Reload the HEAD and index data for a submodule after reading the
configuration. The configuration may specify a `path`, so we must
update HEAD and index data with that path in mind.
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.)
On platforms that lack `core.symlinks`, we should not go looking for
symbolic links and `p_readlink` their target. Instead, we should
examine the file's contents.
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).
This reduces the chances of a crash in the thread tests. This shouldn't
affect general usage too much, since the main usage of these functions
are to read into an empty buffer.
Instead of relying on the size and timestamp, which can hide changes
performed in the same second, hash the file content's when we care about
detecting changes.
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
Inserting new REUC entries can quickly become pathological given that
each insert unsorts the REUC vector, and both subsequent lookups *and*
insertions will require sorting it again before being successful.
To avoid this, we're switching to `git_vector_insert_sorted`: this keeps
the REUC vector constantly sorted and lets us use the `on_dup` callback
to skip an extra binary search on each insertion.
