Stop trying to add file watchers after hitting the system limit

Author: amcasey

src/compiler/sys.ts

@@ -1266,6 +1266,7 @@ namespace ts {
             let activeSession: import("inspector").Session | "stopping" | undefined;
             let profilePath = "./profile.cpuprofile";
 
+            let hitSystemWatcherLimit = false;
 
             const Buffer: {
                 new (input: string, encoding?: string): any;
@@ -1619,6 +1620,12 @@ namespace ts {
                             options = { persistent: true };
                         }
                     }
+
+                    if (hitSystemWatcherLimit) {
+                        sysLog(`sysLog:: ${fileOrDirectory}:: Defaulting to fsWatchFile`);
+                        return watchPresentFileSystemEntryWithFsWatchFile();
+                    }
+
                     try {
                         const presentWatcher = _fs.watch(
                             fileOrDirectory,
@@ -1635,6 +1642,8 @@ namespace ts {
                         // Catch the exception and use polling instead
                         // Eg. on linux the number of watches are limited and one could easily exhaust watches and the exception ENOSPC is thrown when creating watcher at that point
                         // so instead of throwing error, use fs.watchFile
+                        hitSystemWatcherLimit ||= e.code === "ENOSPC";
+                        sysLog(`sysLog:: ${fileOrDirectory}:: Changing to fsWatchFile`);
                         return watchPresentFileSystemEntryWithFsWatchFile();
                     }
                 }
@@ -1656,7 +1665,6 @@ namespace ts {
                  * Eg. on linux the number of watches are limited and one could easily exhaust watches and the exception ENOSPC is thrown when creating watcher at that point
                  */
                 function watchPresentFileSystemEntryWithFsWatchFile(): FileWatcher {
-                    sysLog(`sysLog:: ${fileOrDirectory}:: Changing to fsWatchFile`);
                     return watchFile(
                         fileOrDirectory,
                         createFileWatcherCallback(callback),