process: improve error message for process.cwd() when directory is deleted

doc/api/errors.md

@@ -1116,6 +1116,14 @@ added:
 
 An attempt to invoke an unsupported crypto operation was made.
 
+<a id="ERR_CWD_DELETED"></a>
+
+### `ERR_CWD_DELETED`
+
+The current working directory has been deleted while the process was still inside it.
+
+To resolve this, use `process.chdir()` to switch to a valid directory.
+
 <a id="ERR_DEBUGGER_ERROR"></a>
 
 ### `ERR_DEBUGGER_ERROR`

lib/internal/bootstrap/switches/does_own_process_state.js

@@ -138,7 +138,8 @@ function wrappedUmask(mask) {
 }
 
 function wrappedCwd() {
-  if (cachedCwd === '')
+  if (cachedCwd === '') {
     cachedCwd = rawMethods.cwd();
+  }
   return cachedCwd;
 }

src/node_errors.h

@@ -37,6 +37,7 @@ void OOMErrorHandler(const char* location, const v8::OOMDetails& details);
 
 #define ERRORS_WITH_CODE(V)                                                    \
   V(ERR_ACCESS_DENIED, Error)                                                  \
+  V(ERR_CWD_DELETED, Error)                                                    \
   V(ERR_BUFFER_CONTEXT_NOT_AVAILABLE, Error)                                   \
   V(ERR_BUFFER_OUT_OF_BOUNDS, RangeError)                                      \
   V(ERR_BUFFER_TOO_LARGE, Error)                                               \
@@ -160,6 +161,10 @@ ERRORS_WITH_CODE(V)
   V(ERR_ACCESS_DENIED, "Access to this API has been restricted")               \
   V(ERR_BUFFER_CONTEXT_NOT_AVAILABLE,                                          \
     "Buffer is not available for the current Context")                         \
+  V(ERR_CWD_DELETED,                                                           \
+    "Current working directory does not exist. "                               \
+    "It may have been deleted while the process was still "                    \
+    "inside it. Use process.chdir() to change to a valid directory.")          \
   V(ERR_CLOSED_MESSAGE_PORT, "Cannot send data on closed MessagePort")         \
   V(ERR_CONSTRUCT_CALL_INVALID, "Constructor cannot be called")                \
   V(ERR_CONSTRUCT_CALL_REQUIRED, "Cannot call constructor without `new`")      \

src/node_process_methods.cc

@@ -136,6 +136,10 @@ static void Cwd(const FunctionCallbackInfo<Value>& args) {
   char buf[PATH_MAX_BYTES];
   size_t cwd_len = sizeof(buf);
   int err = uv_cwd(buf, &cwd_len);
+  if (err == UV_ENOENT) {
+    THROW_ERR_CWD_DELETED(env);
+    return;
+  }
   if (err)
     return env->ThrowUVException(err, "uv_cwd");