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96 Commits

Author SHA1 Message Date
Jeff King
7ac4f3a007 fsck: actually fsck blob data
Because fscking a blob has always been a noop, we didn't
bother passing around the blob data. In preparation for
content-level checks, let's fix up a few things:

  1. The fsck_object() function just returns success for any
     blob. Let's a noop fsck_blob(), which we can fill in
     with actual logic later.

  2. The fsck_loose() function in builtin/fsck.c
     just threw away blob content after loading it. Let's
     hold onto it until after we've called fsck_object().

     The easiest way to do this is to just drop the
     parse_loose_object() helper entirely. Incidentally,
     this also fixes a memory leak: if we successfully
     loaded the object data but did not parse it, we would
     have left the function without freeing it.

  3. When fsck_loose() loads the object data, it
     does so with a custom read_loose_object() helper. This
     function streams any blobs, regardless of size, under
     the assumption that we're only checking the sha1.

     Instead, let's actually load blobs smaller than
     big_file_threshold, as the normal object-reading
     code-paths would do. This lets us fsck small files, and
     a NULL return is an indication that the blob was so big
     that it needed to be streamed, and we can pass that
     information along to fsck_blob().

Signed-off-by: Jeff King <peff@peff.net>
2018-05-21 23:55:12 -04:00
Jeff King
ed9c322062 fsck: simplify ".git" check
There's no need for us to manually check for ".git"; it's a
subset of the other filesystem-specific tests. Dropping it
makes our code slightly shorter. More importantly, the
existing code may make a reader wonder why ".GIT" is not
covered here, and whether that is a bug (it isn't, as it's
also covered in the filesystem-specific tests).

Signed-off-by: Jeff King <peff@peff.net>
2018-05-21 23:55:12 -04:00
Brandon Williams
debca9d2fe object: rename function 'typename' to 'type_name'
Rename C++ keyword in order to bring the codebase closer to being able
to be compiled with a C++ compiler.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-14 13:10:05 -08:00
Junio C Hamano
6defdc9fe8 Merge branch 'rs/fsck-null-return-from-lookup'
Improve behaviour of "git fsck" upon finding a missing object.

* rs/fsck-null-return-from-lookup:
  fsck: handle NULL return of lookup_blob() and lookup_tree()
2017-10-11 14:52:23 +09:00
René Scharfe
2720f6db5d fsck: handle NULL return of lookup_blob() and lookup_tree()
lookup_blob() and lookup_tree() can return NULL if they find an object
of an unexpected type.  Accessing the object member is undefined in that
case.  Cast the result to a struct object pointer instead; we can do
that because object is the first member of all object types.  This trick
is already used in other places in the code.

An error message is already shown by object_as_type(), which is called
by the lookup functions.  The walk callback functions are expected to
handle NULL object pointers passed to them, but put_object_name() needs
a valid object, so avoid calling it without one.

Suggested-by: SZEDER Gábor <szeder.dev@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-06 11:04:34 +09:00
Jeff King
1cf01a34ea consistently use "fallthrough" comments in switches
Gcc 7 adds -Wimplicit-fallthrough, which can warn when a
switch case falls through to the next case. The general idea
is that the compiler can't tell if this was intentional or
not, so you should annotate any intentional fall-throughs as
such, leaving it to complain about any unannotated ones.

There's a GNU __attribute__ which can be used for
annotation, but of course we'd have to #ifdef it away on
non-gcc compilers. Gcc will also recognize
specially-formatted comments, which matches our current
practice. Let's extend that practice to all of the
unannotated sites (which I did look over and verify that
they were behaving as intended).

Ideally in each case we'd actually give some reasons in the
comment about why we're falling through, or what we're
falling through to. And gcc does support that with
-Wimplicit-fallthrough=2, which relaxes the comment pattern
matching to anything that contains "fallthrough" (or a
variety of spelling variants). However, this isn't the
default for -Wimplicit-fallthrough, nor for -Wextra. In the
name of simplicity, it's probably better for us to support
the default level, which requires "fallthrough" to be the
only thing in the comment (modulo some window dressing like
"else" and some punctuation; see the gcc manual for the
complete set of patterns).

This patch suppresses all warnings due to
-Wimplicit-fallthrough. We might eventually want to add that
to the DEVELOPER Makefile knob, but we should probably wait
until gcc 7 is more widely adopted (since earlier versions
will complain about the unknown warning type).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22 12:49:57 +09:00
Stefan Beller
8b65a34c4a commit: convert lookup_commit_graft to struct object_id
With this patch, commit.h doesn't contain the string 'sha1' any more.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-13 12:02:40 -07:00
Junio C Hamano
6b526ced6f Merge branch 'bc/object-id'
Conversion from uchar[20] to struct object_id continues.

* bc/object-id: (53 commits)
  object: convert parse_object* to take struct object_id
  tree: convert parse_tree_indirect to struct object_id
  sequencer: convert do_recursive_merge to struct object_id
  diff-lib: convert do_diff_cache to struct object_id
  builtin/ls-tree: convert to struct object_id
  merge: convert checkout_fast_forward to struct object_id
  sequencer: convert fast_forward_to to struct object_id
  builtin/ls-files: convert overlay_tree_on_cache to object_id
  builtin/read-tree: convert to struct object_id
  sha1_name: convert internals of peel_onion to object_id
  upload-pack: convert remaining parse_object callers to object_id
  revision: convert remaining parse_object callers to object_id
  revision: rename add_pending_sha1 to add_pending_oid
  http-push: convert process_ls_object and descendants to object_id
  refs/files-backend: convert many internals to struct object_id
  refs: convert struct ref_update to use struct object_id
  ref-filter: convert some static functions to struct object_id
  Convert struct ref_array_item to struct object_id
  Convert the verify_pack callback to struct object_id
  Convert lookup_tag to struct object_id
  ...
2017-05-29 12:34:43 +09:00
brian m. carlson
c251c83df2 object: convert parse_object* to take struct object_id
Make parse_object, parse_object_or_die, and parse_object_buffer take a
pointer to struct object_id.  Remove the temporary variables inserted
earlier, since they are no longer necessary.  Transform all of the
callers using the following semantic patch:

@@
expression E1;
@@
- parse_object(E1.hash)
+ parse_object(&E1)

@@
expression E1;
@@
- parse_object(E1->hash)
+ parse_object(E1)

@@
expression E1, E2;
@@
- parse_object_or_die(E1.hash, E2)
+ parse_object_or_die(&E1, E2)

@@
expression E1, E2;
@@
- parse_object_or_die(E1->hash, E2)
+ parse_object_or_die(E1, E2)

@@
expression E1, E2, E3, E4, E5;
@@
- parse_object_buffer(E1.hash, E2, E3, E4, E5)
+ parse_object_buffer(&E1, E2, E3, E4, E5)

@@
expression E1, E2, E3, E4, E5;
@@
- parse_object_buffer(E1->hash, E2, E3, E4, E5)
+ parse_object_buffer(E1, E2, E3, E4, E5)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:58 +09:00
brian m. carlson
740ee055c6 Convert lookup_tree to struct object_id
Convert the lookup_tree function to take a pointer to struct object_id.

The commit was created with manual changes to tree.c, tree.h, and
object.c, plus the following semantic patch:

@@
@@
- lookup_tree(EMPTY_TREE_SHA1_BIN)
+ lookup_tree(&empty_tree_oid)

@@
expression E1;
@@
- lookup_tree(E1.hash)
+ lookup_tree(&E1)

@@
expression E1;
@@
- lookup_tree(E1->hash)
+ lookup_tree(E1)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:57 +09:00
brian m. carlson
3aca1fc6c9 Convert lookup_blob to struct object_id
Convert lookup_blob to take a pointer to struct object_id.

The commit was created with manual changes to blob.c and blob.h, plus
the following semantic patch:

@@
expression E1;
@@
- lookup_blob(E1.hash)
+ lookup_blob(&E1)

@@
expression E1;
@@
- lookup_blob(E1->hash)
+ lookup_blob(E1)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:57 +09:00
Johannes Schindelin
1aeb7e756c parse_timestamp(): specify explicitly where we parse timestamps
Currently, Git's source code represents all timestamps as `unsigned
long`. In preparation for using a more appropriate data type, let's
introduce a symbol `parse_timestamp` (currently being defined to
`strtoul`) where appropriate, so that we can later easily switch to,
say, use `strtoull()` instead.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-23 20:19:15 -07:00
brian m. carlson
910650d2f8 Rename sha1_array to oid_array
Since this structure handles an array of object IDs, rename it to struct
oid_array.  Also rename the accessor functions and the initialization
constant.

