The code that reads from a region that mmaps an on-disk index
assumed that "int"/"short" are always 32/16 bits.

* tg/index-struct-sizes:
  read-cache: use fixed width integer types

"git mv A B" when moving a submodule A does "the right thing",
inclusing relocating its working tree and adjusting the paths in
the .gitmodules file.

* jl/submodule-mv: (53 commits)
  rm: delete .gitmodules entry of submodules removed from the work tree
  mv: update the path entry in .gitmodules for moved submodules
  submodule.c: add .gitmodules staging helper functions
  mv: move submodules using a gitfile
  mv: move submodules together with their work trees
  rm: do not set a variable twice without intermediate reading.
  t6131 - skip tests if on case-insensitive file system
  parse_pathspec: accept :(icase)path syntax
  pathspec: support :(glob) syntax
  pathspec: make --literal-pathspecs disable pathspec magic
  pathspec: support :(literal) syntax for noglob pathspec
  kill limit_pathspec_to_literal() as it's only used by parse_pathspec()
  parse_pathspec: preserve prefix length via PATHSPEC_PREFIX_ORIGIN
  parse_pathspec: make sure the prefix part is wildcard-free
  rename field "raw" to "_raw" in struct pathspec
  tree-diff: remove the use of pathspec's raw[] in follow-rename codepath
  remove match_pathspec() in favor of match_pathspec_depth()
  remove init_pathspec() in favor of parse_pathspec()
  remove diff_tree_{setup,release}_paths
  convert common_prefix() to use struct pathspec
  ...

Use the fixed width integer types uint16_t and uint32_t for on-disk
structures; unsigned short and unsigned int do not have a guaranteed
size.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Ondřej Bílka <neleai@seznam.cz>
Reviewed-by: Marc Branchaud <marcnarc@xiplink.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

I attempted to make index_state->cache[] a "const struct cache_entry **"
to find out how existing entries in index are modified and where. The
question I have is what do we do if we really need to keep track of on-disk
changes in the index. The result is

 - diff-lib.c: setting CE_UPTODATE

 - name-hash.c: setting CE_HASHED

 - preload-index.c, read-cache.c, unpack-trees.c and
   builtin/update-index: obvious

 - entry.c: write_entry() may refresh the checked out entry via
   fill_stat_cache_info(). This causes "non-const struct cache_entry
   *" in builtin/apply.c, builtin/checkout-index.c and
   builtin/checkout.c

 - builtin/ls-files.c: --with-tree changes stagemask and may set
   CE_UPDATE

Of these, write_entry() and its call sites are probably most
interesting because it modifies on-disk info. But this is stat info
and can be retrieved via refresh, at least for porcelain
commands. Other just uses ce_flags for local purposes.

So, keeping track of "dirty" entries is just a matter of setting a
flag in index modification functions exposed by read-cache.c. Except
unpack-trees, the rest of the code base does not do anything funny
behind read-cache's back.

The actual patch is less valueable than the summary above. But if
anyone wants to re-identify the above sites. Applying this patch, then
this:

    diff --git a/cache.h b/cache.h
    index 430d021..1692891 100644
    --- a/cache.h
    +++ b/cache.h
    @@ -267,7 +267,7 @@ static inline unsigned int canon_mode(unsigned int mode)
     #define cache_entry_size(len) (offsetof(struct cache_entry,name) + (len) + 1)

     struct index_state {
    -	struct cache_entry **cache;
    +	const struct cache_entry **cache;
     	unsigned int version;
     	unsigned int cache_nr, cache_alloc, cache_changed;
     	struct string_list *resolve_undo;

will help quickly identify them without bogus warnings.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

"git pack-refs" that races with new ref creation or deletion have
been susceptible to lossage of refs under right conditions, which
has been tightened up.

* mh/ref-races:
  for_each_ref: load all loose refs before packed refs
  get_packed_ref_cache: reload packed-refs file when it changes
  add a stat_validity struct
  Extract a struct stat_data from cache_entry
  packed_ref_cache: increment refcount when locked
  do_for_each_entry(): increment the packed refs cache refcount
  refs: manage lifetime of packed refs cache via reference counting
  refs: implement simple transactions for the packed-refs file
  refs: wrap the packed refs cache in a level of indirection
  pack_refs(): split creation of packed refs and entry writing
  repack_without_ref(): split list curation and entry writing

* rs/discard-index-discard-array:
  read-cache: free cache in discard_index
  read-cache: add simple performance test

It can sometimes be useful to know whether a path in the
filesystem has been updated without going to the work of
opening and re-reading its content. We trust the stat()
information on disk already to handle index updates, and we
can use the same trick here.

This patch introduces a "stat_validity" struct which
encapsulates the concept of checking the stat-freshness of a
file. It is implemented on top of "struct stat_data" to
reuse the logic about which stat entries to trust for a
particular platform, but hides the complexity behind two
simple functions: check and update.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Add public functions fill_stat_data() and match_stat_data() to work
with it.  This infrastructure will later be used to check the validity
of other types of file.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>