Merge branch 'ab/grep-patterntype'

Some code clean-up in the "git grep" machinery.

* ab/grep-patterntype:
  grep: simplify config parsing and option parsing
  grep.c: do "if (bool && memchr())" not "if (memchr() && bool)"
  grep.h: make "grep_opt.pattern_type_option" use its enum
  grep API: call grep_config() after grep_init()
  grep.c: don't pass along NULL callback value
  built-ins: trust the "prefix" from run_builtin()
  grep tests: add missing "grep.patternType" config tests
  grep tests: create a helper function for "BRE" or "ERE"
  log tests: check if grep_config() is called by "log"-like cmds
  grep.h: remove unused "regex_t regexp" from grep_opt

9 files changed, 195 insertions, 206 deletions

diff --git a/builtin/grep.c b/builtin/grep.c
index 88144f0630..f1a924eade 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -26,6 +26,8 @@
 #include "object-store.h"
 #include "packfile.h"
 
+static const char *grep_prefix;
+
 static char const * const grep_usage[] = {
 	N_("git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...]"),
 	NULL
@@ -284,7 +286,7 @@ static int wait_all(void)
 static int grep_cmd_config(const char *var, const char *value, void *cb)
 {
 	int st = grep_config(var, value, cb);
-	if (git_color_default_config(var, value, cb) < 0)
+	if (git_color_default_config(var, value, NULL) < 0)
 		st = -1;
 
 	if (!strcmp(var, "grep.threads")) {
@@ -315,11 +317,11 @@ static void grep_source_name(struct grep_opt *opt, const char *filename,
 	strbuf_reset(out);
 
 	if (opt->null_following_name) {
-		if (opt->relative && opt->prefix_length) {
+		if (opt->relative && grep_prefix) {
 			struct strbuf rel_buf = STRBUF_INIT;
 			const char *rel_name =
 				relative_path(filename + tree_name_len,
-					      opt->prefix, &rel_buf);
+					      grep_prefix, &rel_buf);
 
 			if (tree_name_len)
 				strbuf_add(out, filename, tree_name_len);
@@ -332,8 +334,8 @@ static void grep_source_name(struct grep_opt *opt, const char *filename,
 		return;
 	}
 
-	if (opt->relative && opt->prefix_length)
-		quote_path(filename + tree_name_len, opt->prefix, out, 0);
+	if (opt->relative && grep_prefix)
+		quote_path(filename + tree_name_len, grep_prefix, out, 0);
 	else
 		quote_c_style(filename + tree_name_len, out, NULL, 0);
 
@@ -843,7 +845,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	int i;
 	int dummy;
 	int use_index = 1;
-	int pattern_type_arg = GREP_PATTERN_TYPE_UNSPECIFIED;
 	int allow_revs;
 
 	struct option options[] = {
@@ -877,16 +878,16 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			N_("descend at most <depth> levels"), PARSE_OPT_NONEG,
 			NULL, 1 },
 		OPT_GROUP(""),
-		OPT_SET_INT('E', "extended-regexp", &pattern_type_arg,
+		OPT_SET_INT('E', "extended-regexp", &opt.pattern_type_option,
 			    N_("use extended POSIX regular expressions"),
 			    GREP_PATTERN_TYPE_ERE),
-		OPT_SET_INT('G', "basic-regexp", &pattern_type_arg,
+		OPT_SET_INT('G', "basic-regexp", &opt.pattern_type_option,
 			    N_("use basic POSIX regular expressions (default)"),
 			    GREP_PATTERN_TYPE_BRE),
-		OPT_SET_INT('F', "fixed-strings", &pattern_type_arg,
+		OPT_SET_INT('F', "fixed-strings", &opt.pattern_type_option,
 			    N_("interpret patterns as fixed strings"),
 			    GREP_PATTERN_TYPE_FIXED),
-		OPT_SET_INT('P', "perl-regexp", &pattern_type_arg,
+		OPT_SET_INT('P', "perl-regexp", &opt.pattern_type_option,
 			    N_("use Perl-compatible regular expressions"),
 			    GREP_PATTERN_TYPE_PCRE),
 		OPT_GROUP(""),
@@ -962,9 +963,10 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			   PARSE_OPT_NOCOMPLETE),
 		OPT_END()
 	};
+	grep_prefix = prefix;
 
