vim-patch:9.1.1416: completion limits not respected for fuzzy completions

Problem:  completion limits not respected when using fuzzy completion
          (Maxim Kim)
Solution: trim completion array (Girish Palya)

fixes: vim/vim#17379
closes: vim/vim#17386

19ef6b0b4b

Co-authored-by: Girish Palya <girishji@gmail.com>

src/nvim/insexpand.c

@@ -1362,6 +1362,58 @@ static void trigger_complete_changed_event(int cur)
   restore_v_event(v_event, &save_v_event);
 }
 
+/// Trim compl_match_array to enforce max_matches per completion source.
+///
+/// Note: This special-case trimming is a workaround because compl_match_array
+/// becomes inconsistent with compl_first_match (list) after former is sorted by
+/// fuzzy score. The two structures end up in different orders.
+/// Ideally, compl_first_match list should have been sorted instead.
+static void trim_compl_match_array(void)
+{
+  // Count current matches per source.
+  int *match_counts = xcalloc((size_t)cpt_sources_count, sizeof(int));
+  for (int i = 0; i < compl_match_arraysize; i++) {
+    int src_idx = compl_match_array[i].pum_cpt_source_idx;
+    if (src_idx != -1) {
+      match_counts[src_idx]++;
+    }
+  }
+
+  // Calculate size of trimmed array, respecting max_matches per source.
+  int new_size = 0;
+  for (int i = 0; i < cpt_sources_count; i++) {
+    int limit = cpt_sources_array[i].max_matches;
+    new_size += (limit > 0 && match_counts[i] > limit) ? limit : match_counts[i];
+  }
+
+  if (new_size == compl_match_arraysize) {
+    goto theend;
+  }
+
+  // Create trimmed array while enforcing per-source limits
+  pumitem_T *trimmed = xcalloc((size_t)new_size, sizeof(pumitem_T));
+  memset(match_counts, 0, sizeof(int) * (size_t)cpt_sources_count);
+  int trimmed_idx = 0;
+  for (int i = 0; i < compl_match_arraysize; i++) {
+    int src_idx = compl_match_array[i].pum_cpt_source_idx;
+    if (src_idx != -1) {
+      int limit = cpt_sources_array[src_idx].max_matches;
+      if (limit <= 0 || match_counts[src_idx] < limit) {
+        trimmed[trimmed_idx++] = compl_match_array[i];
+        match_counts[src_idx]++;
+      }
+    } else {
+      trimmed[trimmed_idx++] = compl_match_array[i];
+    }
+  }
+  xfree(compl_match_array);
+  compl_match_array = trimmed;
+  compl_match_arraysize = new_size;
+
+theend:
+  xfree(match_counts);
+}
+
 /// pumitem qsort compare func
 static int ins_compl_fuzzy_cmp(const void *a, const void *b)
 {
@@ -1398,7 +1450,7 @@ static int ins_compl_build_pum(void)
   int match_count = 0;
   int cur_source = -1;
   bool max_matches_found = false;
-  bool is_forward = compl_shows_dir_forward() && !fuzzy_filter;
+  bool is_forward = compl_shows_dir_forward();
 
   // If the current match is the original text don't find the first
   // match after it, don't highlight anything.
@@ -1433,7 +1485,7 @@ static int ins_compl_build_pum(void)
       comp->cp_flags &= ~CP_ICASE;
     }
 
-    if (is_forward && comp->cp_cpt_source_idx != -1) {
+    if (is_forward && !fuzzy_sort && comp->cp_cpt_source_idx != -1) {
       if (cur_source != comp->cp_cpt_source_idx) {
         cur_source = comp->cp_cpt_source_idx;
         match_count = 1;
@@ -1490,7 +1542,7 @@ static int ins_compl_build_pum(void)
           shown_match_ok = true;
         }
       }
-      if (is_forward && comp->cp_cpt_source_idx != -1) {
+      if (is_forward && !fuzzy_sort && comp->cp_cpt_source_idx != -1) {
         match_count++;
       }
       i++;
@@ -1534,6 +1586,7 @@ static int ins_compl_build_pum(void)
     compl_match_array[i].pum_kind = comp->cp_text[CPT_KIND];
     compl_match_array[i].pum_info = comp->cp_text[CPT_INFO];
     compl_match_array[i].pum_score = comp->cp_score;
+    compl_match_array[i].pum_cpt_source_idx = comp->cp_cpt_source_idx;
     compl_match_array[i].pum_user_abbr_hlattr = comp->cp_user_abbr_hlattr;
     compl_match_array[i].pum_user_kind_hlattr = comp->cp_user_kind_hlattr;
     compl_match_array[i++].pum_extra = comp->cp_text[CPT_MENU] != NULL
@@ -1553,6 +1606,9 @@ static int ins_compl_build_pum(void)
     shown_match_ok = true;
   }
 
