vim-patch:8.1.1275: cannot navigate to errors before/after the cursor

Problem:    Cannot navigate to errors before/after the cursor.
Solution:   Add the :cbefore and :cafter commands. (Yegappan Lakshmanan,
            closes vim/vim#4340)
https://github.com/vim/vim/commit/cf6a55c4b0cbf38b0c3fbed5ffd9a3fd0d2ede0e

3 files changed, 268 insertions, 70 deletions

diff --git a/src/nvim/ex_cmds.lua b/src/nvim/ex_cmds.lua
index 60faae3268..872f32d874 100644
--- a/src/nvim/ex_cmds.lua
+++ b/src/nvim/ex_cmds.lua
@@ -343,6 +343,12 @@ module.cmds = {
     func='ex_cfile',
   },
   {
+    command='cafter',
+    flags=bit.bor(RANGE, COUNT, TRLBAR),
+    addr_type='ADDR_UNSIGNED',
+    func='ex_cbelow',
+  },
+  {
     command='call',
     flags=bit.bor(RANGE, NEEDARG, EXTRA, NOTRLCOM, SBOXOK, CMDWIN),
     addr_type='ADDR_LINES',
@@ -361,6 +367,12 @@ module.cmds = {
     func='ex_cbuffer',
   },
   {
+    command='cbefore',
+    flags=bit.bor(RANGE, COUNT, TRLBAR),
+    addr_type='ADDR_UNSIGNED',
+    func='ex_cbelow',
+  },
+  {
     command='cbelow',
     flags=bit.bor(RANGE, COUNT, TRLBAR),
     addr_type='ADDR_UNSIGNED',
@@ -1311,6 +1323,12 @@ module.cmds = {
     func='ex_cfile',
   },
   {
+    command='lafter',
+    flags=bit.bor(RANGE, COUNT, TRLBAR),
+    addr_type='ADDR_UNSIGNED',
+    func='ex_cbelow',
+  },
+  {
     command='later',
     flags=bit.bor(TRLBAR, EXTRA, NOSPC, CMDWIN),
     addr_type='ADDR_NONE',
@@ -1323,6 +1341,12 @@ module.cmds = {
     func='ex_cbuffer',
   },
   {
+    command='lbefore',
+    flags=bit.bor(RANGE, COUNT, TRLBAR),
+    addr_type='ADDR_UNSIGNED',
+    func='ex_cbelow',
+  },
+  {
     command='lbelow',
     flags=bit.bor(RANGE, COUNT, TRLBAR),
     addr_type='ADDR_UNSIGNED',
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index f72a5e0020..eaa0117d93 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -4573,74 +4573,150 @@ static qfline_T * qf_find_last_entry_on_line(qfline_T *entry, int *errornr)
   return entry;
 }
 
