From 53ac2ad20ab26b147d64da48a5e3684c2541c844 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Thu, 7 Aug 2025 23:57:55 +0800
Subject: [PATCH] vim-patch:9.1.1599: :bnext doesn't go to unlisted help
 buffers (#35216)

Problem:  :bnext doesn't go to unlisted help buffers when cycling
          through help buffers (after 9.1.0557).
Solution: Don't check if a help buffer is listed (zeertzjq).

From <https://github.com/vim/vim/issues/4478#issuecomment-498831057>:

> I think we should fix that, since once you get to a non-help buffer
> all unlisted buffers are skipped, thus you won't encounter another
> help buffer.

This implies that cycling through help buffers should work even if help
buffers are unlisted. Otherwise this part of :bnext isn't really useful,
as :h makes help buffers unlisted by default.

related: vim/vim#4478
related: vim/vim#15198
closes: vim/vim#17913

https://github.com/vim/vim/commit/9662f334801597baa3c8d809834794b7a1986a17
---
 src/nvim/buffer.c                | 14 +++++++++-----
 test/old/testdir/test_buffer.vim | 11 +++++++++++
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 4ab78b9f8a..d8c46020bc 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -1256,8 +1256,11 @@ static int do_buffer_ext(int action, int start, int dir, int count, int flags)
       buf = buf->b_next;
     }
   } else {
+    const bool help_only = (flags & DOBUF_SKIPHELP) != 0 && buf->b_help;
+
     bp = NULL;
-    while (count > 0 || (!unload && !buf->b_p_bl && bp != buf)) {
+    while (count > 0 || (bp != buf && !unload
+                         && !(help_only ? buf->b_help : buf->b_p_bl))) {
       // remember the buffer where we start, we come back there when all
       // buffers are unlisted.
       if (bp == NULL) {
@@ -1265,12 +1268,13 @@ static int do_buffer_ext(int action, int start, int dir, int count, int flags)
       }
       buf = dir == FORWARD ? (buf->b_next != NULL ? buf->b_next : firstbuf)
                            : (buf->b_prev != NULL ? buf->b_prev : lastbuf);
+      // Avoid non-help buffers if the starting point was a help buffer
+      // and vice-versa.
       // Don't count unlisted buffers.
-      // Avoid non-help buffers if the starting point was a non-help buffer and
-      // vice-versa.
       if (unload
-          || (buf->b_p_bl
-              && ((flags & DOBUF_SKIPHELP) == 0 || buf->b_help == bp->b_help))) {
+          || (help_only
+              ? buf->b_help
+              : (buf->b_p_bl && ((flags & DOBUF_SKIPHELP) == 0 || !buf->b_help)))) {
         count--;
         bp = NULL;              // use this buffer as new starting point
       }
diff --git a/test/old/testdir/test_buffer.vim b/test/old/testdir/test_buffer.vim
index 2bdc709482..cf4d264066 100644
--- a/test/old/testdir/test_buffer.vim
+++ b/test/old/testdir/test_buffer.vim
@@ -169,6 +169,17 @@ func Test_bnext_bprev_help()
   b XHelp1
   blast   | call assert_equal(b4, bufnr())
 
+  " Cycling through help buffers works even if they aren't listed.
+  b XHelp1
+  setlocal nobuflisted
+  bnext | call assert_equal(b3, bufnr())
+  bnext | call assert_equal(b1, bufnr())
+  bprev | call assert_equal(b3, bufnr())
+  setlocal nobuflisted
+  bprev | call assert_equal(b1, bufnr())
+  bprev | call assert_equal(b3, bufnr())
+  bnext | call assert_equal(b1, bufnr())
+
   %bwipe!
 endfunc