached = contentCache.get(path);
+    const resolved = resolvePath(path);
+    const cached = contentCache.get(resolved);
 
     if (cached !== null) {
       if (typeof cached === "string") {
@@ -33,9 +35,9 @@ export function createFdOps(metadataCache, contentCache, transport) {
     }
 
     // Synchronous fetch fallback
-    console.warn("[shim:fs] fd open cache miss, using sync XHR:", path);
+    console.warn("[shim:fs] fd open cache miss, using sync XHR:", resolved);
-    const data = transport.readFileSync(path);
+    const data = transport.readFileSync(resolved);
-    contentCache.set(path, data);
+    contentCache.set(resolved, data);
 
     return data;
   }
@@ -56,8 +58,9 @@ export function createFdOps(metadataCache, contentCache, transport) {
 
   function openSync(path, flags, mode) {
     const hasInCache = isInputCachePath(path) && inputCacheGet(path) !== null;
+    const resolved = resolvePath(path);
 
-    if (!hasInCache && !metadataCache.has(path)) {
+    if (!hasInCache && !metadataCache.has(resolved)) {
       const err = new Error(
         `ENOENT: no such file or directory, open '${path}'`,
       );
@@ -67,7 +70,7 @@ export function createFdOps(metadataCache, contentCache, transport) {
 
     const data = ensureData(path);
     const fd = nextFd++;
-    openFiles.set(fd, { path, data });
+    openFiles.set(fd, { path: resolved, data });
 
     return fd;
   }

src/shims/fs/index.js

@@ -7,7 +7,7 @@ import { createFsWatch } from "./watch.js";
 import { createWatcherClient } from "./watcher-client.js";
 import { createFdOps } from "./fd.js";
 import { constants } from "./constants.js";
-import { registerReadTransform, removeReadTransform } from "./read-transforms.js";
+import { registerReadTransform, removeReadTransform, resolvePath } from "./transforms.js";
 
 const metadataCache = new MetadataCache();
 const contentCache = new ContentCache();
@@ -41,6 +41,10 @@ export const fsShim = {
   watch: fsWatch.watch,
   constants,
 
+  invalidate(path) {
+    contentCache.invalidate(resolvePath(path));
+  },
+
   _metadataCache: metadataCache,
   _contentCache: contentCache,
   _watcherClient: watcherClient,

src/shims/fs/promises.js

@@ -1,19 +1,20 @@
 import { markLocalOp } from "./echo-guard.js";
 import { isInputCachePath, inputCacheGet } from "./input-cache.js";
-import { applyReadTransform } from "./read-transforms.js";
+import { applyReadTransform, applyWriteTransform, resolvePath } from "./transforms.js";
 
 export function createFsPromises(metadataCache, contentCache, transport) {
   return {
     async stat(path) {
-      const cached = metadataCache.toStat(path);
+      const resolved = resolvePath(path);
+      const cached = metadataCache.toStat(resolved);
 
       if (cached) {
         return cached;
       }
 
-      const meta = await transport.stat(path);
+      const meta = await transport.stat(resolved);
-      metadataCache.set(path, meta);
+      metadataCache.set(resolved, meta);
-      return metadataCache.toStat(path);
+      return metadataCache.toStat(resolved);
     },
 
     async lstat(path) {
@@ -46,6 +47,7 @@ export function createFsPromises(metadataCache, contentCache, transport) {
       }
 
       const wantText = encoding === "utf8" || encoding === "utf-8";
+      const resolved = resolvePath(path);
 
       let result = null;
 
@@ -55,7 +57,7 @@ export function createFsPromises(metadataCache, contentCache, transport) {
       }
 
       if (result === null) {
-        const meta = metadataCache.get(path);
+        const meta = metadataCache.get(resolved);
 
         if (meta && meta.type === "directory") {
           const e = new Error("EISDIR: illegal operation on a directory, read");
@@ -63,7 +65,8 @@ export function createFsPromises(metadataCache, contentCache, transport) {
           throw e;
         }
 
-        if (!meta && path) {
+        if (!meta && resolved && resolved === path) {
+          // Throw ENOENT only when not redirected; redirected paths fall through to the transport's fallback.
           const e = new Error(
             `ENOENT: no such file or directory, open '${path}'`,
           );
@@ -71,16 +74,25 @@ export function createFsPromises(metadataCache, contentCache, transport) {
           throw e;
         }
 
