fsck: exit with non-zero status upon error from fsck_obj()

Upon finding a corrupt loose object, we forgot to note the error to
signal it with the exit status of the entire process.

[jc: adjusted t1450 and added another test]

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jk/fsck-exit-code-fix' into jch

* jk/fsck-exit-code-fix:
  fsck: exit with non-zero status upon error from fsck_obj()
fsck: exit with non-zero status upon error from fsck_obj()

Upon finding a corrupt loose object, we forgot to note the error to
signal it with the exit status of the entire process.

[jc: adjusted t1450 and added another test]

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor type_from_string() to allow continuing after detecting an error

In the next commits, we will enhance the fsck_tag() function to check
tag objects more thoroughly. To this end, we need a function to verify
that a given string is a valid object type, but that does not die() in
the negative case.

While at it, prepare type_from_string() for counted strings, i.e. strings
with an explicitly specified length rather than a NUL termination.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fsck_object(): allow passing object data separately from the object itself

When fsck'ing an incoming pack, we need to fsck objects that cannot be
read via read_sha1_file() because they are not local yet (and might even
be rejected if transfer.fsckobjects is set to 'true').

For commits, there is a hack in place: we basically cache commit
objects' buffers anyway, but the same is not true, say, for tag objects.

By refactoring fsck_object() to take the object buffer and size as
optional arguments -- optional, because we still fall back to the
previous method to look at the cached commit objects if the caller
passes NULL -- we prepare the machinery for the upcoming handling of tag
objects.

The assumption that such buffers are inherently NUL terminated is now
wrong, of course, hence we pass the size of the buffer so that we can
add a sanity check later, to prevent running past the end of the buffer.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make sure fsck_commit_buffer() does not run out of the buffer

So far, we assumed that the buffer is NUL terminated, but this is not
a safe assumption, now that we opened the fsck_object() API to pass a
buffer directly.

So let's make sure that there is at least an empty line in the buffer.
That way, our checks would fail if the empty line was encountered
prematurely, and consequently we can get away with the current string
comparisons even with non-NUL-terminated buffers are passed to
fsck_object().

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fsck: check tag objects' headers

We inspect commit objects pretty much in detail in git-fsck, but we just
glanced over the tag objects. Let's be stricter.

Since we do not want to limit 'tag' lines unduly, values that would fail
the refname check only result in warnings, not errors.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add regression tests for stricter tag fsck'ing

The intent of the two new test cases is to catch general breakages in
the fsck_tag() function, not so much to test it extensively, trying to
strike the proper balance between thoroughness and speed.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make sure that index-pack --strict fails upon invalid tag objects

One of the most important use cases for the strict tag object checking
is when transfer.fsckobjects is set to true to catch invalid objects
early on. This new regression test essentially tests the same code path
by directly calling 'index-pack --strict' on a pack containing an
invalid tag object.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jk/fsck-exit-code-fix' into jch

* jk/fsck-exit-code-fix:
  fsck: exit with non-zero status upon error from fsck_obj()
SQUASH???
Merge branch 'js/fsck-tag-validation' into jch

* js/fsck-tag-validation:
  SQUASH???
  Make sure that index-pack --strict fails upon invalid tag objects
  Add regression tests for stricter tag fsck'ing
  fsck: check tag objects' headers
  Make sure fsck_commit_buffer() does not run out of the buffer
  fsck_object(): allow passing object data separately from the object itself
  Refactor type_from_string() to allow continuing after detecting an error