"package io/fs is not in GOROOT" on Go 1.15

[zikaeroh]

Describe the Bug

golang-migrate no longer builds in Go 1.15 due to the addition of io/fs, imported via tests.

Steps to Reproduce
Steps to reproduce the behavior:

Add v4.14.0 to the project, then run go mod tidy. I get:

github.com/hortbot/hortbot/internal/db/migrations imports
	github.com/golang-migrate/migrate/v4/database/postgres tested by
	github.com/golang-migrate/migrate/v4/database/postgres.test imports
	github.com/golang-migrate/migrate/v4/source/file imports
	github.com/golang-migrate/migrate/v4/source/iofs imports
	io/fs: package io/fs is not in GOROOT (/usr/lib/go/src/io/fs)
github.com/hortbot/hortbot/internal/db/migrations imports
	github.com/golang-migrate/migrate/v4/database/postgres tested by
	github.com/golang-migrate/migrate/v4/database/postgres.test imports
	github.com/golang-migrate/migrate/v4/source/file imports
	github.com/golang-migrate/migrate/v4/source/iofs tested by
	github.com/golang-migrate/migrate/v4/source/iofs.test imports
	embed: package embed is not in GOROOT (/usr/lib/go/src/embed)

Expected Behavior

No output.

Migrate Version

v4.14.0

Loaded Source Drivers

N/A

Loaded Database Drivers

N/A

Go Version

go version go1.15.5 linux/amd64

Stacktrace

N/A

Additional context

N/A

[dhui]

Looks like modules ignore build constraints
For now use v4.13.0
I'll release v4.14.1 later that removes the iofs source driver until Go 1.16 is the minimum supported version by migrate

[zikaeroh]

I don't think that's the whole issue. If you just clone this repo and run go mod tidy, it fails.

github.com/golang-migrate/migrate/v4/source/iofs imports
	io/fs: package io/fs is not in GOROOT (/usr/lib/go/src/io/fs)
github.com/golang-migrate/migrate/v4/source/iofs tested by
	github.com/golang-migrate/migrate/v4/source/iofs.test imports
	embed: package embed is not in GOROOT (/usr/lib/go/src/embed)

[zikaeroh]

Unless I'm mistaken, the issue is that the iofs package is not buildable in Go 1.15. There are build tags in the file source package, but the iofs package needs build tags too, even if they just replace things with noops or panics (or nothing at all, which is likely best).

[wayneashleyberry]

I'm seeing the same issue in a project of mine, both go test and go build work but go mod tidy fails.

github.com/overhq/over-projects-api/pkg/migrator imports
	github.com/golang-migrate/migrate/v4/database/mysql tested by
	github.com/golang-migrate/migrate/v4/database/mysql.test imports
	github.com/golang-migrate/migrate/v4/source/file imports
	github.com/golang-migrate/migrate/v4/source/iofs imports
	io/fs: package io/fs is not in GOROOT (/usr/local/Cellar/go/1.15.5/libexec/src/io/fs)
github.com/overhq/over-projects-api/pkg/migrator imports
	github.com/golang-migrate/migrate/v4/database/mysql tested by
	github.com/golang-migrate/migrate/v4/database/mysql.test imports
	github.com/golang-migrate/migrate/v4/source/file imports
	github.com/golang-migrate/migrate/v4/source/iofs tested by
	github.com/golang-migrate/migrate/v4/source/iofs.test imports
	embed: package embed is not in GOROOT (/usr/local/Cellar/go/1.15.5/libexec/src/embed)

[ksegun]

We also make use of this library and this is breaking our builds because of the module dependencies we have to pin over 30+ repos to v4.13.0 is there an outlook for when v4.14.1 will be available?

[johejo]

I'm the author of the #472.
Sorry for breaking the builds of many users.
I made a Pull Request for revert.
Please wait for the next release by maintainer.

[zikaeroh]

Regardless of the revert, when the package is reintroduced (which I would still do for 1.16), it will work with the build tags guarding the imports of io/fs itself. You probably don't need a full revert if you stick // +build go1.16 into the existing files in iofs and add a single file with:

// +build !go1.16

package iofs

That will guard its use in versions below 1.16.

[zikaeroh]

Hm, I say that, but you've done that in iofs already...

[zikaeroh]

Ugh, this is golang/go#40067. Sorry for the noise.

I guess this driver could live in another repo until 1.16 is the minimum. Going via http.FileSystem works as well, though is clearly an unnecessary dep.

[ksegun]

I'm the author of the #472.
Sorry for breaking the builds of many users.
I made a Pull Request for revert.
Please wait for the next release by maintainer.

Thank you so much, I know it was not your intent, and thank you for this library.

[dhui]

Fixed in v4.14.1