-        result = contentCache.get(path);
+        result = contentCache.get(resolved);
       }
 
       if (result === null) {
+        try {
+          result = await transport.readFile(resolved, encoding);
+        } catch (e) {
+          if (resolved !== path && e.code === "ENOENT") {
             result = await transport.readFile(path, encoding);
-        contentCache.set(path, result);
+          } else {
+            throw e;
+          }
+        }
+
+        contentCache.set(resolved, result);
       }
 
       // Apply registered read transforms (e.g., patching synced config files).
-      result = applyReadTransform(path, result);
+      result = applyReadTransform(resolved, result);
 
       if (wantText) {
         return typeof result === "string"
@@ -100,62 +112,74 @@ export function createFsPromises(metadataCache, contentCache, transport) {
         encoding = encoding?.encoding;
       }
 
-      markLocalOp(path);
+      const resolved = resolvePath(path);
-      contentCache.set(path, data);
+      const transformed = applyWriteTransform(resolved, data);
+
+      markLocalOp(resolved);
+      contentCache.set(resolved, transformed);
 
       const size =
-        typeof data === "string" ? data.length : data.byteLength || 0;
+        typeof transformed === "string"
+          ? transformed.length
+          : transformed.byteLength || 0;
 
-      metadataCache.set(path, {
+      metadataCache.set(resolved, {
         type: "file",
         size,
         mtime: Date.now(),
-        ctime: metadataCache.get(path)?.ctime || Date.now(),
+        ctime: metadataCache.get(resolved)?.ctime || Date.now(),
       });
 
-      const result = await transport.writeFile(path, data, encoding);
+      const result = await transport.writeFile(resolved, transformed, encoding);
 
       if (result.mtime) {
-        metadataCache.set(path, {
+        metadataCache.set(resolved, {
           type: "file",
           size: result.size || size,
           mtime: result.mtime,
-          ctime: metadataCache.get(path)?.ctime || Date.now(),
+          ctime: metadataCache.get(resolved)?.ctime || Date.now(),
         });
       }
     },
 
     async appendFile(path, data, encoding) {
-      markLocalOp(path);
+      const resolved = resolvePath(path);
-      contentCache.invalidate(path);
 
-      await transport.appendFile(path, data);
+      markLocalOp(resolved);
+      contentCache.invalidate(resolved);
 
-      const meta = await transport.stat(path);
+      await transport.appendFile(resolved, data);
-      metadataCache.set(path, meta);
+
+      const meta = await transport.stat(resolved);
+      metadataCache.set(resolved, meta);
     },
 
     async unlink(path) {
-      markLocalOp(path);
+      const resolved = resolvePath(path);
-      contentCache.delete(path);
-      metadataCache.delete(path);
 
-      await transport.unlink(path);
+      markLocalOp(resolved);
+      contentCache.delete(resolved);
+      metadataCache.delete(resolved);
+
+      await transport.unlink(resolved);
     },
 
     async rename(oldPath, newPath) {
-      markLocalOp(oldPath);
+      const resolvedOld = resolvePath(oldPath);
-      markLocalOp(newPath);
+      const resolvedNew = resolvePath(newPath);
-      const content = contentCache.get(oldPath);
+
+      markLocalOp(resolvedOld);
+      markLocalOp(resolvedNew);
+      const content = contentCache.get(resolvedOld);
 
       if (content !== null) {
-        contentCache.set(newPath, content);
+        contentCache.set(resolvedNew, content);
-        contentCache.delete(oldPath);
+        contentCache.delete(resolvedOld);
       }
 
-      metadataCache.rename(oldPath, newPath);
+      metadataCache.rename(resolvedOld, resolvedNew);
 
-      await transport.rename(oldPath, newPath);
+      await transport.rename(resolvedOld, resolvedNew);
     },
 
     async mkdir(path, options) {
@@ -178,23 +202,29 @@ export function createFsPromises(metadataCache, contentCache, transport) {
       const recursive =
         typeof options === "object" ? !!options.recursive : false;
 
-      markLocalOp(path);
+      const resolved = resolvePath(path);
-      metadataCache.delete(path);
-      contentCache.delete(path);
 
-      await transport.rm(path, recursive);
+      markLocalOp(resolved);
+      metadataCache.delete(resolved);
+      contentCache.delete(resolved);
+
+      await transport.rm(resolved, recursive);
     },
 
     async copyFile(src, dest) {
-      markLocalOp(dest);
+      const resolvedDest = resolvePath(dest);
-      await transport.copyFile(src, dest);
 