-/// Find the first quickfix entry below line 'lnum' in buffer 'bnr'.
+// Returns true if the specified quickfix entry is
+// after the given line (linewise is true)
+// or after the line and column.
+static bool qf_entry_after_pos(const qfline_T *qfp, const pos_T *pos,
+                               bool linewise)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  if (linewise) {
+    return qfp->qf_lnum > pos->lnum;
+  }
+  return qfp->qf_lnum > pos->lnum
+    || (qfp->qf_lnum == pos->lnum && qfp->qf_col > pos->col);
+}
+
+// Returns true if the specified quickfix entry is
+// before the given line (linewise is true)
+// or before the line and column.
+static bool qf_entry_before_pos(const qfline_T *qfp, const pos_T *pos,
+                                bool linewise)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  if (linewise) {
+    return qfp->qf_lnum < pos->lnum;
+  }
+  return qfp->qf_lnum < pos->lnum
+    || (qfp->qf_lnum == pos->lnum && qfp->qf_col < pos->col);
+}
+
+// Returns true if the specified quickfix entry is
+// on or after the given line (linewise is true)
+// or on or after the line and column.
+static bool qf_entry_on_or_after_pos(const qfline_T *qfp, const pos_T *pos,
+                                     bool linewise)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  if (linewise) {
+    return qfp->qf_lnum >= pos->lnum;
+  }
+  return qfp->qf_lnum > pos->lnum
+    || (qfp->qf_lnum == pos->lnum && qfp->qf_col >= pos->col);
+}
+
+// Returns true if the specified quickfix entry is
+// on or before the given line (linewise is true)
+// or on or before the line and column.
+static bool qf_entry_on_or_before_pos(const qfline_T *qfp, const pos_T *pos,
+                                      bool linewise)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  if (linewise) {
+    return qfp->qf_lnum <= pos->lnum;
+  }
+  return qfp->qf_lnum < pos->lnum
+    || (qfp->qf_lnum == pos->lnum && qfp->qf_col <= pos->col);
+}
+
+/// Find the first quickfix entry after position 'pos' in buffer 'bnr'.
+/// If 'linewise' is true, returns the entry after the specified line and treats
+/// multiple entries on a single line as one. Otherwise returns the entry after
+/// the specified line and column.
 /// 'qfp' points to the very first entry in the buffer and 'errornr' is the
 /// index of the very first entry in the quickfix list.
-/// Returns NULL if an entry is not found after 'lnum'.
-static qfline_T *qf_find_entry_on_next_line(int bnr,
-                                            linenr_T lnum,
-                                            qfline_T *qfp,
-                                            int *errornr)
+/// Returns NULL if an entry is not found after 'pos'.
+static qfline_T *qf_find_entry_after_pos(
+    int bnr,
+    const pos_T *pos,
+    bool linewise,
+    qfline_T *qfp,
+    int *errornr
+)
+  FUNC_ATTR_NONNULL_ALL
 {
-  if (qfp->qf_lnum > lnum) {
-    // First entry is after line 'lnum'
+  if (qf_entry_after_pos(qfp, pos, linewise)) {
+    // First entry is after postion 'pos'
     return qfp;
   }
 
-  // Find the entry just before or at the line 'lnum'
+  // Find the entry just before or at the position 'pos'
   while (qfp->qf_next != NULL
          && qfp->qf_next->qf_fnum == bnr
-         && qfp->qf_next->qf_lnum <= lnum) {
+         && qf_entry_on_or_before_pos(qfp->qf_next, pos, linewise)) {
     qfp = qfp->qf_next;
     (*errornr)++;
   }
 
   if (qfp->qf_next == NULL || qfp->qf_next->qf_fnum != bnr) {
-    // No entries found after 'lnum'
+    // No entries found after position 'pos'
     return NULL;
   }
 
-  // Use the entry just after line 'lnum'
+  // Use the entry just after position 'pos'
   qfp = qfp->qf_next;
   (*errornr)++;
 
   return qfp;
 }
 
-/// Find the first quickfix entry before line 'lnum' in buffer 'bnr'.
+/// Find the first quickfix entry before position 'pos' in buffer 'bnr'.
+/// If 'linewise' is true, returns the entry before the specified line and
+/// treats multiple entries on a single line as one. Otherwise returns the entry
+/// before the specified line and column.
 /// 'qfp' points to the very first entry in the buffer and 'errornr' is the
 /// index of the very first entry in the quickfix list.
-/// Returns NULL if an entry is not found before 'lnum'.
-static qfline_T *qf_find_entry_on_prev_line(int bnr,
-                                            linenr_T lnum,
-                                            qfline_T *qfp,
-                                            int *errornr)
+/// Returns NULL if an entry is not found before 'pos'.
+static qfline_T *qf_find_entry_before_pos(
+    int bnr,
+    const pos_T *pos,
+    bool linewise,
+    qfline_T *qfp,
+    int *errornr
+)
+  FUNC_ATTR_NONNULL_ALL
 {
-  // Find the entry just before the line 'lnum'
+  // Find the entry just before the position 'pos'
   while (qfp->qf_next != NULL
          && qfp->qf_next->qf_fnum == bnr
-         && qfp->qf_next->qf_lnum < lnum) {
+         && qf_entry_before_pos(qfp->qf_next, pos, linewise)) {
     qfp = qfp->qf_next;
     (*errornr)++;
   }
 
-  if (qfp->qf_lnum >= lnum) {  // entry is after 'lnum'
+  if (qf_entry_on_or_after_pos(qfp, pos, linewise)) {
     return NULL;
   }
 
