vim-patch:9.0.1380: CTRL-X on 2**64 subtracts two (#22530)

Problem:    CTRL-X on 2**64 subtracts two. (James McCoy)
Solution:   Correct computation for large number. (closes vim/vim#12103)

5fb78c3fa5

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

src/nvim/charset.c

@@ -1500,9 +1500,10 @@ bool vim_isblankline(char *lbuf)
 /// @param strict If true, fail if the number has unexpected trailing
 ///               alphanumeric chars: *len is set to 0 and nothing else is
 ///               returned.
+/// @param overflow When not NULL, set to true for overflow.
 void vim_str2nr(const char *const start, int *const prep, int *const len, const int what,
                 varnumber_T *const nptr, uvarnumber_T *const unptr, const int maxlen,
-                const bool strict)
+                const bool strict, bool *const overflow)
   FUNC_ATTR_NONNULL_ARG(1)
 {
   const char *ptr = start;
@@ -1626,6 +1627,9 @@ void vim_str2nr(const char *const start, int *const prep, int *const len, const
         un = (base) * un + digit; \
       } else { \
         un = UVARNUMBER_MAX; \
+        if (overflow != NULL) { \
+          *overflow = true; \
+        } \
       } \
       ptr++; \
     } \
@@ -1664,12 +1668,18 @@ vim_str2nr_proceed:
       // avoid ubsan error for overflow
       if (un > VARNUMBER_MAX) {
         *nptr = VARNUMBER_MIN;
+        if (overflow != NULL) {
+          *overflow = true;
+        }
       } else {
         *nptr = -(varnumber_T)un;
       }
     } else {
       if (un > VARNUMBER_MAX) {
         un = VARNUMBER_MAX;
+        if (overflow != NULL) {
+          *overflow = true;
+        }
       }
       *nptr = (varnumber_T)un;
     }

src/nvim/eval.c

@@ -3678,7 +3678,7 @@ static int get_number_tv(char **arg, typval_T *rettv, bool evaluate, bool want_s
     // decimal, hex or octal number
     int len;
     varnumber_T n;
-    vim_str2nr(*arg, NULL, &len, STR2NR_ALL, &n, NULL, 0, true);
+    vim_str2nr(*arg, NULL, &len, STR2NR_ALL, &n, NULL, 0, true, NULL);
     if (len == 0) {
       if (evaluate) {
         semsg(_(e_invexpr2), *arg);

src/nvim/eval/decode.c

@@ -439,7 +439,7 @@ static inline int parse_json_string(const char *const buf, const size_t buf_len,
         t += 4;
         uvarnumber_T ch;
         vim_str2nr(ubuf, NULL, NULL,
-                   STR2NR_HEX | STR2NR_FORCE, NULL, &ch, 4, true);
+                   STR2NR_HEX | STR2NR_FORCE, NULL, &ch, 4, true, NULL);
         if (ch == 0) {
           hasnul = true;
         }
@@ -608,7 +608,7 @@ parse_json_number_check:
     // Convert integer
     varnumber_T nr;
     int num_len;
-    vim_str2nr(s, NULL, &num_len, 0, &nr, NULL, (int)(p - s), true);
+    vim_str2nr(s, NULL, &num_len, 0, &nr, NULL, (int)(p - s), true, NULL);
     if ((int)exp_num_len != num_len) {
       semsg(_("E685: internal error: while converting number \"%.*s\" "
               "to integer vim_str2nr consumed %i bytes in place of %zu"),

src/nvim/eval/funcs.c

@@ -8033,7 +8033,7 @@ static void f_str2nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     break;
   }
   varnumber_T n;
-  vim_str2nr(p, NULL, NULL, what, &n, NULL, 0, false);
+  vim_str2nr(p, NULL, NULL, what, &n, NULL, 0, false, NULL);
   // Text after the number is silently ignored.
   if (isneg) {
     rettv->vval.v_number = -n;

