Currently `git_config()` uses a callback mechanism and file rereads for
config values. Due to this approach, it is not uncommon for the config
files to be parsed several times during the run of a git program, with
different callbacks picking out different variables useful to themselves.

Add a `config_set`, that can be used to construct an in-memory cache for
config-like files that the caller specifies (i.e., files like `.gitmodules`,
`~/.gitconfig` etc.). Add two external functions `git_configset_get_value`
and `git_configset_get_value_multi` for querying from the config sets.
`git_configset_get_value` follows `last one wins` semantic (i.e. if there
are multiple matches for the queried key in the files of the configset the
value returned will be the last entry in `value_list`).
`git_configset_get_value_multi` returns a list of values sorted in order of
increasing priority (i.e. last match will be at the end of the list). Add
type specific query functions like `git_configset_get_bool` and similar.

Add a default `config_set`, `the_config_set` to cache all key-value pairs
read from usual config files (repo specific .git/config, user wide
~/.gitconfig, XDG config and the global /etc/gitconfig). `the_config_set`
is populated using `git_config()`.

Add two external functions `git_config_get_value` and
`git_config_get_value_multi` for querying in a non-callback manner from
`the_config_set`. Also, add type specific query functions that are
implemented as a thin wrapper around the `config_set` API.
Signed-off-by: NMatthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: NTanay Abhra <tanayabh@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There is no fchmod() on native Windows platforms (MinGW and MSVC), and the
equivalent Win32 API (SetFileInformationByHandle) requires Windows Vista.

Use chmod() instead.
Signed-off-by: NKarsten Blees <blees@dcon.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The skip_prefix() function returns a pointer to the content
past the prefix, or NULL if the prefix was not found. While
this is nice and simple, in practice it makes it hard to use
for two reasons:

  1. When you want to conditionally skip or keep the string
     as-is, you have to introduce a temporary variable.
     For example:

       tmp = skip_prefix(buf, "foo");
       if (tmp)
	       buf = tmp;

  2. It is verbose to check the outcome in a conditional, as
     you need extra parentheses to silence compiler
     warnings. For example:

       if ((cp = skip_prefix(buf, "foo"))
	       /* do something with cp */

Both of these make it harder to use for long if-chains, and
we tend to use starts_with() instead. However, the first line
of "do something" is often to then skip forward in buf past
the prefix, either using a magic constant or with an extra
strlen(3) (which is generally computed at compile time, but
means we are repeating ourselves).

This patch refactors skip_prefix() to return a simple boolean,
and to provide the pointer value as an out-parameter. If the
prefix is not found, the out-parameter is untouched. This
lets you write:

  if (skip_prefix(arg, "foo ", &arg))
	  do_foo(arg);
  else if (skip_prefix(arg, "bar ", &arg))
	  do_bar(arg);
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

xcalloc() takes two arguments: the number of elements and their size.
config.c includes several calls to xcalloc() that pass the arguments
in reverse order: the size of a struct lock_file*, followed by the
number to allocate.

Rearrange them so they are in the correct order.
Signed-off-by: NBrian Gesiak <modocache@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git_config_string() does not handle '~' and '~user' as part of the
value. Using git_config_pathname() fixes this.
Signed-off-by: NØystein Walle <oystwa@gmail.com>
Reviewed-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is a convenience wrapper to call tolower on each
character of the string.

This makes config's lowercase() function obsolete, though
note that because we have a strbuf, we are careful to
operate over the whole strbuf, rather than assuming that a
NUL is the end-of-string.

We could continue to offer a pure-string lowercase, but
there would be no callers (in most pure-string cases, we
actually duplicate and lowercase the duplicate, for which we
have the xstrdup_tolower wrapper).
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When core.commentChar is "auto", the comment char starts with '#' as
in default but if it's already in the prepared message, find another
char in a small subset. This should stop surprises because git strips
some lines unexpectedly.

Note that git is not smart enough to recognize '#' as the comment char
in custom templates and convert it if the final comment char is
different. It thinks '#' lines in custom templates as part of the
commit message. So don't use this with custom templates.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We don't support comment _strings_ (at least not yet). And multi-byte
character encoding could also be misinterpreted.

