fsutil error expected single entry

[crazy-max]

Repro on master (7e4021a) on a Windows machine when building https://github.com/dockersamples/avatars:

> docker buildx build -f ./deploy/web.dockerfile .
[+] Building 0.0s (0/0)  docker:default
[+] Building 0.7s (5/9)                                                                                              docker:default
 => [internal] load build definition from web.dockerfile                                                                       0.0s
 => => transferring dockerfile: 335B                                                                                           0.0s
 => [internal] load metadata for docker.io/library/node:18-bullseye-slim                                                       0.6s
 => [internal] load .dockerignore                                                                                              0.0s
 => => transferring context: 58B                                                                                               0.0s
 => ERROR [internal] load build context                                                                                        0.0s
 => => transferring context:                                                                                                   0.0s
 => [stage-0 1/5] FROM docker.io/library/node:18-bullseye-slim@sha256:f06f9ff9dcc5cfec936a7bf08580c5d9cf0f424fbbd857d3677cff5  0.0s
------
 > [internal] load build context:
------
ERROR: failed to solve: rpc error: code = Unknown desc = expected single entry "web\\package.json" but got "web/package.json"

Might be related to tonistiigi/fsutil#167 (tonistiigi/fsutil@36ef4d8...f098008#diff-0ecba5c38a48c9edee18cf59877735dbc0036535be4a4af3d797b45c5862c71fR150) (cc @jedevc)

I looked at running fsutil tests on Windows and found tonistiigi/fsutil#173 (comment)

[crazy-max]

This patch seems to fix the issue crazy-max/fsutil@b3997ab (didn't test all cases atm)

[jedevc]

Aha, yeah, that definitely looks like the right fix. The expected single entry message is pretty much just an internal failure message - it means we tried to get info for a file, but the info we got back was for a different file, which is pretty weird (so erroring makes sense).

Maybe we should annotate the error there that indicates that this is unexpected and internal? Instead of a genuine error that the library consumer can be expected to handle.

[tonistiigi]

tonistiigi/fsutil#167 (review) still needs a follow-up as well I think. This Walk to get a Stat pattern does not make sense afaics (and seems to be error-prone).

[crazy-max]

@glours Use this branch for your patch in compose: tonistiigi/fsutil@master...crazy-max:fsutil:toslash-keep-gogo

It reverts gogo removal to avoid breaking compat in compose related to buildx vendoring.

replace github.com/tonistiigi/fsutil => github.com/crazy-max/fsutil v0.0.0-20240124164449-376dc28ff40f

[jedevc]

tonistiigi/fsutil#167 (review) still needs a follow-up as well I think. This Walk to get a Stat pattern does not make sense afaics (and seems to be error-prone).

Maybe. I remember a discussion about this on slack/sync, I no longer have access. The problem is that, when filtering files, if a directory had all of it's contents excluded it would never get walked (or something like this). This means that calling Stat on that directory is a bit tricky - we don't want to be able to return Stat on a directory that "doesn't exist" according to Walk. I remember coming up with some bizarre workarounds to handle this (like a "ghost directory" 👻)

We could define Stat on the FS, but I think for FilterFS at least, we need to have the same Walk logic to make sure it "exists".

Obviously this could be massively simplified if we removed the assumption that empty directories are just removed - but this is the implication of doing the lazy evaluation of the parent paths. Not sure exactly why we do this, but if we could change this, then I think we might actually be able to entirely remove our custom FS interface and replace it with the Go FS interface?

(sorry, I've kind of lost a lot of the context for this)

[crazy-max]

With latest changes from fsutil tonistiigi/fsutil@35e1166, I have another error which seems to be on the receiver side:

> docker buildx build -f ./deploy/web.dockerfile .
[+] Building 0.0s (0/0)  docker:default
2024/02/21 17:57:36 http2: server: error reading preface from client //./pipe/docker_engine: file has already been close[+] Building 0.6s (7/9)                                                                                  docker:default
 => [internal] load build definition from web.dockerfile                                                           0.0s
 => => transferring dockerfile: 335B                                                                               0.0s
 => [internal] load metadata for docker.io/library/node:18-bullseye-slim                                           0.4s
 => [internal] load .dockerignore                                                                                  0.0s
 => => transferring context: 58B                                                                                   0.0s
 => [stage-0 1/5] FROM docker.io/library/node:18-bullseye-slim@sha256:0a35c023e8b2a44e5c6a22714eb13b45d9c26307a13  0.0s
 => [internal] load build context                                                                                  0.1s
 => => transferring context: 62.41kB                                                                               0.0s
 => CACHED [stage-0 2/5] WORKDIR /app                                                                              0.0s
 => ERROR [stage-0 3/5] COPY web/package.json web/yarn.lock ./                                                     0.0s
------
 > [stage-0 3/5] COPY web/package.json web/yarn.lock ./:
------
web.dockerfile:8
--------------------
   6 |
   7 |     # install dependencies
   8 | >>> COPY web/package.json web/yarn.lock ./
   9 |     RUN --mount=type=cache,target=/cache/yarn \
  10 |       yarn install
--------------------
ERROR: failed to solve: failed to compute cache key: failed to calculate checksum of ref b5835101-3195-42d3-8b06-35d8de84ee90::p5ufq4sjb4lus5xke23imppgr: "/web/yarn.lock": not found