File ../libssh-0.10.4/.git is a regular file while file ./.git is a directory
diff --color -ru ../libssh-0.10.4/src/sftp.c ./src/sftp.c
--- ../libssh-0.10.4/src/sftp.c	2023-05-22 12:45:48.383509085 +0200
+++ ./src/sftp.c	2023-05-22 12:54:31.004037650 +0200
@@ -1755,6 +1755,10 @@
 int sftp_close(sftp_file file){
   int err = SSH_NO_ERROR;
 
+  if (file == NULL) {
+      return err;
+  }
+
   SAFE_FREE(file->name);
   if (file->handle){
     err = sftp_handle_close(file->sftp,file->handle);
@@ -1917,7 +1921,7 @@
 
 /* Read from a file using an opened sftp file handle. */
 ssize_t sftp_read(sftp_file handle, void *buf, size_t count) {
-  sftp_session sftp = handle->sftp;
+  sftp_session sftp;
   sftp_message msg = NULL;
   sftp_status_message status;
   ssh_string datastring;
@@ -1926,6 +1930,11 @@
   uint32_t id;
   int rc;
 
+  if (handle == NULL) {
+      return -1;
+  }
+  sftp = handle->sftp;
+
   if (handle->eof) {
     return 0;
   }
@@ -2147,7 +2156,7 @@
 }
 
 ssize_t sftp_write(sftp_file file, const void *buf, size_t count) {
-  sftp_session sftp = file->sftp;
+  sftp_session sftp;
   sftp_message msg = NULL;
   sftp_status_message status;
   ssh_buffer buffer;
@@ -2156,6 +2165,11 @@
   size_t packetlen;
   int rc;
 
+  if (file == NULL) {
+      return -1;
+  }
+  sftp = file->sftp;
+
   buffer = ssh_buffer_new();
   if (buffer == NULL) {
     ssh_set_error_oom(sftp->session);