grep/pcre2: better support invalid UTF-8 haystacks

Improve the support for invalid UTF-8 haystacks given a non-ASCII
needle when using the PCREv2 backend.

This is a more complete fix for a bug I started to fix in
870eea8166 (grep: do not enter PCRE2_UTF mode on fixed matching,
2019-07-26), now that PCREv2 has the PCRE2_MATCH_INVALID_UTF mode we
can make use of it.

This fixes the sort of case described in 8a5999838e (grep: stess test
PCRE v2 on invalid UTF-8 data, 2019-07-26), i.e.:

    - The subject string is non-ASCII (e.g. "ævar")
    - We're under a is_utf8_locale(), e.g. "en_US.UTF-8", not "C"
    - We are using --ignore-case, or we're a non-fixed pattern

If those conditions were satisfied and we matched found non-valid
UTF-8 data PCREv2 might bark on it, in practice this only happened
under the JIT backend (turned on by default on most platforms).

Ultimately this fixes a "regression" in b65abcafc7 ("grep: use PCRE v2
for optimized fixed-string search", 2019-07-01), I'm putting that in
scare-quotes because before then we wouldn't properly support these
complex case-folding, locale etc. cases either, it just broke in
different ways.

There was a bug related to this the PCRE2_NO_START_OPTIMIZE flag fixed
in PCREv2 10.36. It can be worked around by setting the
PCRE2_NO_START_OPTIMIZE flag. Let's do that in those cases, and add
tests for the bug.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Makefile b/Makefile
index 4edfda3e009d5b124d06de1ff59d277f250e8bf2..42a7ed96e2778a453347738cb12c92f046903020 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -722,6 +722,7 @@ TEST_BUILTINS_OBJS += test-online-cpus.o
 TEST_BUILTINS_OBJS += test-parse-options.o
 TEST_BUILTINS_OBJS += test-parse-pathspec-file.o
 TEST_BUILTINS_OBJS += test-path-utils.o
+TEST_BUILTINS_OBJS += test-pcre2-config.o
 TEST_BUILTINS_OBJS += test-pkt-line.o
 TEST_BUILTINS_OBJS += test-prio-queue.o
 TEST_BUILTINS_OBJS += test-proc-receive.o

diff --git a/grep.c b/grep.c
index efeb6dc58dbec7dad4ea715909d92780faa27ee0..ad0af66a260cef6785fba53e8e76fd8c9439f9ae 100644 (file)
--- a/grep.c
+++ b/grep.c
@@ -492,7 +492,23 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
        }
        if (!opt->ignore_locale && is_utf8_locale() && has_non_ascii(p->pattern) &&
            !(!opt->ignore_case && (p->fixed || p->is_fixed)))
-               options |= PCRE2_UTF;
+               options |= (PCRE2_UTF | PCRE2_MATCH_INVALID_UTF);
+
+       /* Work around https://bugs.exim.org/show_bug.cgi?id=2642 fixed in 10.36 */
+       if (PCRE2_MATCH_INVALID_UTF && options & (PCRE2_UTF | PCRE2_CASELESS)) {
+               struct strbuf buf;
+               int len;
+               int err;
+
+               if ((len = pcre2_config(PCRE2_CONFIG_VERSION, NULL)) < 0)
+                       BUG("pcre2_config(..., NULL) failed: %d", len);
+               strbuf_init(&buf, len + 1);
+               if ((err = pcre2_config(PCRE2_CONFIG_VERSION, buf.buf)) < 0)
+                       BUG("pcre2_config(..., buf.buf) failed: %d", err);
+               if (versioncmp(buf.buf, "10.36") < 0)
+                       options |= PCRE2_NO_START_OPTIMIZE;
+               strbuf_release(&buf);
+       }
 
        p->pcre2_pattern = pcre2_compile((PCRE2_SPTR)p->pattern,
                                         p->patternlen, options, &error, &erroffset,

diff --git a/grep.h b/grep.h
index b5c4e223a8f337fb476b5e375685045189389e82..ade21c8812b04d6e08853dd1940c5ea5ded43fef 100644 (file)
--- a/grep.h
+++ b/grep.h
@@ -18,6 +18,10 @@ typedef int pcre2_code;
 typedef int pcre2_match_data;
 typedef int pcre2_compile_context;
 #endif
+#ifndef PCRE2_MATCH_INVALID_UTF
+/* PCRE2_MATCH_* dummy also with !USE_LIBPCRE2, for test-pcre2-config.c */
+#define PCRE2_MATCH_INVALID_UTF 0
+#endif
 #include "thread-utils.h"
 #include "userdiff.h"
 

diff --git a/t/helper/test-pcre2-config.c b/t/helper/test-pcre2-config.c
new file mode 100644 (file)
index 0000000..5258fdd
--- /dev/null
+++ b/t/helper/test-pcre2-config.c
@@ -0,0 +1,12 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "grep.h"
+
+int cmd__pcre2_config(int argc, const char **argv)
+{
+       if (argc == 2 && !strcmp(argv[1], "has-PCRE2_MATCH_INVALID_UTF")) {
+               int value = PCRE2_MATCH_INVALID_UTF;
+               return !value;
+       }
+       return 1;
+}

diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 9d6d14d92937533e84bb30fc689750cceb1180b1..f97cd9f48a69048db519ffc0519a99559f543b31 100644 (file)
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -46,6 +46,7 @@ static struct test_cmd cmds[] = {
        { "parse-options", cmd__parse_options },
        { "parse-pathspec-file", cmd__parse_pathspec_file },
        { "path-utils", cmd__path_utils },
+       { "pcre2-config", cmd__pcre2_config },
        { "pkt-line", cmd__pkt_line },
        { "prio-queue", cmd__prio_queue },
        { "proc-receive", cmd__proc_receive},

diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index a6470ff62c42521d3ba16e505d37b31b53554925..28072c0ad5ab446eab4b37d915222b6768dc2e66 100644 (file)
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -35,6 +35,7 @@ int cmd__online_cpus(int argc, const char **argv);
 int cmd__parse_options(int argc, const char **argv);
 int cmd__parse_pathspec_file(int argc, const char** argv);
 int cmd__path_utils(int argc, const char **argv);
+int cmd__pcre2_config(int argc, const char **argv);
 int cmd__pkt_line(int argc, const char **argv);
 int cmd__prio_queue(int argc, const char **argv);
 int cmd__proc_receive(int argc, const char **argv);

diff --git a/t/t7812-grep-icase-non-ascii.sh b/t/t7812-grep-icase-non-ascii.sh
index 38457c2e4f10eb43829ee9524101c5f87eaf4c36..e5d1e4ea6862694b0392415807d37ef4d3efc71b 100755 (executable)
--- a/t/t7812-grep-icase-non-ascii.sh
+++ b/t/t7812-grep-icase-non-ascii.sh
@@ -57,7 +57,12 @@ test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: setup invalid UTF-8 data'
        printf "\\200\\n" >invalid-0x80 &&
        echo "ævar" >expected &&
        cat expected >>invalid-0x80 &&
-       git add invalid-0x80
+       git add invalid-0x80 &&
+
+       # Test for PCRE2_MATCH_INVALID_UTF bug
+       # https://bugs.exim.org/show_bug.cgi?id=2642
+       printf "\\345Aæ\\n" >invalid-0xe5 &&
+       git add invalid-0xe5
 '
 
 test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep ASCII from invalid UTF-8 data' '
@@ -67,6 +72,13 @@ test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep ASCII from invalid UT
        test_cmp expected actual
 '
 
+test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep ASCII from invalid UTF-8 data (PCRE2 bug #2642)' '
+       git grep -h "Aæ" invalid-0xe5 >actual &&
+       test_cmp invalid-0xe5 actual &&
+       git grep -h "(*NO_JIT)Aæ" invalid-0xe5 >actual &&
+       test_cmp invalid-0xe5 actual
+'
+
 test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep non-ASCII from invalid UTF-8 data' '
        git grep -h "æ" invalid-0x80 >actual &&
        test_cmp expected actual &&
@@ -74,9 +86,41 @@ test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep non-ASCII from invali
        test_cmp expected actual
 '
 
+test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep non-ASCII from invalid UTF-8 data (PCRE2 bug #2642)' '
+       git grep -h "Aæ" invalid-0xe5 >actual &&
+       test_cmp invalid-0xe5 actual &&
+       git grep -h "(*NO_JIT)Aæ" invalid-0xe5 >actual &&
+       test_cmp invalid-0xe5 actual
+'
+
+test_lazy_prereq PCRE2_MATCH_INVALID_UTF '
+       test-tool pcre2-config has-PCRE2_MATCH_INVALID_UTF
+'
+
 test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep non-ASCII from invalid UTF-8 data with -i' '
        test_might_fail git grep -hi "Æ" invalid-0x80 >actual &&
        test_might_fail git grep -hi "(*NO_JIT)Æ" invalid-0x80 >actual
 '
 
+test_expect_success GETTEXT_LOCALE,LIBPCRE2,PCRE2_MATCH_INVALID_UTF 'PCRE v2: grep non-ASCII from invalid UTF-8 data with -i' '
+       git grep -hi "Æ" invalid-0x80 >actual &&
+       test_cmp expected actual &&
+       git grep -hi "(*NO_JIT)Æ" invalid-0x80 >actual &&
+       test_cmp expected actual
+'
+
+test_expect_success GETTEXT_LOCALE,LIBPCRE2,PCRE2_MATCH_INVALID_UTF 'PCRE v2: grep non-ASCII from invalid UTF-8 data with -i (PCRE2 bug #2642)' '
+       git grep -hi "Æ" invalid-0xe5 >actual &&
+       test_cmp invalid-0xe5 actual &&
+       git grep -hi "(*NO_JIT)Æ" invalid-0xe5 >actual &&
+       test_cmp invalid-0xe5 actual &&
+
+       # Only the case of grepping the ASCII part in a way that
+       # relies on -i fails
+       git grep -hi "aÆ" invalid-0xe5 >actual &&
+       test_cmp invalid-0xe5 actual &&
+       git grep -hi "(*NO_JIT)aÆ" invalid-0xe5 >actual &&
+       test_cmp invalid-0xe5 actual
+'
+
 test_done