[PATCH resend] Do not create commits whose message contains NUL

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

We assume that the commit log messages are uninterpreted sequences of
non-NUL bytes (see Documentation/i18n.txt). However the assumption
does not really stand out and it's quite easy to set an editor to save
in a NUL-included encoding. Currently we silently cut at the first NUL
we see.

Make it more obvious that NUL is not welcome by refusing to create
such commits. Those who deliberately want to create them can still do
with hash-object.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 This is from UTF-16 in commit message discussion [1] a few months
 ago. I don't want to resurrect the discussion again. However I think
 it's a good idea to stop users from shooting themselves in this case,
 especially at porcelain level.
 
 There were no comments on this patch previously. So, any comments
 this time ? Should I drop it?

 [1] http://thread.gmane.org/gmane.comp.version-control.git/184123/focus=184335
 commit.c               |    3 +++
 t/t3900-i18n-commit.sh |    6 ++++++
 t/t3900/UTF-16.txt     |  Bin 0 -> 32 bytes
 3 files changed, 9 insertions(+), 0 deletions(-)
 create mode 100644 t/t3900/UTF-16.txt

diff --git a/commit.c b/commit.c
index d67b8c7..0775eec 100644
--- a/commit.c
+++ b/commit.c
@@ -855,6 +855,9 @@ int commit_tree(const char *msg, size_t msg_len, unsigned char *tree,
 
 	assert_sha1_type(tree, OBJ_TREE);
 
+	if (strlen(msg) < msg_len)
+		die(_("cannot commit with NUL in commit message"));
+
 	/* Not having i18n.commitencoding is the same as having utf-8 */
 	encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
 
diff --git a/t/t3900-i18n-commit.sh b/t/t3900-i18n-commit.sh
index 1f62c15..d48a7c0 100755
--- a/t/t3900-i18n-commit.sh
+++ b/t/t3900-i18n-commit.sh
@@ -34,6 +34,12 @@ test_expect_success 'no encoding header for base case' '
 	test z = "z$E"
 '
 
+test_expect_failure 'UTF-16 refused because of NULs' '
+	echo UTF-16 >F &&
+	git commit -a -F "$TEST_DIRECTORY"/t3900/UTF-16.txt
+'
+
+
 for H in ISO8859-1 eucJP ISO-2022-JP
 do
 	test_expect_success "$H setup" '
diff --git a/t/t3900/UTF-16.txt b/t/t3900/UTF-16.txt
new file mode 100644
index 0000000000000000000000000000000000000000..53296be684253f40964c0604be7fa7ff12e200cb
GIT binary patch
literal 32
mcmezOpWz6@X@-jo=NYasZ~@^#h9rjP3@HpR7}6Nh8Mpw;r3yp<

literal 0
HcmV?d00001

-- 
1.7.8.36.g69ee2