vim-patch:9.0.0950: the pattern "\_s\zs" matches at EOL (#21192)

Problem:    The pattern "\_s\zs" matches at EOL.
Solution:   Make the pattern "\_s\zs" match at the start of the next line.
            (closes vim/vim#11617)

c96311b5be

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/search.c

@@ -655,6 +655,8 @@ int searchit(win_T *win, buf_T *buf, pos_T *pos, pos_T *end_pos, Direction dir,
           // match (this is vi compatible) or on the next char.
           if (dir == FORWARD && at_first_line) {
             match_ok = true;
+            matchcol = col;
+
             // When the match starts in a next line it's certainly
             // past the start position.
             // When match lands on a NUL the cursor will be put
@@ -679,20 +681,21 @@ int searchit(win_T *win, buf_T *buf, pos_T *pos, pos_T *end_pos, Direction dir,
                   break;
                 }
                 matchcol = endpos.col;
-                // for empty match (matchcol == matchpos.col): advance one char
+                // for empty match: advance one char
+                if (matchcol == matchpos.col && ptr[matchcol] != NUL) {
+                  matchcol += utfc_ptr2len(ptr + matchcol);
+                }
               } else {
-                // Prepare to start after first matched character.
+                // Advance "matchcol" to the next character.
-                matchcol = matchpos.col;
+                // This does not use matchpos.col, because
+                // "\zs" may have have set it.
+                if (ptr[matchcol] != NUL) {
+                  matchcol += utfc_ptr2len(ptr + matchcol);
+                }
               }
-
-              if (matchcol == matchpos.col && ptr[matchcol] != NUL) {
-                matchcol += utfc_ptr2len(ptr + matchcol);
-              }
-
               if (matchcol == 0 && (options & SEARCH_START)) {
                 break;
               }
-
               if (ptr[matchcol] == NUL
                   || (nmatched = vim_regexec_multi(&regmatch, win, buf,
                                                    lnum, matchcol, tm,

src/nvim/testdir/test_search.vim

@@ -1816,7 +1816,7 @@ func Test_search_smartcase_utf8()
 
   set ignorecase& smartcase&
   let &encoding = save_enc
-  close!
+  bwipe!
 endfunc
 
 " Test searching past the end of a file
@@ -1825,7 +1825,29 @@ func Test_search_past_eof()
   call setline(1, ['Line'])
   exe "normal /\\n\\zs\<CR>"
   call assert_equal([1, 4], [line('.'), col('.')])
-  close!
+  bwipe!
+endfunc
+
+" Test setting the start of the match and still finding a next match in the
+" same line.
+func Test_search_set_start_same_line()
+  new
+  set cpo-=c
+
+  call setline(1, ['1', '2', '3 .', '4', '5'])
+  exe "normal /\\_s\\zs\\S\<CR>"
+  call assert_equal([2, 1], [line('.'), col('.')])
+  exe 'normal n'
+  call assert_equal([3, 1], [line('.'), col('.')])
+  exe 'normal n'
+  call assert_equal([3, 3], [line('.'), col('.')])
+  exe 'normal n'
+  call assert_equal([4, 1], [line('.'), col('.')])
+  exe 'normal n'
+  call assert_equal([5, 1], [line('.'), col('.')])
+
+  set cpo+=c
+  bwipe!
 endfunc
 
 " Test for various search offsets