vim-patch:7.4.2117

Problem:    Deleting an augroup that still has autocmds does not give a
            warning.  The next defined augroup takes its place.
Solution:   Give a warning and prevent the index being used for another group
            name.

https://github.com/vim/vim/commit/f2c4c391192cab6e923b1a418d4af09106fba25f

3 files changed, 76 insertions, 18 deletions

diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index bbfa56dfbf..3f82b4ee97 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -5366,6 +5366,7 @@ static AutoPatCmd *active_apc_list = NULL; /* stack of active autocommands */
  */
 static garray_T augroups = {0, 0, sizeof(char_u *), 10, NULL};
 #define AUGROUP_NAME(i) (((char_u **)augroups.ga_data)[i])
+static char_u *deleted_augroup = NULL;
 
 /*
  * The ID of the current group.  Group 0 is the default one.
@@ -5399,10 +5400,11 @@ static void show_autocmd(AutoPat *ap, event_T event)
     return;
   if (event != last_event || ap->group != last_group) {
     if (ap->group != AUGROUP_DEFAULT) {
-      if (AUGROUP_NAME(ap->group) == NULL)
-        msg_puts_attr((char_u *)_("--Deleted--"), hl_attr(HLF_E));
-      else
+      if (AUGROUP_NAME(ap->group) == NULL) {
+        msg_puts_attr(deleted_augroup, hl_attr(HLF_E));
+      } else {
         msg_puts_attr(AUGROUP_NAME(ap->group), hl_attr(HLF_T));
+      }
       msg_puts((char_u *)"  ");
     }
     msg_puts_attr(event_nr2name(event), hl_attr(HLF_T));
@@ -5568,11 +5570,34 @@ static void au_del_group(char_u *name)
   int i;
 
   i = au_find_group(name);
-  if (i == AUGROUP_ERROR)       /* the group doesn't exist */
+  if (i == AUGROUP_ERROR) {      // the group doesn't exist
     EMSG2(_("E367: No such group: \"%s\""), name);
-  else {
+  } else {
+    event_T event;
+    AutoPat *ap;
+    int in_use = false;
+
+    for (event = (event_T)0; (int)event < (int)NUM_EVENTS;
+         event = (event_T)((int)event + 1)) {
+      for (ap = first_autopat[(int)event]; ap != NULL; ap = ap->next) {
+        if (ap->group == i) {
+          give_warning((char_u *)
+                       _("W19: Deleting augroup that is still in use"), true);
+          in_use = true;
+          event = NUM_EVENTS;
+          break;
+        }
+      }
+    }
     xfree(AUGROUP_NAME(i));
-    AUGROUP_NAME(i) = NULL;
+    if (in_use) {
+      if (deleted_augroup == NULL) {
+        deleted_augroup = (char_u *)_("--Deleted--");
+      }
+      AUGROUP_NAME(i) = deleted_augroup;
+    } else {
+      AUGROUP_NAME(i) = NULL;
+    }
   }
 }
 
@@ -5584,8 +5609,9 @@ static void au_del_group(char_u *name)
 static int au_find_group(const char_u *name)
   FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  for (int i = 0; i < augroups.ga_len; ++i) {
-    if (AUGROUP_NAME(i) != NULL && STRCMP(AUGROUP_NAME(i), name) == 0) {
+  for (int i = 0; i < augroups.ga_len; i++) {
+    if (AUGROUP_NAME(i) != NULL && AUGROUP_NAME(i) != deleted_augroup
+        && STRCMP(AUGROUP_NAME(i), name) == 0) {
       return i;
     }
   }
@@ -5633,10 +5659,21 @@ void do_augroup(char_u *arg, int del_group)
 #if defined(EXITFREE)
 void free_all_autocmds(void)
 {
+  int i;
+  char_u *s;
+
   for (current_augroup = -1; current_augroup < augroups.ga_len;
-       ++current_augroup)
-    do_autocmd((char_u *)"", TRUE);
-  ga_clear_strings(&augroups);
+       current_augroup++) {
+    do_autocmd((char_u *)"", true);
+  }
+
+  for (i = 0; i < augroups.ga_len; i++) {
+      s = ((char_u **)(augroups.ga_data))[i];
+      if (s != deleted_augroup) {
+          xfree(s);
+      }
+  }
+  ga_clear(&augroups);
 }
 
 #endif
@@ -7098,9 +7135,11 @@ char_u *get_augroup_name(expand_T *xp, int idx)
     return (char_u *)"END";
   if (idx >= augroups.ga_len)           /* end of list */
     return NULL;
-  if (AUGROUP_NAME(idx) == NULL)        /* skip deleted entries */
+  if (AUGROUP_NAME(idx) == NULL || AUGROUP_NAME(idx) == deleted_augroup) {
+    // skip deleted entries
     return (char_u *)"";
-  return AUGROUP_NAME(idx);             /* return a name */
+  }
+  return AUGROUP_NAME(idx);             // return a name
 }
 
 static int include_groups = FALSE;
@@ -7157,10 +7196,12 @@ set_context_in_autocmd (
  */
 char_u *get_event_name(expand_T *xp, int idx)
 {
-  if (idx < augroups.ga_len) {          /* First list group names, if wanted */
-    if (!include_groups || AUGROUP_NAME(idx) == NULL)
-      return (char_u *)"";              /* skip deleted entries */
-    return AUGROUP_NAME(idx);           /* return a name */
+  if (idx < augroups.ga_len) {          // First list group names, if wanted
+    if (!include_groups || AUGROUP_NAME(idx) == NULL
+        || AUGROUP_NAME(idx) == deleted_augroup) {
+      return (char_u *)"";              // skip deleted entries
+    }
+    return AUGROUP_NAME(idx);           // return a name
   }
   return (char_u *)event_names[idx - augroups.ga_len].name;
 }
diff --git a/src/nvim/testdir/test_autocmd.vim b/src/nvim/testdir/test_autocmd.vim
index b9d5cfe27b..d856d3296a 100644
--- a/src/nvim/testdir/test_autocmd.vim
+++ b/src/nvim/testdir/test_autocmd.vim
@@ -151,3 +151,20 @@ func Test_early_bar()
   au! vimBarTest|echo 'hello'
   call assert_equal(1, len(split(execute('au vimBarTest'), "\n")))
 endfunc
+
+func Test_augroup_warning()
+  augroup TheWarning
+    au VimEnter * echo 'entering'
+  augroup END
+  call assert_true(match(execute('au VimEnter'), "TheWarning.*VimEnter") >= 0)
+  redir => res
+  augroup! TheWarning
+  redir END
+  call assert_true(match(res, "W19:") >= 0)
+  call assert_true(match(execute('au VimEnter'), "-Deleted-.*VimEnter") >= 0)
+
+  " check "Another" does not take the pace of the deleted entry
+  augroup Another
+  augroup END
+  call assert_true(match(execute('au VimEnter'), "-Deleted-.*VimEnter") >= 0)
+endfunc
diff --git a/src/nvim/version.c b/src/nvim/version.c
index f1ea69c30e..260e4c743e 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -323,7 +323,7 @@ static int included_patches[] = {
   // 2120,
   // 2119,
   // 2118 NA
-  // 2117,
+  2117,
   // 2116 NA
   // 2115 NA
   // 2114 NA