vim-patch:9.0.0816: CTRL-Z at end of file is always dropped

Problem:    CTRL-Z at end of file is always dropped.
Solution:   Add the 'endoffile' option, like the 'endofline' option.
            (closes vim/vim#11408, closes vim/vim#11397)

Cherry-pick test_fixeol.vim changes from patch 8.2.1432.
Cherry-pick 'endoffile' changes from latest Vim runtime update.

https://github.com/vim/vim/commit/fb0cf2357e0c85bbfd9f9178705ad8d77b6b3b4e

vim-patch:f0b567e32a46

Revert unintended Makefile change

https://github.com/vim/vim/commit/f0b567e32a462fe838170a202919d18b53eff987

vim-patch:72c8e3c070b3

Fix wrong struct access for member.

https://github.com/vim/vim/commit/72c8e3c070b30f82bc0d203a62c168e43a13e99b

vim-patch:3f68a4136eb9

Add missing entry for the 'endoffile' option.

https://github.com/vim/vim/commit/3f68a4136eb99840d739af5133ab31948f273f63

Co-authored-by: Bram Moolenaar <Bram@vim.org>

6 files changed, 33 insertions, 9 deletions

diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index 043a31bf16..8e29edc0f5 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -675,6 +675,7 @@ struct file_buffer {
   char *b_p_cfu;                ///< 'completefunc'
   char *b_p_ofu;                ///< 'omnifunc'
   char *b_p_tfu;                ///< 'tagfunc'
+  int b_p_eof;                  ///< 'endoffile'
   int b_p_eol;                  ///< 'endofline'
   int b_p_fixeol;               ///< 'fixendofline'
   int b_p_et;                   ///< 'expandtab'
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index cfdd6fe697..ae0340cdc6 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -525,6 +525,7 @@ int readfile(char *fname, char *sfname, linenr_T from, linenr_T lines_to_skip,
     // correctly set when reading stdin.
     if (!read_buffer) {
       curbuf->b_p_eol = true;
+      curbuf->b_p_eof = false;
       curbuf->b_start_eol = true;
     }
     curbuf->b_p_bomb = false;
@@ -1629,12 +1630,13 @@ failed:
       && !got_int
       && linerest != 0
       && !(!curbuf->b_p_bin
-           && fileformat == EOL_DOS
-           && *line_start == Ctrl_Z
-           && ptr == line_start + 1)) {
+           && fileformat == EOL_DOS)) {
     // remember for when writing
     if (set_options) {
       curbuf->b_p_eol = false;
+      if (*line_start == Ctrl_Z && ptr == line_start + 1) {
+        curbuf->b_p_eof = false;
+      }
     }
     *ptr = NUL;
     len = (colnr_T)(ptr - line_start + 1);
@@ -3191,6 +3193,11 @@ restore_backup:
         len = 0;
         write_info.bw_start_lnum = lnum;
       }
+      if (!buf->b_p_fixeol && buf->b_p_eof) {
+        // write trailing CTRL-Z
+        (void)write_eintr(write_info.bw_fd, "\x1a", 1);
+      }
+
       // write failed or last line has no EOL: stop here
       if (end == 0
           || (lnum == end
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 06662afd08..8de86ce76e 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -3978,6 +3978,8 @@ static char_u *get_varp(vimoption_T *p)
     return (char_u *)&(curbuf->b_p_cfu);
   case PV_OFU:
     return (char_u *)&(curbuf->b_p_ofu);
+  case PV_EOF:
+    return (char_u *)&(curbuf->b_p_eof);
   case PV_EOL:
     return (char_u *)&(curbuf->b_p_eol);
   case PV_FIXEOL:
diff --git a/src/nvim/option_defs.h b/src/nvim/option_defs.h
index 19e4780e0a..7c33773e41 100644
--- a/src/nvim/option_defs.h
+++ b/src/nvim/option_defs.h
@@ -497,6 +497,7 @@ EXTERN char_u *p_ef;            // 'errorfile'
 EXTERN char *p_efm;             // 'errorformat'
 EXTERN char *p_gefm;            // 'grepformat'
 EXTERN char *p_gp;              // 'grepprg'
+EXTERN int p_eof;               ///< 'endoffile'
 EXTERN int p_eol;               ///< 'endofline'
 EXTERN char *p_ei;              // 'eventignore'
 EXTERN int p_et;                ///< 'expandtab'
@@ -858,6 +859,7 @@ enum {
   BV_CFU,
   BV_DEF,
   BV_INC,
+  BV_EOF,
   BV_EOL,
   BV_FIXEOL,
   BV_EP,
diff --git a/src/nvim/options.lua b/src/nvim/options.lua
index ba483d3714..088aa40fda 100644
--- a/src/nvim/options.lua
+++ b/src/nvim/options.lua
@@ -641,6 +641,15 @@ return {
       defaults={if_true=macros('ENC_DFLT')}
     },
     {
+      full_name='endoffile', abbreviation='eof',
+      short_desc=N_("write CTRL-Z for last line in file"),
+      type='bool', scope={'buffer'},
+      no_mkrc=true,
+      redraw={'statuslines'},
+      varname='p_eof',
+      defaults={if_true=true}
+    },
+    {
       full_name='endofline', abbreviation='eol',
       short_desc=N_("write <EOL> for last line in file"),
       type='bool', scope={'buffer'},
diff --git a/src/nvim/testdir/test_fixeol.vim b/src/nvim/testdir/test_fixeol.vim
index 32cb059e26..3ede84f49e 100644
--- a/src/nvim/testdir/test_fixeol.vim
+++ b/src/nvim/testdir/test_fixeol.vim
@@ -1,16 +1,17 @@
-" Tests for 'fixeol' and 'eol'
+" Tests for 'fixeol', 'eof' and 'eol'
+
 func Test_fixeol()
   " first write two test files – with and without trailing EOL
   " use Unix fileformat for consistency
   set ff=unix
   enew!
-  call setline('.', 'with eol')
+  call setline('.', 'with eol or eof')
   w! XXEol
   enew!
-  set noeol nofixeol
-  call setline('.', 'without eol')
+  set noeof noeol nofixeol
+  call setline('.', 'without eol or eof')
   w! XXNoEol
-  set eol fixeol
+  set eol eof fixeol
   bwipe XXEol XXNoEol
 
   " try editing files with 'fixeol' disabled
@@ -43,6 +44,8 @@ func Test_fixeol()
   call delete('XXNoEol')
   call delete('XXTestEol')
   call delete('XXTestNoEol')
-  set ff& fixeol& eol&
+  set ff& fixeol& eof& eol&
   enew!
 endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab