From 19d13f17813b35c4cc426bdf2244ef460974e0d9 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Mon, 18 Feb 2019 13:13:29 +1030
Subject: [PATCH] type_to_string: return const char *.

Always be const if you can.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 common/type_to_string.c      |  6 +++---
 common/type_to_string.h      | 14 +++++++-------
 lightningd/channel.c         |  2 +-
 lightningd/opening_control.c |  2 +-
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/common/type_to_string.c b/common/type_to_string.c
index 13afd7ee9..25d5c3ef3 100644
--- a/common/type_to_string.c
+++ b/common/type_to_string.c
@@ -13,10 +13,10 @@ REGISTER_TYPE_TO_HEXSTR(ripemd160);
 /* This one in bitcoin/ but doesn't have its own C file */
 REGISTER_TYPE_TO_HEXSTR(preimage);
 
-char *type_to_string_(const tal_t *ctx,  const char *typename,
-		      union printable_types u)
+const char *type_to_string_(const tal_t *ctx,  const char *typename,
+			    union printable_types u)
 {
-	char *s = NULL;
+	const char *s = NULL;
 	size_t i;
 	static size_t num_p;
 	static struct type_to_string **t = NULL;
diff --git a/common/type_to_string.h b/common/type_to_string.h
index 521a1f931..45a5e125b 100644
--- a/common/type_to_string.h
+++ b/common/type_to_string.h
@@ -38,12 +38,12 @@ union printable_types {
 			((void)sizeof((ptr) == (type *)NULL),		\
 			 ((union printable_types)((const type *)ptr))))
 
-char *type_to_string_(const tal_t *ctx, const char *typename,
-		      union printable_types u);
+const char *type_to_string_(const tal_t *ctx, const char *typename,
+			    union printable_types u);
 
 #define REGISTER_TYPE_TO_STRING(typename, fmtfn)			\
-	static char *fmt_##typename##_(const tal_t *ctx,		\
-				       union printable_types u)		\
+	static const char *fmt_##typename##_(const tal_t *ctx,		\
+					     union printable_types u)	\
 	{								\
 		return fmtfn(ctx, u.typename);				\
 	}								\
@@ -53,8 +53,8 @@ char *type_to_string_(const tal_t *ctx, const char *typename,
 	AUTODATA(type_to_string, &ttos_##typename)
 
 #define REGISTER_TYPE_TO_HEXSTR(typename)				\
-	static char *fmt_##typename##_(const tal_t *ctx,		\
-				       union printable_types u)		\
+	static const char *fmt_##typename##_(const tal_t *ctx,		\
+					     union printable_types u)	\
 	{								\
 		return tal_hexstr(ctx, u.typename, sizeof(*u.typename)); \
 	}								\
@@ -65,7 +65,7 @@ char *type_to_string_(const tal_t *ctx, const char *typename,
 
 struct type_to_string {
 	const char *typename;
-	char *(*fmt)(const tal_t *ctx, union printable_types u);
+	const char *(*fmt)(const tal_t *ctx, union printable_types u);
 };
 AUTODATA_TYPE(type_to_string, struct type_to_string);
 #endif /* LIGHTNING_COMMON_TYPE_TO_STRING_H */
diff --git a/lightningd/channel.c b/lightningd/channel.c
index 109aac274..3d85c527b 100644
--- a/lightningd/channel.c
+++ b/lightningd/channel.c
@@ -195,7 +195,7 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 	if (!log) {
 		/* FIXME: update log prefix when we get scid */
 		/* FIXME: Use minimal unique pubkey prefix for logs! */
-		char *idname = type_to_string(peer, struct pubkey, &peer->id);
+		const char *idname = type_to_string(peer, struct pubkey, &peer->id);
 		channel->log = new_log(channel,
 				       peer->log_book, "%s chan #%"PRIu64":",
 				       idname, dbid);
diff --git a/lightningd/opening_control.c b/lightningd/opening_control.c
index da9368373..150cdec8e 100644
--- a/lightningd/opening_control.c
+++ b/lightningd/opening_control.c
@@ -604,7 +604,7 @@ new_uncommitted_channel(struct peer *peer)
 {
 	struct lightningd *ld = peer->ld;
 	struct uncommitted_channel *uc = tal(ld, struct uncommitted_channel);
-	char *idname;
+	const char *idname;
 
 	uc->peer = peer;
 	assert(!peer->uncommitted_channel);