Don't put the configuration in a subdir of the sandbox named
`config`, lest some tests decide to create their own directory
called `config`. Prefix with some underscores for uniqueness.
Ensure that `git_index_read_index` clears the uptodate bit on
files that it modifies.
Further, do not propagate the cache from an on-disk index into
another on-disk index. Although this should not be done, as
`git_index_read_index` is used to bring an in-memory index into
another index (that may or may not be on-disk), ensure that we do
not accidentally bring in these bits when misused.
Test that entries are only smudged when we write the index: the
entry smudging is to prevent us from updating an index in a way
that it would be impossible to tell that an item was racy.
Consider when we load an index: any entries that have the same
(or newer) timestamp than the index itself are considered racy,
and are subject to further scrutiny.
If we *save* that index with the same entries that we loaded,
then the index would now have a newer timestamp than the entries,
and they would no longer be given that additional scrutiny, failing
our racy detection! So test that we smudge those entries only on
writing the new index, but that we can detect them (in diff) without
having to write.
When there's no matching index entry (for whatever reason), don't
try to dereference the null return value to get at the id.
Otherwise when we break something in the index API, the checkout
test crashes for confusing reasons and causes us to step through
it in a debugger thinking that we had broken much more than we
actually did.
Keep track of entries that we believe are up-to-date, because we
added the index entries since the index was loaded. This prevents
us from unnecessarily examining files that we wrote during the
cleanup of racy entries (when we smudge racily clean files that have
a timestamp newer than or equal to the index's timestamp when we
read it). Without keeping track of this, we would examine every
file that we just checked out for raciness, since all their timestamps
would be newer than the index's timestamp.
When creating a filebuf, detect a directory that exists in our
target file location. This prevents a failure later, when we try
to move the lock file to the destination.
Test that on platforms without `core.symlinks`, we preserve symlinks
in `git_index_add_bypath`. (Users should correct the actual index
entry's mode to change a link to a regular file.)
When `core.symlinks = false`, we write the symlinks content (target)
to a regular file. We should ensure that when we later see that
regular file, we treat it specially - and that changing that regular
file would actually change the symlink target. (For compatibility
with Git for Windows).
We currently use the timestamp in order to decide whether a config file
has changed since we last read it.
This scheme falls down if the file is written twice within the same
second, as we fail to detect the file change after the first read in
that second.
Using calloc instead of malloc because the parse error will lead to an immediate free of committer (and its properties, which can segfault on free if undefined - test_refs_reflog_reflog__reading_a_reflog_with_invalid_format_returns_error segfaulted before the fix).
#3458
Provide a new merge option, GIT_MERGE_TREE_FAIL_ON_CONFLICT, which
will stop on the first conflict and fail the merge operation with
GIT_EMERGECONFLICT.
Test that nanoseconds are round-tripped correctly when we read
an index file that contains them. We should, however, ignore them
because we don't understand them, and any new entries in the index
should contain a `0` nsecs field, while existing preserving entries.