The test with two commas is updated because it violates this. It's
added with the patch that introduces core.commentChar in eff80a9f
(Allow custom "comment char" - 2013-01-16). It's not clear to me _why_
that behavior is wanted.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Users may already store sensitive data such as imap.pass in
.git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

[v2: updated for section renames, as noted by Junio]
Signed-off-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This can help avoid -Wuninitialized false positives in
git_config_int and git_config_ulong, as the compiler now
knows that we do not return "ret" if we hit the error
codepath.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The patch extends git config --file interface to allow read config from
stdin.

Editing stdin or setting value in stdin is an error.

Include by absolute path is allowed in stdin config, but not by relative
path.
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We're going to have more options for config source.

Let's alter git_config_with_options() interface to accept struct with
all source options.
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we see a relative config include like:

  [include]
  path = foo

we make it relative to the containing directory of the file
that contains the snippet. This makes no sense for config
read from a blob, as it is not on the filesystem.  Something
like "HEAD:some/path" could have a relative path within the
tree, but:

  1. It would not be part of include.path, which explicitly
     refers to the filesystem.

  2. It would need different parsing rules anyway to
     determine that it is a tree path.

The current code just uses the "name" field, which is wrong.
Let's split that into "name" and "path" fields, use the
latter for relative includes, and fill in only the former
for blobs.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we see config like:

  [include]
  path

the expand_user_path helper notices that the config value is
empty, but we then dereference NULL while printing the error
message (glibc will helpfully print "(null)" for us here,
but we cannot rely on that).

  $ git -c include.path rev-parse
  error: Could not expand include path '(null)'
  fatal: unable to parse command-line config

Instead of tweaking our message, let's actually use
config_error_nonbool to match other config variables that
expect a value:

  $ git -c include.path rev-parse
  error: Missing value for 'include.path'
  fatal: unable to parse command-line config
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-config used a static match array to hold the matches we want to
unset/replace when using --unset or --replace-all.  Use a
variable-sized array instead.

This in particular fixes the symptoms git-svn had when storing large
numbers of svn-remote.*.added-placeholder entries in the config file.

While the tests are rather more paranoid than just --unset and
--replace-all, the other operations already worked.  Indeed git-svn's
usage only breaks the first time *after* creating so many entries,
when it wants to unset and re-add them all.
Reported-by: NJess Hottenstein <jess.hottenstein@gmail.com>
Signed-off-by: NThomas Rast <tr@thomasrast.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Leaving only the function definitions and declarations so that any
new topic in flight can still make use of the old functions, replace
existing uses of the prefixcmp() and suffixcmp() with new API
functions.

The change can be recreated by mechanically applying this:

    $ git grep -l -e prefixcmp -e suffixcmp -- \*.c |
      grep -v strbuf\\.c |
      xargs perl -pi -e '
        s|!prefixcmp\(|starts_with\(|g;
        s|prefixcmp\(|!starts_with\(|g;
        s|!suffixcmp\(|ends_with\(|g;
        s|suffixcmp\(|!ends_with\(|g;
      '

on the result of preparatory changes in this series.
Signed-off-by: NChristian Couder <chriscool@tuxfamily.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Commit 7192777d refactors git_parse_ulong, which is public, into a more
generic function.  But since we kept the git_parse_ulong wrapper, only
that part needs to be public; nobody outside the file calls the
lower-level git_parse_unsigned.

Noticed with sparse.  ("'git_parse_unsigned' was not declared. Should
it be static?")
Signed-off-by: NRamsay Jones <ramsay@ramsay1.demon.co.uk>
Explained-by: NJeff King <peff@peff.net>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>

When you run "git config --int", the maximum size of integer
you get depends on how git was compiled, and what it
considers to be an "int".

This is almost useful, because your scripts calling "git
config" will behave similarly to git internally. But relying
on this is dubious; you have to actually know how git treats
each value internally (e.g., int versus unsigned long),
which is not documented and is subject to change. And even
if you know it is "unsigned long", we do not have a
git-config option to match that behavior.

Furthermore, you may simply be asking git to store a value
on your behalf (e.g., configuration for a hook). In that
case, the relevant range check has nothing at all to do with
git, but rather with whatever scripting tools you are using
(and git has no way of knowing what the appropriate range is
there).