-      const meta = await transport.stat(dest);
+      markLocalOp(resolvedDest);
-      metadataCache.set(dest, meta);
+      await transport.copyFile(src, resolvedDest);
+
+      const meta = await transport.stat(resolvedDest);
+      metadataCache.set(resolvedDest, meta);
     },
 
     async access(path) {
-      if (metadataCache.has(path)) {
+      const resolved = resolvePath(path);
+
+      if (metadataCache.has(resolved)) {
         return;
       }
 
@@ -214,18 +244,21 @@ export function createFsPromises(metadataCache, contentCache, transport) {
     },
 
     async utimes(path, atime, mtime) {
-      await transport.utimes(path, atime, mtime);
+      const resolved = resolvePath(path);
-      const meta = metadataCache.get(path);
+
+      await transport.utimes(resolved, atime, mtime);
+      const meta = metadataCache.get(resolved);
       if (meta) {
         meta.mtime = typeof mtime === "number" ? mtime : mtime.getTime();
-        metadataCache.set(path, meta);
+        metadataCache.set(resolved, meta);
       }
     },
 
     async open(path, flags) {
       const hasInCache = isInputCachePath(path) && inputCacheGet(path) !== null;
+      const resolved = resolvePath(path);
 
-      if (!hasInCache && !metadataCache.has(path)) {
+      if (!hasInCache && !metadataCache.has(resolved)) {
         const err = new Error(
           `ENOENT: no such file or directory, open '${path}'`,
         );
@@ -237,7 +270,7 @@ export function createFsPromises(metadataCache, contentCache, transport) {
       const fileData =
         typeof data === "string" ? new TextEncoder().encode(data) : data;
 
-      const fileStat = metadataCache.toStat(path) || {
+      const fileStat = metadataCache.toStat(resolved) || {
         size: fileData.length,
         isFile: () => true,
         isDirectory: () => false,

src/shims/fs/read-transforms.js

@@ -1,39 +0,0 @@
-// Post-read transforms for specific file paths.
-// Allows patching file content after reading but before returning to the caller.
-// Used to prevent synced config files from activating conflicting features.
-
-const transforms = new Map();
-
-function normalize(p) {
-  return (p || "")
-    .replace(/\\/g, "/")
-    .replace(/^\/+/, "")
-    .replace(/\/+$/, "");
-}
-
-export function registerReadTransform(path, fn) {
-  transforms.set(normalize(path), fn);
-}
-
-export function removeReadTransform(path) {
-  transforms.delete(normalize(path));
-}
-
-export function applyReadTransform(path, data) {
-  const norm = normalize(path);
-  const fn = transforms.get(norm);
-
-  if (!fn) {
-    return data;
-  }
-
-  try {
-    return fn(data);
-  } catch {
-    return data;
-  }
-}
-
-export function hasReadTransform(path) {
-  return transforms.has(normalize(path));
-}

src/shims/fs/sync.js

@@ -1,6 +1,10 @@
 import { markLocalOp } from "./echo-guard.js";
 import { isInputCachePath, inputCacheGet } from "./input-cache.js";
-import { applyReadTransform } from "./read-transforms.js";
+import {
+  applyReadTransform,
+  applyWriteTransform,
+  resolvePath,
+} from "./transforms.js";
 
 export function createFsSync(metadataCache, contentCache, transport) {
   return {
@@ -9,7 +13,8 @@ export function createFsSync(metadataCache, contentCache, transport) {
         return true;
       }
 
-      return metadataCache.has(path);
+      const resolved = resolvePath(path);
+      return metadataCache.has(resolved);
     },
 
     statSync(path) {
@@ -27,7 +32,8 @@ export function createFsSync(metadataCache, contentCache, transport) {
         };
       }
 
-      const stat = metadataCache.toStat(path);
+      const resolved = resolvePath(path);
+      const stat = metadataCache.toStat(resolved);
 
       if (!stat) {
         const err = new Error(
@@ -45,7 +51,9 @@ export function createFsSync(metadataCache, contentCache, transport) {
         return;
       }
 