-	git_config(grep_cmd_config, NULL);
-	grep_init(&opt, the_repository, prefix);
+	grep_init(&opt, the_repository);
+	git_config(grep_cmd_config, &opt);
 
 	/*
 	 * If there is no -- then the paths must exist in the working
@@ -979,7 +981,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, options, grep_usage,
 			     PARSE_OPT_KEEP_DASHDASH |
 			     PARSE_OPT_STOP_AT_NON_OPTION);
-	grep_commit_pattern_type(pattern_type_arg, &opt);
 
 	if (use_index && !startup_info->have_repository) {
 		int fallback = 0;
diff --git a/builtin/log.c b/builtin/log.c
index 905b234232..c211d66d1d 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -533,8 +533,6 @@ static int git_log_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
-	if (grep_config(var, value, cb) < 0)
-		return -1;
 	if (git_gpg_config(var, value, cb) < 0)
 		return -1;
 	return git_diff_ui_config(var, value, cb);
@@ -549,6 +547,8 @@ int cmd_whatchanged(int argc, const char **argv, const char *prefix)
 	git_config(git_log_config, NULL);
 
 	repo_init_revisions(the_repository, &rev, prefix);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.diff = 1;
 	rev.simplify_history = 0;
 	memset(&opt, 0, sizeof(opt));
@@ -663,6 +663,8 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 
 	memset(&match_all, 0, sizeof(match_all));
 	repo_init_revisions(the_repository, &rev, prefix);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.diff = 1;
 	rev.always_show_header = 1;
 	rev.no_walk = 1;
@@ -746,6 +748,8 @@ int cmd_log_reflog(int argc, const char **argv, const char *prefix)
 
 	repo_init_revisions(the_repository, &rev, prefix);
 	init_reflog_walk(&rev.reflog_info);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.verbose_header = 1;
 	memset(&opt, 0, sizeof(opt));
 	opt.def = "HEAD";
@@ -779,6 +783,8 @@ int cmd_log(int argc, const char **argv, const char *prefix)
 	git_config(git_log_config, NULL);
 
 	repo_init_revisions(the_repository, &rev, prefix);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.always_show_header = 1;
 	memset(&opt, 0, sizeof(opt));
 	opt.def = "HEAD";
@@ -1861,10 +1867,13 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	extra_hdr.strdup_strings = 1;
 	extra_to.strdup_strings = 1;
 	extra_cc.strdup_strings = 1;
+
 	init_log_defaults();
 	init_display_notes(&notes_opt);
 	git_config(git_format_config, NULL);
 	repo_init_revisions(the_repository, &rev, prefix);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.show_notes = show_notes;
 	memcpy(&rev.notes_opt, &notes_opt, sizeof(notes_opt));
 	rev.commit_format = CMIT_FMT_EMAIL;
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index 3a442631c7..6cb554cbb0 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -150,7 +150,7 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 
 	git_config(git_default_config, NULL);
 	ls_tree_prefix = prefix;
-	if (prefix && *prefix)
+	if (prefix)
 		chomp_prefix = strlen(prefix);
 
 	argc = parse_options(argc, argv, prefix, ls_tree_options,
diff --git a/git.c b/git.c
index 340665d4a0..a25940d72e 100644
--- a/git.c
+++ b/git.c
@@ -436,6 +436,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 	} else {
 		prefix = NULL;
 	}
+	assert(!prefix || *prefix);
 	precompose_argv_prefix(argc, argv, NULL);
 	if (use_pager == -1 && run_setup &&
 		!(p->option & DELAY_PAGER_CONFIG))
diff --git a/grep.c b/grep.c
index 5bec7fd793..d5ad9617d9 100644
--- a/grep.c
+++ b/grep.c
@@ -19,27 +19,6 @@ static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 	fwrite(buf, size, 1, stdout);
 }
 
