vim-patch:9.1.0418: Cannot move to previous/next rare word (#28822)

Problem:  Cannot move to previous/next rare word
          (Colin Kennedy)
Solution: Add the ]r and [r motions (Christ van Willegen)

fixes: vim/vim#14773
closes: vim/vim#14780

https://github.com/vim/vim/commit/8e4c4c7d87def2b100a5d64dc518ef85d9de8765

Co-authored-by: Christ van Willegen - van Noort <github.com@vanwillegen-vannoort.nl>

9 files changed, 95 insertions, 11 deletions

diff --git a/runtime/doc/spell.txt b/runtime/doc/spell.txt
index 29e4a7b0aa..269d52352d 100644
--- a/runtime/doc/spell.txt
+++ b/runtime/doc/spell.txt
@@ -51,6 +51,17 @@ To search for the next misspelled word:
 							*[S*
 [S			Like "]S" but search backwards.
 
+							*]r*
+]r			Move to next "rare" word after the cursor.
+			A count before the command can be used to repeat.
+			'wrapscan' applies.
+
+							*[r*
+[r			Like "]r" but search backwards, find the "rare"
+			word before the cursor.  Doesn't recognize words
+			split over two lines, thus may stop at words that are
+			not highlighted as rare.
+
 
 To add words to your own word list:
 
diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 283f7d9d61..07944081da 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -1415,7 +1415,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, int col_rows, s
       pos_T pos = wp->w_cursor;
       wp->w_cursor.lnum = lnum;
       wp->w_cursor.col = linecol;
-      size_t len = spell_move_to(wp, FORWARD, true, true, &spell_hlf);
+      size_t len = spell_move_to(wp, FORWARD, SMT_ALL, true, &spell_hlf);
 
       // spell_move_to() may call ml_get() and make "line" invalid
       line = ml_get_buf(wp->w_buffer, lnum);
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 1fc80e88c4..0b4b79c6ca 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -8308,7 +8308,7 @@ static void f_spellbadword(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
   size_t len = 0;
   if (argvars[0].v_type == VAR_UNKNOWN) {
     // Find the start and length of the badly spelled word.
-    len = spell_move_to(curwin, FORWARD, true, true, &attr);
+    len = spell_move_to(curwin, FORWARD, SMT_ALL, true, &attr);
     if (len != 0) {
       word = get_cursor_pos_ptr();
       curwin->w_set_curswant = true;
diff --git a/src/nvim/insexpand.c b/src/nvim/insexpand.c
index 15ec0ab08d..c51b3b916d 100644
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -4570,7 +4570,7 @@ void free_insexpand_stuff(void)
 static void spell_back_to_badword(void)
 {
   pos_T tpos = curwin->w_cursor;
-  spell_bad_len = spell_move_to(curwin, BACKWARD, true, true, NULL);
+  spell_bad_len = spell_move_to(curwin, BACKWARD, SMT_ALL, true, NULL);
   if (curwin->w_cursor.col != tpos.col) {
     start_arrow(&tpos);
   }
diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index 2f1477b9d5..02bd3d05c1 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -2710,7 +2710,7 @@ static int nv_zg_zw(cmdarg_T *cap, int nchar)
     // off this fails and find_ident_under_cursor() is
     // used below.
     emsg_off++;
-    len = spell_move_to(curwin, FORWARD, true, true, NULL);
+    len = spell_move_to(curwin, FORWARD, SMT_ALL, true, NULL);
     emsg_off--;
     if (len != 0 && curwin->w_cursor.col <= pos.col) {
       ptr = ml_get_pos(&curwin->w_cursor);
@@ -4272,12 +4272,15 @@ static void nv_brackets(cmdarg_T *cap)
                      cap->count1) == false) {
       clearopbeep(cap->oap);
     }
-  } else if (cap->nchar == 's' || cap->nchar == 'S') {
-    // "[s", "[S", "]s" and "]S": move to next spell error.
+  } else if (cap->nchar == 'r' || cap->nchar == 's' || cap->nchar == 'S') {
+    // "[r", "[s", "[S", "]r", "]s" and "]S": move to next spell error.
     setpcmark();
     for (n = 0; n < cap->count1; n++) {
       if (spell_move_to(curwin, cap->cmdchar == ']' ? FORWARD : BACKWARD,
-                        cap->nchar == 's', false, NULL) == 0) {
+                        cap->nchar == 's'
+                        ? SMT_ALL
+                        : cap->nchar == 'r' ? SMT_RARE : SMT_BAD,
+                        false, NULL) == 0) {
         clearopbeep(cap->oap);
         break;
       }
diff --git a/src/nvim/spell.c b/src/nvim/spell.c
index 190501028e..6f0c7bab8e 100644
--- a/src/nvim/spell.c
+++ b/src/nvim/spell.c
@@ -1290,11 +1290,11 @@ static inline bool can_syn_spell(win_T *wp, linenr_T lnum, int col)
 /// to after badly spelled word before the cursor.
 ///
 /// @param dir  FORWARD or BACKWARD
-/// @param allwords  true for "[s"/"]s", false for "[S"/"]S"
+/// @param behaviour  Behaviour of the function
 /// @param attrp  return: attributes of bad word or NULL (only when "dir" is FORWARD)
 ///
 /// @return  0 if not found, length of the badly spelled word otherwise.
-size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *attrp)
+size_t spell_move_to(win_T *wp, int dir, smt_T behaviour, bool curline, hlf_T *attrp)
 {
   pos_T found_pos;
   size_t found_len = 0;
@@ -1398,7 +1398,9 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
 