+  if (is_forward && fuzzy_sort && cpt_sources_array != NULL) {
+    trim_compl_match_array();  // Truncate by max_matches in 'cpt'
+  }
   if (!shown_match_ok) {  // no displayed match at all
     cur = -1;
   }

src/nvim/popupmenu.h

@@ -16,6 +16,7 @@ typedef struct {
   char *pum_info;       ///< extra info
   int pum_score;        ///< fuzzy match score
   int pum_idx;          ///< index of item before sorting by score
+  int pum_cpt_source_idx;    ///< index of completion source in 'cpt'
   int pum_user_abbr_hlattr;  ///< highlight attribute for abbr
   int pum_user_kind_hlattr;  ///< highlight attribute for kind
 } pumitem_T;

test/old/testdir/test_ins_complete.vim

@@ -4159,7 +4159,7 @@ func Test_complete_multiline_marks()
 endfunc
 
 func Test_complete_match_count()
-  func PrintMenuWords()
+  func! PrintMenuWords()
     let info = complete_info(["selected", "matches"])
     call map(info.matches, {_, v -> v.word})
     return info
@@ -4279,8 +4279,50 @@ func Test_complete_match_count()
   call assert_equal(3, g:CallCount)
   bw!
 
+  " Test 'fuzzy' with max_items
+  " XXX: Cannot use complete_info() since it is broken for 'fuzzy'
+  new
+  set completeopt=menu,noselect,fuzzy
+  set complete=.
+  call setline(1, ["abcd", "abac", "abdc"])
+  execute "normal Goa\<c-n>c\<c-n>"
+  call assert_equal('abac', getline(4))
+  execute "normal Sa\<c-n>c\<c-n>\<c-n>\<c-n>\<c-n>\<c-n>"
+  call assert_equal('abac', getline(4))
+  set complete=.^1
+  execute "normal Sa\<c-n>c\<c-n>\<c-n>\<c-n>"
+  call assert_equal('abac', getline(4))
+  set complete=.^2
+  execute "normal Sa\<c-n>c\<c-n>\<c-n>\<c-n>\<c-n>"
+  call assert_equal('abac', getline(4))
+  set complete=.^3
+  execute "normal Sa\<c-n>c\<c-n>\<c-n>\<c-n>\<c-n>\<c-n>"
+  call assert_equal('abac', getline(4))
+  set complete=.^4
+  execute "normal Sa\<c-n>c\<c-n>\<c-n>\<c-n>\<c-n>\<c-n>"
+  call assert_equal('abac', getline(4))
+
+  func! ComplFunc(findstart, base)
+    if a:findstart
+      return col(".")
+    endif
+    return ["abcde", "abacr"]
+  endfunc
+
+  set complete=.,FComplFunc^1
+  execute "normal Sa\<c-n>c\<c-n>\<c-n>"
+  call assert_equal('abacr', getline(4))
+  execute "normal Sa\<c-n>c\<c-n>\<c-n>\<c-n>\<c-n>\<c-n>\<c-n>"
+  call assert_equal('abac', getline(4))
+  set complete=.^1,FComplFunc^1
+  execute "normal Sa\<c-n>c\<c-n>\<c-n>\<c-n>\<c-n>"
+  call assert_equal('abac', getline(4))
+  bw!
+
   set completeopt& complete&
   delfunc PrintMenuWords
+  delfunc ComplFunc
+  delfunc CompleteItemsSelect
 endfunc
 
 func Test_complete_append_selected_match_default()
@@ -4402,7 +4444,7 @@ endfunc
 " Test 'nearest' flag of 'completeopt'
 func Test_nearest_cpt_option()
 
-  func PrintMenuWords()
+  func! PrintMenuWords()
     let info = complete_info(["selected", "matches"])
     call map(info.matches, {_, v -> v.word})
     return info