-static struct grep_opt grep_defaults = {
-	.relative = 1,
-	.pathname = 1,
-	.max_depth = -1,
-	.pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED,
-	.colors = {
-		[GREP_COLOR_CONTEXT] = "",
-		[GREP_COLOR_FILENAME] = GIT_COLOR_MAGENTA,
-		[GREP_COLOR_FUNCTION] = "",
-		[GREP_COLOR_LINENO] = GIT_COLOR_GREEN,
-		[GREP_COLOR_COLUMNNO] = GIT_COLOR_GREEN,
-		[GREP_COLOR_MATCH_CONTEXT] = GIT_COLOR_BOLD_RED,
-		[GREP_COLOR_MATCH_SELECTED] = GIT_COLOR_BOLD_RED,
-		[GREP_COLOR_SELECTED] = "",
-		[GREP_COLOR_SEP] = GIT_COLOR_CYAN,
-	},
-	.only_matching = 0,
-	.color = -1,
-	.output = std_output,
-};
-
 static const char *color_grep_slots[] = {
 	[GREP_COLOR_CONTEXT]	    = "context",
 	[GREP_COLOR_FILENAME]	    = "filename",
@@ -75,20 +54,12 @@ define_list_config_array_extra(color_grep_slots, {"match"});
  */
 int grep_config(const char *var, const char *value, void *cb)
 {
-	struct grep_opt *opt = &grep_defaults;
+	struct grep_opt *opt = cb;
 	const char *slot;
 
 	if (userdiff_config(var, value) < 0)
 		return -1;
 
-	/*
-	 * The instance of grep_opt that we set up here is copied by
-	 * grep_init() to be used by each individual invocation.
-	 * When populating a new field of this structure here, be
-	 * sure to think about ownership -- e.g., you might need to
-	 * override the shallow copy in grep_init() with a deep copy.
-	 */
-
 	if (!strcmp(var, "grep.extendedregexp")) {
 		opt->extended_regexp_option = git_config_bool(var, value);
 		return 0;
@@ -134,78 +105,16 @@ int grep_config(const char *var, const char *value, void *cb)
 	return 0;
 }
 
-/*
- * Initialize one instance of grep_opt and copy the
- * default values from the template we read the configuration
- * information in an earlier call to git_config(grep_config).
- */
-void grep_init(struct grep_opt *opt, struct repository *repo, const char *prefix)
+void grep_init(struct grep_opt *opt, struct repository *repo)
 {
-	*opt = grep_defaults;
+	struct grep_opt blank = GREP_OPT_INIT;
+	memcpy(opt, &blank, sizeof(*opt));
 
 	opt->repo = repo;
-	opt->prefix = prefix;
-	opt->prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 	opt->pattern_tail = &opt->pattern_list;
 	opt->header_tail = &opt->header_list;
 }
 
