apply --ignore-space-change: lines with and without leading whitespaces do not match

The fuzzy_matchlines() function is used when attempting to resurrect
a patch that is whitespace-damaged, or when applying a patch that
was produced against an old codebase to the codebase after
indentation change.

The patch may want to change a line "a_bc" ("_" is used throught
this description for a whitespace to make it stand out) in the
original into something else, and we may not find "a_bc" in the
current source, but there may be "a__bc" (two spaces instead of one
the whitespace-damaged patch claims to expect).  By ignoring the
amount of whitespaces, it forces "git apply" to consider that "a_bc"
in the broken patch meant to refer to "a__bc" in reality.

However, the implementation special cases a run of whitespaces at
the beginning of a line and makes "abc" match "_abc", even though a
whitespace in the middle of string never matches a 0-width gap,
e.g. "a_bc" does not match "abc".  A run of whitespace at the end of
one string does not match a 0-width end of line on the other line,
either, e.g. "abc_" does not match "abc".

Fix this inconsistency by making the code skip leading whitespaces
only when both strings begin with a whitespace.  This makes the
option mean the same as the option of the same name in "diff" and
"git diff".

Note that I am not sure if anybody sane should use this option in
the first place.  The fuzzy match logic may be able to find the
original line that the patch author may have meant to touch because
it does not fully trust what the original lines say (i.e. context
lines prefixed by " " and old lines prefixed by "-" does not have to
exactly match the contents the patch is applied to).  There is no
reason for us to trust what the replacement lines (i.e. new lines
prefixed by "+") say, either, but with this option enabled, we end
up copying these new lines with suspicious whitespace distributions
literally into the patched result.  But as long as we keep it, we
should make it do its insane thing consistently.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
doc: submodule.* config are keyed by submodule names

Ever since 941987a5 (git-submodule: give submodules proper names,
2007-06-11) introduced the ability to move a submodule from one path
to another inside its superproject tree without losing its identity,
we should have consistently used submodule.<name>.* to access
settings related to the named submodule.

Reported-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
doc: submodule.*.branch config is keyed by name

Ever since 941987a5 (git-submodule: give submodules proper names,
2007-06-11) introduced the ability to move a submodule from one path
to another inside its superproject tree without losing its identity,
we should have consistently used submodule.<name>.* to access
settings related to the named submodule.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'wt/doc-submodule-name-path-confusion-1' into jch

* wt/doc-submodule-name-path-confusion-1:
  doc: submodule.* config are keyed by submodule names
Merge branch 'wt/doc-submodule-name-path-confusion-2' into jch

* wt/doc-submodule-name-path-confusion-2:
  doc: submodule.*.branch config is keyed by name
MSVC: link in invalidcontinue.obj for better POSIX compatibility

By default, Windows abort()'s instead of setting
errno=EINVAL when invalid arguments are passed to standard functions.

For example, when PAGER quits and git detects it with
errno=EPIPE on write(), check_pipe() in write_or_die.c tries raise(SIGPIPE)
but since there is no SIGPIPE on Windows, it is treated as invalid argument,
causing abort() and crash report window.

Linking in invalidcontinue.obj (provided along with MS compiler) allows
raise(SIGPIPE) to return with errno=EINVAL.

Signed-off-by: Marat Radchenko <marat@slonopotamus.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'mr/msvc-link-with-invalidcontinue' into jch

* mr/msvc-link-with-invalidcontinue:
  MSVC: link in invalidcontinue.obj for better POSIX compatibility
Merge branch 'jc/apply-ignore-whitespace' into jch

An RFC.  "--ignore-space-change" option of "git apply" ignored the
spaces at the beginning of line too aggressively, which is
inconsistent with the option of the same name "diff" and "git diff"
have.

* jc/apply-ignore-whitespace:
  apply --ignore-space-change: lines with and without leading whitespaces do not match