-  // If multiple entries are on the same line, then use the first entry
-  qfp = qf_find_first_entry_on_line(qfp, errornr);
+  if (linewise) {
+    // If multiple entries are on the same line, then use the first entry
+    qfp = qf_find_first_entry_on_line(qfp, errornr);
+  }
 
   return qfp;
 }
 
-/// Find a quickfix entry in 'qfl' closest to line 'lnum' in buffer 'bnr' in
+/// Find a quickfix entry in 'qfl' closest to position 'pos' in buffer 'bnr' in
 /// the direction 'dir'.
-static qfline_T *qf_find_closest_entry(qf_list_T *qfl,
-                                       int bnr,
-                                       linenr_T lnum,
-                                       int dir,
-                                       int *errornr)
+static qfline_T *qf_find_closest_entry(
+    qf_list_T *qfl,
+    int bnr,
+    const pos_T *pos,
+    Direction dir,
+    bool linewise,
+    int *errornr
+)
+  FUNC_ATTR_NONNULL_ALL
 {
   qfline_T *qfp;
 
@@ -4653,33 +4729,38 @@ static qfline_T *qf_find_closest_entry(qf_list_T *qfl,
   }
 
   if (dir == FORWARD) {
-    qfp = qf_find_entry_on_next_line(bnr, lnum, qfp, errornr);
+    qfp = qf_find_entry_after_pos(bnr, pos, linewise, qfp, errornr);
   } else {
-    qfp = qf_find_entry_on_prev_line(bnr, lnum, qfp, errornr);
+    qfp = qf_find_entry_before_pos(bnr, pos, linewise, qfp, errornr);
   }
 
   return qfp;
 }
 
-/// Get the nth quickfix entry below the specified entry treating multiple
-/// entries on a single line as one. Searches forward in the list.
-static void qf_get_nth_below_entry(qfline_T *entry,
-                                   int *errornr,
-                                   linenr_T n)
+/// Get the nth quickfix entry below the specified entry.  Searches forward in
+/// the list. If linewise is true, then treat multiple entries on a single line
+/// as one.
+static void qf_get_nth_below_entry(qfline_T *entry, linenr_T n,
+                                   bool linewise, int *errornr)
+  FUNC_ATTR_NONNULL_ALL
 {
   while (n-- > 0 && !got_int) {
     // qfline_T *first_entry = entry;
     int first_errornr = *errornr;
 
-    // Treat all the entries on the same line in this file as one
-    entry = qf_find_last_entry_on_line(entry, errornr);
+    if (linewise) {
+      // Treat all the entries on the same line in this file as one
+      entry = qf_find_last_entry_on_line(entry, errornr);
+    }
 
     if (entry->qf_next == NULL
         || entry->qf_next->qf_fnum != entry->qf_fnum) {
-      // If multiple entries are on the same line, then use the first
-      // entry
-      // entry = first_entry;
-      *errornr = first_errornr;
+      if (linewise) {
+        // If multiple entries are on the same line, then use the first
+        // entry
+        // entry = first_entry;
+        *errornr = first_errornr;
+      }
       break;
     }
 
@@ -4688,11 +4769,12 @@ static void qf_get_nth_below_entry(qfline_T *entry,
   }
 }
 
-/// Get the nth quickfix entry above the specified entry treating multiple
-/// entries on a single line as one. Searches backwards in the list.
-static void qf_get_nth_above_entry(qfline_T *entry,
-                                   int *errornr,
-                                   linenr_T n)
+/// Get the nth quickfix entry above the specified entry.  Searches backwards in
+/// the list. If linewise is TRUE, then treat multiple entries on a single line
+/// as one.
+static void qf_get_nth_above_entry(qfline_T *entry, linenr_T n,
+                                   bool linewise, int *errornr)
+  FUNC_ATTR_NONNULL_ALL
 {
   while (n-- > 0 && !got_int) {
     if (entry->qf_prev == NULL
@@ -4703,25 +4785,30 @@ static void qf_get_nth_above_entry(qfline_T *entry,
     entry = entry->qf_prev;
     (*errornr)--;
 
