vim-patch:9.1.1850: completion: not triggered after i_Ctrl-W/i_Ctrl-U (#36156)

Problem:  completion: not triggered after i_Ctrl-W/i_Ctrl-U
Solution: Trigger autocomplete when entering Insert mode
          (Girish Palya).

fixes: vim/vim#18535
closes: vim/vim#18543

da2dabc6f7

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

runtime/doc/insert.txt

@@ -69,10 +69,11 @@ CTRL-W		Delete the word before the cursor (see |i_backspacing| about
 		By default, sets a new undo point before deleting.
 		|default-mappings|
 						*i_CTRL-U*
-CTRL-U		Delete all entered characters before the cursor in the current
+CTRL-U		Delete all characters that were entered after starting Insert
-		line.  If there are no newly entered characters and
+		mode and before the cursor in the current line.
-		'backspace' is not empty, delete all characters before the
+		If there are no newly entered characters and 'backspace' is
-		cursor in the current line.
+		not empty, delete all characters before the cursor in the
+		current line.
 		If C-indenting is enabled the indent will be adjusted if the
 		line becomes blank.
 		See |i_backspacing| about joining lines.

src/nvim/edit.c

@@ -88,6 +88,7 @@ typedef struct {
   int mincol;
   int cmdchar;
   int cmdchar_todo;                  // cmdchar to handle once in init_prompt
+  bool ins_just_started;
   int startln;
   int count;
   int c;
@@ -144,12 +145,33 @@ static linenr_T o_lnum = 0;
 
 static kvec_t(char) replace_stack = KV_INITIAL_VALUE;
 
+#define TRIGGER_AUTOCOMPLETE() \
+  do { \
+    redraw_later(curwin, UPD_VALID); \
+    update_screen();  /* Show char deletion immediately */ \
+    ui_flush(); \
+    ins_compl_enable_autocomplete(); \
+    insert_do_complete(s); \
+    break; \
+  } while (0)
+
+#define MAY_TRIGGER_AUTOCOMPLETE(c) \
+  do { \
+    if (ins_compl_has_autocomplete() && !char_avail() && curwin->w_cursor.col > 0) { \
+      (c) = char_before_cursor(); \
+      if (vim_isprintc(c)) { \
+        TRIGGER_AUTOCOMPLETE(); \
+      } \
+    } \
+  } while (0)
+
 static void insert_enter(InsertState *s)
 {
   s->did_backspace = true;
   s->old_topfill = -1;
   s->replaceState = MODE_REPLACE;
   s->cmdchar_todo = s->cmdchar;
+  s->ins_just_started = true;
   // Remember whether editing was restarted after CTRL-O
   did_restart_edit = restart_edit;
   // sleep before redrawing, needed for "CTRL-O :" that results in an
@@ -532,6 +554,22 @@ static int insert_check(VimState *state)
     dont_sync_undo = kFalse;
   }
 
+  // Trigger autocomplete when entering Insert mode, either directly
+  // or via change commands like 'ciw', 'cw', etc., before the first
+  // character is typed.
+  if (s->ins_just_started) {
+    s->ins_just_started = false;
+    if (ins_compl_has_autocomplete() && !char_avail() && curwin->w_cursor.col > 0) {
+      s->c = char_before_cursor();
+      if (vim_isprintc(s->c)) {
+        ins_compl_enable_autocomplete();
+        ins_compl_init_get_longest();
+        insert_do_complete(s);
+        return 1;
+      }
+    }
+  }
+
   return 1;
 }
 
@@ -855,17 +893,8 @@ static int insert_handle_key(InsertState *s)
   case Ctrl_H:
     s->did_backspace = ins_bs(s->c, BACKSPACE_CHAR, &s->inserted_space);
     auto_format(false, true);
-    if (s->did_backspace && ins_compl_has_autocomplete() && !char_avail()
+    if (s->did_backspace) {
-        && curwin->w_cursor.col > 0) {
+      MAY_TRIGGER_AUTOCOMPLETE(s->c);
-      s->c = char_before_cursor();
-      if (vim_isprintc(s->c)) {
-        redraw_later(curwin, UPD_VALID);
-        update_screen();  // Show char deletion immediately
-        ui_flush();
-        ins_compl_enable_autocomplete();
-        insert_do_complete(s);  // Trigger autocompletion
-        return 1;
-      }
     }
     break;
 
@@ -881,6 +910,9 @@ static int insert_handle_key(InsertState *s)
     }
     s->did_backspace = ins_bs(s->c, BACKSPACE_WORD, &s->inserted_space);
     auto_format(false, true);
+    if (s->did_backspace) {
+      MAY_TRIGGER_AUTOCOMPLETE(s->c);
+    }
     break;
 
   case Ctrl_U:        // delete all inserted text in current line
@@ -891,6 +923,9 @@ static int insert_handle_key(InsertState *s)
       s->did_backspace = ins_bs(s->c, BACKSPACE_LINE, &s->inserted_space);
       auto_format(false, true);
       s->inserted_space = false;
+      if (s->did_backspace) {
+        MAY_TRIGGER_AUTOCOMPLETE(s->c);
+      }
     }
     break;
 
@@ -1244,11 +1279,7 @@ normalchar:
     foldOpenCursor();
     // Trigger autocompletion
     if (ins_compl_has_autocomplete() && !char_avail() && vim_isprintc(s->c)) {
-      redraw_later(curwin, UPD_VALID);
+      TRIGGER_AUTOCOMPLETE();
-      update_screen();  // Show character immediately
-      ui_flush();
-      ins_compl_enable_autocomplete();
-      insert_do_complete(s);
     }
 
     break;

test/old/testdir/test_ins_complete.vim

@@ -5528,10 +5528,33 @@ func Test_autocomplete_trigger()
   call assert_equal(['fodabc', 'fodxyz'], b:matches->mapnew('v:val.word'))
   call assert_equal(-1, b:selected)
 
+  " Test 8: Ctrl_W / Ctrl_U (delete word/line) should restart autocompletion
+  func! TestComplete(findstart, base)
+    if a:findstart
+      return col('.') - 1
+    endif
+    return ['fooze', 'faberge']
+  endfunc
+  set omnifunc=TestComplete
+  set complete+=o
+  call feedkeys("Sprefix->fo\<F2>\<Esc>0", 'tx!')
+  call assert_equal(['fodabc', 'fodxyz', 'foobar', 'fooze'], b:matches->mapnew('v:val.word'))
+  call feedkeys("Sprefix->fo\<C-W>\<F2>\<Esc>0", 'tx!')
+  call assert_equal(['fooze', 'faberge'], b:matches->mapnew('v:val.word'))
+  call feedkeys("Sprefix->\<Esc>afo\<C-U>\<F2>\<Esc>0", 'tx!')
+  call assert_equal(['fooze', 'faberge'], b:matches->mapnew('v:val.word'))
+
+  " Test 9: Trigger autocomplete immediately upon entering Insert mode
+  call feedkeys("Sprefix->foo\<Esc>a\<F2>\<Esc>0", 'tx!')
+  call assert_equal(['foobar', 'fooze', 'faberge'], b:matches->mapnew('v:val.word'))
+  call feedkeys("Sprefix->fooxx\<Esc>hcw\<F2>\<Esc>0", 'tx!')
+  call assert_equal(['foobar', 'fooze', 'faberge'], b:matches->mapnew('v:val.word'))
+
   bw!
   call Ntest_override("char_avail", 0)
   delfunc NonKeywordComplete
-  set autocomplete&
+  delfunc TestComplete
+  set autocomplete& omnifunc& complete&
   unlet g:CallCount
 endfunc