vim-patch:8.2.0886: cannot use octal numbers in scriptversion 4

Problem:    Cannot use octal numbers in scriptversion 4.
Solution:   Add the "0o" notation. (Ken Takata, closes vim/vim#5304)
https://github.com/vim/vim/commit/c17e66c5c0acd5038f1eb3d7b3049b64bb6ea30b

:scriptversion is N/A.

Cherry-pick latest str2nr() doc changes from v8.1.2035.
Cherry-pick various mentions of the 0o prefix from:
 - v8.2.2324
 - https://github.com/vim/vim/commit/2346a6378483c9871016f9fc821ec5cbea638f13
 - https://github.com/vim/vim/commit/11e3c5ba820325b69cb56f70e13c21d7b8808d33
 - https://github.com/vim/vim/commit/82be4849eed0b8fbee45bc8da99b685ec89af59a

Patch used ascii_isbdigit() by mistake, which was fixed in v8.2.2309.

Make STR2NR_OOCT work the same as STR2NR_OCT when forcing.
In Vim, STR2NR_FORCE | STR2NR_OOCT isn't handled, and doesn't actually
force anything. Rather than abort(), make it work as STR2NR_OCT.

This means STR2NR_FORCE | STR2NR_OCT works the same as
STR2NR_FORCE | STR2NR_OOCT and STR2NR_FORCE | STR2NR_OCT | STR2NR_OOCT.

4 files changed, 41 insertions, 12 deletions

diff --git a/src/nvim/charset.c b/src/nvim/charset.c
index 7b08488925..94b6b7a8d7 100644
--- a/src/nvim/charset.c
+++ b/src/nvim/charset.c
@@ -1385,6 +1385,8 @@ bool vim_isblankline(char_u *lbuf)
 /// If "prep" is not NULL, returns a flag to indicate the type of the number:
 ///   0      decimal
 ///   '0'    octal
+///   'O'    octal
+///   'o'    octal
 ///   'B'    bin
 ///   'b'    bin
 ///   'X'    hex
@@ -1402,8 +1404,8 @@ bool vim_isblankline(char_u *lbuf)
 ///
 /// @param start
 /// @param prep Returns guessed type of number 0 = decimal, 'x' or 'X' is
-///             hexadecimal, '0' = octal, 'b' or 'B' is binary. When using
-///             STR2NR_FORCE is always zero.
+///             hexadecimal, '0', 'o' or 'O' is octal, 'b' or 'B' is binary.
+///             When using STR2NR_FORCE is always zero.
 /// @param len Returns the detected length of number.
 /// @param what Recognizes what number passed, @see ChStr2NrFlags.
 /// @param nptr Returns the signed result.
@@ -1433,8 +1435,8 @@ 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.
+    // When forcing main consideration is skipping the prefix. Decimal numbers
+    // have no prefixes to skip. pre is not set.
     switch (what & ~(STR2NR_FORCE | STR2NR_QUOTE)) {
       case STR2NR_HEX: {
         if (!STRING_ENDED(ptr + 2)
@@ -1454,7 +1456,16 @@ void vim_str2nr(const char_u *const start, int *const prep, int *const len,
         }
         goto vim_str2nr_bin;
       }
-      case STR2NR_OCT: {
+      // Make STR2NR_OOCT work the same as STR2NR_OCT when forcing.
+      case STR2NR_OCT:
+      case STR2NR_OOCT:
+      case STR2NR_OCT | STR2NR_OOCT: {
+        if (!STRING_ENDED(ptr + 2)
+            && ptr[0] == '0'
+            && (ptr[1] == 'o' || ptr[1] == 'O')
+            && ascii_isbdigit(ptr[2])) {
+          ptr += 2;
+        }
         goto vim_str2nr_oct;
       }
       case 0: {
@@ -1464,9 +1475,9 @@ void vim_str2nr(const char_u *const start, int *const prep, int *const len,
         abort();
       }
     }
-  } else if ((what & (STR2NR_HEX|STR2NR_OCT|STR2NR_BIN))
-             && !STRING_ENDED(ptr + 1)
-             && ptr[0] == '0' && ptr[1] != '8' && ptr[1] != '9') {
+  } else if ((what & (STR2NR_HEX | STR2NR_OCT | STR2NR_OOCT | STR2NR_BIN))
+             && !STRING_ENDED(ptr + 1) && ptr[0] == '0' && ptr[1] != '8'
+             && ptr[1] != '9') {
     pre = ptr[1];
     // Detect hexadecimal: 0x or 0X followed by hex digit.
     if ((what & STR2NR_HEX)
@@ -1484,7 +1495,15 @@ void vim_str2nr(const char_u *const start, int *const prep, int *const len,
       ptr += 2;
       goto vim_str2nr_bin;
     }
-    // Detect octal number: zero followed by octal digits without '8' or '9'.
+    // Detect octal: 0o or 0O followed by octal digits (without '8' or '9').
+    if ((what & STR2NR_OOCT)
+        && !STRING_ENDED(ptr + 2)
+        && (pre == 'O' || pre == 'o')
+        && ascii_isbdigit(ptr[2])) {
+      ptr += 2;
+      goto vim_str2nr_oct;
+    }
+    // Detect old octal format: 0 followed by octal digits.
     pre = 0;
     if (!(what & STR2NR_OCT)
         || !('0' <= ptr[1] && ptr[1] <= '7')) {
diff --git a/src/nvim/charset.h b/src/nvim/charset.h
index b5f1f8506b..2fef4d78a2 100644
--- a/src/nvim/charset.h
+++ b/src/nvim/charset.h
@@ -23,14 +23,19 @@ typedef enum {
   STR2NR_BIN = (1 << 0),  ///< Allow binary numbers.
   STR2NR_OCT = (1 << 1),  ///< Allow octal numbers.
   STR2NR_HEX = (1 << 2),  ///< Allow hexadecimal numbers.
+  STR2NR_OOCT = (1 << 3),  ///< Octal with prefix "0o": 0o777
   /// Force one of the above variants.
   ///
   /// STR2NR_FORCE|STR2NR_DEC is actually not different from supplying zero
   /// as flags, but still present for completeness.
+  ///
+  /// STR2NR_FORCE|STR2NR_OCT|STR2NR_OOCT is the same as STR2NR_FORCE|STR2NR_OCT
+  /// or STR2NR_FORCE|STR2NR_OOCT.
   STR2NR_FORCE = (1 << 7),
   /// Recognize all formats vim_str2nr() can recognize.
-  STR2NR_ALL = STR2NR_BIN | STR2NR_OCT | STR2NR_HEX,
-  STR2NR_NO_OCT = STR2NR_BIN | STR2NR_HEX,  ///< Disallow octal numbers.
+  STR2NR_ALL = STR2NR_BIN | STR2NR_OCT | STR2NR_HEX | STR2NR_OOCT,
+  /// Disallow octals numbers without the 0o prefix.
+  STR2NR_NO_OCT = STR2NR_BIN | STR2NR_HEX | STR2NR_OOCT,
   STR2NR_QUOTE = (1 << 4),  ///< Ignore embedded single quotes.
 } ChStr2NrFlags;
 
