At the moment the module resolver will end up in an infinite loop in Windows because we are assuming that the root directory is always `/` however in windows this can be any drive letter example `c:/` or `d:/` etc...
With this change we also resolve the drive letter in windows, when using `AbsoluteFsPath.from` for consistence so under `/foo` will be converted to `c:/foo` this is also needed because of relative paths with different drive letters.
PR Close#30297
If an entry-point has a missing dependency then all the entry-points
that would have pointed to that dependency are also removed from
the dependency graph.
Previously we were still processing the dependencies of an entry-point
even if it had already been removed from the graph because it depended
upon a missing dependency that had previously been removed due to another
entry-point depending upon it.
This caused the dependency processing to crash rather than gracefully
logging and handling the missing invalid entry-point.
Fixes#29624
PR Close#30270
This commit introduces a new interface, which abstracts access
to the underlying `FileSystem`. There is initially one concrete
implementation, `NodeJsFileSystem`, which is simply wrapping the
`fs` library of NodeJs.
Going forward, we can provide a `MockFileSystem` for test, which
should allow us to stop using `mock-fs` for most of the unit tests.
We could also implement a `CachedFileSystem` that may improve the
performance of ngcc.
PR Close#29643