This commit was produced mechanically by providing non-Documentation
files to the following Perl one-liners:

    perl -pi -E 's/struct sha1_array/struct oid_array/g'
    perl -pi -E 's/\bsha1_array_/oid_array_/g'
    perl -pi -E 's/SHA1_ARRAY_INIT/OID_ARRAY_INIT/g'

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-31 08:33:56 -07:00
brian m. carlson
5d3206d501 Convert sha1_array_lookup to take struct object_id
Convert this function by changing the declaration and definition and
applying the following semantic patch to update the callers:

@@
expression E1, E2;
@@
- sha1_array_lookup(E1, E2.hash)
+ sha1_array_lookup(E1, &E2)

@@
expression E1, E2;
@@
- sha1_array_lookup(E1, E2->hash)
+ sha1_array_lookup(E1, E2)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-31 08:33:55 -07:00
brian m. carlson
98a72ddc12 Make sha1_array_append take a struct object_id *
Convert the callers to pass struct object_id by changing the function
declaration and definition and applying the following semantic patch:

@@
expression E1, E2;
@@
- sha1_array_append(E1, E2.hash)
+ sha1_array_append(E1, &E2)

@@
expression E1, E2;
@@
- sha1_array_append(E1, E2->hash)
+ sha1_array_append(E1, E2)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-31 08:33:55 -07:00
brian m. carlson
ee3051bd23 sha1-array: convert internal storage for struct sha1_array to object_id
Make the internal storage for struct sha1_array use an array of struct
object_id internally.  Update the users of this struct which inspect its
internals.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-28 09:59:34 -07:00
brian m. carlson
365c27fbff fsck: convert init_skiplist to struct object_id
Convert a hardcoded constant buffer size to a use of GIT_MAX_HEXSZ, and
use parse_oid_hex to reduce the dependency on the size of the hash.
This function is a caller of sha1_array_append, which will be converted
later.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-28 09:59:33 -07:00
Jeff King
a2b22854bd fsck: lazily load types under --connectivity-only
The recent fixes to "fsck --connectivity-only" load all of
the objects with their correct types. This keeps the
connectivity-only code path close to the regular one, but it
also introduces some unnecessary inefficiency. While getting
the type of an object is cheap compared to actually opening
and parsing the object (as the non-connectivity-only case
would do), it's still not free.

For reachable non-blob objects, we end up having to parse
them later anyway (to see what they point to), making our
type lookup here redundant.

For unreachable objects, we might never hit them at all in
the reachability traversal, making the lookup completely
wasted. And in some cases, we might have quite a few
unreachable objects (e.g., when alternates are used for
shared object storage between repositories, it's normal for
there to be objects reachable from other repositories but
not the one running fsck).

The comment in mark_object_for_connectivity() claims two
benefits to getting the type up front:

  1. We need to know the types during fsck_walk(). (And not
     explicitly mentioned, but we also need them when
     printing the types of broken or dangling commits).

     We can address this by lazy-loading the types as
     necessary. Most objects never need this lazy-load at
     all, because they fall into one of these categories:

       a. Reachable from our tips, and are coerced into the
	  correct type as we traverse (e.g., a parent link
	  will call lookup_commit(), which converts OBJ_NONE
	  to OBJ_COMMIT).

       b. Unreachable, but not at the tip of a chunk of
          unreachable history. We only mention the tips as
	  "dangling", so an unreachable commit which links
	  to hundreds of other objects needs only report the
	  type of the tip commit.

  2. It serves as a cross-check that the coercion in (1a) is
     correct (i.e., we'll complain about a parent link that
     points to a blob). But we get most of this for free
     already, because right after coercing, we'll parse any
     non-blob objects. So we'd notice then if we expected a
     commit and got a blob.

     The one exception is when we expect a blob, in which
     case we never actually read the object contents.

     So this is a slight weakening, but given that the whole
     point of --connectivity-only is to sacrifice some data
     integrity checks for speed, this seems like an
     acceptable tradeoff.

Here are before and after timings for an extreme case with
~5M reachable objects and another ~12M unreachable (it's the
torvalds/linux repository on GitHub, connected to shared
storage for all of the other kernel forks):

  [before]
  $ time git fsck --no-dangling --connectivity-only
  real	3m4.323s
  user	1m25.121s
  sys	1m38.710s

  [after]
  $ time git fsck --no-dangling --connectivity-only
  real	0m51.497s
  user	0m49.575s
  sys	0m1.776s

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-26 10:51:09 -08:00
David Turner
8354fa3d4c fsck: handle bad trees like other errors
Instead of dying when fsck hits a malformed tree object, log the error
like any other and continue.  Now fsck can tell the user which tree is
bad, too.

Signed-off-by: David Turner <dturner@twosigma.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-27 14:09:10 -07:00
Johannes Schindelin
90cf590f53 fsck: optionally show more helpful info for broken links
When reporting broken links between commits/trees/blobs, it would be
quite helpful at times if the user would be told how the object is
supposed to be reachable.

With the new --name-objects option, git-fsck will try to do exactly
that: name the objects in a way that shows how they are reachable.

For example, when some reflog got corrupted and a blob is missing that
should not be, the user might want to remove the corresponding reflog
entry. This option helps them find that entry: `git fsck` will now
report something like this:

	broken link from    tree b5eb6ff...  (refs/stash@{<date>}~37:)
	              to    blob ec5cf80...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-18 15:15:59 -07:00
Johannes Schindelin
1cd772cc41 fsck: give the error function a chance to see the fsck_options
We will need this in the next commit, where fsck will be taught to
optionally name the objects when reporting issues about them.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-18 11:35:00 -07:00
Johannes Schindelin
7b35efd734 fsck_walk(): optionally name objects on the go
If fsck_options->name_objects is initialized, and if it already has
name(s) for the object(s) that are to be the starting point(s) for
fsck_walk(), then that function will now add names for the objects
that were walked.

This will be highly useful for teaching git-fsck to identify root causes
for broken links, which is the task for the next patch in this series.

Note that this patch opts for decorating the objects with plain strings
instead of full-blown structs (à la `struct rev_name` in the code of
the `git name-rev` command), for several reasons:

- the code is much simpler than if it had to work with structs that
  describe arbitrarily long names such as "master~14^2~5:builtin/am.c",

- the string processing is actually quite light-weight compared to the
  rest of fsck's operation,

- the caller of fsck_walk() is expected to provide names for the
  starting points, and using plain and simple strings is just the
  easiest way to do that.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-18 11:35:00 -07:00
Junio C Hamano
6bfb7de89e Merge branch 'jc/fsck-nul-in-commit'
"git fsck" learned to catch NUL byte in a commit object as
potential error and warn.

* jc/fsck-nul-in-commit:
  fsck: detect and warn a commit with embedded NUL
  fsck_commit_buffer(): do not special case the last validation
2016-05-17 14:38:34 -07:00
Junio C Hamano
6d2d780f63 fsck: detect and warn a commit with embedded NUL
Even though a Git commit object is designed to be capable of storing
any binary data as its payload, in practice people use it to describe
the changes in textual form, and tools like "git log" are designed to
treat the payload as text.

Detect and warn when we see any commit object with a NUL byte in
it.

Note that a NUL byte in the header part is already detected as a
grave error.  This change is purely about the message part.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-10 10:02:06 -07:00
brian m. carlson
ce6663a9da tree-walk: convert tree_entry_extract() to use struct object_id
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-25 14:26:28 -07:00
brian m. carlson
7d924c9139 struct name_entry: use struct object_id instead of unsigned char sha1[20]
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-25 14:23:42 -07:00
Junio C Hamano
5af297185e fsck_commit_buffer(): do not special case the last validation
The pattern taken by all the validations in this function is:

	if (notice a violation exists) {
		err = report(... VIOLATION_KIND ...);
		if (err)
			return err;
	}

where report() returns zero if specified kind of violation is set to
be ignored, and otherwise shows an error message and returns non-zero.

