[RFC/PATCH 5/7] grep: drop support for \0 in --fixed-strings <pattern>

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Change "-f <file>" to not support patterns with "\0" in them under
--fixed-strings, we'll now only support these under --perl-regexp with
PCRE v2.

A previous change to Documentation/git-grep.txt changed the
description of "-f <file>" to be vague enough as to not promise that
this would work, and by dropping support for this we make it a whole
lot easier to move away from the kwset backend, which a subsequent
change will try to do.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 grep.c                         |  6 +--
 t/t7816-grep-binary-pattern.sh | 82 +++++++++++++++++-----------------
 2 files changed, 44 insertions(+), 44 deletions(-)

diff --git a/grep.c b/grep.c
index 261bd3a342..14570c7ac1 100644
--- a/grep.c
+++ b/grep.c
@@ -644,6 +644,9 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 	p->word_regexp = opt->word_regexp;
 	p->ignore_case = opt->ignore_case;
 
+	if (memchr(p->pattern, 0, p->patternlen) && !opt->pcre2)
+		die(_("given pattern contains NULL byte (via -f <file>). This is only supported with -P under PCRE v2"));
+
 	/*
 	 * Even when -F (fixed) asks us to do a non-regexp search, we
 	 * may not be able to correctly case-fold when -i
@@ -666,9 +669,6 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 		return;
 	}
 
-	if (memchr(p->pattern, 0, p->patternlen) && !opt->pcre2)
-		die(_("given pattern contains NULL byte (via -f <file>). This is only supported with -P under PCRE v2"));
-
 	if (opt->fixed) {
 		/*
 		 * We come here when the pattern has the non-ascii
diff --git a/t/t7816-grep-binary-pattern.sh b/t/t7816-grep-binary-pattern.sh
index 9e09bd5d6a..60bab291e4 100755
--- a/t/t7816-grep-binary-pattern.sh
+++ b/t/t7816-grep-binary-pattern.sh
@@ -60,23 +60,23 @@ test_expect_success 'setup' "
 "
 
 # Simple fixed-string matching that can use kwset (no -i && non-ASCII)
-nul_match 1 1 1 '-F' 'yQf'
-nul_match 0 0 0 '-F' 'yQx'
-nul_match 1 1 1 '-Fi' 'YQf'
-nul_match 0 0 0 '-Fi' 'YQx'
-nul_match 1 1 1 '' 'yQf'
-nul_match 0 0 0 '' 'yQx'
-nul_match 1 1 1 '' 'æQð'
-nul_match 1 1 1 '-F' 'eQm[*]c'
-nul_match 1 1 1 '-Fi' 'EQM[*]C'
+nul_match P P P '-F' 'yQf'
+nul_match P P P '-F' 'yQx'
+nul_match P P P '-Fi' 'YQf'
+nul_match P P P '-Fi' 'YQx'
+nul_match P P 1 '' 'yQf'
+nul_match P P 0 '' 'yQx'
+nul_match P P 1 '' 'æQð'
+nul_match P P P '-F' 'eQm[*]c'
+nul_match P P P '-Fi' 'EQM[*]C'
 
 # Regex patterns that would match but shouldn't with -F
-nul_match 0 0 0 '-F' 'yQ[f]'
-nul_match 0 0 0 '-F' '[y]Qf'
-nul_match 0 0 0 '-Fi' 'YQ[F]'
-nul_match 0 0 0 '-Fi' '[Y]QF'
-nul_match 0 0 0 '-F' 'æQ[ð]'
-nul_match 0 0 0 '-F' '[æ]Qð'
+nul_match P P P '-F' 'yQ[f]'
+nul_match P P P '-F' '[y]Qf'
+nul_match P P P '-Fi' 'YQ[F]'
+nul_match P P P '-Fi' '[Y]QF'
+nul_match P P P '-F' 'æQ[ð]'
+nul_match P P P '-F' '[æ]Qð'
 
 # The -F kwset codepath can't handle -i && non-ASCII...
 nul_match P 1 1 '-i' '[æ]Qð'
@@ -90,38 +90,38 @@ nul_match P 0 1 '-i' '[Æ]Qð'
 nul_match P 0 1 '-i' 'ÆQÐ'
 
 # \0 in regexes can only work with -P & PCRE v2
-nul_match P 1 1 '' 'yQ[f]'
-nul_match P 1 1 '' '[y]Qf'
-nul_match P 1 1 '-i' 'YQ[F]'
-nul_match P 1 1 '-i' '[Y]Qf'
-nul_match P 1 1 '' 'æQ[ð]'
-nul_match P 1 1 '' '[æ]Qð'
-nul_match P 0 1 '-i' 'ÆQ[Ð]'
-nul_match P 1 1 '' 'eQm.*cQ'
-nul_match P 1 1 '-i' 'EQM.*cQ'
-nul_match P 0 0 '' 'eQm[*]c'
-nul_match P 0 0 '-i' 'EQM[*]C'
+nul_match P P 1 '' 'yQ[f]'
+nul_match P P 1 '' '[y]Qf'
+nul_match P P 1 '-i' 'YQ[F]'
+nul_match P P 1 '-i' '[Y]Qf'
+nul_match P P 1 '' 'æQ[ð]'
+nul_match P P 1 '' '[æ]Qð'
+nul_match P P 1 '-i' 'ÆQ[Ð]'
+nul_match P P 1 '' 'eQm.*cQ'
+nul_match P P 1 '-i' 'EQM.*cQ'
+nul_match P P 0 '' 'eQm[*]c'
+nul_match P P 0 '-i' 'EQM[*]C'
 
 # Assert that we're using REG_STARTEND and the pattern doesn't match
 # just because it's cut off at the first \0.
-nul_match 0 0 0 '-i' 'NOMATCHQð'
-nul_match P 0 0 '-i' '[Æ]QNOMATCH'
-nul_match P 0 0 '-i' '[æ]QNOMATCH'
+nul_match P P 0 '-i' 'NOMATCHQð'
+nul_match P P 0 '-i' '[Æ]QNOMATCH'
+nul_match P P 0 '-i' '[æ]QNOMATCH'
 
 # Ensure that the matcher doesn't regress to something that stops at
 # \0
-nul_match 0 0 0 '-F' 'yQ[f]'
-nul_match 0 0 0 '-Fi' 'YQ[F]'
-nul_match 0 0 0 '' 'yQNOMATCH'
-nul_match 0 0 0 '' 'QNOMATCH'
-nul_match 0 0 0 '-i' 'YQNOMATCH'
-nul_match 0 0 0 '-i' 'QNOMATCH'
-nul_match 0 0 0 '-F' 'æQ[ð]'
+nul_match P P P '-F' 'yQ[f]'
+nul_match P P P '-Fi' 'YQ[F]'
+nul_match P P 0 '' 'yQNOMATCH'
+nul_match P P 0 '' 'QNOMATCH'
+nul_match P P 0 '-i' 'YQNOMATCH'
+nul_match P P 0 '-i' 'QNOMATCH'
+nul_match P P P '-F' 'æQ[ð]'
 nul_match P P P '-Fi' 'ÆQ[Ð]'
-nul_match P 0 1 '-i' 'ÆQ[Ð]'
-nul_match 0 0 0 '' 'yQNÓMATCH'
-nul_match 0 0 0 '' 'QNÓMATCH'
-nul_match 0 0 0 '-i' 'YQNÓMATCH'
-nul_match 0 0 0 '-i' 'QNÓMATCH'
+nul_match P P 1 '-i' 'ÆQ[Ð]'
+nul_match P P 0 '' 'yQNÓMATCH'
+nul_match P P 0 '' 'QNÓMATCH'
+nul_match P P 0 '-i' 'YQNÓMATCH'
+nul_match P P 0 '-i' 'QNÓMATCH'
 
 test_done
-- 
2.22.0.455.g172b71a6c5