src/nvim/eval/typval.c

@@ -3890,7 +3890,7 @@ varnumber_T tv_get_number_chk(const typval_T *const tv, bool *const ret_error)
   case VAR_STRING: {
     varnumber_T n = 0;
     if (tv->vval.v_string != NULL) {
-      vim_str2nr(tv->vval.v_string, NULL, NULL, STR2NR_ALL, &n, NULL, 0, false);
+      vim_str2nr(tv->vval.v_string, NULL, NULL, STR2NR_ALL, &n, NULL, 0, false, NULL);
     }
     return n;
   }

src/nvim/ex_cmds.c

@@ -580,7 +580,7 @@ void ex_sort(exarg_T *eap)
     }
 
     if (sort_nr || sort_flt) {
-      // Make sure vim_str2nr doesn't read any digits past the end
+      // Make sure vim_str2nr() doesn't read any digits past the end
       // of the match, by temporarily terminating the string there
       s2 = s + end_col;
       c = *s2;
@@ -605,7 +605,7 @@ void ex_sort(exarg_T *eap)
         } else {
           nrs[lnum - eap->line1].st_u.num.is_number = true;
           vim_str2nr(s, NULL, NULL, sort_what,
-                     &nrs[lnum - eap->line1].st_u.num.value, NULL, 0, false);
+                     &nrs[lnum - eap->line1].st_u.num.value, NULL, 0, false, NULL);
         }
       } else {
         s = skipwhite(p);

src/nvim/ex_getln.c

@@ -4241,7 +4241,7 @@ int get_list_range(char **str, int *num1, int *num2)
 
   *str = skipwhite((*str));
   if (**str == '-' || ascii_isdigit(**str)) {  // parse "from" part of range
-    vim_str2nr(*str, NULL, &len, 0, &num, NULL, 0, false);
+    vim_str2nr(*str, NULL, &len, 0, &num, NULL, 0, false, NULL);
     *str += len;
     *num1 = (int)num;
     first = true;
@@ -4249,7 +4249,7 @@ int get_list_range(char **str, int *num1, int *num2)
   *str = skipwhite((*str));
   if (**str == ',') {                   // parse "to" part of range
     *str = skipwhite((*str) + 1);
-    vim_str2nr(*str, NULL, &len, 0, &num, NULL, 0, false);
+    vim_str2nr(*str, NULL, &len, 0, &num, NULL, 0, false, NULL);
     if (len > 0) {
       *num2 = (int)num;
       *str = skipwhite((*str) + len);

src/nvim/keycodes.c

@@ -673,7 +673,7 @@ int find_special_key(const char **const srcp, const size_t src_len, int *const m
     if (end - bp > 3 && bp[0] == 't' && bp[1] == '_') {
       bp += 3;  // skip t_xx, xx may be '-' or '>'
     } else if (end - bp > 4 && STRNICMP(bp, "char-", 5) == 0) {
-      vim_str2nr(bp + 5, NULL, &l, STR2NR_ALL, NULL, NULL, 0, true);
+      vim_str2nr(bp + 5, NULL, &l, STR2NR_ALL, NULL, NULL, 0, true, NULL);
       if (l == 0) {
         emsg(_(e_invarg));
         return 0;
@@ -704,7 +704,7 @@ int find_special_key(const char **const srcp, const size_t src_len, int *const m
       if (STRNICMP(last_dash + 1, "char-", 5) == 0
           && ascii_isdigit(last_dash[6])) {
         // <Char-123> or <Char-033> or <Char-0x33>
-        vim_str2nr(last_dash + 6, NULL, &l, STR2NR_ALL, NULL, &n, 0, true);
+        vim_str2nr(last_dash + 6, NULL, &l, STR2NR_ALL, NULL, &n, 0, true, NULL);
         if (l == 0) {
           emsg(_(e_invarg));
           return 0;

src/nvim/ops.c

@@ -4658,11 +4658,12 @@ int do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1)
                 : length);
     }
 
