fix(nvim__set_complete): pum preview info truncated during completion #32555

Problem:
1. The original info text is truncated in pum_set_preview_text.
2. There is an extra newline character at the end of the info text.
3. Incorrect usage of plines_win leads to errors in calculating the window height.

Solution:
1. Improved string handling in pum_preview_set_text to safely process line content without modifying the original text. Now, the preview info is correctly preserved while splitting lines.
2. Do not append a trailing newline to the preview buffer when one is present at the end.
3. Set w_widher_inner in advance; otherwise, plines_win cannot correctly calculate the wrapped line height.

2 files changed, 265 insertions, 116 deletions

diff --git a/src/nvim/popupmenu.c b/src/nvim/popupmenu.c
index 3860ba8f6a..b057cae08d 100644
--- a/src/nvim/popupmenu.c
+++ b/src/nvim/popupmenu.c
@@ -803,14 +803,25 @@ static void pum_preview_set_text(buf_T *buf, char *info, linenr_T *lnum, int *ma
   Error err = ERROR_INIT;
   Arena arena = ARENA_EMPTY;
   Array replacement = ARRAY_DICT_INIT;
-  char *token = NULL;
-  char *line = os_strtok(info, "\n", &token);
   buf->b_p_ma = true;
-  while (line != NULL) {
-    ADD(replacement, STRING_OBJ(cstr_to_string(line)));
+
+  // Iterate through the string line by line by temporarily replacing newlines with NUL
+  for (char *curr = info, *next; curr; curr = next ? next + 1 : NULL) {
+    if ((next = strchr(curr, '\n'))) {
+      *next = NUL;  // Temporarily replace the newline with a string terminator
+    }
+    // Only skip if this is an empty line AND it's the last line
+    if (*curr == '\0' && !next) {
+      break;
+    }
+
+    *max_width = MAX(*max_width, (int)mb_string2cells(curr));
+    ADD(replacement, STRING_OBJ(cstr_to_string(curr)));
     (*lnum)++;
-    (*max_width) = MAX(*max_width, (int)mb_string2cells(line));
-    line = os_strtok(NULL, "\n", &token);
+
+    if (next) {
+      *next = '\n';
+    }
   }
 
   int original_textlock = textlock;
@@ -828,8 +839,23 @@ static void pum_preview_set_text(buf_T *buf, char *info, linenr_T *lnum, int *ma
   buf->b_p_ma = false;
 }
 
+/// Calculate the total height (in screen lines) of the first 'count' buffer lines in window 'wp'.
+/// Takes line wrapping and other display factors into account.
+///
+/// @param wp    Window pointer
+/// @param count Number of buffer lines to measure (1-based)
+/// @return      Total height in screen lines
+static inline int pum_preview_win_height(win_T *wp, linenr_T count)
+{
+  int height = 0;
+  for (int i = 1; i <= count; i++) {
+    height += plines_win(wp, i, false);
+  }
+  return height;
+}
+
 /// adjust floating info preview window position
-static void pum_adjust_info_position(win_T *wp, int height, int width)
+static void pum_adjust_info_position(win_T *wp, int width)
 {
   int col = pum_col + pum_width + pum_scrollbar + 1;
   // TODO(glepnir): support config align border by using completepopup
@@ -850,8 +876,10 @@ static void pum_adjust_info_position(win_T *wp, int height, int width)
   }
   // when pum_above is SW otherwise is NW
   wp->w_config.anchor = pum_above ? kFloatAnchorSouth : 0;
-  wp->w_config.row = pum_above ? pum_row + height : pum_row;
-  wp->w_config.height = MIN(Rows, height);
+  linenr_T count = wp->w_buffer->b_ml.ml_line_count;
+  wp->w_width_inner = wp->w_config.width;
+  wp->w_config.height = MIN(Rows, pum_preview_win_height(wp, count));
+  wp->w_config.row = pum_above ? pum_row + wp->w_config.height : pum_row;
   wp->w_config.hide = false;
   win_config_float(wp, wp->w_config);
 }
@@ -884,10 +912,7 @@ win_T *pum_set_info(int selected, char *info)
   RedrawingDisabled--;
   redraw_later(wp, UPD_NOT_VALID);
 
-  if (wp->w_p_wrap) {
-    lnum += plines_win(wp, lnum, true);
-  }
-  pum_adjust_info_position(wp, lnum, max_info_width);
+  pum_adjust_info_position(wp, max_info_width);
   unblock_autocmds();
   return wp;
 }
@@ -1063,11 +1088,8 @@ static bool pum_set_selected(int n, int repeat)
           curwin->w_cursor.col = 0;
 
           if (use_float) {
-            if (curwin->w_p_wrap) {
-              lnum += plines_win(curwin, lnum, true);
-            }
             // adjust floating window by actually height and max info text width
-            pum_adjust_info_position(curwin, lnum, max_info_width);
+            pum_adjust_info_position(curwin, max_info_width);
           }
 
           if ((curwin != curwin_save && win_valid(curwin_save))
diff --git a/test/functional/ui/popupmenu_spec.lua b/test/functional/ui/popupmenu_spec.lua
index 3b52f62464..6f3b38ce83 100644
--- a/test/functional/ui/popupmenu_spec.lua
+++ b/test/functional/ui/popupmenu_spec.lua
@@ -1851,15 +1851,16 @@ describe('builtin popupmenu', function()
     end)
 
     describe('floating window preview popup', function()
-      it('pum popup preview', function()
+      before_each(function()
         --row must > 10
         screen:try_resize(40, 11)
         exec([[
+          let g:list = [#{word: "one", info: "1info"}, #{word: "two", info: "2info"}, #{word: "looooooooooooooong"}]
           funct Omni_test(findstart, base)
             if a:findstart
               return col(".") - 1
             endif
-            return [#{word: "one", info: "1info"}, #{word: "two", info: "2info"}, #{word: "looooooooooooooong"}]
+            return g:list
           endfunc
           set omnifunc=Omni_test
           set completeopt=menu,popup
@@ -1886,28 +1887,42 @@ describe('builtin popupmenu', function()
             autocmd! Group
             autocmd CompleteChanged * call TsHl()
           endfunc
+          funct Append_multipe()
+            call extend(g:list, [#{word: "for .. ipairs", info: "```lua\nfor index, value in ipairs(t) do\n\t\nend\n```"}])
+          endfunc
         ]])
+      end)
+
+      it('pum popup preview', function()
         feed('Gi<C-x><C-o>')
         --floating preview in right
         if multigrid then
-          screen:expect {
+          screen:expect({
             grid = [[
-          ## grid 1
-            [2:----------------------------------------]|*10
-            [3:----------------------------------------]|
-          ## grid 2
-            one^                                     |
-            {1:~                                       }|*9
-          ## grid 3
-            {2:-- }{5:match 1 of 3}                         |
-          ## grid 4
-            {n:1info}|
-            {n:     }|
-          ## grid 5
-            {s:one                }|
-            {n:two                }|
-            {n:looooooooooooooong }|
-          ]],
+            ## grid 1
+              [2:----------------------------------------]|*10
+              [3:----------------------------------------]|
+            ## grid 2
+              one^                                     |
+              {1:~                                       }|*9
+            ## grid 3
+              {2:-- }{5:match 1 of 3}                         |
+            ## grid 4
+              {n:1info}|
+            ## grid 5
+              {s:one                }|
+              {n:two                }|
+              {n:looooooooooooooong }|
+            ]],
+            win_pos = {
+              [2] = {
+                height = 10,
+                startcol = 0,
+                startrow = 0,
+                width = 40,
+                win = 1000,
+              },
+            },
             float_pos = {
               [5] = { -1, 'NW', 2, 1, 0, false, 100 },
               [4] = { 1001, 'NW', 1, 1, 19, false, 50 },
@@ -1925,25 +1940,39 @@ describe('builtin popupmenu', function()
               [4] = {
                 win = 1001,
                 topline = 0,
-                botline = 2,
+                botline = 1,
                 curline = 0,
                 curcol = 0,
                 linecount = 1,
                 sum_scroll_delta = 0,
               },
             },
-          }
+            win_viewport_margins = {
+              [2] = {
+                bottom = 0,
+                left = 0,
+                right = 0,
+                top = 0,
+                win = 1000,
+              },
+              [4] = {
+                bottom = 0,
+                left = 0,
+                right = 0,
+                top = 0,
+                win = 1001,
+              },
+            },
+          })
         else
-          screen:expect {
-            grid = [[
+          screen:expect([[
             one^                                     |
             {s:one                }{n:1info}{1:                }|
-            {n:two                     }{1:                }|
+            {n:two                }{1:                     }|
             {n:looooooooooooooong }{1:                     }|
             {1:~                                       }|*6
             {2:-- }{5:match 1 of 3}                         |
-          ]],
-          }
+          ]])
         end
 