-    // If multiple entries are on the same line, then use the first entry
-    entry = qf_find_first_entry_on_line(entry, errornr);
+    if (linewise) {
+      entry = qf_find_first_entry_on_line(entry, errornr);
+    }
   }
 }
 
-/// Find the n'th quickfix entry adjacent to line 'lnum' in buffer 'bnr' in the
-/// specified direction.
-/// Returns the error number in the quickfix list or 0 if an entry is not found.
-static int qf_find_nth_adj_entry(qf_list_T *qfl,
-                                 int bnr,
-                                 linenr_T lnum,
-                                 linenr_T n,
-                                 int dir)
+/// Find the n'th quickfix entry adjacent to position 'pos' in buffer 'bnr' in
+/// the specified direction.  Returns the error number in the quickfix list or 0
+/// if an entry is not found.
+static int qf_find_nth_adj_entry(
+    qf_list_T *qfl,
+    int bnr,
+    pos_T *pos,
+    linenr_T n,
+    Direction dir,
+    bool linewise
+)
+  FUNC_ATTR_NONNULL_ALL
 {
-  qfline_T *adj_entry;
   int errornr;
 
-  // Find an entry closest to the specified line
-  adj_entry = qf_find_closest_entry(qfl, bnr, lnum, dir, &errornr);
+  // Find an entry closest to the specified position
+  qfline_T *const adj_entry = qf_find_closest_entry(qfl, bnr, pos, dir,
+                                                    linewise, &errornr);
   if (adj_entry == NULL) {
     return 0;
   }
@@ -4729,24 +4816,25 @@ static int qf_find_nth_adj_entry(qf_list_T *qfl,
   if (--n > 0) {
     // Go to the n'th entry in the current buffer
     if (dir == FORWARD) {
-      qf_get_nth_below_entry(adj_entry, &errornr, n);
+      qf_get_nth_below_entry(adj_entry, n, linewise, &errornr);
     } else {
-      qf_get_nth_above_entry(adj_entry, &errornr, n);
+      qf_get_nth_above_entry(adj_entry, n, linewise, &errornr);
     }
   }
 
   return errornr;
 }
 
-/// Jump to a quickfix entry in the current file nearest to the current line.
-/// ":cabove", ":cbelow", ":labove" and ":lbelow" commands
+/// Jump to a quickfix entry in the current file nearest to the current line or
+/// current line/col.
+/// ":cabove", ":cbelow", ":labove", ":lbelow", ":cafter", ":cbefore",
+/// ":lafter" and ":lbefore" commands
 void ex_cbelow(exarg_T *eap)
 {
   qf_info_T *qi;
   qf_list_T *qfl;
   int dir;
   int buf_has_flag;
-  int errornr = 0;
 
   if (eap->addr_count > 0 && eap->line2 <= 0) {
     EMSG(_(e_invrange));
@@ -4754,7 +4842,8 @@ void ex_cbelow(exarg_T *eap)
   }
 
   // Check whether the current buffer has any quickfix entries
-  if (eap->cmdidx == CMD_cabove || eap->cmdidx == CMD_cbelow) {
+  if (eap->cmdidx == CMD_cabove || eap->cmdidx == CMD_cbelow
+      || eap->cmdidx == CMD_cbefore || eap->cmdidx == CMD_cafter) {
     buf_has_flag = BUF_HAS_QF_ENTRY;
   } else {
     buf_has_flag = BUF_HAS_LL_ENTRY;
@@ -4775,14 +4864,30 @@ void ex_cbelow(exarg_T *eap)
     return;
   }
 
-  if (eap->cmdidx == CMD_cbelow || eap->cmdidx == CMD_lbelow) {
+  if (eap->cmdidx == CMD_cbelow
+      || eap->cmdidx == CMD_lbelow
+      || eap->cmdidx == CMD_cafter
+      || eap->cmdidx == CMD_lafter) {
+    // Forward motion commands
     dir = FORWARD;
   } else {
     dir = BACKWARD;
   }
 