-      if (!metadataCache.has(path)) {
+      const resolved = resolvePath(path);
+
+      if (!metadataCache.has(resolved)) {
         const err = new Error(
           `ENOENT: no such file or directory, access '${path}'`,
         );
@@ -60,8 +68,9 @@ export function createFsSync(metadataCache, contentCache, transport) {
       }
 
       const wantText = encoding === "utf8" || encoding === "utf-8";
+      const resolved = resolvePath(path);
 
-      const meta = metadataCache.get(path);
+      const meta = metadataCache.get(resolved);
       if (meta && meta.type === "directory") {
         const e = new Error("EISDIR: illegal operation on a directory, read");
         e.code = "EISDIR";
@@ -80,17 +89,31 @@ export function createFsSync(metadataCache, contentCache, transport) {
       }
 
       if (result === null) {
-        result = contentCache.get(path);
+        result = contentCache.get(resolved);
       }
 
       if (result === null) {
-        console.warn("[shim:fs] readFileSync cache miss, using sync XHR:", path);
+        // ENOENT fallback: if the resolved path doesn't exist, try the original.
+        // Covers per-name workspace files that haven't been saved yet.
+        try {
+          result = transport.readFileSync(resolved, encoding);
+        } catch (e) {
+          if (resolved !== path && e.code === "ENOENT") {
+            console.warn(
+              "[shim:fs] readFileSync cache miss, using sync XHR:",
+              path,
+            );
             result = transport.readFileSync(path, encoding);
-        contentCache.set(path, result);
+          } else {
+            throw e;
+          }
+        }
+
+        contentCache.set(resolved, result);
       }
 
       // Apply registered read transforms (e.g., patching synced config files).
-      result = applyReadTransform(path, result);
+      result = applyReadTransform(resolved, result);
 
       if (wantText) {
         return typeof result === "string"
@@ -106,40 +129,47 @@ export function createFsSync(metadataCache, contentCache, transport) {
         encoding = encoding?.encoding;
       }
 
-      markLocalOp(path);
+      const resolved = resolvePath(path);
-      contentCache.set(path, data);
+      const transformed = applyWriteTransform(resolved, data);
+
+      markLocalOp(resolved);
+      contentCache.set(resolved, transformed);
 
       const size =
-        typeof data === "string" ? data.length : data.byteLength || 0;
+        typeof transformed === "string"
+          ? transformed.length
+          : transformed.byteLength || 0;
 
-      metadataCache.set(path, {
+      metadataCache.set(resolved, {
         type: "file",
         size,
         mtime: Date.now(),
-        ctime: metadataCache.get(path)?.ctime || Date.now(),
+        ctime: metadataCache.get(resolved)?.ctime || Date.now(),
       });
 
       // Fire-and-forget async send to server
-      transport.writeFile(path, data, encoding).catch((e) => {
+      transport.writeFile(resolved, transformed, encoding).catch((e) => {
         console.error(
           "[shim:fs] writeFileSync background save failed:",
-          path,
+          resolved,
           e,
         );
       });
     },
 
     unlinkSync(path) {
-      markLocalOp(path);
+      const resolved = resolvePath(path);
-      contentCache.delete(path);
+
-      metadataCache.delete(path);
+      markLocalOp(resolved);
+      contentCache.delete(resolved);
+      metadataCache.delete(resolved);
 
       // Fire-and-forget. suppress ENOENT (file already gone)
-      transport.unlink(path).catch((e) => {
+      transport.unlink(resolved).catch((e) => {
         if (e.code !== "ENOENT") {
           console.error(
             "[shim:fs] unlinkSync background delete failed:",
-            path,
+            resolved,
             e,
           );
         }

