patch 8.2.4330: Vim9: no error if script imports itselfv8.2.4330

Problem:    Vim9: no error if script imports itself.
Solution:   Give an error when a script imports itself.

4 files changed, 20 insertions, 2 deletions

diff --git a/src/errors.h b/src/errors.h
index ecd4eb92d0..c66d26d8d9 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -2802,7 +2802,8 @@ EXTERN char e_function_reference_invalid[]
 	INIT(= N_("E1086: Function reference invalid"));
 EXTERN char e_cannot_use_index_when_declaring_variable[]
 	INIT(= N_("E1087: Cannot use an index when declaring a variable"));
-// E1088 unused
+EXTERN char e_script_cannot_import_itself[]
+	INIT(= N_("E1088: Script cannot import itself"));
 EXTERN char e_unknown_variable_str[]
 	INIT(= N_("E1089: Unknown variable: %s"));
 EXTERN char e_cannot_assign_to_argument[]
diff --git a/src/testdir/test_vim9_import.vim b/src/testdir/test_vim9_import.vim
index 1e8851e92d..652e4d36b6 100644
--- a/src/testdir/test_vim9_import.vim
+++ b/src/testdir/test_vim9_import.vim
@@ -500,7 +500,16 @@ def Test_import_fails()
   v9.CheckScriptFailure(lines, 'E1262:')
 
   delete('Xthat.vim')
- 
+
+  lines =<< trim END
+      vim9script
+      export var item = 'hello'
+      import './Xyourself.vim'
+  END
+  writefile(lines, 'Xyourself.vim')
+  assert_fails('source Xyourself.vim', 'E1088:')
+  delete('Xyourself.vim')
+
   mkdir('Ximport')
 
   writefile(['vim9script'], 'Ximport/.vim')
diff --git a/src/version.c b/src/version.c
index 2feed3cf37..d7da6df6e0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4330,
+/**/
     4329,
 /**/
     4328,
diff --git a/src/vim9script.c b/src/vim9script.c
index 5c1c055668..872108827e 100644
--- a/src/vim9script.c
+++ b/src/vim9script.c
@@ -516,6 +516,12 @@ handle_import(
 	goto erret;
     }
 
+    if (sid == current_sctx.sc_sid)
+    {
+	emsg(_(e_script_cannot_import_itself));
+	goto erret;
+    }
+
     import_gap = gap != NULL ? gap : &SCRIPT_ITEM(import_sid)->sn_imports;
     for (i = 0; i < import_gap->ga_len; ++i)
     {