-  errornr = qf_find_nth_adj_entry(qfl, curbuf->b_fnum, curwin->w_cursor.lnum,
-                                  eap->addr_count > 0 ? eap->line2 : 0, dir);
+  pos_T pos = curwin->w_cursor;
+  // A quickfix entry column number is 1 based whereas cursor column
+  // number is 0 based. Adjust the column number.
+  pos.col++;
+  const int errornr = qf_find_nth_adj_entry(
+      qfl,
+      curbuf->b_fnum,
+      &pos,
+      eap->addr_count > 0 ? eap->line2 : 0,
+      dir,
+      eap->cmdidx == CMD_cbelow
+      || eap->cmdidx == CMD_lbelow
+      || eap->cmdidx == CMD_cabove
+      || eap->cmdidx == CMD_labove);
 
   if (errornr > 0) {
     qf_jump(qi, 0, errornr, false);
diff --git a/src/nvim/testdir/test_quickfix.vim b/src/nvim/testdir/test_quickfix.vim
index 49d66d8c1f..f9d1abeaec 100644
--- a/src/nvim/testdir/test_quickfix.vim
+++ b/src/nvim/testdir/test_quickfix.vim
@@ -40,6 +40,8 @@ func s:setup_commands(cchar)
     command! -nargs=0 -count Xcc <count>cc
     command! -count=1 -nargs=0 Xbelow <mods><count>cbelow
     command! -count=1 -nargs=0 Xabove <mods><count>cabove
+    command! -count=1 -nargs=0 Xbefore <mods><count>cbefore
+    command! -count=1 -nargs=0 Xafter <mods><count>cafter
     let g:Xgetlist = function('getqflist')
     let g:Xsetlist = function('setqflist')
     call setqflist([], 'f')
@@ -75,6 +77,8 @@ func s:setup_commands(cchar)
     command! -nargs=0 -count Xcc <count>ll
     command! -count=1 -nargs=0 Xbelow <mods><count>lbelow
     command! -count=1 -nargs=0 Xabove <mods><count>labove
+    command! -count=1 -nargs=0 Xbefore <mods><count>lbefore
+    command! -count=1 -nargs=0 Xafter <mods><count>lafter
     let g:Xgetlist = function('getloclist', [0])
     let g:Xsetlist = function('setloclist', [0])
     call setloclist(0, [], 'f')
@@ -4201,17 +4205,22 @@ func Test_empty_qfbuf()
 endfunc
 
 " Test for the :cbelow, :cabove, :lbelow and :labove commands.
+" And for the :cafter, :cbefore, :lafter and :lbefore commands.
 func Xtest_below(cchar)
   call s:setup_commands(a:cchar)
 
   " No quickfix/location list
   call assert_fails('Xbelow', 'E42:')
   call assert_fails('Xabove', 'E42:')
+  call assert_fails('Xbefore', 'E42:')
+  call assert_fails('Xafter', 'E42:')
 
   " Empty quickfix/location list
   call g:Xsetlist([])
   call assert_fails('Xbelow', 'E42:')
   call assert_fails('Xabove', 'E42:')
+  call assert_fails('Xbefore', 'E42:')
+  call assert_fails('Xafter', 'E42:')
 
   call s:create_test_file('X1')
   call s:create_test_file('X2')
@@ -4225,39 +4234,74 @@ func Xtest_below(cchar)
   call assert_fails('Xabove', 'E42:')
   call assert_fails('3Xbelow', 'E42:')
   call assert_fails('4Xabove', 'E42:')
+  call assert_fails('Xbefore', 'E42:')
+  call assert_fails('Xafter', 'E42:')
+  call assert_fails('3Xbefore', 'E42:')
+  call assert_fails('4Xafter', 'E42:')
 
