BTW are you trying to avoid port mapping because ports are dynamic and not known in advance? If so you could try running the container with --net=host and in Docker Desktop Settings navigate to Resources / Network and Enable Host Networking. This will automatically set up tunnels when applications listen on a port in the container.

Thanks for the links, I'll dig into those!

> TCG > Added support for Apple Silicon hosts (macOS)

Apart from the too-many-ports problem, I think the main remaining problem is that too many 3rd party libraries require Unix-isms to build, like shell scripts. This necessitates the presence of cygwin for build (but not at runtime). However the ongoing "dune-ification" of the OCaml universe should help fix this since dune can do everything directly from OCaml code. I'm really looking forward to being able to open a powershell window and type "git clone"; "dune build" and have everything just work.

There are some interesting experiments combining the two more closely -- take a look at "duniverse" https://github.com/avsm/duniverse which is a prototype system which would use opam to solve package version constraints and download the sources, allowing dune to build everything at once. The nice thing about this is that you could patch one of your dependencies and then dune will be able to perform an incremental build, as if all the code was in one big project. I'm personally hoping this will help speed up Mirage development as it can be time-consuming to propose a change to an interface and then find all the places that need changing (a cost of having lots of small repos versus a big monorepo)

I'm looking forward to the day when I won't need Cygwin even in the build environment. Since the OCaml compiler itself works fine on Windows and modern build systems like "dune" are also Windows-friendly I'm fairly optimistic this can happen soon. I think it'll mostly be a matter of removing accidental Unix-isms (like unnecessary use of symlinks) in the build scripts.

There's a push to remove "optional dependencies" which are the reason why opam dependencies rebuild again and again: http://rgrinberg.com/posts/optional-dependencies-considered-... For example in the Mirage project we've been working on this https://discuss.ocaml.org/t/ann-major-releases-of-cohttp-con... but it has caused some breakage here and there.

jbuilder (from Jane Street) is excellent: expressive, easy to understand, builds packages extremely quickly, is actively developed, has minimal dependencies and a lovely manual http://jbuilder.readthedocs.io/en/latest/ It takes care of generating boilerplate for other tools like merlin (which to be honest I never got around to manually configuring). There's also work to integrate it with utop https://github.com/janestreet/jbuilder/issues/114

jbuilder also supports building multiple libraries in one big source tree, so we could switch to a package lockfile model: the author uses opam to create a solution to the package constraints and checks in the specific versions known to work, the build clones the dependency sources and jbuilder builds it all simultaneously. I'm keen to try this on one of my larger projects so that "git clone; make" just works, irrespective of where the host OCaml comes from.

PPX syntax extensions depend on specific compiler versions, so when (for example) homebrew updates to OCaml 4.05 you might find that extensions you need have not been ported yet. ocaml-migrate-parsetree aims to fix this problem http://ocamllabs.io/projects/2017/02/15/ocaml-migrate-parset...

There's obviously still plenty of work to do, but I think things are improving!

Apologies for the inconvenience this has caused.

There was a race condition in a previous release which could allow multiple hypervisor instances to open the Docker.qcow2 simultaneously. Unfortunately this can corrupt the file by allocating the same physical block (cluster) twice, resulting in bad things happening. When this file-locking bug was fixed we also added an integrity check which checks the structure of the Docker.qcow2 on every application launch. For safety the app refuses to start if corruption is detected.

I believe that in these cases, the corruption happened in the past and is now being detected since the upgrade. Unfortunately if the app refuses to start it makes it difficult to reach the "Reset to Factory defaults" menu option. The workaround described here https://github.com/docker/for-mac/issues/1159#issuecomment-2... is to remove the qcow2 and restart the app. Unfortunately containers and images will need to be rebuilt.

For what it's worth after the integrity check and the locking fix went in, I've not seen any recurrence of this error. Please open an issue if you see any other problems!