Merge branch 'jk/gcc-function-attributes'

Use the function attributes extension to catch mistakes in use of
our own variadic functions that use NULL sentinel at the end
(i.e. like execl(3)) and format strings (i.e. like printf(3)).

* jk/gcc-function-attributes:
  Add the LAST_ARG_MUST_BE_NULL macro
  wt-status: use "format" function attribute for status_printf
  use "sentinel" function attribute for variadic lists
  add missing "format" function attributes

10 files changed, 21 insertions, 5 deletions

diff --git a/advice.h b/advice.h
index 93a7d110ea..08fbc8ee3c 100644
--- a/advice.h
+++ b/advice.h
@@ -21,6 +21,7 @@ extern int advice_object_name_warning;
 extern int advice_rm_hints;
 
 int git_default_advice_config(const char *var, const char *value);
+__attribute__((format (printf, 1, 2)))
 void advise(const char *advice, ...);
 int error_resolve_conflict(const char *me);
 extern void NORETURN die_resolve_conflict(const char *me);
diff --git a/argv-array.h b/argv-array.h
index 40248d424c..85ba438ac1 100644
--- a/argv-array.h
+++ b/argv-array.h
@@ -15,6 +15,7 @@ void argv_array_init(struct argv_array *);
 void argv_array_push(struct argv_array *, const char *);
 __attribute__((format (printf,2,3)))
 void argv_array_pushf(struct argv_array *, const char *fmt, ...);
+LAST_ARG_MUST_BE_NULL
 void argv_array_pushl(struct argv_array *, ...);
 void argv_array_pop(struct argv_array *);
 void argv_array_clear(struct argv_array *);
diff --git a/builtin/revert.c b/builtin/revert.c
index 0401fdb02c..1d2648b756 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -54,6 +54,7 @@ static int option_parse_x(const struct option *opt,
 	return 0;
 }
 
+LAST_ARG_MUST_BE_NULL
 static void verify_opt_compatible(const char *me, const char *base_opt, ...)
 {
 	const char *this_opt;
@@ -70,6 +71,7 @@ static void verify_opt_compatible(const char *me, const char *base_opt, ...)
 		die(_("%s: %s cannot be used with %s"), me, this_opt, base_opt);
 }
 
+LAST_ARG_MUST_BE_NULL
 static void verify_opt_mutually_compatible(const char *me, ...)
 {
 	const char *opt1, *opt2 = NULL;
diff --git a/exec_cmd.h b/exec_cmd.h
index e2b546b615..e4c9702f02 100644
--- a/exec_cmd.h
+++ b/exec_cmd.h
@@ -7,6 +7,7 @@ extern const char *git_exec_path(void);
 extern void setup_path(void);
 extern const char **prepare_git_cmd(const char **argv);
 extern int execv_git_cmd(const char **argv); /* NULL terminated */
+LAST_ARG_MUST_BE_NULL
 extern int execl_git_cmd(const char *cmd, ...);
 extern const char *system_path(const char *path);
 
diff --git a/git-compat-util.h b/git-compat-util.h
index ff193f4aa2..cc4ba4d18f 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -303,6 +303,13 @@ extern char *gitbasename(char *);
 #endif
 #endif
 
+/* The sentinel attribute is valid from gcc version 4.0 */
+#if defined(__GNUC__) && (__GNUC__ >= 4)
+#define LAST_ARG_MUST_BE_NULL __attribute__((sentinel))
+#else
+#define LAST_ARG_MUST_BE_NULL
+#endif
+
 #include "compat/bswap.h"
 
 #ifdef USE_WILDMATCH
diff --git a/run-command.h b/run-command.h
index 221ce33140..6b985afd07 100644
--- a/run-command.h
+++ b/run-command.h
@@ -46,6 +46,7 @@ int finish_command(struct child_process *);
 int run_command(struct child_process *);
 
 extern char *find_hook(const char *name);
+LAST_ARG_MUST_BE_NULL
 extern int run_hook(const char *index_file, const char *name, ...);
 
 #define RUN_COMMAND_NO_STDIN 1
diff --git a/trace.c b/trace.c
index 5ec0e3bd16..3d744d1d4d 100644
--- a/trace.c
+++ b/trace.c
@@ -75,6 +75,7 @@ static void trace_vprintf(const char *key, const char *fmt, va_list ap)
 	strbuf_release(&buf);
 }
 
+__attribute__((format (printf, 2, 3)))
 static void trace_printf_key(const char *key, const char *fmt, ...)
 {
 	va_list ap;
diff --git a/transport-helper.c b/transport-helper.c
index db9bd18298..45a35df66e 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -982,6 +982,7 @@ int transport_helper_init(struct transport *transport, const char *name)
 #define PBUFFERSIZE 8192
 
 /* Print bidirectional transfer loop debug message. */
+__attribute__((format (printf, 1, 2)))
 static void transfer_debug(const char *fmt, ...)
 {
 	va_list args;
@@ -1067,7 +1068,7 @@ static int udt_do_read(struct unidirectional_transfer *t)
 		return -1;
 	} else if (bytes == 0) {
 		transfer_debug("%s EOF (with %i bytes in buffer)",
-			t->src_name, t->bufuse);
+			t->src_name, (int)t->bufuse);
 		t->state = SSTATE_FLUSHING;
 	} else if (bytes > 0) {
 		t->bufuse += bytes;
diff --git a/utf8.h b/utf8.h
index 32a7bfb987..65d0e42b96 100644
--- a/utf8.h
+++ b/utf8.h
@@ -10,6 +10,7 @@ int utf8_strwidth(const char *string);
 int is_utf8(const char *text);
 int is_encoding_utf8(const char *name);
 int same_encoding(const char *, const char *);
+__attribute__((format (printf, 2, 3)))
 int utf8_fprintf(FILE *, const char *, ...);
 
 void strbuf_add_wrapped_text(struct strbuf *buf,
diff --git a/wt-status.h b/wt-status.h
index 4121bc208d..fb7152e187 100644
--- a/wt-status.h
+++ b/wt-status.h
@@ -96,9 +96,9 @@ void wt_status_get_state(struct wt_status_state *state, int get_detached_from);
 void wt_shortstatus_print(struct wt_status *s);
 void wt_porcelain_print(struct wt_status *s);
 
-void status_printf_ln(struct wt_status *s, const char *color, const char *fmt, ...)
-	;
-void status_printf(struct wt_status *s, const char *color, const char *fmt, ...)
-	;
+__attribute__((format (printf, 3, 4)))
+void status_printf_ln(struct wt_status *s, const char *color, const char *fmt, ...);
+__attribute__((format (printf, 3, 4)))
+void status_printf(struct wt_status *s, const char *color, const char *fmt, ...);
 
 #endif /* STATUS_H */