help: move list_config_help to builtin/help

Starting in 3ac68a93fd2, help.o began to depend on builtin/branch.o,
builtin/clean.o, and builtin/config.o. This meant that help.o was
unusable outside of the context of the main Git executable.

To make help.o usable by other commands again, move list_config_help()
into builtin/help.c (where it makes sense to assume other builtin libraries
are present).

When command-list.h is included but a member is not used, we start to
hear a compiler warning. Since the config list is generated in a fairly
different way than the command list, and since commands and config
options are semantically different, move the config list into its own
header and move the generator into its own script and build rule.

For reasons explained in 976aaedc (msvc: add a Makefile target to
pre-generate the Visual Studio solution, 2019-07-29), some build
artifacts we consider non-source files cannot be generated in the
Visual Studio environment, and we already have some Makefile tweaks
to help Visual Studio to use generated command-list.h header file.
Do the same to a new generated file, config-list.h, introduced by
this change.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>

9 files changed, 123 insertions, 113 deletions

diff --git a/.gitignore b/.gitignore
index aebe7c0908..ea97de83f3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -189,6 +189,7 @@
 /gitweb/gitweb.cgi
 /gitweb/static/gitweb.js
 /gitweb/static/gitweb.min.*
+/config-list.h
 /command-list.h
 *.tar.gz
 *.dsc
diff --git a/Makefile b/Makefile
index 09f98b777c..5a022367d4 100644
--- a/Makefile
+++ b/Makefile
@@ -814,6 +814,7 @@ LIB_FILE = libgit.a
 XDIFF_LIB = xdiff/lib.a
 VCSSVN_LIB = vcs-svn/lib.a
 
+GENERATED_H += config-list.h
 GENERATED_H += command-list.h
 
 LIB_H := $(sort $(patsubst ./%,%,$(shell git ls-files '*.h' ':!t/' ':!Documentation/' 2>/dev/null || \
@@ -2128,7 +2129,7 @@ git$X: git.o GIT-LDFLAGS $(BUILTIN_OBJS) $(GITLIBS)
 
 help.sp help.s help.o: command-list.h
 
-builtin/help.sp builtin/help.s builtin/help.o: command-list.h GIT-PREFIX
+builtin/help.sp builtin/help.s builtin/help.o: config-list.h GIT-PREFIX
 builtin/help.sp builtin/help.s builtin/help.o: EXTRA_CPPFLAGS = \
 	'-DGIT_HTML_PATH="$(htmldir_relative_SQ)"' \
 	'-DGIT_MAN_PATH="$(mandir_relative_SQ)"' \
@@ -2148,6 +2149,12 @@ $(BUILT_INS): git$X
 	ln -s $< $@ 2>/dev/null || \
 	cp $< $@
 
+config-list.h: generate-configlist.sh
+
+config-list.h:
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-configlist.sh \
+		>$@+ && mv $@+ $@
+
 command-list.h: generate-cmdlist.sh command-list.txt
 
 command-list.h: $(wildcard Documentation/git*.txt) Documentation/*config.txt Documentation/config/*.txt
@@ -2781,7 +2788,7 @@ $(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
 .PHONY: sparse $(SP_OBJ)
 sparse: $(SP_OBJ)
 
-EXCEPT_HDRS := command-list.h unicode-width.h compat/% xdiff/%
+EXCEPT_HDRS := command-list.h config-list.h unicode-width.h compat/% xdiff/%
 ifndef GCRYPT_SHA256
 	EXCEPT_HDRS += sha256/gcrypt.h
 endif
@@ -2803,7 +2810,7 @@ hdr-check: $(HCO)
 style:
 	git clang-format --style file --diff --extensions c,h
 
-check: command-list.h
+check: config-list.h command-list.h
 	@if sparse; \
 	then \
 		echo >&2 "Use 'make sparse' instead"; \
diff --git a/builtin/help.c b/builtin/help.c
index e5590d7787..1c5f2b9255 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -8,6 +8,7 @@
 #include "parse-options.h"
 #include "run-command.h"
 #include "column.h"
+#include "config-list.h"
 #include "help.h"
 #include "alias.h"
 
@@ -62,6 +63,91 @@ static const char * const builtin_help_usage[] = {
 	NULL
 };
 
+struct slot_expansion {
+	const char *prefix;
+	const char *placeholder;
+	void (*fn)(struct string_list *list, const char *prefix);
+	int found;
+};
+
+static void list_config_help(int for_human)
+{
+	struct slot_expansion slot_expansions[] = {
+		{ "advice", "*", list_config_advices },
+		{ "color.branch", "<slot>", list_config_color_branch_slots },
+		{ "color.decorate", "<slot>", list_config_color_decorate_slots },
+		{ "color.diff", "<slot>", list_config_color_diff_slots },
+		{ "color.grep", "<slot>", list_config_color_grep_slots },
+		{ "color.interactive", "<slot>", list_config_color_interactive_slots },
+		{ "color.remote", "<slot>", list_config_color_sideband_slots },
+		{ "color.status", "<slot>", list_config_color_status_slots },
+		{ "fsck", "<msg-id>", list_config_fsck_msg_ids },
+		{ "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
+		{ NULL, NULL, NULL }
+	};
+	const char **p;
+	struct slot_expansion *e;
+	struct string_list keys = STRING_LIST_INIT_DUP;
+	int i;
+
+	for (p = config_name_list; *p; p++) {
+		const char *var = *p;
+		struct strbuf sb = STRBUF_INIT;
+
+		for (e = slot_expansions; e->prefix; e++) {
+
+			strbuf_reset(&sb);
+			strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
+			if (!strcasecmp(var, sb.buf)) {
+				e->fn(&keys, e->prefix);
+				e->found++;
+				break;
+			}
+		}
+		strbuf_release(&sb);
+		if (!e->prefix)
+			string_list_append(&keys, var);
+	}
+
+	for (e = slot_expansions; e->prefix; e++)
+		if (!e->found)
+			BUG("slot_expansion %s.%s is not used",
+			    e->prefix, e->placeholder);
+
+	string_list_sort(&keys);
+	for (i = 0; i < keys.nr; i++) {
+		const char *var = keys.items[i].string;
+		const char *wildcard, *tag, *cut;
+
+		if (for_human) {
+			puts(var);
+			continue;
+		}
+
+		wildcard = strchr(var, '*');
+		tag = strchr(var, '<');
+
+		if (!wildcard && !tag) {
+			puts(var);
+			continue;
+		}
+
+		if (wildcard && !tag)
+			cut = wildcard;
+		else if (!wildcard && tag)
+			cut = tag;
+		else
+			cut = wildcard < tag ? wildcard : tag;
+
+		/*
+		 * We may produce duplicates, but that's up to
+		 * git-completion.bash to handle
+		 */
+		printf("%.*s\n", (int)(cut - var), var);
+	}
+	string_list_clear(&keys, 0);
+}
+
 static enum help_format parse_help_format(const char *format)
 {
 	if (!strcmp(format, "man"))
diff --git a/compat/vcbuild/README b/compat/vcbuild/README
index 1b6dabf5a2..42292e7c09 100644
--- a/compat/vcbuild/README
+++ b/compat/vcbuild/README
@@ -92,8 +92,8 @@ The Steps of Build Git with VS2008
    the git operations.
 
 3. Inside Git's directory run the command:
-       make command-list.h
-   to generate the command-list.h file needed to compile git.
+       make command-list.h config-list.h
+   to generate the header file needed to compile git.
 
 4. Then either build Git with the GNU Make Makefile in the Git projects
    root
diff --git a/config.mak.uname b/config.mak.uname
index 0ab8e00938..f880cc2792 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -721,9 +721,9 @@ vcxproj:
 	 echo '</Project>') >git-remote-http/LinkOrCopyRemoteHttp.targets
 	git add -f git/LinkOrCopyBuiltins.targets git-remote-http/LinkOrCopyRemoteHttp.targets
 
-	# Add command-list.h
-	$(MAKE) MSVC=1 SKIP_VCPKG=1 prefix=/mingw64 command-list.h
-	git add -f command-list.h
+	# Add command-list.h and config-list.h
+	$(MAKE) MSVC=1 SKIP_VCPKG=1 prefix=/mingw64 config-list.h command-list.h
+	git add -f config-list.h command-list.h
 
 	# Add scripts
 	rm -f perl/perl.mak
diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
index 71158f7d8b..45fecf8bdf 100755
--- a/generate-cmdlist.sh
+++ b/generate-cmdlist.sh
@@ -76,23 +76,6 @@ print_command_list () {
 	echo "};"
 }
 
-print_config_list () {
-	cat <<EOF
-static const char *config_name_list[] = {
-EOF
-	grep -h '^[a-zA-Z].*\..*::$' Documentation/*config.txt Documentation/config/*.txt |
-	sed '/deprecated/d; s/::$//; s/,  */\n/g' |
-	sort |
-	while read line
-	do
-		echo "	\"$line\","
-	done
-	cat <<EOF
-	NULL,
-};
-EOF
-}
-
 exclude_programs=
 while test "--exclude-program" = "$1"
 do
@@ -113,5 +96,3 @@ echo
 define_category_names "$1"
 echo
 print_command_list "$1"
-echo
-print_config_list
diff --git a/generate-configlist.sh b/generate-configlist.sh
new file mode 100755
index 0000000000..8692fe5cf4
--- /dev/null
+++ b/generate-configlist.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+echo "/* Automatically generated by generate-configlist.sh */"
+echo
+
+print_config_list () {
+	cat <<EOF
+static const char *config_name_list[] = {
+EOF
+	grep -h '^[a-zA-Z].*\..*::$' Documentation/*config.txt Documentation/config/*.txt |
+	sed '/deprecated/d; s/::$//; s/,  */\n/g' |
+	sort |
+	sed 's/^.*$/	"&",/'
+	cat <<EOF
+	NULL,
+};
+EOF
+}
+
+echo
+print_config_list
diff --git a/help.c b/help.c
index cf67624a94..a21487db77 100644
--- a/help.c
+++ b/help.c
@@ -407,91 +407,6 @@ void list_common_guides_help(void)
 	putchar('\n');
 }
 
-struct slot_expansion {
-	const char *prefix;
-	const char *placeholder;
-	void (*fn)(struct string_list *list, const char *prefix);
-	int found;
-};
-
-void list_config_help(int for_human)
-{
-	struct slot_expansion slot_expansions[] = {
-		{ "advice", "*", list_config_advices },
-		{ "color.branch", "<slot>", list_config_color_branch_slots },
-		{ "color.decorate", "<slot>", list_config_color_decorate_slots },
-		{ "color.diff", "<slot>", list_config_color_diff_slots },
-		{ "color.grep", "<slot>", list_config_color_grep_slots },
-		{ "color.interactive", "<slot>", list_config_color_interactive_slots },
-		{ "color.remote", "<slot>", list_config_color_sideband_slots },
-		{ "color.status", "<slot>", list_config_color_status_slots },
-		{ "fsck", "<msg-id>", list_config_fsck_msg_ids },
-		{ "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
-		{ NULL, NULL, NULL }
-	};
-	const char **p;
-	struct slot_expansion *e;
-	struct string_list keys = STRING_LIST_INIT_DUP;
-	int i;
-
-	for (p = config_name_list; *p; p++) {
-		const char *var = *p;
-		struct strbuf sb = STRBUF_INIT;
-
-		for (e = slot_expansions; e->prefix; e++) {
-
-			strbuf_reset(&sb);
-			strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
-			if (!strcasecmp(var, sb.buf)) {
-				e->fn(&keys, e->prefix);
-				e->found++;
-				break;
-			}
-		}
-		strbuf_release(&sb);
-		if (!e->prefix)
-			string_list_append(&keys, var);
-	}
-
-	for (e = slot_expansions; e->prefix; e++)
-		if (!e->found)
-			BUG("slot_expansion %s.%s is not used",
-			    e->prefix, e->placeholder);
-
-	string_list_sort(&keys);
-	for (i = 0; i < keys.nr; i++) {
-		const char *var = keys.items[i].string;
-		const char *wildcard, *tag, *cut;
-
-		if (for_human) {
-			puts(var);
-			continue;
-		}
-
-		wildcard = strchr(var, '*');
-		tag = strchr(var, '<');
-
-		if (!wildcard && !tag) {
-			puts(var);
-			continue;
-		}
-
-		if (wildcard && !tag)
-			cut = wildcard;
-		else if (!wildcard && tag)
-			cut = tag;
-		else
-			cut = wildcard < tag ? wildcard : tag;
-
-		/*
-		 * We may produce duplicates, but that's up to
-		 * git-completion.bash to handle
-		 */
-		printf("%.*s\n", (int)(cut - var), var);
-	}
-	string_list_clear(&keys, 0);
-}
-
 static int get_alias(const char *var, const char *value, void *data)
 {
 	struct string_list *list = data;
diff --git a/help.h b/help.h
index 7a455beeb7..9071894e8c 100644
--- a/help.h
+++ b/help.h
@@ -22,7 +22,6 @@ static inline void mput_char(char c, unsigned int num)
 void list_common_cmds_help(void);
 void list_all_cmds_help(void);
 void list_common_guides_help(void);
-void list_config_help(int for_human);
 
 void list_all_main_cmds(struct string_list *list);
 void list_all_other_cmds(struct string_list *list);