## Changes
Introduce `libs/vfs` for an implementation of `fs.FS` and friends that
_includes_ the absolute path it is anchored to.
This is needed for:
1. Intercepting file operations to inject custom logic (e.g., logging,
access control).
2. Traversing directories to find specific leaf directories (e.g.,
`.git`).
3. Converting virtual paths to OS-native paths.
Options 2 and 3 are not possible with the standard `fs.FS` interface.
They are needed such that we can provide an instance to the sync package
and still detect the containing `.git` directory and convert paths to
native paths.
This change focuses on making the following packages use `vfs.Path`:
* libs/fileset
* libs/git
* libs/sync
All entries returned by `fileset.All` are now slash-separated. This has
2 consequences:
* The sync snapshot now always uses slash-separated paths
* We don't need to call `filepath.FromSlash` as much as we did
## Tests
* All unit tests pass
* All integration tests pass
* Manually confirmed that a deployment made on Windows by a previous
version of the CLI can be deployed by a new version of the CLI while
retaining the validity of the local sync snapshot as well as the remote
deployment state.
## Changes
This change replaces usage of the `repofiles` package with the `filer`
package to consolidate WSFS code paths.
The `repofiles` package implemented the following behavior. If a file at
`foo/bar.txt` was created and removed, the directory `foo` was kept
around because we do not perform directory tracking. If subsequently, a
file at `foo` was created, it resulted in an `fs.ErrExist` because it is
impossible to overwrite a directory. It would then perform a recursive
delete of the path if this happened and retry the file write.
To make this use case work without resorting to a recursive delete on
conflict, we need to implement directory tracking as part of sync. The
approach in this commit is as follows:
1. Maintain set of directories needed for current set of files. Compare
to previous set of files. This results in mkdir of added directories and
rmdir of removed directories.
2. Creation of new directories should happen prior to writing files.
Otherwise, many file writes may race to create the same parent
directories, resulting in additional API calls. Removal of existing
directories should happen after removing files.
3. Making new directories can be deduped across common prefixes where
only the longest prefix is created recursively.
4. Removing existing directories must happen sequentially, starting with
the longest prefix.
5. Removal of directories is a best effort. It fails only if the
directory is not empty, and if this happens we know something placed a
file or directory manually, outside of sync.
## Tests
* Existing integration tests pass (modified where it used to assert
directories weren't cleaned up)
* New integration test to confirm the inability to remove a directory
doesn't fail the sync run
Pieter Noordhuis