       if (attr != HLF_COUNT) {
         // We found a bad word.  Check the attribute.
-        if (allwords || attr == HLF_SPB) {
+        if (behaviour == SMT_ALL
+            || (behaviour == SMT_BAD && attr == HLF_SPB)
+            || (behaviour == SMT_RARE && attr == HLF_SPR)) {
           // When searching forward only accept a bad word after
           // the cursor.
           if (dir == BACKWARD
diff --git a/src/nvim/spell.h b/src/nvim/spell.h
index adbdd3705e..85e16d7f6c 100644
--- a/src/nvim/spell.h
+++ b/src/nvim/spell.h
@@ -21,6 +21,13 @@ extern char *e_format;
 extern char *repl_from;
 extern char *repl_to;
 
+/// Values for behaviour in spell_move_to
+typedef enum {
+  SMT_ALL = 0,  ///< Move to "all" words
+  SMT_BAD,      ///< Move to "bad" words only
+  SMT_RARE,     ///< Move to "rare" words only
+} smt_T;
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "spell.h.generated.h"
 #endif
diff --git a/src/nvim/spellsuggest.c b/src/nvim/spellsuggest.c
index 32480443c4..a7de20d14e 100644
--- a/src/nvim/spellsuggest.c
+++ b/src/nvim/spellsuggest.c
@@ -484,7 +484,7 @@ void spell_suggest(int count)
       badlen = get_cursor_line_len() - curwin->w_cursor.col;
     }
     // Find the start of the badly spelled word.
-  } else if (spell_move_to(curwin, FORWARD, true, true, NULL) == 0
+  } else if (spell_move_to(curwin, FORWARD, SMT_ALL, true, NULL) == 0
              || curwin->w_cursor.col > prev_cursor.col) {
     // No bad word or it starts after the cursor: use the word under the
     // cursor.
diff --git a/test/old/testdir/test_spellrare.vim b/test/old/testdir/test_spellrare.vim
new file mode 100644
index 0000000000..bbb13c27c2
--- /dev/null
+++ b/test/old/testdir/test_spellrare.vim
@@ -0,0 +1,61 @@
+" Test spell checking
+
+source check.vim
+CheckFeature spell
+
+" Test spellbadword() with argument, specifically to move to "rare" words
+" in normal mode.
+func Test_spellrareword()
+  set spell
+
+  " Create a small word list to test that spellbadword('...')
+  " can return ['...', 'rare'].
+  let lines =<< trim END
+     foo
+     foobar/?
+     foobara/?
+END
+   call writefile(lines, 'Xwords', 'D')
+
+   mkspell! Xwords.spl Xwords
+   set spelllang=Xwords.spl
+   call assert_equal(['foobar', 'rare'], spellbadword('foo foobar'))
+
+  new
+  call setline(1, ['foo', '', 'foo bar foo bar foobara foo foo foo foobar', '', 'End'])
+  set spell wrapscan
+  normal ]s
+  call assert_equal('foo', expand('<cword>'))
+  normal ]s
+  call assert_equal('bar', expand('<cword>'))
+
+  normal ]r
+  call assert_equal('foobara', expand('<cword>'))
+  normal ]r
+  call assert_equal('foobar', expand('<cword>'))
+  normal ]r
+  call assert_equal('foobara', expand('<cword>'))
+  normal 2]r
+  call assert_equal('foobara', expand('<cword>'))
+ 
+  normal [r
+  call assert_equal('foobar', expand('<cword>'))
+  normal [r
+  call assert_equal('foobara', expand('<cword>'))
+  normal [r
+  call assert_equal('foobar', expand('<cword>'))
+  normal 2[r
+  call assert_equal('foobar', expand('<cword>'))
+
+  bwipe!
+  set nospell
+
+  call delete('Xwords.spl')
+  set spelllang&
+  set spell&
+
+  " set 'encoding' to clear the word list
+  set encoding=utf-8
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab