Patch 8.2.3809
Problem:    Vim9: crash when garbage collecting a nested partial. (Virginia
            Senioria)
Solution:   Set references in all the funcstacks. (closes #9348)
Files:      src/vim9execute.c, src/proto/vim9execute.pro, src/structs.h,
            src/eval.c, src/testdir/test_vim9_func.vim


*** ../vim-8.2.3808/src/vim9execute.c   2021-12-14 14:29:12.053734514 +0000
--- src/vim9execute.c   2021-12-14 17:58:36.178986528 +0000
***************
*** 468,473 ****
--- 468,498 ----
  // Get pointer to item in the stack.
  #define STACK_TV(idx) (((typval_T *)ectx->ec_stack.ga_data) + idx)
  
+ // Double linked list of funcstack_T in use.
+ static funcstack_T *first_funcstack = NULL;
+ 
+     static void
+ add_funcstack_to_list(funcstack_T *funcstack)
+ {
+       // Link in list of funcstacks.
+     if (first_funcstack != NULL)
+       first_funcstack->fs_prev = funcstack;
+     funcstack->fs_next = first_funcstack;
+     funcstack->fs_prev = NULL;
+     first_funcstack = funcstack;
+ }
+ 
+     static void
+ remove_funcstack_from_list(funcstack_T *funcstack)
+ {
+     if (funcstack->fs_prev == NULL)
+       first_funcstack = funcstack->fs_next;
+     else
+       funcstack->fs_prev->fs_next = funcstack->fs_next;
+     if (funcstack->fs_next != NULL)
+       funcstack->fs_next->fs_prev = funcstack->fs_prev;
+ }
+ 
  /*
   * Used when returning from a function: Check if any closure is still
   * referenced.  If so then move the arguments and variables to a separate 
piece
***************
*** 540,545 ****
--- 565,571 ----
        // Move them to the called function.
        if (funcstack == NULL)
            return FAIL;
+ 
        funcstack->fs_var_offset = argcount + STACK_FRAME_SIZE;
        funcstack->fs_ga.ga_len = funcstack->fs_var_offset + dfunc->df_varcount;
        stack = ALLOC_CLEAR_MULT(typval_T, funcstack->fs_ga.ga_len);
***************
*** 549,554 ****
--- 575,581 ----
            vim_free(funcstack);
            return FAIL;
        }
+       add_funcstack_to_list(funcstack);
  
        // Move or copy the arguments.
        for (idx = 0; idx < argcount; ++idx)
***************
*** 571,577 ****
            // local variable, has a reference count for the variable, thus
            // will never go down to zero.  When all these refcounts are one
            // then the funcstack is unused.  We need to count how many we have
!           // so we need when to check.
            if (tv->v_type == VAR_PARTIAL && tv->vval.v_partial != NULL)
            {
                int         i;
--- 598,604 ----
            // local variable, has a reference count for the variable, thus
            // will never go down to zero.  When all these refcounts are one
            // then the funcstack is unused.  We need to count how many we have
!           // so we know when to check.
            if (tv->v_type == VAR_PARTIAL && tv->vval.v_partial != NULL)
            {
                int         i;
***************
*** 643,653 ****
--- 670,703 ----
        for (i = 0; i < gap->ga_len; ++i)
            clear_tv(stack + i);
        vim_free(stack);
+       remove_funcstack_from_list(funcstack);
        vim_free(funcstack);
      }
  }
  
  /*
+  * For garbage collecting: set references in all variables referenced by
+  * all funcstacks.
+  */
+     int
+ set_ref_in_funcstacks(int copyID)
+ {
+     funcstack_T *funcstack;
+ 
+     for (funcstack = first_funcstack; funcstack != NULL;
+                                               funcstack = funcstack->fs_next)
+     {
+       typval_T    *stack = funcstack->fs_ga.ga_data;
+       int         i;
+ 
+       for (i = 0; i < funcstack->fs_ga.ga_len; ++i)
+           if (set_ref_in_item(stack + i, copyID, NULL, NULL))
+               return TRUE;  // abort
+     }
+     return FALSE;
+ }
+ 
+ /*
   * Return from the current function.
   */
      static int
*** ../vim-8.2.3808/src/proto/vim9execute.pro   2021-09-02 17:49:02.744932328 
+0100
--- src/proto/vim9execute.pro   2021-12-14 17:47:09.295704754 +0000
***************
*** 1,6 ****
--- 1,7 ----
  /* vim9execute.c */
  void to_string_error(vartype_T vartype);
  void funcstack_check_refcount(funcstack_T *funcstack);
+ int set_ref_in_funcstacks(int copyID);
  char_u *char_from_string(char_u *str, varnumber_T index);
  char_u *string_slice(char_u *str, varnumber_T first, varnumber_T last, int 
exclusive);
  int fill_partial_and_closure(partial_T *pt, ufunc_T *ufunc, ectx_T *ectx);
*** ../vim-8.2.3808/src/structs.h       2021-12-13 14:26:40.992627753 +0000
--- src/structs.h       2021-12-14 17:46:09.915820923 +0000
***************
*** 2009,2016 ****
   * Structure to hold the context of a compiled function, used by closures
   * defined in that function.
   */
! typedef struct funcstack_S
  {
      garray_T  fs_ga;          // contains the stack, with:
                                // - arguments
                                // - frame
--- 2009,2021 ----
   * Structure to hold the context of a compiled function, used by closures
   * defined in that function.
   */
! typedef struct funcstack_S funcstack_T;
! 
! struct funcstack_S
  {
+     funcstack_T *fs_next;     // linked list at "first_funcstack"
+     funcstack_T *fs_prev;
+ 
      garray_T  fs_ga;          // contains the stack, with:
                                // - arguments
                                // - frame
***************
*** 2021,2027 ****
      int               fs_refcount;    // nr of closures referencing this 
funcstack
      int               fs_min_refcount; // nr of closures on this funcstack
      int               fs_copyID;      // for garray_T collection
! } funcstack_T;
  