src/shims/fs/transforms.js

@@ -0,0 +1,89 @@
+// FS shim translation registry.
+// Path resolvers map logical paths to physical paths; read transforms post-process bytes after a read; write transforms pre-process bytes before a write.
+// All hooks run at the shim's public surface, so caches and transport see only physical paths and as-stored bytes.
+
+function normalize(p) {
+  return (p || "").replace(/\\/g, "/").replace(/^\/+/, "").replace(/\/+$/, "");
+}
+
+// --- Path resolvers ---
+
+const pathResolvers = [];
+
+export function registerPathResolver(matcher, resolver) {
+  pathResolvers.push({ matcher, resolver });
+}
+
+export function resolvePath(path) {
+  const norm = normalize(path);
+
+  for (const { matcher, resolver } of pathResolvers) {
+    try {
+      if (matcher(norm)) {
+        const resolved = resolver(norm);
+
+        if (typeof resolved === "string" && resolved.length > 0) {
+          return resolved;
+        }
+      }
+    } catch {}
+  }
+
+  return norm;
+}
+
+// --- Read transforms ---
+
+const readTransforms = new Map();
+
+export function registerReadTransform(path, fn) {
+  readTransforms.set(normalize(path), fn);
+}
+
+export function removeReadTransform(path) {
+  readTransforms.delete(normalize(path));
+}
+
+export function applyReadTransform(path, data) {
+  const fn = readTransforms.get(normalize(path));
+
+  if (!fn) {
+    return data;
+  }
+
+  try {
+    return fn(data);
+  } catch {
+    return data;
+  }
+}
+
+export function hasReadTransform(path) {
+  return readTransforms.has(normalize(path));
+}
+
+// --- Write transforms ---
+
+const writeTransforms = new Map();
+
+export function registerWriteTransform(path, fn) {
+  writeTransforms.set(normalize(path), fn);
+}
+
+export function removeWriteTransform(path) {
+  writeTransforms.delete(normalize(path));
+}
+
+export function applyWriteTransform(path, data) {
+  const fn = writeTransforms.get(normalize(path));
+
+  if (!fn) {
+    return data;
+  }
+
+  try {
+    return fn(data);
+  } catch {
+    return data;
+  }
+}

src/shims/fs/transport.js

@@ -1,10 +1,4 @@
-import {
-  rewriteWorkspacePath,
-  rewriteWorkspacesContent,
-} from "../workspace.js";
-
 const API_BASE = "/api/fs";
-const WORKSPACES_PATH = ".obsidian/workspaces.json";
 
 function normPath(p) {
   return (p || "").replace(/^\/+/, "");
@@ -116,26 +110,10 @@ export const transport = {
   },
 
   async readFile(path, encoding) {
-    const norm = normPath(path);
+    const res = await request("GET", "/readFile", {
-    const rewritten = rewriteWorkspacePath(norm);
+      path: normPath(path),
-
-    let res;
-
-    try {
-      res = await request("GET", "/readFile", {
-        path: rewritten,
       encoding: encoding || "",
     });
-    } catch (e) {
-      if (rewritten !== norm && e.code === "ENOENT") {
-        res = await request("GET", "/readFile", {
-          path: norm,
-          encoding: encoding || "",
-        });
-      } else {
-        throw e;
-      }
-    }
 
     if (encoding === "utf8" || encoding === "utf-8") {
       return res.text();
@@ -146,17 +124,10 @@ export const transport = {
   },
 
   async writeFile(path, content, encoding) {
-    const norm = normPath(path);
+    const isText = typeof content === "string";
-    let data = content;
-
-    if (norm === WORKSPACES_PATH && typeof data === "string") {
-      data = rewriteWorkspacesContent(data);
-    }
-
-    const isText = typeof data === "string";
     return requestJson("POST", "/writeFile", {
-      path: rewriteWorkspacePath(norm),
+      path: normPath(path),
-      content: isText ? data : uint8ToBase64(data),
+      content: isText ? content : uint8ToBase64(content),
       encoding: encoding || (isText ? "utf-8" : "binary"),
       base64: !isText,
     });
@@ -222,26 +193,10 @@ export const transport = {
   },
 
   readFileSync(path, encoding) {
-    const norm = normPath(path);
+    const xhr = requestSync("GET", "/readFile", {
-    const rewritten = rewriteWorkspacePath(norm);
+      path: normPath(path),
-
-    let xhr;
-
-    try {
-      xhr = requestSync("GET", "/readFile", {
-        path: rewritten,
       encoding: encoding || "",
     });
-    } catch (e) {
-      if (rewritten !== norm && e.code === "ENOENT") {
-        xhr = requestSync("GET", "/readFile", {
-          path: norm,
-          encoding: encoding || "",
-        });
-      } else {
-        throw e;
-      }
-    }
 
     if (encoding === "utf8" || encoding === "utf-8") {
       return xhr.responseText;
@@ -258,17 +213,10 @@ export const transport = {
   },
 
