patch 8.2.4653: "import autoload" does not check the file name

Problem:    "import autoload" does not check the file name.
Solution:   Give an error if the file is not readable. (closes #10049)

src/errors.h

@@ -30,8 +30,9 @@ EXTERN char e_invalid_expression_str[]
 #endif
 EXTERN char e_invalid_range[]
 	INIT(= N_("E16: Invalid range"));
-#if defined(UNIX) || defined(FEAT_SYN_HL) || defined(FEAT_SPELL)
-EXTERN char e_src_is_directory[]
+#if defined(UNIX) || defined(FEAT_SYN_HL) \
+	    || defined(FEAT_SPELL) || defined(FEAT_EVAL)
+EXTERN char e_str_is_directory[]
 	INIT(= N_("E17: \"%s\" is a directory"));
 #endif
 #ifdef FEAT_EVAL

src/ex_cmds.c

@@ -2116,7 +2116,7 @@ check_overwrite(
 	    // with UNIX it is possible to open a directory
 	    if (mch_isdir(ffname))
 	    {
-		semsg(_(e_src_is_directory), ffname);
+		semsg(_(e_str_is_directory), ffname);
 		return FAIL;
 	    }
 #endif

src/ex_docmd.c

@@ -8386,7 +8386,7 @@ open_exfile(
     // with Unix it is possible to open a directory
     if (mch_isdir(fname))
     {
-	semsg(_(e_src_is_directory), fname);
+	semsg(_(e_str_is_directory), fname);
 	return NULL;
     }
 #endif

src/filepath.c

@@ -892,33 +892,35 @@ f_exepath(typval_T *argvars, typval_T *rettv)
     rettv->vval.v_string = p;
 }
 
+/*
+ * Return TRUE if "fname" is a readable file.
+ */
+    int
+file_is_readable(char_u *fname)
+{
+    int		fd;
+
+#ifndef O_NONBLOCK
+# define O_NONBLOCK 0
+#endif
+    if (*fname && !mch_isdir(fname)
+	      && (fd = mch_open((char *)fname, O_RDONLY | O_NONBLOCK, 0)) >= 0)
+    {
+	close(fd);
+	return TRUE;
+    }
+    return FALSE;
+}
+
 /*
  * "filereadable()" function
  */
     void
 f_filereadable(typval_T *argvars, typval_T *rettv)
 {
-    int		fd;
-    char_u	*p;
-    int		n;
-
     if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
 	return;
-
-#ifndef O_NONBLOCK
-# define O_NONBLOCK 0
-#endif
-    p = tv_get_string(&argvars[0]);
-    if (*p && !mch_isdir(p) && (fd = mch_open((char *)p,
-					      O_RDONLY | O_NONBLOCK, 0)) >= 0)
-    {
-	n = TRUE;
-	close(fd);
-    }
-    else
-	n = FALSE;
-
-    rettv->vval.v_number = n;
+    rettv->vval.v_number = file_is_readable(tv_get_string(&argvars[0]));
 }
 
 /*
@@ -1761,7 +1763,7 @@ read_file_or_blob(typval_T *argvars, typval_T *rettv, int always_blob)
 
     if (mch_isdir(fname))
     {
-	semsg(_(e_src_is_directory), fname);
+	semsg(_(e_str_is_directory), fname);
 	return;
     }
     if (*fname == NUL || (fd = mch_fopen((char *)fname, READBIN)) == NULL)

src/proto/filepath.pro

@@ -5,6 +5,7 @@ void f_chdir(typval_T *argvars, typval_T *rettv);
 void f_delete(typval_T *argvars, typval_T *rettv);
 void f_executable(typval_T *argvars, typval_T *rettv);
 void f_exepath(typval_T *argvars, typval_T *rettv);
+int file_is_readable(char_u *fname);
 void f_filereadable(typval_T *argvars, typval_T *rettv);
 void f_filewritable(typval_T *argvars, typval_T *rettv);
 void f_finddir(typval_T *argvars, typval_T *rettv);

src/spellfile.c

@@ -5976,7 +5976,7 @@ mkspell(
 	}
 	if (mch_isdir(wfname))
 	{
-	    semsg(_(e_src_is_directory), wfname);
+	    semsg(_(e_str_is_directory), wfname);
 	    goto theend;
 	}
 

src/testdir/test_vim9_import.vim

@@ -2508,13 +2508,19 @@ def Test_import_autoload_fails()
       vim9script
       import autoload './doesNotExist.vim'
   END
-  v9.CheckScriptSuccess(lines)
+  v9.CheckScriptFailure(lines, 'E282:', 2)
 
   lines =<< trim END
       vim9script
       import autoload '/dir/doesNotExist.vim'
   END
-  v9.CheckScriptSuccess(lines)
+  v9.CheckScriptFailure(lines, 'E282:', 2)
+
+  lines =<< trim END
+      vim9script
+      import autoload '../testdir'
+  END
+  v9.CheckScriptFailure(lines, 'E17:', 2)
 
   lines =<< trim END
       vim9script

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4653,
 /**/
     4652,
 /**/