  typedef struct outer_S outer_T;
  struct outer_S {
--- 2026,2032 ----
      int               fs_refcount;    // nr of closures referencing this 
funcstack
      int               fs_min_refcount; // nr of closures on this funcstack
      int               fs_copyID;      // for garray_T collection
! };
  
  typedef struct outer_S outer_T;
  struct outer_S {
*** ../vim-8.2.3808/src/eval.c  2021-12-14 12:06:12.533925687 +0000
--- src/eval.c  2021-12-14 17:44:20.900034455 +0000
***************
*** 4510,4515 ****
--- 4510,4518 ----
      // function call arguments, if v:testing is set.
      abort = abort || set_ref_in_func_args(copyID);
  
+     // funcstacks keep variables for closures
+     abort = abort || set_ref_in_funcstacks(copyID);
+ 
      // v: vars
      abort = abort || garbage_collect_vimvars(copyID);
  
***************
*** 4869,4883 ****
            for (i = 0; i < pt->pt_argc; ++i)
                abort = abort || set_ref_in_item(&pt->pt_argv[i], copyID,
                                                        ht_stack, list_stack);
!           if (pt->pt_funcstack != NULL)
!           {
!               typval_T    *stack = pt->pt_funcstack->fs_ga.ga_data;
! 
!               for (i = 0; i < pt->pt_funcstack->fs_ga.ga_len; ++i)
!                   abort = abort || set_ref_in_item(stack + i, copyID,
!                                                        ht_stack, list_stack);
!           }
! 
        }
      }
  #ifdef FEAT_JOB_CHANNEL
--- 4872,4878 ----
            for (i = 0; i < pt->pt_argc; ++i)
                abort = abort || set_ref_in_item(&pt->pt_argv[i], copyID,
                                                        ht_stack, list_stack);
!           // pt_funcstack is handled in set_ref_in_funcstacks()
        }
      }
  #ifdef FEAT_JOB_CHANNEL
*** ../vim-8.2.3808/src/testdir/test_vim9_func.vim      2021-12-13 
18:14:11.760881287 +0000
--- src/testdir/test_vim9_func.vim      2021-12-14 18:11:57.841770846 +0000
***************
*** 1903,1908 ****
--- 1903,1943 ----
    delete('XToDelFunc')
  enddef
  
+ func Test_free_dict_while_in_funcstack()
+   " relies on the sleep command
+   CheckUnix
+   call Run_Test_free_dict_while_in_funcstack()
+ endfunc
+ 
+ def Run_Test_free_dict_while_in_funcstack()
+ 
+   # this was freeing the TermRun() default argument dictionary while it was
+   # still referenced in a funcstack_T
+   var lines =<< trim END
+       vim9script
+ 
+       &updatetime = 400
+       def TermRun(_ = {})
+           def Post()
+           enddef
+           def Exec()
+               term_start('sleep 1', {
+                   term_finish: 'close',
+                   exit_cb: (_, _) => Post(),
+               })
+           enddef
+           Exec()
+       enddef
+       nnoremap <F4> <Cmd>call <SID>TermRun()<CR>
+       timer_start(100, (_) => feedkeys("\<F4>"))
+       timer_start(1000, (_) => feedkeys("\<F4>"))
+       sleep 1500m
+   END
+   CheckScriptSuccess(lines)
+   nunmap <F4>
+   set updatetime&
+ enddef
+ 
  def Test_redef_failure()
    writefile(['def Func0(): string',  'return "Func0"', 'enddef'], 'Xdef')
    so Xdef
*** ../vim-8.2.3808/src/version.c       2021-12-14 14:29:12.057734501 +0000
--- src/version.c       2021-12-14 18:12:54.005677305 +0000
***************
*** 751,752 ****
--- 751,754 ----
  {   /* Add new patch number below this line */
+ /**/
+     3809,
  /**/

-- 
hundred-and-one symptoms of being an internet addict:
32. You don't know what sex three of your closest friends are, because they
    have neutral nicknames and you never bothered to ask.

 /// Bram Moolenaar -- [email protected] -- http://www.Moolenaar.net   \\\
///                                                                      \\\
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