         -- delete one character make the pum width smaller than before
@@ -1962,10 +1991,18 @@ describe('builtin popupmenu', function()
               {2:-- }{5:match 1 of 3}                         |
             ## grid 4
               {n:1info}|
-              {n:     }|
             ## grid 5
               {s:one            }|
             ]],
+            win_pos = {
+              [2] = {
+                height = 10,
+                startcol = 0,
+                startrow = 0,
+                width = 40,
+                win = 1000,
+              },
+            },
             float_pos = {
               [5] = { -1, 'NW', 2, 1, 0, false, 100 },
               [4] = { 1001, 'NW', 1, 1, 15, false, 50 },
@@ -1983,7 +2020,7 @@ describe('builtin popupmenu', function()
               [4] = {
                 win = 1001,
                 topline = 0,
-                botline = 2,
+                botline = 1,
                 curline = 0,
                 curcol = 0,
                 linecount = 1,
@@ -2008,15 +2045,12 @@ describe('builtin popupmenu', function()
             },
           })
         else
-          screen:expect({
-            grid = [[
-              on^                                      |
-              {s:one            }{n:1info}{1:                    }|
-              {1:~              }{n:     }{1:                    }|
-              {1:~                                       }|*7
-              {2:-- }{5:match 1 of 3}                         |
-            ]],
-          })
+          screen:expect([[
+            on^                                      |
+            {s:one            }{n:1info}{1:                    }|
+            {1:~                                       }|*8
+            {2:-- }{5:match 1 of 3}                         |
+          ]])
         end
 
         -- when back to original the preview float should be closed.
@@ -2034,7 +2068,6 @@ describe('builtin popupmenu', function()
               {2:-- }{8:Back at original}                     |
             ## grid 4 (hidden)
               {n:1info}|
-              {n:     }|
             ## grid 5
               {n:one            }|
             ]],
@@ -2063,7 +2096,7 @@ describe('builtin popupmenu', function()
               [4] = {
                 win = 1001,
                 topline = 0,
-                botline = 2,
+                botline = 1,
                 curline = 0,
                 curcol = 0,
                 linecount = 1,
@@ -2097,9 +2130,11 @@ describe('builtin popupmenu', function()
             ]],
           })
         end
+        feed('<C-E><ESC>')
+      end)
 
-        -- test nvim__complete_set_info
-        feed('<ESC>S<C-X><C-O><C-N><C-N>')
+      it('nvim__set_complete', function()
+        feed('S<C-X><C-O><C-N><C-N>')
         if multigrid then
           screen:expect({
             grid = [[
@@ -2111,13 +2146,12 @@ describe('builtin popupmenu', function()
               {1:~                                       }|*9
             ## grid 3
               {2:-- }{5:match 3 of 3}                         |
+            ## grid 4
+              {n:3info}|
             ## grid 5
               {n:one                }|
               {n:two                }|
               {s:looooooooooooooong }|
-            ## grid 6
-              {n:3info}|
-              {n:     }|
             ]],
             win_pos = {
               [2] = {
@@ -2130,7 +2164,7 @@ describe('builtin popupmenu', function()
             },
             float_pos = {
               [5] = { -1, 'NW', 2, 1, 0, false, 100 },
-              [6] = { 1002, 'NW', 1, 1, 19, false, 50 },
+              [4] = { 1001, 'NW', 1, 1, 19, false, 50 },
             },
             win_viewport = {
               [2] = {
@@ -2142,10 +2176,10 @@ describe('builtin popupmenu', function()
                 linecount = 1,
                 sum_scroll_delta = 0,
               },
-              [6] = {
-                win = 1002,
+              [4] = {
+                win = 1001,
                 topline = 0,
-                botline = 2,
+                botline = 1,
                 curline = 0,
                 curcol = 0,
                 linecount = 1,
@@ -2160,30 +2194,29 @@ describe('builtin popupmenu', function()
                 top = 0,
                 win = 1000,
               },
-              [6] = {
+              [4] = {
                 bottom = 0,
                 left = 0,
                 right = 0,
                 top = 0,
-                win = 1002,
+                win = 1001,
               },
             },
           })
         else
-          screen:expect {
-            grid = [[
+          screen:expect([[
             looooooooooooooong^                      |
             {n:one                3info}{1:                }|
-            {n:two                     }{1:                }|
+            {n:two                }{1:                     }|
             {s:looooooooooooooong }{1:                     }|
             {1:~                                       }|*6
             {2:-- }{5:match 3 of 3}                         |
-          ]],
-          }
+          ]])
         end
+        feed('<C-E><ESC>')
+      end)
 
