patch 9.1.0359: MS-Windows: relative import in a script sourced from a buffer doesn't work

Problem:  MS-Windows: Relative import in a script sourced from a buffer
          doesn't work (Ernie Rael)
Solution: Set a filename, so that we are not trying to use
          script-relative filename (Yegappan Lakshmanan)

When a script is sourced from a buffer, the file name is set to ":source
buffer=". In MS-Windows, the ":" is a path separator character (used
after a drive letter). This results in the code trying to use the ":"
prefix to import the script on MS-Windows. To fix this, when importing a
script from a script sourced from a buffer with nofile, don't use
a script relative path name.

fixes #14588
closes: #14603

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/scriptfile.c

@@ -1430,8 +1430,13 @@ do_source_buffer_init(source_cookie_T *sp, exarg_T *eap)
 	return NULL;
 
     // Use ":source buffer=<num>" as the script name
-    vim_snprintf((char *)IObuff, IOSIZE, ":source buffer=%d", curbuf->b_fnum);
-    fname = vim_strsave(IObuff);
+    if (curbuf->b_ffname != NULL)
+	fname = vim_strsave(curbuf->b_ffname);
+    else
+    {
+	vim_snprintf((char *)IObuff, IOSIZE, ":source buffer=%d", curbuf->b_fnum);
+	fname = vim_strsave(IObuff);
+    }
     if (fname == NULL)
 	return NULL;
 

src/testdir/test_vim9_import.vim

@@ -1140,13 +1140,9 @@ def Test_autoload_import_relative()
   v9.CheckScriptFailure(lines, 'E484:')
 enddef
 
+" autoload relative, access from compiled function.
+" Github issues: #14565, #14579
 def Test_autoload_import_relative_compiled_buffer()
-  if !has('unix')
-    # temporary, until it's discovered why the test fails on Windows.
-    CheckUnix
-    return
-  endif
-  # autoload relative, access from compiled function. #14565, #14579
   var lines =<< trim END
     vim9script
 
@@ -1168,6 +1164,40 @@ def Test_autoload_import_relative_compiled_buffer()
   new
   setline(1, lines)
   :source
+  # source one more time to detect issues with clearing the script state and
+  # variables
+  :source
+  :bw!
+enddef
+
+" Test for relative import when sourcing a buffer in another directory
+def Test_autoload_import_relative_from_buffer_in_dir()
+  mkdir('Ximportrelative/dir1/dir2', 'pR')
+  var lines =<< trim END
+    vim9script
+
+    export def F1(): string
+        return 'InFile.vim'
+    enddef
+  END
+  writefile(lines, 'Ximportrelative/dir1/dir2/Ximport.vim')
+  lines =<< trim END
+    vim9script
+
+    import autoload './Ximport.vim' as xfile
+
+    def F(): string
+      return xfile.F1()
+    enddef
+    assert_equal('InFile.vim', F())
+  END
+  writefile(lines, 'Ximportrelative/dir1/dir2/Xrelative.vim')
+
+  split Ximportrelative/dir1/dir2/Xrelative.vim
+  :source
+  # source one more time to detect issues with clearing the script state and
+  # variables
+  :source
   :bw!
 enddef
 

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    359,
 /**/
     358,
 /**/

src/vim9script.c

@@ -456,15 +456,24 @@ handle_import(
 	scriptitem_T	*si = SCRIPT_ITEM(current_sctx.sc_sid);
 	char_u		*tail = gettail(si->sn_name);
 	char_u		*from_name;
+	int		sourced_from_nofile_buf = FALSE;
 
-	// Relative to current script: "./name.vim", "../../name.vim".
-	len = STRLEN(si->sn_name) - STRLEN(tail) + STRLEN(tv.vval.v_string) + 2;
-	from_name = alloc((int)len);
-	if (from_name == NULL)
-	    goto erret;
-	vim_strncpy(from_name, si->sn_name, tail - si->sn_name);
-	add_pathsep(from_name);
-	STRCAT(from_name, tv.vval.v_string);
+	if (STRNCMP(si->sn_name, ":source buffer=", 15) == 0)
+	    sourced_from_nofile_buf = TRUE;
+
+	if (!sourced_from_nofile_buf)
+	{
+	    // Relative to current script: "./name.vim", "../../name.vim".
+	    len = STRLEN(si->sn_name) - STRLEN(tail) + STRLEN(tv.vval.v_string) + 2;
+	    from_name = alloc((int)len);
+	    if (from_name == NULL)
+		goto erret;
+	    vim_strncpy(from_name, si->sn_name, tail - si->sn_name);
+	    add_pathsep(from_name);
+	    STRCAT(from_name, tv.vval.v_string);
+	}
+	else
+	    from_name = vim_strsave(tv.vval.v_string);
 	simplify_filename(from_name);
 
 	res = handle_import_fname(from_name, is_autoload, &sid);