Merge pull request #29136 from zeertzjq/vim-8.2.0083

vim-patch:8.2.{0083,0109}

2 files changed, 37 insertions, 6 deletions

diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index 595b4da589..f6e2dbfa4e 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -4421,18 +4421,30 @@ static bool ins_tab(void)
       // Delete following spaces.
       int i = cursor->col - fpos.col;
       if (i > 0) {
-        STRMOVE(ptr, ptr + i);
+        if (!(State & VREPLACE_FLAG)) {
+          char *newp = xmalloc((size_t)(curbuf->b_ml.ml_line_len - i));
+          ptrdiff_t col = ptr - curbuf->b_ml.ml_line_ptr;
+          if (col > 0) {
+            memmove(newp, ptr - col, (size_t)col);
+          }
+          memmove(newp + col, ptr + i, (size_t)(curbuf->b_ml.ml_line_len - col - i));
+          if (curbuf->b_ml.ml_flags & (ML_LINE_DIRTY | ML_ALLOCATED)) {
+            xfree(curbuf->b_ml.ml_line_ptr);
+          }
+          curbuf->b_ml.ml_line_ptr = newp;
+          curbuf->b_ml.ml_line_len -= i;
+          curbuf->b_ml.ml_flags = (curbuf->b_ml.ml_flags | ML_LINE_DIRTY) & ~ML_EMPTY;
+          inserted_bytes(fpos.lnum, change_col,
+                         cursor->col - change_col, fpos.col - change_col);
+        } else {
+          STRMOVE(ptr, ptr + i);
+        }
         // correct replace stack.
         if ((State & REPLACE_FLAG) && !(State & VREPLACE_FLAG)) {
           for (temp = i; --temp >= 0;) {
             replace_join(repl_off);
           }
         }
-        if (!(State & VREPLACE_FLAG)) {
-          curbuf->b_ml.ml_line_len -= i;
-          inserted_bytes(fpos.lnum, change_col,
-                         cursor->col - change_col, fpos.col - change_col);
-        }
       }
       cursor->col -= i;
 
diff --git a/test/functional/lua/buffer_updates_spec.lua b/test/functional/lua/buffer_updates_spec.lua
index d4af7e4732..6b575ad0ef 100644
--- a/test/functional/lua/buffer_updates_spec.lua
+++ b/test/functional/lua/buffer_updates_spec.lua
@@ -379,6 +379,25 @@ describe('lua buffer event callbacks: on_lines', function()
       ]],
     })
   end)
+
+  it('line lengths are correct when pressing TAB with folding #29119', function()
+    api.nvim_buf_set_lines(0, 0, -1, true, { 'a', 'b' })
+
+    exec_lua([[
+      _G.res = {}
+      vim.o.foldmethod = 'indent'
+      vim.o.softtabstop = -1
+      vim.api.nvim_buf_attach(0, false, {
+        on_lines = function(_, bufnr, _, row, _, end_row)
+          local lines = vim.api.nvim_buf_get_lines(bufnr, row, end_row, true)
+          table.insert(_G.res, lines)
+        end
+      })
+    ]])
+
+    feed('i<Tab>')
+    eq({ '\ta' }, exec_lua('return _G.res[#_G.res]'))
+  end)
 end)
 
 describe('lua: nvim_buf_attach on_bytes', function()