-        -- preview in left
-        feed('<ESC>cc')
+      it('popup preview place in left', function()
         insert(('test'):rep(5))
         feed('i<C-x><C-o>')
         if multigrid then
@@ -2193,17 +2226,16 @@ describe('builtin popupmenu', function()
               [2:----------------------------------------]|*10
               [3:----------------------------------------]|
             ## grid 2
-              itesttesttesttesttesone^t                |
+              testtesttesttesttesone^t                 |
               {1:~                                       }|*9
             ## grid 3
               {2:-- }{5:match 1 of 3}                         |
+            ## grid 4
+              {n:1info}|
             ## grid 5
               {s: one                }|
               {n: two                }|
               {n: looooooooooooooong }|
-            ## grid 7
-              {n:1info}|
-              {n:     }|
             ]],
             win_pos = {
               [2] = {
@@ -2215,8 +2247,8 @@ describe('builtin popupmenu', function()
               },
             },
             float_pos = {
-              [7] = { 1003, 'NW', 1, 1, 14, false, 50 },
-              [5] = { -1, 'NW', 2, 1, 19, false, 100 },
+              [5] = { -1, 'NW', 2, 1, 18, false, 100 },
+              [4] = { 1001, 'NW', 1, 1, 13, false, 50 },
             },
             win_viewport = {
               [2] = {
@@ -2224,14 +2256,14 @@ describe('builtin popupmenu', function()
                 topline = 0,
                 botline = 2,
                 curline = 0,
-                curcol = 23,
+                curcol = 22,
                 linecount = 1,
                 sum_scroll_delta = 0,
               },
-              [7] = {
-                win = 1003,
+              [4] = {
+                win = 1001,
                 topline = 0,
-                botline = 2,
+                botline = 1,
                 curline = 0,
                 curcol = 0,
                 linecount = 1,
@@ -2246,30 +2278,29 @@ describe('builtin popupmenu', function()
                 top = 0,
                 win = 1000,
               },
-              [7] = {
+              [4] = {
                 bottom = 0,
                 left = 0,
                 right = 0,
                 top = 0,
-                win = 1003,
+                win = 1001,
               },
             },
           })
         else
-          screen:expect {
-            grid = [[
-            itesttesttesttesttesone^t                |
-            {1:~             }{n:1info}{s: one                }{1: }|
-            {1:~             }{n:      two                }{1: }|
-            {1:~                  }{n: looooooooooooooong }{1: }|
+          screen:expect([[
+            testtesttesttesttesone^t                 |
+            {1:~            }{n:1info}{s: one                }{1:  }|
+            {1:~                 }{n: two                }{1:  }|
+            {1:~                 }{n: looooooooooooooong }{1:  }|
             {1:~                                       }|*6
             {2:-- }{5:match 1 of 3}                         |
-          ]],
-          }
+          ]])
         end
         feed('<C-E><Esc>')
+      end)
 
