Composer path repositories install a package as a symlink, so a source
directory reached through one contributed no files at all: PHP's
RecursiveDirectoryIterator does not descend into symlinked directories
unless asked, because RecursiveIteratorIterator calls hasChildren() and
its $allowLinks argument defaults to false.
The build still reported success, and the missing classes only surfaced
at runtime as `class 'X' is undefined`.
Scan with FilesystemIterator::FOLLOW_SYMLINKS. A linked directory is an
ordinary source entry with no setting of its own; what is compiled stays
with `sources` and `ignore`.
Exclusions match the path that reached a file, the one the project wrote
and the scanner traversed. An `ignore` entry is no longer resolved to its
link target, which compared a real path against a linked one and so never
matched.
Real paths are kept for identity alone. A link is refused when it closes
the branch that reached it, so a link to one of its own ancestors cannot
recurse; files reachable through several links are reduced to one path
after exclusions have run, since deduplicating before that would drop an
allowed alias along with an excluded one.
Alexandre Gomes Gaigalas
60f2361b96