-static void grep_set_pattern_type_option(enum grep_pattern_type pattern_type, struct grep_opt *opt)
-{
-	/*
-	 * When committing to the pattern type by setting the relevant
-	 * fields in grep_opt it's generally not necessary to zero out
-	 * the fields we're not choosing, since they won't have been
-	 * set by anything. The extended_regexp_option field is the
-	 * only exception to this.
-	 *
-	 * This is because in the process of parsing grep.patternType
-	 * & grep.extendedRegexp we set opt->pattern_type_option and
-	 * opt->extended_regexp_option, respectively. We then
-	 * internally use opt->extended_regexp_option to see if we're
-	 * compiling an ERE. It must be unset if that's not actually
-	 * the case.
-	 */
-	if (pattern_type != GREP_PATTERN_TYPE_ERE &&
-	    opt->extended_regexp_option)
-		opt->extended_regexp_option = 0;
-
-	switch (pattern_type) {
-	case GREP_PATTERN_TYPE_UNSPECIFIED:
-		/* fall through */
-
-	case GREP_PATTERN_TYPE_BRE:
-		break;
-
-	case GREP_PATTERN_TYPE_ERE:
-		opt->extended_regexp_option = 1;
-		break;
-
-	case GREP_PATTERN_TYPE_FIXED:
-		opt->fixed = 1;
-		break;
-
-	case GREP_PATTERN_TYPE_PCRE:
-		opt->pcre2 = 1;
-		break;
-	}
-}
-
-void grep_commit_pattern_type(enum grep_pattern_type pattern_type, struct grep_opt *opt)
-{
-	if (pattern_type != GREP_PATTERN_TYPE_UNSPECIFIED)
-		grep_set_pattern_type_option(pattern_type, opt);
-	else if (opt->pattern_type_option != GREP_PATTERN_TYPE_UNSPECIFIED)
-		grep_set_pattern_type_option(opt->pattern_type_option, opt);
-	else if (opt->extended_regexp_option)
-		/*
-		 * This branch *must* happen after setting from the
-		 * opt->pattern_type_option above, we don't want
-		 * grep.extendedRegexp to override grep.patternType!
-		 */
-		grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, opt);
-}
-
 static struct grep_pat *create_grep_pat(const char *pat, size_t patlen,
 					const char *origin, int no,
 					enum grep_pat_token t,
@@ -523,11 +432,17 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 	int err;
 	int regflags = REG_NEWLINE;
 
+	if (opt->pattern_type_option == GREP_PATTERN_TYPE_UNSPECIFIED)
+		opt->pattern_type_option = (opt->extended_regexp_option
+					    ? GREP_PATTERN_TYPE_ERE
+					    : GREP_PATTERN_TYPE_BRE);
+
 	p->word_regexp = opt->word_regexp;
 	p->ignore_case = opt->ignore_case;
-	p->fixed = opt->fixed;
+	p->fixed = opt->pattern_type_option == GREP_PATTERN_TYPE_FIXED;
 
-	if (memchr(p->pattern, 0, p->patternlen) && !opt->pcre2)
+	if (opt->pattern_type_option != GREP_PATTERN_TYPE_PCRE &&
+	    memchr(p->pattern, 0, p->patternlen))
 		die(_("given pattern contains NULL byte (via -f <file>). This is only supported with -P under PCRE v2"));
 
 	p->is_fixed = is_fixed(p->pattern, p->patternlen);
@@ -578,14 +493,14 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 		return;
 	}
 
-	if (opt->pcre2) {
+	if (opt->pattern_type_option == GREP_PATTERN_TYPE_PCRE) {
 		compile_pcre2_pattern(p, opt);
 		return;
 	}
 
 	if (p->ignore_case)
 		regflags |= REG_ICASE;
-	if (opt->extended_regexp_option)
+	if (opt->pattern_type_option == GREP_PATTERN_TYPE_ERE)
 		regflags |= REG_EXTENDED;
 	err = regcomp(&p->regexp, p->pattern, regflags);
 	if (err) {
diff --git a/grep.h b/grep.h
index 6a1f0ab017..c722d25ed9 100644
--- a/grep.h
+++ b/grep.h
@@ -134,9 +134,6 @@ struct grep_opt {
 	 */
 	struct repository *repo;
 
-	const char *prefix;
-	int prefix_length;
-	regex_t regexp;
 	int linenum;
 	int columnnum;
 	int invert;
@@ -146,7 +143,6 @@ struct grep_opt {
 	int unmatch_name_only;
 	int count;
 	int word_regexp;
-	int fixed;
 	int all_match;
 	int no_body_match;
 	int body_hit;
@@ -157,7 +153,6 @@ struct grep_opt {
 	int allow_textconv;
 	int extended;
 	int use_reflog_filter;
-	int pcre2;
 	int relative;
 	int pathname;
 	int null_following_name;
@@ -167,7 +162,7 @@ struct grep_opt {
 	int funcname;
 	int funcbody;
 	int extended_regexp_option;
-	int pattern_type_option;
+	enum grep_pattern_type pattern_type_option;
 	int ignore_locale;
 	char colors[NR_GREP_COLORS][COLOR_MAXLEN];
 	unsigned pre_context;
@@ -182,9 +177,29 @@ struct grep_opt {
 	void *output_priv;
 };
 