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 61f535e32e..801b0f9d1c 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -10022,7 +10022,7 @@ static void f_str2nr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
       break;
     }
     case 8: {
-      what |= STR2NR_OCT | STR2NR_FORCE;
+      what |= STR2NR_OCT | STR2NR_OOCT | STR2NR_FORCE;
       break;
     }
     case 16: {
diff --git a/src/nvim/testdir/test_functions.vim b/src/nvim/testdir/test_functions.vim
index 2e838f73b6..ed46730cbb 100644
--- a/src/nvim/testdir/test_functions.vim
+++ b/src/nvim/testdir/test_functions.vim
@@ -152,6 +152,10 @@ func Test_str2nr()
   call assert_equal(65, str2nr('0101', 8))
   call assert_equal(-65, str2nr('-101', 8))
   call assert_equal(-65, str2nr('-0101', 8))
+  call assert_equal(65, str2nr('0o101', 8))
+  call assert_equal(65, str2nr('0O0101', 8))
+  call assert_equal(-65, str2nr('-0O101', 8))
+  call assert_equal(-65, str2nr('-0o0101', 8))
 
   call assert_equal(11259375, str2nr('abcdef', 16))
   call assert_equal(11259375, str2nr('ABCDEF', 16))
@@ -170,6 +174,7 @@ func Test_str2nr()
 
   call assert_equal(0, str2nr('0x10'))
   call assert_equal(0, str2nr('0b10'))
+  call assert_equal(0, str2nr('0o10'))
   call assert_equal(1, str2nr('12', 2))
   call assert_equal(1, str2nr('18', 8))
   call assert_equal(1, str2nr('1g', 16))