vim-patch:8.1.0018: using "gn" may select wrong text when wrapping

Problem:    Using "gn" may select wrong text when wrapping.
Solution:   Avoid wrapping when searching forward. (Christian Brabandt)
https://github.com/vim/vim/commit/bdb657924d73c98b0ab28411749571e893b699a9

2 files changed, 50 insertions, 19 deletions

diff --git a/src/nvim/search.c b/src/nvim/search.c
index e9d8f92226..457a6c309d 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -3953,7 +3953,9 @@ current_search(
     dec_cursor();
 
   pos_T orig_pos;               /* position of the cursor at beginning */
+  pos_T first_match;            // position of first match
   pos_T pos;                    /* position after the pattern */
+  int result;                   // result of various function calls
 
   if (VIsual_active) {
     orig_pos = pos = curwin->w_cursor;
@@ -3988,7 +3990,7 @@ current_search(
     if (!dir && !one_char)
       flags = SEARCH_END;
 
-    int result = searchit(curwin, curbuf, &pos, (dir ? FORWARD : BACKWARD),
+    result = searchit(curwin, curbuf, &pos, (dir ? FORWARD : BACKWARD),
         spats[last_idx].pat, i ? count : 1,
         SEARCH_KEEP | flags, RE_SEARCH, 0, NULL);
 
@@ -4012,6 +4014,9 @@ current_search(
             ml_get(curwin->w_buffer->b_ml.ml_line_count));
       }
     }
+    if (i == 0) {
+      first_match = pos;
+    }
     p_ws = old_p_ws;
   }
 
@@ -4029,9 +4034,26 @@ current_search(
 
   /* move to match, except for zero-width matches, in which case, we are
    * already on the next match */
-  if (!one_char)
-    searchit(curwin, curbuf, &pos, direction,
-        spats[last_idx].pat, 0L, flags | SEARCH_KEEP, RE_SEARCH, 0, NULL);
+  if (!one_char) {
+    p_ws = false;
+    for (int i = 0; i < 2; i++) {
+      result = searchit(curwin, curbuf, &pos, direction,
+                        spats[last_idx].pat, 0L, flags | SEARCH_KEEP, RE_SEARCH,
+                        0, NULL);
+      // Search successfull, break out from the loop
+      if (result) {
+        break;
+      }
+      // search failed, try again from the last search position match
+      pos = first_match;
+    }
+  }
+
+  p_ws = old_p_ws;
+  // not found
+  if (!result) {
+    return FAIL;
+  }
 
   if (!VIsual_active)
     VIsual = start_pos;
diff --git a/src/nvim/testdir/test_gn.vim b/src/nvim/testdir/test_gn.vim
index f56e707da1..405425a42b 100644
--- a/src/nvim/testdir/test_gn.vim
+++ b/src/nvim/testdir/test_gn.vim
@@ -5,51 +5,51 @@ func Test_gn_command()
   noautocmd new
   " replace a single char by itsself quoted:
   call setline('.', 'abc x def x ghi x jkl')
-  let @/='x'
+  let @/ = 'x'
   exe "norm! cgn'x'\<esc>.."
   call assert_equal("abc 'x' def 'x' ghi 'x' jkl", getline('.'))
   sil! %d_
 
   " simple search match
   call setline('.', 'foobar')
-  let @/='foobar'
+  let @/ = 'foobar'
   exe "norm! gncsearchmatch"
   call assert_equal('searchmatch', getline('.'))
   sil! %d _
 
   " replace a multi-line match
   call setline('.', ['', 'one', 'two'])
-  let @/='one\_s*two\_s'
+  let @/ = 'one\_s*two\_s'
   exe "norm! gnceins\<CR>zwei"
   call assert_equal(['','eins','zwei'], getline(1,'$'))
   sil! %d _
 
