hash-object: reduce file-scope statics

Most of the knobs that affect helper functions called from
cmd_hash_object() were passed to them as parameters already, and the
only effect of having them as file-scope statics was to make the
reader wonder if the parameters are hiding the file-scope global
values by accident.  Adjust their initialisation and make them
function-local variables.

The only exception was no_filters hash_stdin_paths() peeked from the
file-scope global, which was converted to a parameter to the helper
function.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
hash-object: pass 'write_object' as a flag

Instead of forcing callers of lower level functions write
(write_object ? HASH_WRITE_OBJECT : 0), prepare the flag to be
passed down in the callchain from the command line parser.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
hash-object: add --literally option

This allows "hash-object --stdin" to just hash any garbage into a
"loose object" that may not pass the standard object parsing check
or fsck, so that different kind of corrupt objects we may encounter
in the field can be imitated in our test suite.  That would in turn
allow us to test features that catch these corrupt objects.

Note that "cat-file" may need to learn "--literally" option to allow
us peek into a truly broken object.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
Merge branch 'jc/hash-object' into fsck-tag-plus

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge branch 'jk/fsck-exit-code-fix' into fsck-tag-plus

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
t1450: make sure fsck detects a malformed tagger line

With "hash-object --literally", write a tag object that is not
supposed to pass one of the new checks added to "fsck", and make
sure that the new check catches the breakage.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>