The last validation in the function immediately before the function
returns 0 to declare "all good" can cheat and directly return the
return value from report(), and the current code does so, i.e.

	if (notice a violation exists)
		return report(... VIOLATION_KIND ...);
	return 0;

But that is a selfish code that declares it is the ultimate and
final form of the function, never to be enhanced later.  To allow
and invite future enhancements, make the last test follow the same
pattern.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-14 11:15:48 -07:00
Jeff King
b32fa95fd8 convert trivial cases to ALLOC_ARRAY
Each of these cases can be converted to use ALLOC_ARRAY or
REALLOC_ARRAY, which has two advantages:

  1. It automatically checks the array-size multiplication
     for overflow.

  2. It always uses sizeof(*array) for the element-size,
     so that it can never go out of sync with the declared
     type of the array.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-22 14:51:09 -08:00
Junio C Hamano
844a9ce472 Merge branch 'bc/object-id'
More transition from "unsigned char[40]" to "struct object_id".

This needed a few merge fixups, but is mostly disentangled from other
topics.

* bc/object-id:
  remote: convert functions to struct object_id
  Remove get_object_hash.
  Convert struct object to object_id
  Add several uses of get_object_hash.
  object: introduce get_object_hash macro.
  ref_newer: convert to use struct object_id
  push_refs_with_export: convert to struct object_id
  get_remote_heads: convert to struct object_id
  parse_fetch: convert to use struct object_id
  add_sought_entry_mem: convert to struct object_id
  Convert struct ref to use object_id.
  sha1_file: introduce has_object_file helper.
2015-12-10 12:36:13 -08:00
René Scharfe
8a272f291a fsck: treat a NUL in a tag header as an error
We check the return value of verify_header() for commits already, so do
the same for tags as well.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>
2015-11-20 08:02:07 -05:00
brian m. carlson
ed1c9977cb Remove get_object_hash.
Convert all instances of get_object_hash to use an appropriate reference
to the hash member of the oid member of struct object.  This provides no
functional change, as it is essentially a macro substitution.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
2015-11-20 08:02:05 -05:00
brian m. carlson
f2fd0760f6 Convert struct object to object_id
struct object is one of the major data structures dealing with object
IDs.  Convert it to use struct object_id instead of an unsigned char
array.  Convert get_object_hash to refer to the new member as well.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
2015-11-20 08:02:05 -05:00
brian m. carlson
7999b2cf77 Add several uses of get_object_hash.
Convert most instances where the sha1 member of struct object is
dereferenced to use get_object_hash.  Most instances that are passed to
functions that have versions taking struct object_id, such as
get_sha1_hex/get_oid_hex, or instances that can be trivially converted
to use struct object_id instead, are not converted.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
2015-11-20 08:02:05 -05:00
Junio C Hamano
b2f44feba5 Merge branch 'js/fsck-opt'
Allow ignoring fsck errors on specific set of known-to-be-bad
objects, and also tweaking warning level of various kinds of non
critical breakages reported.

* js/fsck-opt:
  fsck: support ignoring objects in `git fsck` via fsck.skiplist
  fsck: git receive-pack: support excluding objects from fsck'ing
  fsck: introduce `git fsck --connectivity-only`
  fsck: support demoting errors to warnings
  fsck: document the new receive.fsck.<msg-id> options
  fsck: allow upgrading fsck warnings to errors
  fsck: optionally ignore specific fsck issues completely
  fsck: disallow demoting grave fsck errors to warnings
  fsck: add a simple test for receive.fsck.<msg-id>
  fsck: make fsck_tag() warn-friendly
  fsck: handle multiple authors in commits specially
  fsck: make fsck_commit() warn-friendly
  fsck: make fsck_ident() warn-friendly
  fsck: report the ID of the error/warning
  fsck (receive-pack): allow demoting errors to warnings
  fsck: offer a function to demote fsck errors to warnings
  fsck: provide a function to parse fsck message IDs
  fsck: introduce identifiers for fsck messages
  fsck: introduce fsck options
2015-08-03 11:01:18 -07:00
Junio C Hamano
acf7189512 Merge branch 'jc/fsck-retire-require-eoh'
A fix to a minor regression to "git fsck" in v2.2 era that started
complaining about a body-less tag object when it lacks a separator
empty line after its header to separate it with a non-existent body.