+#define GREP_OPT_INIT { \
+	.relative = 1, \
+	.pathname = 1, \
+	.max_depth = -1, \
+	.pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED, \
+	.colors = { \
+		[GREP_COLOR_CONTEXT] = "", \
+		[GREP_COLOR_FILENAME] = GIT_COLOR_MAGENTA, \
+		[GREP_COLOR_FUNCTION] = "", \
+		[GREP_COLOR_LINENO] = GIT_COLOR_GREEN, \
+		[GREP_COLOR_COLUMNNO] = GIT_COLOR_GREEN, \
+		[GREP_COLOR_MATCH_CONTEXT] = GIT_COLOR_BOLD_RED, \
+		[GREP_COLOR_MATCH_SELECTED] = GIT_COLOR_BOLD_RED, \
+		[GREP_COLOR_SELECTED] = "", \
+		[GREP_COLOR_SEP] = GIT_COLOR_CYAN, \
+	}, \
+	.only_matching = 0, \
+	.color = -1, \
+	.output = std_output, \
+}
+
 int grep_config(const char *var, const char *value, void *);
-void grep_init(struct grep_opt *, struct repository *repo, const char *prefix);
-void grep_commit_pattern_type(enum grep_pattern_type, struct grep_opt *opt);
+void grep_init(struct grep_opt *, struct repository *repo);
 
 void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen, const char *origin, int no, enum grep_pat_token t);
 void append_grep_pattern(struct grep_opt *opt, const char *pat, const char *origin, int no, enum grep_pat_token t);
diff --git a/revision.c b/revision.c
index 4c55c55880..2bb913f2f3 100644
--- a/revision.c
+++ b/revision.c
@@ -1846,7 +1846,7 @@ void repo_init_revisions(struct repository *r,
 	revs->commit_format = CMIT_FMT_DEFAULT;
 	revs->expand_tabs_in_log_default = 8;
 
-	grep_init(&revs->grep_filter, revs->repo, prefix);
+	grep_init(&revs->grep_filter, revs->repo);
 	revs->grep_filter.status_only = 1;
 
 	repo_diff_setup(revs->repo, &revs->diffopt);
@@ -2882,8 +2882,6 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 
 	diff_setup_done(&revs->diffopt);
 
-	grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
-				 &revs->grep_filter);
 	if (!is_encoding_utf8(get_log_output_encoding()))
 		revs->grep_filter.ignore_locale = 1;
 	compile_grep_patterns(&revs->grep_filter);
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 544f0aa82e..55fac64446 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -462,6 +462,30 @@ test_expect_success !FAIL_PREREQS 'log with various grep.patternType configurati
 	)
 '
 
+for cmd in show whatchanged reflog format-patch
+do
+	case "$cmd" in
+	format-patch) myarg="HEAD~.." ;;
+	*) myarg= ;;
+	esac
+
+	test_expect_success "$cmd: understands grep.patternType, like 'log'" '
+		git init "pattern-type-$cmd" &&
+		(
+			cd "pattern-type-$cmd" &&
+			test_commit 1 file A &&
+			test_commit "(1|2)" file B 2 &&
+
+			git -c grep.patternType=fixed $cmd --grep="..." $myarg >actual &&
+			test_must_be_empty actual &&
+
+			git -c grep.patternType=basic $cmd --grep="..." $myarg >actual &&
+			test_file_not_empty actual
+		)
+	'
+done
+test_done
+
 test_expect_success 'log --author' '
 	cat >expect <<-\EOF &&
 	Author: <BOLD;RED>A U<RESET> Thor <author@example.com>
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 424c31c328..6935601171 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -98,6 +98,37 @@ test_expect_success 'grep should not segfault with a bad input' '
 
