Fix monorepo build detection: watch only root .compiler.log; run reanalyze from workspace root

- Server: restrict .compiler.log watching to ROOT/lib/bs/.compiler.log per workspace folder to avoid event floods from packages/** and node_modules/**.\n- Server: fix Start Build spawning for v12 layouts by preferring rescript.exe and falling back to rescript (also respects rescript.settings.binaryPath).\n- Client: anchor Start Code Analysis to the VSCode workspace folder root rather than the active file directory.\n- Client: resolve code-analysis binary relative to the chosen cwd (workspace root) to avoid subpackage-anchored tool lookup.\n\nFiles: server/src/server.ts, client/src/extension.ts, client/src/commands/code_analysis.ts

Author: cristianoc

client/src/commands/code_analysis.ts

@@ -213,9 +213,14 @@ export const runCodeAnalysisWithReanalyze = (
   let currentDocument = window.activeTextEditor.document;
   let cwd = targetDir ?? path.dirname(currentDocument.uri.fsPath);
 
+  // Resolve the project root from `cwd` (which is the workspace root when code analysis is started),
+  // rather than from the currently-open file (which may be in a subpackage).
   let projectRootPath: NormalizedPath | null = findProjectRootOfFileInDir(
-    currentDocument.uri.fsPath,
+    path.join(cwd, "bsconfig.json"),
   );
+  if (projectRootPath == null) {
+    projectRootPath = findProjectRootOfFileInDir(currentDocument.uri.fsPath);
+  }
 
   // Try v12+ path first: @rescript/{platform}-{arch}/bin/rescript-tools.exe
   // Then fall back to legacy paths via getBinaryPath

client/src/extension.ts

@@ -442,12 +442,11 @@ export function activate(context: ExtensionContext) {
 
     inCodeAnalysisState.active = true;
 
-    // Pointing reanalyze to the dir of the current file path is fine, because
-    // reanalyze will walk upwards looking for a bsconfig.json in order to find
-    // the correct project root.
-    inCodeAnalysisState.activatedFromDirectory = path.dirname(
-      currentDocument.uri.fsPath,
-    );
+    // Run reanalyze from the workspace root (so monorepos consistently analyze the root project),
+    // instead of from whatever file happened to be active when analysis was started.
+    const wsFolder = workspace.getWorkspaceFolder(currentDocument.uri);
+    inCodeAnalysisState.activatedFromDirectory =
+      wsFolder?.uri.fsPath ?? path.dirname(currentDocument.uri.fsPath);
 
     codeAnalysisRunningStatusBarItem.command =
       "rescript-vscode.stop_code_analysis";

server/src/server.ts

@@ -118,16 +118,28 @@ let findRescriptBinary = async (
 ): Promise<utils.NormalizedPath | null> => {
   if (
     config.extensionConfiguration.binaryPath != null &&
-    fs.existsSync(
-      path.join(config.extensionConfiguration.binaryPath, "rescript"),
-    )
+    (fs.existsSync(
+      path.join(config.extensionConfiguration.binaryPath, "rescript.exe"),
+    ) ||
+      fs.existsSync(
+        path.join(config.extensionConfiguration.binaryPath, "rescript"),
+      ))
   ) {
     return utils.normalizePath(
-      path.join(config.extensionConfiguration.binaryPath, "rescript"),
+      fs.existsSync(
+        path.join(config.extensionConfiguration.binaryPath, "rescript.exe"),
+      )
+        ? path.join(config.extensionConfiguration.binaryPath, "rescript.exe")
+        : path.join(config.extensionConfiguration.binaryPath, "rescript"),
     );
   }
 
-  return utils.findRescriptBinary(projectRootPath);
+  // Prefer the native rescript.exe (v12+) for spawning `build -w`.
+  // Fall back to the legacy/JS wrapper `rescript` path if needed.
+  return (
+    (await utils.findRescriptExeBinary(projectRootPath)) ??
+    (await utils.findRescriptBinary(projectRootPath))
+  );
 };
 
 let createInterfaceRequest = new v.RequestType<
@@ -1388,11 +1400,10 @@ async function onMessage(msg: p.Message) {
       const watchers = Array.from(workspaceFolders).flatMap(
         (projectRootPath) => [
           {
-            globPattern: path.join(
-              projectRootPath,
-              "**",
-              c.compilerLogPartialPath,
-            ),
+            // Only watch the root compiler log for each workspace folder.
+            // In monorepos, `**/lib/bs/.compiler.log` matches every package and dependency,
+            // causing a burst of events per save.
+            globPattern: path.join(projectRootPath, c.compilerLogPartialPath),
             kind: p.WatchKind.Change | p.WatchKind.Create | p.WatchKind.Delete,
           },
           {