   " Test the commands with various arguments
-  Xexpr ["X1:5:L5", "X2:5:L5", "X2:10:L10", "X2:15:L15", "X3:3:L3"]
+  Xexpr ["X1:5:3:L5", "X2:5:2:L5", "X2:10:3:L10", "X2:15:4:L15", "X3:3:5:L3"]
   edit +7 X2
   Xabove
   call assert_equal(['X2', 5], [bufname(''), line('.')])
   call assert_fails('Xabove', 'E553:')
+  normal 7G
+  Xbefore
+  call assert_equal(['X2', 5, 2], [bufname(''), line('.'), col('.')])
+  call assert_fails('Xbefore', 'E553:')
+
   normal 2j
   Xbelow
   call assert_equal(['X2', 10], [bufname(''), line('.')])
+  normal 7G
+  Xafter
+  call assert_equal(['X2', 10, 3], [bufname(''), line('.'), col('.')])
+
   " Last error in this file
   Xbelow 99
   call assert_equal(['X2', 15], [bufname(''), line('.')])
   call assert_fails('Xbelow', 'E553:')
+  normal gg
+  Xafter 99
+  call assert_equal(['X2', 15, 4], [bufname(''), line('.'), col('.')])
+  call assert_fails('Xafter', 'E553:')
+
   " First error in this file
   Xabove 99
   call assert_equal(['X2', 5], [bufname(''), line('.')])
   call assert_fails('Xabove', 'E553:')
+  normal G
+  Xbefore 99
+  call assert_equal(['X2', 5, 2], [bufname(''), line('.'), col('.')])
+  call assert_fails('Xbefore', 'E553:')
+
   normal gg
   Xbelow 2
   call assert_equal(['X2', 10], [bufname(''), line('.')])
+  normal gg
+  Xafter 2
+  call assert_equal(['X2', 10, 3], [bufname(''), line('.'), col('.')])
+
   normal G
   Xabove 2
   call assert_equal(['X2', 10], [bufname(''), line('.')])
+  normal G
+  Xbefore 2
+  call assert_equal(['X2', 10, 3], [bufname(''), line('.'), col('.')])
+
   edit X4
   call assert_fails('Xabove', 'E42:')
   call assert_fails('Xbelow', 'E42:')
+  call assert_fails('Xbefore', 'E42:')
+  call assert_fails('Xafter', 'E42:')
   if a:cchar == 'l'
     " If a buffer has location list entries from some other window but not
     " from the current window, then the commands should fail.
     edit X1 | split | call setloclist(0, [], 'f')
     call assert_fails('Xabove', 'E776:')
     call assert_fails('Xbelow', 'E776:')
+    call assert_fails('Xbefore', 'E776:')
+    call assert_fails('Xafter', 'E776:')
     close
   endif
 
@@ -4268,27 +4312,52 @@ func Xtest_below(cchar)
   edit +1 X2
   Xbelow 2
   call assert_equal(['X2', 10, 1], [bufname(''), line('.'), col('.')])
+  normal 1G
+  Xafter 2
+  call assert_equal(['X2', 5, 2], [bufname(''), line('.'), col('.')])
+
   normal gg
   Xbelow 99
   call assert_equal(['X2', 15, 1], [bufname(''), line('.'), col('.')])
+  normal gg
+  Xafter 99
+  call assert_equal(['X2', 15, 3], [bufname(''), line('.'), col('.')])
+
   normal G
   Xabove 2
   call assert_equal(['X2', 10, 1], [bufname(''), line('.'), col('.')])
   normal G
+  Xbefore 2
+  call assert_equal(['X2', 15, 2], [bufname(''), line('.'), col('.')])
+
+  normal G
   Xabove 99
   call assert_equal(['X2', 5, 1], [bufname(''), line('.'), col('.')])
+  normal G
+  Xbefore 99
+  call assert_equal(['X2', 5, 1], [bufname(''), line('.'), col('.')])
+
   normal 10G
   Xabove
   call assert_equal(['X2', 5, 1], [bufname(''), line('.'), col('.')])
+  normal 10G$
+  2Xbefore
+  call assert_equal(['X2', 10, 2], [bufname(''), line('.'), col('.')])
+
   normal 10G
   Xbelow
   call assert_equal(['X2', 15, 1], [bufname(''), line('.'), col('.')])
+  normal 9G
+  5Xafter
+  call assert_equal(['X2', 15, 2], [bufname(''), line('.'), col('.')])
 
   " Invalid range
   if a:cchar == 'c'
     call assert_fails('-2cbelow', 'E16:')
+    call assert_fails('-2cafter', 'E16:')
   else
     call assert_fails('-2lbelow', 'E16:')
+    call assert_fails('-2lafter', 'E16:')
   endif
 
   call delete('X1')