 test_invalid_grep_expression --and -e A
 
+test_pattern_type () {
+	H=$1 &&
+	HC=$2 &&
+	L=$3 &&
+	type=$4 &&
+	shift 4 &&
+
+	expected_str= &&
+	case "$type" in
+	BRE)
+		expected_str="${HC}ab:a+bc"
+		;;
+	ERE)
+		expected_str="${HC}ab:abc"
+		;;
+	FIX)
+		expected_str="${HC}ab:a+b*c"
+		;;
+	*)
+		BUG "unknown pattern type '$type'"
+		;;
+	esac &&
+	config_str="$@" &&
+
+	test_expect_success "grep $L with '$config_str' interpreted as $type" '
+		echo $expected_str >expected &&
+		git $config_str grep "a+b*c" $H ab >actual &&
+		test_cmp expected actual
+	'
+}
+
 for H in HEAD ''
 do
 	case "$H" in
@@ -393,35 +424,13 @@ do
 		git grep --no-recursive -n -e vvv $H -- t . >actual &&
 		test_cmp expected actual
 	'
-	test_expect_success "grep $L with grep.extendedRegexp=false" '
-		echo "${HC}ab:a+bc" >expected &&
-		git -c grep.extendedRegexp=false grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
 
-	test_expect_success "grep $L with grep.extendedRegexp=true" '
-		echo "${HC}ab:abc" >expected &&
-		git -c grep.extendedRegexp=true grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
 
-	test_expect_success "grep $L with grep.patterntype=basic" '
-		echo "${HC}ab:a+bc" >expected &&
-		git -c grep.patterntype=basic grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
-
-	test_expect_success "grep $L with grep.patterntype=extended" '
-		echo "${HC}ab:abc" >expected &&
-		git -c grep.patterntype=extended grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
-
-	test_expect_success "grep $L with grep.patterntype=fixed" '
-		echo "${HC}ab:a+b*c" >expected &&
-		git -c grep.patterntype=fixed grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
+	test_pattern_type "$H" "$HC" "$L" BRE -c grep.extendedRegexp=false
+	test_pattern_type "$H" "$HC" "$L" ERE -c grep.extendedRegexp=true
+	test_pattern_type "$H" "$HC" "$L" BRE -c grep.patternType=basic
+	test_pattern_type "$H" "$HC" "$L" ERE -c grep.patternType=extended
+	test_pattern_type "$H" "$HC" "$L" FIX -c grep.patternType=fixed
 
 	test_expect_success PCRE "grep $L with grep.patterntype=perl" '
 		echo "${HC}ab:a+b*c" >expected &&
@@ -433,59 +442,76 @@ do
 		test_must_fail git -c grep.patterntype=perl grep "foo.*bar"
 	'
 
-	test_expect_success "grep $L with grep.patternType=default and grep.extendedRegexp=true" '
-		echo "${HC}ab:abc" >expected &&
-		git \
-			-c grep.patternType=default \
-			-c grep.extendedRegexp=true \
-			grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
-
-	test_expect_success "grep $L with grep.extendedRegexp=true and grep.patternType=default" '
-		echo "${HC}ab:abc" >expected &&
-		git \
-			-c grep.extendedRegexp=true \
-			-c grep.patternType=default \
-			grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
-
-	test_expect_success "grep $L with grep.patternType=extended and grep.extendedRegexp=false" '
-		echo "${HC}ab:abc" >expected &&
-		git \
-			-c grep.patternType=extended \
-			-c grep.extendedRegexp=false \
-			grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
-
-	test_expect_success "grep $L with grep.patternType=basic and grep.extendedRegexp=true" '
-		echo "${HC}ab:a+bc" >expected &&
-		git \
-			-c grep.patternType=basic \
-			-c grep.extendedRegexp=true \
-			grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
-
-	test_expect_success "grep $L with grep.extendedRegexp=false and grep.patternType=extended" '
-		echo "${HC}ab:abc" >expected &&
-		git \
-			-c grep.extendedRegexp=false \
-			-c grep.patternType=extended \
-			grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
-
-	test_expect_success "grep $L with grep.extendedRegexp=true and grep.patternType=basic" '
-		echo "${HC}ab:a+bc" >expected &&
-		git \
-			-c grep.extendedRegexp=true \
-			-c grep.patternType=basic \
-			grep "a+b*c" $H ab >actual &&
-		test_cmp expected actual
-	'
+	test_pattern_type "$H" "$HC" "$L" ERE \
+		-c grep.patternType=default \
+		-c grep.extendedRegexp=true
+	test_pattern_type "$H" "$HC" "$L" ERE \
+		-c grep.extendedRegexp=true \
+		-c grep.patternType=default
+	test_pattern_type "$H" "$HC" "$L" ERE \
+		-c grep.patternType=extended \
+		-c grep.extendedRegexp=false
+	test_pattern_type "$H" "$HC" "$L" BRE \
+		-c grep.patternType=basic \
+		-c grep.extendedRegexp=true
+	test_pattern_type "$H" "$HC" "$L" ERE \
+		-c grep.extendedRegexp=false \
+		-c grep.patternType=extended
+	test_pattern_type "$H" "$HC" "$L" BRE \
+		-c grep.extendedRegexp=true \
+		-c grep.patternType=basic
+
+	# grep.extendedRegexp is last-one-wins
+	test_pattern_type "$H" "$HC" "$L" BRE \
+		-c grep.extendedRegexp=true \
+		-c grep.extendedRegexp=false
+
+	# grep.patternType=basic pays no attention to grep.extendedRegexp
+	test_pattern_type "$H" "$HC" "$L" BRE \
+		-c grep.extendedRegexp=true \
+		-c grep.patternType=basic \
+		-c grep.extendedRegexp=false
+
+	# grep.patternType=extended pays no attention to grep.extendedRegexp
+	test_pattern_type "$H" "$HC" "$L" ERE \
+		-c grep.extendedRegexp=true \
+		-c grep.patternType=extended \
+		-c grep.extendedRegexp=false
+
+	# grep.extendedRegexp is used with a last-one-wins grep.patternType=default
+	test_pattern_type "$H" "$HC" "$L" ERE \
+		-c grep.patternType=fixed \
+		-c grep.extendedRegexp=true \
+		-c grep.patternType=default
+
+	# grep.extendedRegexp is used with earlier grep.patternType=default
+	test_pattern_type "$H" "$HC" "$L" ERE \
+		-c grep.extendedRegexp=false \
+		-c grep.patternType=default \
+		-c grep.extendedRegexp=true
+
+	# grep.extendedRegexp is used with a last-one-loses grep.patternType=default
+	test_pattern_type "$H" "$HC" "$L" ERE \
+		-c grep.extendedRegexp=false \
+		-c grep.extendedRegexp=true \
+		-c grep.patternType=default
+
+	# grep.extendedRegexp and grep.patternType are both last-one-wins independently
+	test_pattern_type "$H" "$HC" "$L" BRE \
+		-c grep.patternType=default \
+		-c grep.extendedRegexp=true \
+		-c grep.patternType=basic
+
+	# grep.patternType=extended and grep.patternType=default
+	test_pattern_type "$H" "$HC" "$L" BRE \
+		-c grep.patternType=extended \
+		-c grep.patternType=default
+
+	# grep.patternType=[extended -> default -> fixed] (BRE)" '
+	test_pattern_type "$H" "$HC" "$L" FIX \
+		-c grep.patternType=extended \
+		-c grep.patternType=default \
+		-c grep.patternType=fixed
 
 	test_expect_success "grep --count $L" '
 		echo ${HC}ab:3 >expected &&