regex: bugfix for #18363, [^\s]+ act different from \S+ (#18371)

Author: penguindark

vlib/regex/regex.v

@@ -2202,6 +2202,77 @@ pub fn (mut re RE) match_base(in_txt &u8, in_txt_len int) (int, int) {
 			}
 			// char class IST
 			else if ist == regex.ist_char_class_pos || ist == regex.ist_char_class_neg {
+				// check next token to be false
+				mut next_check_flag := false
+
+				// if we are done with max go on dot char are dedicated case!!
+				if re.prog[state.pc].rep >= re.prog[state.pc].rep_max {
+					re.state_list.pop()
+					m_state = .ist_next
+					continue
+				}
+
+				if re.prog[state.pc].last_dot_flag == false && re.prog[state.pc].cc_check_pc >= 0
+					&& re.prog[state.pc].rep >= re.prog[state.pc].rep_min {
+					// load the char
+					// ch_t, _ := re.get_charb(in_txt, state.i+char_len)
+					ch_t := ch
+					chk_pc := re.prog[state.pc].cc_check_pc
+
+					// simple char
+					if re.prog[chk_pc].ist == regex.ist_simple_char {
+						if re.prog[chk_pc].ch == ch_t {
+							next_check_flag = true
+						}
+						// println("Check [ist_simple_char] [${re.prog[chk_pc].ch}]==[${ch_t:c}] => $next_check_flag")
+					}
+					// char char_class
+					else if re.prog[chk_pc].ist == regex.ist_char_class_pos
+						|| re.prog[chk_pc].ist == regex.ist_char_class_neg {
+						mut cc_neg := false
+						if re.prog[chk_pc].ist == regex.ist_char_class_neg {
+							cc_neg = true
+						}
+						mut cc_res := re.check_char_class(chk_pc, ch_t)
+
+						if cc_neg {
+							cc_res = !cc_res
+						}
+						next_check_flag = cc_res
+						// println("Check [ist_char_class] => $next_check_flag")
+					}
+					// check bsls
+					else if re.prog[chk_pc].ist == regex.ist_bsls_char {
+						next_check_flag = re.prog[chk_pc].validator(u8(ch_t))
+						// println("Check [ist_bsls_char] => $next_check_flag")
+					}
+				}
+
+				// check if we must continue or pass to the next IST
+				if next_check_flag == true && re.prog[state.pc + 1].ist != regex.ist_prog_end {
+					// println("save the state!!")
+					mut dot_state := StateObj{
+						group_index: state.group_index
+						match_flag: state.match_flag
+						match_index: state.match_index
+						first_match: state.first_match
+						pc: state.pc
+						i: state.i + char_len
+						char_len: char_len
+						last_dot_pc: state.pc
+					}
+					// if we are managing a \[something]* stay on the same char on return
+					if re.prog[state.pc].rep_min == 0 {
+						dot_state.i -= char_len
+					}
+
+					re.state_list << dot_state
+
+					m_state = .ist_quant_n
+					// println("dot_char stack len: ${re.state_list.len}")
+					continue
+				}
+
 				state.match_flag = false
 				mut cc_neg := false
 

vlib/regex/regex_test.v

@@ -105,7 +105,6 @@ match_test_suite = [
 	TestItem{"this cpapaz adce aabe third",r"(c(pa)+z)(\s[\a]+){2}$",-1,0},
 	TestItem{"1234this cpapaz adce aabe ter",r"(c(pa)+z)(\s[\a]+){2}$",-1,0},
 	TestItem{"cpapaz ole. pipipo,",r"^.*c.+ol?e.*p([ip])+o$",-1,0},
-	TestItem{"/home/us_er/pippo/info-01.jpeg", r"(/?[-\w_]+)*\.txt$",-1,26}
 
 	// check unicode
 	TestItem{"this is a Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Ⅵ test",r".*a [Ⅰ-Ⅵ ]+",0,34},
@@ -174,6 +173,14 @@ match_test_suite = [
     TestItem{"refs/remotes/origin/master", r"refs/remotes/origin/(.*)",0,26},
     TestItem{"refs/remotes/origin/mastep", r"refs/remotes/origin/(\w*)",0,26},
     TestItem{"refs/remotes/origin/master", r"refs/remotes/origin/(\w*)",0,26},
+
+    // test \S+ vs [^\s]+
+    TestItem{"ab.c", r"\S+\.",0,3},
+    TestItem{"ab.c", r"[^\s]+\.",0,3},
+    TestItem{"ab.c", r"\S*\.",0,3},
+    TestItem{"ab.c", r"[^\s]*\.",0,3},
+    TestItem{"ab c", r"[\S]+\s",0,3},
+    TestItem{"ab c", r"[^\s]+\s",0,3},
 ]
 )