Not only is the range check useless, but it is actively
harmful, as there is no way at all for scripts to look
at config variables with large values. For instance, one
cannot reliably get the value of pack.packSizeLimit via
git-config. On an LP64 system, git happily uses a 64-bit
"unsigned long" internally to represent the value, but the
script cannot read any value over 2G.

Ideally, the "--int" option would simply represent an
arbitrarily large integer. For practical purposes, however,
a 64-bit integer is large enough, and is much easier to
implement (and if somebody overflows it, we will still
notice the problem, and not simply return garbage).
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If we try to parse an integer config argument and get a
number outside of the representable range, we die with the
cryptic message: "bad config value for '%s'".

We can improve two things:

  1. Show the value that produced the error (e.g., bad
     config value '3g' for 'foo.bar').

  2. Mention the reason the value was rejected (e.g.,
     "invalid unit" versus "out of range").

A few tests need to be updated with the new output, but that
should not be representative of real-world breakage, as
scripts should not be depending on the exact text of our
stderr output, which is subject to i18n anyway.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we are parsing an integer or unsigned long, we use
the strto*max functions, which properly set errno to ERANGE
if we get a large value. However, we also do further range
checks after applying our multiplication factor, but do not
set ERANGE. This means that a caller cannot tell if an error
was caused by ERANGE or if the input was simply not a valid
number.

This patch teaches git_parse_signed and git_parse_unsigned to set
ERANGE for range errors, and EINVAL for other errors, so that the
caller can reliably tell these cases apart.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we look at a config value as an integer using the
git_config_int function, we carefully range-check the value
we get and complain if it is out of our range. But the range
we compare to is that of a "long", which we then cast to an
"int" in the function's return value. This means that on
systems where "int" and "long" have different sizes (e.g.,
LP64 systems), we may pass the range check, but then return
nonsense by truncating the value as we cast it to an int.

We can solve this by converting git_parse_long into
git_parse_int, and range-checking the "int" range. Nobody
actually cared that we used a "long" internally, since the
result was truncated anyway. And the only other caller of
git_parse_long is git_config_maybe_bool, which should be
fine to just use int (though we will now forbid out-of-range
nonsense like setting "merge.ff" to "10g" to mean "true",
which is probably a good thing).
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we are parsing integers for config, we use an intmax_t
(or uintmax_t) internally, and then check against the size
of our result type at the end. We can parameterize the
maximum representable value, which will let us re-use the
parsing code for a variety of range checks.

Unfortunately, we cannot combine the signed and unsigned
parsing functions easily, as we have to rely on the signed
and unsigned C types internally.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

According to C99, section 7.1.4:

  Any function declared in a header may be additionally
  implemented as a function-like macro defined in the
  header.

Therefore calling our struct member function pointer "fgetc"
may run afoul of unwanted macro expansion when we call:

  char c = cf->fgetc(cf);

This turned out to be a problem on uclibc, which defines
fgetc as a macro and causes compilation failure.

The standard suggests fixing this in a few ways:

  1. Using extra parentheses to inhibit the function-like
     macro expansion. E.g., "(cf->fgetc)(cf)". This is
     undesirable as it's ugly, and each call site needs to
     remember to use it (and on systems without the macro,
     forgetting will compile just fine).

  2. Using #undef (because a conforming implementation must
     also be providing fgetc as a function). This is
     undesirable because presumably the implementation was
     using the macro for a performance benefit, and we are
     dropping that optimization.

Instead, we can simply use non-colliding names.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If a config parsing error in a file occurs we can die and let the user
fix the issue. This is different for the buf parsing function since it
can be used to parse blobs of .gitmodules files. If a parsing error
occurs here we should proceed since otherwise a database containing such
an error in a single revision could be rendered unusable.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This can be used to read configuration values directly from git's
database. For example it is useful for reading to be checked out
.gitmodules files directly from the database.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

To simplify adding other sources we extract all functions needed for
parsing into a list of callbacks. We implement those callbacks for the
current file parsing. A new source can implement its own set of callbacks.