   writeFileSync(path, content, encoding) {
-    const norm = normPath(path);
+    const isText = typeof content === "string";
-    let data = content;
-
-    if (norm === WORKSPACES_PATH && typeof data === "string") {
-      data = rewriteWorkspacesContent(data);
-    }
-
-    const isText = typeof data === "string";
     requestSync("POST", "/writeFile", {
-      path: rewriteWorkspacePath(norm),
+      path: normPath(path),
-      content: isText ? data : uint8ToBase64(data),
+      content: isText ? content : uint8ToBase64(content),
       encoding: encoding || (isText ? "utf-8" : "binary"),
       base64: !isText,
     });

src/shims/init.js

@@ -2,7 +2,7 @@ import { fsShim } from "./fs/index.js";
 import { installRequestUrlShim } from "./request-url.js";
 import { vaultService } from "../services/vault-service.js";
 import { showPluginInstallDialog } from "../ui/bootstrap.js";
-import { registerReadTransform } from "./fs/read-transforms.js";
+import { registerReadTransform } from "./fs/transforms.js";
 import { resolveWorkspaceName, initWorkspacePatch } from "./workspace.js";
 import { prefetchVaultContent } from "./fs/indexer-prefetch.js";
 

src/shims/workspace.js

@@ -1,30 +1,31 @@
 import { fsShim } from "./fs/index.js";
-import { registerReadTransform } from "./fs/read-transforms.js";
+import {
+  registerPathResolver,
+  registerReadTransform,
+  registerWriteTransform,
+} from "./fs/transforms.js";
 
 const WORKSPACE_PATH = ".obsidian/workspace.json";
 const WORKSPACES_PATH = ".obsidian/workspaces.json";
 
-export function rewriteWorkspacePath(normalizedPath) {
+// Redirect workspace.json to a per-name file when a workspace is active in this tab.
-  const name = window.__workspaceName;
+registerPathResolver(
+  (path) => path === WORKSPACE_PATH && !!window.__workspaceName,
+  () => `.obsidian/workspace.${window.__workspaceName}.json`,
+);
 
-  if (!name) {
+// Keep workspaces.json's active field at the canonical value on disk so other tabs see a stable state.
-    return normalizedPath;
+registerWriteTransform(WORKSPACES_PATH, (content) => {
-  }
-
-  if (normalizedPath === WORKSPACE_PATH) {
-    return `.obsidian/workspace.${name}.json`;
-  }
-
-  return normalizedPath;
-}
-
-export function rewriteWorkspacesContent(content) {
   const original = window.__originalActiveWorkspace;
 
   if (!original || !window.__workspaceName) {
     return content;
   }
 
+  if (typeof content !== "string") {
+    return content;
+  }
+
   try {
     const parsed = JSON.parse(content);
 
@@ -35,7 +36,7 @@ export function rewriteWorkspacesContent(content) {
   } catch {}
 
   return content;
-}
+});
 
 function setWorkspaceParam(name) {
   const url = new URL(window.location.href);
@@ -136,29 +137,33 @@ export function initWorkspacePatch() {
     instance.loadWorkspace = function (name) {
       window.__workspaceName = name;
       setWorkspaceParam(name);
-      fsShim._contentCache.invalidate(".obsidian/workspace.json");
+      fsShim.invalidate(WORKSPACE_PATH);
       return origLoad(name);
     };
 
     instance.saveWorkspace = function (name) {
-      // Grab the current layout before switching the transport target.
+      // Grab the current layout before changing __workspaceName.
-      const currentLayout = fsShim._contentCache.get(".obsidian/workspace.json");
+      let currentLayout = null;
+
+      try {
+        currentLayout = fsShim.readFileSync(WORKSPACE_PATH, "utf-8");
+      } catch {}
 
       window.__workspaceName = name;
       setWorkspaceParam(name);
-      fsShim._contentCache.invalidate(".obsidian/workspace.json");
+      fsShim.invalidate(WORKSPACE_PATH);
       const result = origSave(name);
 
       // Write the layout to the new workspace file so it exists on disk immediately.
       if (currentLayout) {
-        fsShim.writeFileSync(".obsidian/workspace.json", currentLayout, "utf-8");
+        fsShim.writeFileSync(WORKSPACE_PATH, currentLayout, "utf-8");
       }
 
       return result;
     };
 
     // Override the active field on reads so the menu matches this tab's workspace.
-    registerReadTransform(".obsidian/workspaces.json", (data) => {
+    registerReadTransform(WORKSPACES_PATH, (data) => {
       if (!window.__workspaceName) {
         return data;
       }