Allow restricting [:xdigit:] to ASCII for POSIX compatibility

ChangeLog

@@ -119,7 +119,7 @@ does the same, except for \u{...}, which is recognized only when
 PCRE2_EXTRA_ALT_BSUX is set. This an ECMAScript, non-Perl compatible,
 extension, so PCRE2 follows ECMAScript rather than Perl.
 
-31. Applied pull request #300 bu Carlo, which fixes #261. The bug was that
+31. Applied pull request #300 by Carlo, which fixes #261. The bug was that
 pcre2_match() was not fully resetting all captures that had been set within a
 (possibly recursive) subroutine call such as (?3).
 
@@ -128,8 +128,9 @@ now matches characters whose general categories are L or N or whose particular
 categories are Mn (non-spacing mark) or Pc (combining puntuation). The latter
 includes underscore.
 
-33. Changed the meaning of [:digit:] in UCP mode to match Perl. It now also
-matches the "fullwidth" versions of the hex digits.
+33. Changed the meaning of [:xdigit:] in UCP mode to match Perl. It now also
+matches the "fullwidth" versions of the hex digits. Just like it is done for
+[:digit:], PCRE2_EXTRA_ASCII_DIGIT can be used to keep this class ASCII only.
 
 
 Version 10.42 11-December-2022

doc/pcre2pattern.3

@@ -1569,9 +1569,11 @@ plus those characters with code points less than 256 that have the S (Symbol)
 property.
 .TP 10
 [:xdigit:]
-In addition to the ASCII hexadecimal digits, this also matches the "fullwidth" 
-versions of those characters, whose Unicode code points start at U+FF10. This 
-is a change that was made in PCRE release 10.43 for Perl compatibility.
+In addition to the ASCII hexadecimal digits, this also matches the "fullwidth"
+versions of those characters, whose Unicode code points start at U+FF10. Just
+like in the case of [:digit:], the effect of PCRE2_UCP can be negated by
+setting the PCRE2_EXTRA_ASCII_DIGIT option. This is a change that was made in
+PCRE release 10.43 for Perl compatibility.
 .P
 The other POSIX classes are unchanged by PCRE2_UCP, and match only characters
 with code points less than 256. The effect of PCRE2_UCP on POSIX classes can be

src/pcre2_compile.c

@@ -706,6 +706,7 @@ static const char posix_names[] =
 static const uint8_t posix_name_lengths[] = {
   5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 6, 0 };
 
+#define PC_DIGIT   7
 #define PC_GRAPH   8
 #define PC_PRINT   9
 #define PC_PUNCT  10
@@ -722,20 +723,20 @@ absolute value of the third field has these meanings: 0 => no tweaking, 1 =>
 remove vertical space characters, 2 => remove underscore. */
 
 static const int posix_class_maps[] = {
-  cbit_word,  cbit_digit, -2,             /* alpha */
-  cbit_lower, -1,          0,             /* lower */
-  cbit_upper, -1,          0,             /* upper */
-  cbit_word,  -1,          2,             /* alnum - word without underscore */
-  cbit_print, cbit_cntrl,  0,             /* ascii */
-  cbit_space, -1,          1,             /* blank - a GNU extension */
-  cbit_cntrl, -1,          0,             /* cntrl */
-  cbit_digit, -1,          0,             /* digit */
-  cbit_graph, -1,          0,             /* graph */
-  cbit_print, -1,          0,             /* print */
-  cbit_punct, -1,          0,             /* punct */
-  cbit_space, -1,          0,             /* space */
-  cbit_word,  -1,          0,             /* word - a Perl extension */
-  cbit_xdigit,-1,          0              /* xdigit */
+  cbit_word,   cbit_digit, -2,            /* alpha */
+  cbit_lower,  -1,          0,            /* lower */
+  cbit_upper,  -1,          0,            /* upper */
+  cbit_word,   -1,          2,            /* alnum - word without underscore */
+  cbit_print,  cbit_cntrl,  0,            /* ascii */
+  cbit_space,  -1,          1,            /* blank - a GNU extension */
+  cbit_cntrl,  -1,          0,            /* cntrl */
+  cbit_digit,  -1,          0,            /* digit */
+  cbit_graph,  -1,          0,            /* graph */
+  cbit_print,  -1,          0,            /* print */
+  cbit_punct,  -1,          0,            /* punct */
+  cbit_space,  -1,          0,            /* space */
+  cbit_word,   -1,          0,            /* word - a Perl extension */
+  cbit_xdigit, -1,          0             /* xdigit */
 };
 
 #ifdef SUPPORT_UNICODE
@@ -3676,7 +3677,8 @@ while (ptr < ptrend)
 #ifdef SUPPORT_UNICODE
         if ((options & PCRE2_UCP) != 0 &&
             (xoptions & PCRE2_EXTRA_ASCII_POSIX) == 0 &&
-            !(posix_class == 7 && (xoptions & PCRE2_EXTRA_ASCII_DIGIT) != 0))
+            !((xoptions & PCRE2_EXTRA_ASCII_DIGIT) != 0 &&
+              (posix_class == PC_DIGIT || posix_class == PC_XDIGIT)))
           {
           int ptype = posix_substitutes[2*posix_class];
           int pvalue = posix_substitutes[2*posix_class + 1];

testdata/testinput5

@@ -1234,6 +1234,8 @@
 
 /[[:xdigit:]]/B,ucp
 
+/[[:xdigit:]]/B,ucp,ascii_digit
+
 # Unicode properties for \b and \B
 
 /\b...\B/utf,ucp
@@ -2445,6 +2447,22 @@
 /[[:digit:]]+/utf,ucp,ascii_posix
     123\x{660}456
 
+/^[[:xdigit:]]+$/utf,ucp
+    f0
+    1A
+    d\x{ff10}\=no_jit
+    \x{ff26}8
+\= Expect no match
+    8g\=no_jit
+
+/^[[:xdigit:]]+$/utf,ucp,ascii_digit
+    f0
+    1A
+\= Expect no match
+    d\x{xfff0}
+    \x{ff26}8
+    8g
+
 />[[:space:]]+</utf,ucp
     >\x{a0} \x{a0}<
     >\x{a0}\x{a0}\x{a0}<

testdata/testoutput5

@@ -2583,6 +2583,14 @@ No match
         End
 ------------------------------------------------------------------
 
+/[[:xdigit:]]/B,ucp,ascii_digit
+------------------------------------------------------------------
+        Bra
+        [0-9A-Fa-f]
+        Ket
+        End
+------------------------------------------------------------------
+
 # Unicode properties for \b and \B
 
 /\b...\B/utf,ucp
@@ -5384,6 +5392,32 @@ No match
     123\x{660}456
  0: 123
 
+/^[[:xdigit:]]+$/utf,ucp
+    f0
+ 0: f0
+    1A
+ 0: 1A
+    d\x{ff10}\=no_jit
+ 0: d\x{ff10}
+    \x{ff26}8
+ 0: \x{ff26}8
+\= Expect no match
+    8g\=no_jit
+No match
+
+/^[[:xdigit:]]+$/utf,ucp,ascii_digit
+    f0
+ 0: f0
+    1A
+ 0: 1A
+\= Expect no match
+    d\x{xfff0}
+No match
+    \x{ff26}8
+No match
+    8g
+No match
+
 />[[:space:]]+</utf,ucp
     >\x{a0} \x{a0}<
  0: >\x{a0} \x{a0}<