Instead of storing the concrete FILE pointer for parsing we store a void
pointer. A new source can use this to store its custom data.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The global variable cf is set with an initialized value in all codepaths before
calling this function.

The complete call graph looks like this:

  git_config_from_file
    -> do_config_from
      -> git_parse_file
        -> get_next_char
        -> get_value
            -> get_next_char
            -> parse_value
                -> get_next_char
        -> get_base_var
            -> get_next_char
            -> get_extended_base_var
                -> get_next_char

The variable is initialized in do_config_from.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Because a config callback may start parsing a new file, the
global context regarding the current config file is stored
as a stack. Currently we only need to manage that stack from
git_config_from_file. Let's factor it out to allow new
sources of config data.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

5f44324d (core: log offset pack data accesses happened - 2011-07-06)
provides a way to observe pack access patterns via a config
switch. Setting an environment variable looks more obvious than a
config var, especially when you just need to _observe_, and more
inline with other tracing knobs we have.

Document it as it may be useful for remote troubleshooting.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

c08e4d5b (Enable minimal stat checking, 2013-01-22) advertised
the configuration variable core.checkstat in the documentation and
its log message, but the code expected core.statinfo instead.

For now, add core.checkstat, and warn people who have core.statinfo
in their configuration file that we will remove it in Git 2.0.
Noticed-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The changes v1.7.12.1~2^2~4 (config: warn on inaccessible files,
2012-08-21) and v1.8.1.1~22^2~2 (config: treat user and xdg config
permission problems as errors, 2012-10-13) were intended to prevent
important configuration (think "[transfer] fsckobjects") from being
ignored when the configuration is unintentionally unreadable (for
example with EIO on a flaky filesystem, or with ENOMEM due to a DoS
attack).  Usually ~/.gitconfig and ~/.config/git are readable by the
current user, and if they aren't then it would be easy to fix those
permissions, so the damage from adding this check should have been
minimal.

Unfortunately the access() check often trips when git is being run as
a server.  A daemon (such as inetd or git-daemon) starts as "root",
creates a listening socket, and then drops privileges, meaning that
when git commands are invoked they cannot access $HOME and die with

 fatal: unable to access '/root/.config/git/config': Permission denied

Any patch to fix this would have one of three problems:

  1. We annoy sysadmins who need to take an extra step to handle HOME
     when dropping privileges (the current behavior, or any other
     proposal that they have to opt into).

  2. We annoy sysadmins who want to set HOME when dropping privileges,
     either by making what they want to do impossible, or making them
     set an extra variable or option to accomplish what used to work
     (e.g., a patch to git-daemon to set HOME when --user is passed).

  3. We loosen the check, so some cases which might be noteworthy are
     not caught.

This patch is of type (3).

Treat user and xdg configuration that are inaccessible due to
permissions (EACCES) as though no user configuration was provided at
all.

An alternative method would be to check if $HOME is readable, but that
would not help in cases where the user who dropped privileges had a
globally readable HOME with only .config or .gitconfig being private.

This does not change the behavior when /etc/gitconfig or .git/config
is unreadable (since those are more serious configuration errors),
nor when ~/.gitconfig or ~/.config/git is unreadable due to problems
other than permissions.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Improved-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The config callback functions get keys of the general form:

  section.subsection.key

(where the subsection may be contain arbitrary data, or may
be missing). For matching keys without subsections, it is
simple enough to call "strcmp". Matching keys with
subsections is a little more complicated, and each callback
does it in an ad-hoc way, usually involving error-prone
pointer arithmetic.

Let's provide a helper that keeps the pointer arithmetic all
in one place.
Signed-off-by: NJeff King <peff@peff.net>
Reviewed-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Specifically the fields uid, gid, ctime, ino and dev are set to zero
by JGit. Other implementations, eg. Git in cygwin are allegedly also
somewhat incompatible with Git For Windows and on *nix platforms
the resolution of the timestamps may differ.

Any stat checking by git will then need to check content, which may
be very slow, particularly on Windows. Since mtime and size
is typically enough we should allow the user to tell git to avoid
checking these fields if they are set to zero in the index.

