From 5c90bbae2aad0c3129ed8efa0f1b03980f7f28a3 Mon Sep 17 00:00:00 2001
From: Jan Edmund Lazo <janedmundlazo@hotmail.com>
Date: Mon, 27 Aug 2018 10:14:57 -0400
Subject: [PATCH] vim-patch:8.0.1383: local additions in help skips some files

Problem:    Local additions in help skips some files. (joshklod)
Solution:   Check the base file name length equals.
https://github.com/vim/vim/commit/35c5e8155da797f14124d98fdc6189067b965688
---
 src/nvim/ex_cmds.c             | 10 +++++-----
 src/nvim/testdir/test_help.vim | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index ca975ee02a..78f422f211 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -5017,11 +5017,9 @@ void fix_help_buffer(void)
                 const char_u *const f1 = fnames[i1];
                 const char_u *const f2 = fnames[i2];
                 const char_u *const t1 = path_tail(f1);
-                if (fnamencmp(f1, f2, t1 - f1) != 0) {
-                  continue;
-                }
+                const char_u *const t2 = path_tail(f2);
                 const char_u *const e1 = STRRCHR(t1, '.');
-                const char_u *const e2 = STRRCHR(path_tail(f2), '.');
+                const char_u *const e2 = STRRCHR(t2, '.');
                 if (e1 == NULL || e2 == NULL) {
                   continue;
                 }
@@ -5032,8 +5030,10 @@ void fix_help_buffer(void)
                   fnames[i1] = NULL;
                   continue;
                 }
-                if (fnamencmp(f1, f2, e1 - f1) != 0)
+                if (e1 - f1 != e2 - f2
+                    || fnamencmp(f1, f2, e1 - f1) != 0) {
                   continue;
+                }
                 if (fnamecmp(e1, ".txt") == 0
                     && fnamecmp(e2, fname + 4) == 0) {
                   /* use .abx instead of .txt */
diff --git a/src/nvim/testdir/test_help.vim b/src/nvim/testdir/test_help.vim
index e7bd602dbc..ed3181564c 100644
--- a/src/nvim/testdir/test_help.vim
+++ b/src/nvim/testdir/test_help.vim
@@ -31,3 +31,22 @@ func Test_help_keyword()
   close
   bwipe!
 endfunc
+
+func Test_help_local_additions()
+  call mkdir('Xruntime/doc', 'p')
+  call writefile(['*mydoc.txt* my awesome doc'], 'Xruntime/doc/mydoc.txt')
+  call writefile(['*mydoc-ext.txt* my extended awesome doc'], 'Xruntime/doc/mydoc-ext.txt')
+  let rtp_save = &rtp
+  set rtp+=./Xruntime
+  help
+  1
+  call search('mydoc.txt')
+  call assert_equal('|mydoc.txt| my awesome doc', getline('.'))
+  1
+  call search('mydoc-ext.txt')
+  call assert_equal('|mydoc-ext.txt| my extended awesome doc', getline('.'))
+  close
+
+  call delete('Xruntime', 'rf')
+  let &rtp = rtp_save
+endfunc