+    bool overflow = false;
     vim_str2nr(ptr + col, &pre, &length,
                0 + (do_bin ? STR2NR_BIN : 0)
                + (do_oct ? STR2NR_OCT : 0)
                + (do_hex ? STR2NR_HEX : 0),
-               NULL, &n, maxlen, false);
+               NULL, &n, maxlen, false, &overflow);
 
     // ignore leading '-' for hex, octal and bin numbers
     if (pre && negative) {
@@ -4682,8 +4683,10 @@ int do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1)
 
     oldn = n;
 
-    n = subtract ? n - (uvarnumber_T)Prenum1
+    if (!overflow) {  // if number is too big don't add/subtract
-                 : n + (uvarnumber_T)Prenum1;
+      n = subtract ? n - (uvarnumber_T)Prenum1
+                   : n + (uvarnumber_T)Prenum1;
+    }
 
     // handle wraparound for decimal numbers
     if (!pre) {

src/nvim/option.c

@@ -814,7 +814,7 @@ static void do_set_num(int opt_idx, int opt_flags, char **argp, int nextchar, co
   } else if (*arg == '-' || ascii_isdigit(*arg)) {
     int i;
     // Allow negative, octal and hex numbers.
-    vim_str2nr(arg, NULL, &i, STR2NR_ALL, &value, NULL, 0, true);
+    vim_str2nr(arg, NULL, &i, STR2NR_ALL, &value, NULL, 0, true, NULL);
     if (i == 0 || (arg[i] != NUL && !ascii_iswhite(arg[i]))) {
       *errmsg = e_number_required_after_equal;
       return;

src/nvim/testdir/test_increment.vim

@@ -841,6 +841,22 @@ func Test_increment_unsigned()
   set nrformats-=unsigned
 endfunc
 
+func Test_in_decrement_large_number()
+  " NOTE: 18446744073709551616 == 2^64
+  call setline(1, '18446744073709551616')
+  exec "norm! gg0\<C-X>"
+  call assert_equal('18446744073709551615', getline(1))
+
+  exec "norm! gg0\<C-X>"
+  call assert_equal('18446744073709551614', getline(1))
+
+  exec "norm! gg0\<C-A>"
+  call assert_equal('18446744073709551615', getline(1))
+
+  exec "norm! gg0\<C-A>"
+  call assert_equal('-18446744073709551615', getline(1))
+endfunc
+
 func Test_normal_increment_with_virtualedit()
   set virtualedit=all
 

src/nvim/viml/parser/expressions.c

@@ -376,7 +376,7 @@ LexExprToken viml_pexpr_next_token(ParserState *const pstate, const int flags)
       }
       if (exp_start) {
         vim_str2nr(pline.data + exp_start, NULL, NULL, 0, NULL, &exp_part,
-                   (int)(ret.len - exp_start), false);
+                   (int)(ret.len - exp_start), false, NULL);
       }
       if (exp_negative) {
         exp_part += frac_size;
@@ -394,7 +394,7 @@ LexExprToken viml_pexpr_next_token(ParserState *const pstate, const int flags)
       int len;
       int prep;
       vim_str2nr(pline.data, &prep, &len, STR2NR_ALL, NULL,
-                 &ret.data.num.val.integer, (int)pline.size, false);
+                 &ret.data.num.val.integer, (int)pline.size, false, NULL);
       ret.len = (size_t)len;
       const uint8_t bases[] = {
         [0] = 10,

test/unit/charset/vim_str2nr_spec.lua

@@ -63,7 +63,7 @@ local function test_vim_str2nr(s, what, exp, maxlen, strict)
         cv[k] = args[k]
       end
     end
-    lib.vim_str2nr(s, cv.pre, cv.len, what, cv.num, cv.unum, maxlen, strict)
+    lib.vim_str2nr(s, cv.pre, cv.len, what, cv.num, cv.unum, maxlen, strict, nil)
     for cck, ccv in pairs(cv) do
       if exp[cck] ~= tonumber(ccv[0]) then
         error(('Failed check (%s = %d) in test (s=%s, w=%u, m=%d, strict=%s): %d'):format(