vim-patch:8.1.2036: the str2nr() tests fail

Problem:    The str2nr() tests fail.
Solution:   Add missing part of patch.
https://github.com/vim/vim/commit/1ac90b4fa63414d56750559506a3e076df6923b0

Add extra tests for quoted numbers in vim_str2nr_spec.lua, as the
included ones in this patch are somewhat lacking.

2 files changed, 34 insertions, 2 deletions

diff --git a/src/nvim/charset.c b/src/nvim/charset.c
index 9f11e85b01..7b08488925 100644
--- a/src/nvim/charset.c
+++ b/src/nvim/charset.c
@@ -1396,6 +1396,7 @@ bool vim_isblankline(char_u *lbuf)
 /// If "what" contains STR2NR_OCT recognize octal numbers.
 /// If "what" contains STR2NR_HEX recognize hex numbers.
 /// If "what" contains STR2NR_FORCE always assume bin/oct/hex.
+/// If "what" contains STR2NR_QUOTE ignore embedded single quotes
 /// If maxlen > 0, check at a maximum maxlen chars.
 /// If strict is true, check the number strictly. return *len = 0 if fail.
 ///
@@ -1434,7 +1435,7 @@ void vim_str2nr(const char_u *const start, int *const prep, int *const len,
   if (what & STR2NR_FORCE) {
     // When forcing main consideration is skipping the prefix. Octal and decimal
     // numbers have no prefixes to skip. pre is not set.
-    switch ((unsigned)what & (~(unsigned)STR2NR_FORCE)) {
+    switch (what & ~(STR2NR_FORCE | STR2NR_QUOTE)) {
       case STR2NR_HEX: {
         if (!STRING_ENDED(ptr + 2)
             && ptr[0] == '0'
@@ -1504,7 +1505,18 @@ void vim_str2nr(const char_u *const start, int *const prep, int *const len,
   abort();  // Should’ve used goto earlier.
 #define PARSE_NUMBER(base, cond, conv) \
   do { \
-    while (!STRING_ENDED(ptr) && (cond)) { \
+    const char *const after_prefix = ptr; \
+    while (!STRING_ENDED(ptr)) { \
+      if ((what & STR2NR_QUOTE) && ptr > after_prefix && *ptr == '\'') { \
+        ptr++; \
+        if (!STRING_ENDED(ptr) && (cond)) { \
+          continue; \
+        } \
+        ptr--; \
+      } \
+      if (!(cond)) { \
+        break; \
+      } \
       const uvarnumber_T digit = (uvarnumber_T)(conv); \
       /* avoid ubsan error for overflow */ \
       if (un < UVARNUMBER_MAX / base \
diff --git a/test/unit/charset/vim_str2nr_spec.lua b/test/unit/charset/vim_str2nr_spec.lua
index 2728a16e20..ebcceca7ae 100644
--- a/test/unit/charset/vim_str2nr_spec.lua
+++ b/test/unit/charset/vim_str2nr_spec.lua
@@ -354,4 +354,24 @@ describe('vim_str2nr()', function()
       end
     end
   end)
+  -- Test_str2nr() in test_functions.vim already tests normal usage
+  itp('works with weirdly quoted numbers', function()
+    local flags = lib.STR2NR_DEC + lib.STR2NR_QUOTE
+    test_vim_str2nr("'027", flags, {len = 0}, 0)
+    test_vim_str2nr("'027", flags, {len = 0}, 0, false)
+    test_vim_str2nr("1'2'3'4", flags, {len = 7, num = 1234, unum = 1234, pre = 0}, 0)
+
+    -- counter-intuitive, but like Vim, strict=true should partially accept
+    -- these: (' and - are not alpha-numeric)
+    test_vim_str2nr("7''331", flags, {len = 1, num = 7, unum = 7, pre = 0}, 0)
+    test_vim_str2nr("123'x4", flags, {len = 3, num = 123, unum = 123, pre = 0}, 0)
+    test_vim_str2nr("1337'", flags, {len = 4, num = 1337, unum = 1337, pre = 0}, 0)
+    test_vim_str2nr("-'", flags, {len = 1, num = 0, unum = 0, pre = 0}, 0)
+
+    flags = lib.STR2NR_HEX + lib.STR2NR_QUOTE
+    local hex = ('x'):byte()
+    test_vim_str2nr("0x'abcd", flags, {len = 0}, 0)
+    test_vim_str2nr("0x'abcd", flags, {len = 1, num = 0, unum = 0, pre = 0}, 0, false)
+    test_vim_str2nr("0xab''cd", flags, {len = 4, num = 171, unum = 171, pre = hex}, 0)
+  end)
 end)