-        -- works when scroll with treesitter highlight
+      it('works when scroll with treesitter highlight', function()
         command('call TestTs()')
         feed('S<C-x><C-o>')
         if multigrid then
@@ -2283,17 +2314,16 @@ describe('builtin popupmenu', function()
               {1:~                                       }|*9
             ## grid 3
               {2:-- }{5:match 1 of 3}                         |
-            ## grid 5
-              {s:one                }|
-              {n:two                }|
-              {n:looooooooooooooong }|
-            ## grid 8
+            ## grid 4
               {n:```lua         }|
               {n:function test()}|
               {n:  print('foo') }|
               {n:end            }|
               {n:```            }|
-              {n:               }|
+            ## grid 5
+              {s:one                }|
+              {n:two                }|
+              {n:looooooooooooooong }|
             ]],
             win_pos = {
               [2] = {
@@ -2306,7 +2336,7 @@ describe('builtin popupmenu', function()
             },
             float_pos = {
               [5] = { -1, 'NW', 2, 1, 0, false, 100 },
-              [8] = { 1004, 'NW', 1, 1, 19, false, 50 },
+              [4] = { 1001, 'NW', 1, 1, 19, false, 50 },
             },
             win_viewport = {
               [2] = {
@@ -2318,10 +2348,10 @@ describe('builtin popupmenu', function()
                 linecount = 1,
                 sum_scroll_delta = 0,
               },
-              [8] = {
-                win = 1004,
+              [4] = {
+                win = 1001,
                 topline = 0,
-                botline = 6,
+                botline = 5,
                 curline = 0,
                 curcol = 0,
                 linecount = 5,
@@ -2336,30 +2366,127 @@ describe('builtin popupmenu', function()
                 top = 0,
                 win = 1000,
               },
-              [8] = {
+              [4] = {
                 bottom = 0,
                 left = 0,
                 right = 0,
                 top = 0,
-                win = 1004,
+                win = 1001,
               },
             },
           })
         else
+          screen:expect([[
+            one^                                     |
+            {s:one                }{n:```lua         }{1:      }|
+            {n:two                function test()}{1:      }|
+            {n:looooooooooooooong   print('foo') }{1:      }|
+            {1:~                  }{n:end            }{1:      }|
+            {1:~                  }{n:```            }{1:      }|
+            {1:~                                       }|*4
+            {2:-- }{5:match 1 of 3}                         |
+          ]])
+        end
+        feed('<C-E><ESC>')
+      end)
+
+      it('#avoid modified original info text', function()
+        screen:try_resize(40, 11)
+        command('call Append_multipe()')
+        feed('S<C-x><C-o><C-P><C-P>')
+        if multigrid then
           screen:expect({
             grid = [[
-              one^                                     |
-              {s:one                }{n:```lua         }{1:      }|
-              {n:two                function test()}{1:      }|
-              {n:looooooooooooooong   print('foo') }{1:      }|
-              {1:~                  }{n:end            }{1:      }|
-              {1:~                  }{n:```            }{1:      }|
-              {1:~                  }{n:               }{1:      }|
-              {1:~                                       }|*3
-              {2:-- }{5:match 1 of 3}                         |
+            ## grid 1
+              [2:----------------------------------------]|*10
+              [3:----------------------------------------]|
+            ## grid 2
+              for .. ipairs^                           |
+              {1:~                                       }|*9
+            ## grid 3
+              {2:-- }{5:match 1 of 4}                         |
+            ## grid 4
+              {n:one                }|
+              {n:two                }|
+              {n:looooooooooooooong }|
+              {s:for .. ipairs      }|
+            ## grid 5
+              {n:```lua              }|
+              {n:for index, value in }|
+              {n:ipairs(t) do        }|
+              {n:                    }|
+              {n:end                 }|
+              {n:```                 }|
             ]],
+            win_pos = {
+              [2] = {
+                height = 10,
+                startcol = 0,
+                startrow = 0,
+                width = 40,
+                win = 1000,
+              },
+            },
+            float_pos = {
+              [5] = { 1001, 'NW', 1, 1, 19, false, 50 },
+              [4] = { -1, 'NW', 2, 1, 0, false, 100 },
+            },
+            win_viewport = {
+              [2] = {
+                win = 1000,
+                topline = 0,
+                botline = 2,
+                curline = 0,
+                curcol = 13,
+                linecount = 1,
+                sum_scroll_delta = 0,
+              },
+              [5] = {
+                win = 1001,
+                topline = 0,
+                botline = 5,
+                curline = 0,
+                curcol = 0,
+                linecount = 5,
+                sum_scroll_delta = 0,
+              },
+            },
+            win_viewport_margins = {
+              [2] = {
+                bottom = 0,
+                left = 0,
+                right = 0,
+                top = 0,
+                win = 1000,
+              },
+              [5] = {
+                bottom = 0,
+                left = 0,
+                right = 0,
+                top = 0,
+                win = 1001,
+              },
+            },
           })
+        else
+          screen:expect([[
+            for .. ipairs^                           |
+            {n:one                ```lua              }{1: }|
+            {n:two                for index, value in }{1: }|
+            {n:looooooooooooooong ipairs(t) do        }{1: }|
+            {s:for .. ipairs      }{n:                    }{1: }|
+            {1:~                  }{n:end                 }{1: }|
+            {1:~                  }{n:```                 }{1: }|
+            {1:~                                       }|*3
+            {2:-- }{5:match 1 of 4}                         |
+          ]])
         end
+
+        feed('<C-N><C-N><C-N><C-N><C-N>')
+        if not multigrid then
+          screen:expect_unchanged()
+        end
+        feed('<C-E><ESC>')
       end)
     end)