This change introduces a core.checkstat config option where the
the user can select to check all fields (default), or just size
and the whole second part of mtime (minimal).
Signed-off-by: NRobin Rosenberg <robin.rosenberg@dewire.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Some users do want to write a line that begin with a pound sign, #,
in their commit log message.  Many tracking system recognise
a token of #<bugid> form, for example.

The support we offer these use cases is not very friendly to the end
users.  They have a choice between

 - Don't do it.  Avoid such a line by rewrapping or indenting; and

 - Use --cleanup=whitespace but remove all the hint lines we add.

Give them a way to set a custom comment char, e.g.

    $ git -c core.commentchar="%" commit

so that they do not have to do either of the two workarounds.

[jc: although I started the topic, all the tests and documentation
updates, many of the call sites of the new strbuf_add_commented_*()
functions, and the change to git-submodule.sh scripted Porcelain are
from Ralf.]
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Signed-off-by: NRalf Thielow <ralf.thielow@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There are a few error functions that simply wrap error() and
provide a standardized message text. Like error(), they
always return -1; knowing that can help the compiler silence
some false positive -Wuninitialized warnings.

One strategy would be to just declare these as inline in the
header file so that the compiler can see that they always
return -1. However, gcc does not always inline them (e.g.,
it will not inline opterror, even with -O3), which renders
our change pointless.

Instead, let's follow the same route we did with error() in
the last patch, and define a macro that makes the constant
return value obvious to the compiler.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In a bare repository, there isn't a simple way to respect an
in-tree mailmap without extracting it to a temporary file.
This patch provides a config variable, similar to
mailmap.file, which reads the mailmap from a blob in the
repository.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The get_value function has a goto label for cleaning up on
errors, but it only cleans up half of what the function
might allocate. Let's also clean up the key and regexp
variables there.

Note that we need to take special care when compiling the
regex fails to clean it up ourselves, since it is in a
half-constructed state (we would want to free it, but not
regfree it).

Similarly, we fix git_config_parse_key to return NULL when
it fails, not a pointer to some already-freed memory.
Signed-off-by: NJeff King <peff@peff.net>

There is convenience in warning and moving on when somebody has a
bogus permissions on /etc/gitconfig and cannot do anything about it.
But the cost in predictability and security is too high --- when
unreadable config files are skipped, it means an I/O error or
permissions problem causes important configuration to be bypassed.

For example, servers may depend on /etc/gitconfig to enforce security
policy (setting transfer.fsckObjects or receive.deny*).  Best to
always error out when encountering trouble accessing a config file.

This may add inconvenience in some cases:

  1. You are inspecting somebody else's repo, and you do not have
     access to their .git/config file.  Git typically dies in this
     case already since we cannot read core.repositoryFormatVersion,
     so the change should not be too noticeable.

  2. You have used "sudo -u" or a similar tool to switch uid, and your
     environment still points Git at your original user's global
     config, which is not readable.  In this case people really would
     be inconvenienced (they would rather see the harmless warning and
     continue the operation) but they can work around it by setting
     HOME appropriately after switching uids.

  3. You do not have access to /etc/gitconfig due to a broken setup.
     In this case, erroring out is a good way to put pressure on the
     sysadmin to fix the setup.  While they wait for a reply, users
     can set GIT_CONFIG_NOSYSTEM to true to keep Git working without
     complaint.

After this patch, errors accessing the repository-local and systemwide
config files and files requested in include directives cause Git to
exit, just like errors accessing ~/.gitconfig.
Explained-by: NJeff King <peff@peff.net>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Git reads multiple configuration files: settings come first from the
system config file (typically /etc/gitconfig), then the xdg config
file (typically ~/.config/git/config), then the user's dotfile
(~/.gitconfig), then the repository configuration (.git/config).

Git has always used access(2) to decide whether to use each file; as
an unfortunate side effect, that means that if one of these files is
unreadable (e.g., EPERM or EIO), git skips it.  So if I use
~/.gitconfig to override some settings but make a mistake and give it
the wrong permissions then I am subject to the settings the sysadmin
chose for /etc/gitconfig.

Better to error out and ask the user to correct the problem.

This only affects the user and xdg config files, since the user
presumably has enough access to fix their permissions.  If the system
config file is unreadable, the best we can do is to warn about it so
the user knows to notify someone and get on with work in the meantime.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>