vim-patch:9.0.2059: outstanding exceptions may be skipped (#25736)

Problem:  outstanding exceptions may be skipped
Solution: When restoring exception state, process remaining outstanding
          exceptions

closes: vim/vim#13386

0ab500dede

Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>

runtime/doc/userfunc.txt

@@ -410,7 +410,8 @@ Any return value of the deferred function is discarded.  The function cannot
 be followed by anything, such as "->func" or ".member".  Currently `:defer
 GetArg()->TheFunc()` does not work, it may work in a later version.
 
-Errors are reported but do not cause aborting execution of deferred functions.
+Errors are reported but do not cause aborting execution of deferred functions
+or altering execution outside of deferred functions.
 
 No range is accepted.  The function can be a partial with extra arguments, but
 not with a dictionary. *E1300*

src/nvim/ex_eval.c

@@ -668,17 +668,21 @@ void exception_state_save(exception_state_T *estate)
   estate->estate_did_throw = did_throw;
   estate->estate_need_rethrow = need_rethrow;
   estate->estate_trylevel = trylevel;
+  estate->estate_did_emsg = did_emsg;
 }
 
 /// Restore the current exception state from "estate"
 void exception_state_restore(exception_state_T *estate)
 {
-  if (current_exception == NULL) {
-    current_exception = estate->estate_current_exception;
+  // Handle any outstanding exceptions before restoring the state
+  if (did_throw) {
+    handle_did_throw();
   }
-  did_throw |= estate->estate_did_throw;
-  need_rethrow |= estate->estate_need_rethrow;
-  trylevel |= estate->estate_trylevel;
+  current_exception = estate->estate_current_exception;
+  did_throw = estate->estate_did_throw;
+  need_rethrow = estate->estate_need_rethrow;
+  trylevel = estate->estate_trylevel;
+  did_emsg = estate->estate_did_emsg;
 }
 
 /// Clear the current exception state
@@ -688,6 +692,7 @@ void exception_state_clear(void)
   did_throw = false;
   need_rethrow = false;
   trylevel = 0;
+  did_emsg = 0;
 }
 
 // Flags specifying the message displayed by report_pending.

src/nvim/ex_eval_defs.h

@@ -126,6 +126,7 @@ struct exception_state_S {
   bool estate_did_throw;
   bool estate_need_rethrow;
   int estate_trylevel;
+  int estate_did_emsg;
 };
 
 #endif  // NVIM_EX_EVAL_DEFS_H

test/old/testdir/test_user_func.vim

@@ -827,7 +827,68 @@ func Test_defer_after_exception()
 
   delfunc Defer
   delfunc Foo
+  delfunc Bar
   unlet g:callTrace
 endfunc
 
+" Test for multiple deferred function which throw exceptions.
+" Exceptions thrown by deferred functions should result in error messages but
+" not propagated into the calling functions.
+func Test_multidefer_with_exception()
+  let g:callTrace = []
+  func Except()
+    let g:callTrace += [1]
+    throw 'InnerException'
+    let g:callTrace += [2]
+  endfunc
+
+  func FirstDefer()
+    let g:callTrace += [3]
+    let g:callTrace += [4]
+  endfunc
+
+  func SecondDeferWithExcept()
+    let g:callTrace += [5]
+    call Except()
+    let g:callTrace += [6]
+  endfunc
+
+  func ThirdDefer()
+    let g:callTrace += [7]
+    let g:callTrace += [8]
+  endfunc
+
+  func Foo()
+    let g:callTrace += [9]
+    defer FirstDefer()
+    defer SecondDeferWithExcept()
+    defer ThirdDefer()
+    let g:callTrace += [10]
+  endfunc
+
+  let v:errmsg = ''
+  try
+    let g:callTrace += [11]
+    call Foo()
+    let g:callTrace += [12]
+  catch /TestException/
+    let g:callTrace += [13]
+  catch
+    let g:callTrace += [14]
+  finally
+    let g:callTrace += [15]
+  endtry
+  let g:callTrace += [16]
+
+  call assert_equal('E605: Exception not caught: InnerException', v:errmsg)
+  call assert_equal([11, 9, 10, 7, 8, 5, 1, 3, 4, 12, 15, 16], g:callTrace)
+
+  unlet g:callTrace
+  delfunc Except
+  delfunc FirstDefer
+  delfunc SecondDeferWithExcept
+  delfunc ThirdDefer
+  delfunc Foo
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab