repository: require a build flag to use SHA-256

At this point, SHA-256 support is experimental and some behavior may
change. To avoid surprising unsuspecting users, require a build flag,
ENABLE_SHA256, to allow use of a non-SHA-1 algorithm. Enable this flag
by default when the DEVELOPER make flag is set so that contributors can
test this case adequately.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/config.mak.dev b/config.mak.dev
index bf1f3fcdeed3a819b7098baf1d710be29f16c93e..2e1943591509914383eea002593744d2326ca739 100644 (file)
--- a/config.mak.dev
+++ b/config.mak.dev
@@ -17,6 +17,8 @@ DEVELOPER_CFLAGS += -Wstrict-prototypes
 DEVELOPER_CFLAGS += -Wunused
 DEVELOPER_CFLAGS += -Wvla
 
+DEVELOPER_CFLAGS += -DENABLE_SHA256
+
 ifndef COMPILER_FEATURES
 COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
 endif

diff --git a/repository.c b/repository.c
index a4174ddb0629cdd690142fb42c5d4182492485c4..6f7f6f002b1a45faa52305ca8c370e2e959b2f5e 100644 (file)
--- a/repository.c
+++ b/repository.c
@@ -89,6 +89,10 @@ void repo_set_gitdir(struct repository *repo,
 void repo_set_hash_algo(struct repository *repo, int hash_algo)
 {
        repo->hash_algo = &hash_algos[hash_algo];
+#ifndef ENABLE_SHA256
+       if (hash_algo != GIT_HASH_SHA1)
+               die(_("The hash algorithm %s is not supported in this build."), repo->hash_algo->name);
+#endif
 }
 
 /*