PCRE2 broke assign and for_windows

[Billli11]

Please fill out the following:

• Sway Version:

broken version
sway version 1.8-dev-f614f35e (Mar 12 2022, branch 'master')

working version
sway version 1.8-dev-04676936 (Mar 12 2022, branch 'master')

installed via arch AUR sway-git

• Debug Log:
  sway.log

• Description:

The latest commit broke assign and for_windows .
The command now do nothing.

sway seem to accept the message but when opening the windows with matching criteria nothing happen.

00:00:40.849 [INFO] [sway/commands.c:258] Handling command 'for_window [title="^xeyes$"] floating enable'
00:00:40.849 [DEBUG] [sway/criteria.c:718] Found pair: title=^xeyes$
00:00:40.849 [DEBUG] [sway/commands/for_window.c:34] for_window: '[title="^xeyes$"]' -> 'floating enable' added
00:00:40.849 [DEBUG] [sway/ipc-server.c:959] Added IPC reply of type 0x0 to client 85 queue: [ { "success": true } ]

here is some of the command tried.

for_window [title="^xeyes$"] floating enable
for_window [title=^xeyes$] floating enable
for_window [title="xeyes"] floating enable
assign [app_id="^com.obsproject.Studio$"] $ws5
assign [class="^discord$"] $ws5

those command is working when built without this commit

[emersion]

cc @ndren, ref #6883

[Scrumplex]

I have written this code to compare pcre and pcre2 (grabbed the respective code from Sway):

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define PCRE2_CODE_UNIT_WIDTH 8
#include <pcre2.h>
#include <pcre.h>

static bool generate_regex(pcre **regex, char *value) {
	const char *reg_err;
	int offset;

	*regex = pcre_compile(value, PCRE_UTF8 | PCRE_UCP, &reg_err, &offset, NULL);

	if (!*regex) {
		printf("Regex compilation for '%s' failed: %s", value, reg_err);
		return false;
	}
    
	return true;
}

static bool generate_regex2(pcre2_code **regex, char *value) {
	int errorcode;
	PCRE2_SIZE offset;

	*regex = pcre2_compile((PCRE2_SPTR)value, PCRE2_ZERO_TERMINATED, PCRE2_UTF | PCRE2_UCP, &errorcode, &offset, NULL);
	if (!*regex) {
		PCRE2_UCHAR buffer[256];
		pcre2_get_error_message(errorcode, buffer, sizeof(buffer));

		printf("Regex compilation for '%s' failed: %s", value, buffer);
		return false;
	}

	return true;
}

static int regex_cmp(const char *item, const pcre *regex) {
	return pcre_exec(regex, NULL, item, strlen(item), 0, 0, NULL, 0);
}

static int regex_cmp2(const char *item, const pcre2_code *regex) {
	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(regex, NULL);
	int result = pcre2_match(regex, (PCRE2_SPTR)item, strlen(item), 0, 0, match_data, NULL);
	pcre2_match_data_free(match_data);
	return result;
}

int main() {
    pcre *regex;

    generate_regex(&regex, "discord");
    int a1 = regex_cmp("discord", regex);

    pcre2_code *regex2;

    generate_regex2(&regex2, "discord");
    int a2 = regex_cmp2("discord", regex2);

    printf("%d %d", a1, a2);
}

$ gcc pcre.c -l pcre -l pcre2-posix -l pcre2-8
$ ./a.out
0 1

[markstos]

Should the PCRE2 merge be backed out until this is resolved?

[Billli11]

Seem like pcre2 will always return value >= 1 if matched.

From pcre2_match man page

The return from pcre2_match() is one more than the highest numbered capturing pair that has been set (for example, 1 if there are no captures), zero if the vector of offsets is too small, or a negative error code for no match and other errors.

And from pcre_exec man page

It returns offsets to captured substrings.

Trying "dis(cor)d" with pcre2 returned 2 instead of 1 and pcre is still returning 0.
And both will return -1 if there are no matching string.

[KogasaPls]

Related, I get "no matching node" when trying to match against marks (e.g. swaymsg [con_mark="test"] kill) even when they exist

[Billli11]

Changing
if (regex_cmp(title, criteria->title->regex) != 0) {
and
if (regex_cmp(con->marks->items[i], criteria->con_mark->regex) == 0) {
to
if (regex_cmp(title, criteria->title->regex) < 0) {
and
if (regex_cmp(con->marks->items[i], criteria->con_mark->regex) >= 0) {
in criteria.c
seem to fixed the problem.

tested with
for_window [title=xeyes] floating enable
assign [title=xeyes] 2
using default config file

Here is the diff

[ErikReider]

@Billli11 Your patch works on my end :)

[emersion]

@Billli11 can you submit a PR?