* jc/fsck-retire-require-eoh:
  fsck: it is OK for a tag and a commit to lack the body
2015-07-13 14:00:24 -07:00
Junio C Hamano
84d18c0bcf fsck: it is OK for a tag and a commit to lack the body
When fsck validates a commit or a tag, it scans each line in the
header of the object using helper functions such as "start_with()",
etc. that work on a NUL terminated buffer, but before a1e920a0
(index-pack: terminate object buffers with NUL, 2014-12-08), the
validation functions were fed the object data in a piece of memory
that is not necessarily terminated with a NUL.

We added a helper function require_end_of_header() to be called at
the beginning of these validation functions to insist that the
object data contains an empty line before its end.  The theory is
that the validating functions will notice and stop when it hits an
empty line as a normal end of header (or a required header line that
is missing) without scanning past the end of potentially not
NUL-terminated buffer.

But the theory forgot that in the older days, Git itself happily
created objects with only the header lines without a body. This
caused Git 2.2 and later to issue an unnecessary warning in some
existing repositories.

With a1e920a0, we do not need to require an empty line (or the body)
in these objects to safely parse and validate them.  Drop the
offending "must have an empty line" check from this helper function,
while keeping the other check to make sure that there is no NUL in
the header part of the object, and adjust the name of the helper to
what it does accordingly.

Noticed-by: Wolfgang Denk <wd@denx.de>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-28 14:47:28 -07:00
Johannes Schindelin
cd94c6f91e fsck: git receive-pack: support excluding objects from fsck'ing
The optional new config option `receive.fsck.skipList` specifies the path
to a file listing the names, i.e. SHA-1s, one per line, of objects that
are to be ignored by `git receive-pack` when `receive.fsckObjects = true`.

This is extremely handy in case of legacy repositories where it would
cause more pain to change incorrect objects than to live with them
(e.g. a duplicate 'author' line in an early commit object).

The intended use case is for server administrators to inspect objects
that are reported by `git push` as being too problematic to enter the
repository, and to add the objects' SHA-1 to a (preferably sorted) file
when the objects are legitimate, i.e. when it is determined that those
problematic objects should be allowed to enter the server.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:37 -07:00
Johannes Schindelin
f27d05b170 fsck: allow upgrading fsck warnings to errors
The 'invalid tag name' and 'missing tagger entry' warnings can now be
upgraded to errors by specifying `invalidTagName` and
`missingTaggerEntry` in the receive.fsck.<msg-id> config setting.

Incidentally, the missing tagger warning is now really shown as a warning
(as opposed to being reported with the "error:" prefix, as it used to be
the case before this commit).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:36 -07:00
Johannes Schindelin
efaba7cc77 fsck: optionally ignore specific fsck issues completely
An fsck issue in a legacy repository might be so common that one would
like not to bother the user with mentioning it at all. With this change,
that is possible by setting the respective message type to "ignore".

This change "abuses" the missingEmail=warn test to verify that "ignore"
is also accepted and works correctly. And while at it, it makes sure
that multiple options work, too (they are passed to unpack-objects or
index-pack as a comma-separated list via the --strict=... command-line
option).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:36 -07:00
Johannes Schindelin
f50c440730 fsck: disallow demoting grave fsck errors to warnings
Some kinds of errors are intrinsically unrecoverable (e.g. errors while
uncompressing objects). It does not make sense to allow demoting them to
mere warnings.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:36 -07:00
Johannes Schindelin
7d7d5b0568 fsck: make fsck_tag() warn-friendly
When fsck_tag() identifies a problem with the commit, it should try
to make it possible to continue checking the commit object, in case the
user wants to demote the detected errors to mere warnings.

Just like fsck_commit(), there are certain problems that could hide other
issues with the same tag object. For example, if the 'type' line is not
encountered in the correct position, the 'tag' line – if there is any –
would not be handled at all.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:35 -07:00
Johannes Schindelin
c9ad147f83 fsck: handle multiple authors in commits specially
This problem has been detected in the wild, and is the primary reason
to introduce an option to demote certain fsck errors to warnings. Let's
offer to ignore this particular problem specifically.

Technically, we could handle such repositories by setting
receive.fsck.<msg-id> to missingCommitter=warn, but that could hide
missing tree objects in the same commit because we cannot continue
verifying any commit object after encountering a missing committer line,
while we can continue in the case of multiple author lines.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:35 -07:00
Johannes Schindelin
b3584761eb fsck: make fsck_commit() warn-friendly
When fsck_commit() identifies a problem with the commit, it should try
to make it possible to continue checking the commit object, in case the
user wants to demote the detected errors to mere warnings.