   " test count argument
   call setline('.', ['', 'abcdx | abcdx | abcdx'])
-  let @/='[a]bcdx'
+  let @/ = '[a]bcdx'
   exe "norm! 2gnd"
   call assert_equal(['','abcdx |  | abcdx'], getline(1,'$'))
   sil! %d _
 
   " join lines
   call setline('.', ['join ', 'lines'])
-  let @/='$'
+  let @/ = '$'
   exe "norm! 0gnd"
   call assert_equal(['join lines'], getline(1,'$'))
   sil! %d _
 
   " zero-width match
   call setline('.', ['', 'zero width pattern'])
-  let @/='\>\zs'
+  let @/ = '\>\zs'
   exe "norm! 0gnd"
   call assert_equal(['', 'zerowidth pattern'], getline(1,'$'))
   sil! %d _
 
   " delete first and last chars
   call setline('.', ['delete first and last chars'])
-  let @/='^'
+  let @/ = '^'
   exe "norm! 0gnd$"
-  let @/='\zs'
+  let @/ = '\zs'
   exe "norm! gnd"
   call assert_equal(['elete first and last char'], getline(1,'$'))
   sil! %d _
@@ -62,14 +62,14 @@ func Test_gn_command()
 
   " backwards search
   call setline('.', ['my very excellent mother just served us nachos'])
-  let @/='mother'
+  let @/ = 'mother'
   exe "norm! $cgNmongoose"
   call assert_equal(['my very excellent mongoose just served us nachos'], getline(1,'$'))
   sil! %d _
 
   " search for single char
   call setline('.', ['','for (i=0; i<=10; i++)'])
-  let @/='i'
+  let @/ = 'i'
   exe "norm! cgnj"
   call assert_equal(['','for (j=0; i<=10; i++)'], getline(1,'$'))
   sil! %d _
@@ -77,28 +77,28 @@ func Test_gn_command()
   " search hex char
   call setline('.', ['','Y'])
   set noignorecase
-  let @/='\%x59'
+  let @/ = '\%x59'
   exe "norm! gnd"
   call assert_equal(['',''], getline(1,'$'))
   sil! %d _
 
   " test repeating gdn
   call setline('.', ['', '1', 'Johnny', '2', 'Johnny', '3'])
-  let @/='Johnny'
+  let @/ = 'Johnny'
   exe "norm! dgn."
   call assert_equal(['','1', '', '2', '', '3'], getline(1,'$'))
   sil! %d _
 
   " test repeating gUgn
   call setline('.', ['', '1', 'Depp', '2', 'Depp', '3'])
-  let @/='Depp'
+  let @/ = 'Depp'
   exe "norm! gUgn."
   call assert_equal(['', '1', 'DEPP', '2', 'DEPP', '3'], getline(1,'$'))
   sil! %d _
 
   " test using look-ahead assertions
   call setline('.', ['a:10', '', 'a:1', '', 'a:20'])
-  let @/='a:0\@!\zs\d\+'
+  let @/ = 'a:0\@!\zs\d\+'
   exe "norm! 2nygno\<esc>p"
   call assert_equal(['a:10', '', 'a:1', '1', '', 'a:20'], getline(1,'$'))
   sil! %d _
@@ -114,12 +114,21 @@ func Test_gn_command()
   " search upwards with nowrapscan set
   call setline('.', ['foo', 'bar', 'foo', 'baz'])
   set nowrapscan
-  let @/='foo'
+  let @/ = 'foo'
   $
   norm! dgN
   call assert_equal(['foo', 'bar', '', 'baz'], getline(1,'$'))
   sil! %d_
 
+  " search using the \zs atom
+  call setline(1, [' nnoremap', '' , 'nnoremap'])
+  set wrapscan&vim
+  let @/ = '\_s\zsnnoremap'
+  $
+  norm! cgnmatch
+  call assert_equal([' nnoremap', '', 'match'], getline(1,'$'))
+  sil! %d_
+
   set wrapscan&vim
   set belloff&vim
 endfu