Note that some problems are too problematic to simply ignore. For
example, when the header lines are mixed up, we punt after encountering
an incorrect line. Therefore, demoting certain warnings to errors can
hide other problems. Example: demoting the missingauthor error to
a warning would hide a problematic committer line.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:35 -07:00
Johannes Schindelin
e6826e335a fsck: make fsck_ident() warn-friendly
When fsck_ident() identifies a problem with the ident, it should still
advance the pointer to the next line so that fsck can continue in the
case of a mere warning.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:35 -07:00
Johannes Schindelin
71ab8fa840 fsck: report the ID of the error/warning
Some repositories written by legacy code have objects with non-fatal
fsck issues. To allow the user to ignore those issues, let's print
out the ID (e.g. when encountering "missingEmail", the user might
want to call `git config --add receive.fsck.missingEmail=warn`).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:35 -07:00
Johannes Schindelin
5d477a334a fsck (receive-pack): allow demoting errors to warnings
For example, missing emails in commit and tag objects can be demoted to
mere warnings with

	git config receive.fsck.missingemail=warn

The value is actually a comma-separated list.

In case that the same key is listed in multiple receive.fsck.<msg-id>
lines in the config, the latter configuration wins (this can happen for
example when both $HOME/.gitconfig and .git/config contain message type
settings).

As git receive-pack does not actually perform the checks, it hands off
the setting to index-pack or unpack-objects in the form of an optional
argument to the --strict option.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:27:34 -07:00
Johannes Schindelin
0282f4dced fsck: offer a function to demote fsck errors to warnings
There are legacy repositories out there whose older commits and tags
have issues that prevent pushing them when 'receive.fsckObjects' is set.
One real-life example is a commit object that has been hand-crafted to
list two authors.

Often, it is not possible to fix those issues without disrupting the
work with said repositories, yet it is still desirable to perform checks
by setting `receive.fsckObjects = true`. This commit is the first step
to allow demoting specific fsck issues to mere warnings.

The `fsck_set_msg_types()` function added by this commit parses a list
of settings in the form:

	missingemail=warn,badname=warn,...

Unfortunately, the FSCK_WARN/FSCK_ERROR flag is only really heeded by
git fsck so far, but other call paths (e.g. git index-pack --strict)
error out *always* no matter what type was specified. Therefore, we need
to take extra care to set all message types to FSCK_ERROR by default in
those cases.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-23 14:26:46 -07:00
Johannes Schindelin
f417eed8cd fsck: provide a function to parse fsck message IDs
These functions will be used in the next commits to allow the user to
ask fsck to handle specific problems differently, e.g. demoting certain
errors to warnings. The upcoming `fsck_set_msg_types()` function has to
handle partial strings because we would like to be able to parse, say,
'missingemail=warn,missingtaggerentry=warn' command line parameters
(which will be passed by receive-pack to index-pack and unpack-objects).

To make the parsing robust, we generate strings from the enum keys, and
using these keys, we match up strings without dashes case-insensitively
to the corresponding enum values.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-22 12:53:25 -07:00
Johannes Schindelin
c99ba492f1 fsck: introduce identifiers for fsck messages
Instead of specifying whether a message by the fsck machinery constitutes
an error or a warning, let's specify an identifier relating to the
concrete problem that was encountered. This is necessary for upcoming
support to be able to demote certain errors to warnings.

In the process, simplify the requirements on the calling code: instead of
having to handle full-blown varargs in every callback, we now send a
string buffer ready to be used by the callback.

We could use a simple enum for the message IDs here, but we want to
guarantee that the enum values are associated with the appropriate
message types (i.e. error or warning?). Besides, we want to introduce a
parser in the next commit that maps the string representation to the
enum value, hence we use the slightly ugly preprocessor construct that
is extensible for use with said parser.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-22 10:24:27 -07:00
Johannes Schindelin
22410549fc fsck: introduce fsck options
Just like the diff machinery, we are about to introduce more settings,
therefore it makes sense to carry them around as a (pointer to a) struct
containing all of them.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-22 10:23:32 -07:00