This package imports all "importable" packages, i.e., packages that:
- are not applications ("main")
- are not internal
- and that have non-test go-files
We do this to verify that our code can be consumed as a dependency
in "module mode". When using a dependency that does not have a go.mod
(i.e.; is not a "module"), go implicitly generates a go.mod. Lacking
information from the dependency itself, it assumes "go1.16" language
(see [DefaultGoModVersion]). Starting with Go1.21, go downgrades the
language version used for such dependencies, which means that any
language feature used that is not supported by go1.16 results in a
compile error;
# github.com/docker/cli/cli/context/store
/go/pkg/mod/github.com/docker/cli@v25.0.0-beta.2+incompatible/cli/context/store/storeconfig.go:6:24: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
/go/pkg/mod/github.com/docker/cli@v25.0.0-beta.2+incompatible/cli/context/store/store.go:74:12: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
These errors do NOT occur when using GOPATH mode, nor do they occur
when using "pseudo module mode" (the "-mod=mod -modfile=vendor.mod"
approach used in this repository).
As a workaround for this situation, we must include "//go:build" comments
in any file that uses newer go-language features (such as the "any" type
or the "min()", "max()" builtins).
From the go toolchain docs (https://go.dev/doc/toolchain):
> The go line for each module sets the language version the compiler enforces
> when compiling packages in that module. The language version can be changed
> on a per-file basis by using a build constraint.
>
> For example, a module containing code that uses the Go 1.21 language version
> should have a go.mod file with a go line such as go 1.21 or go 1.21.3.
> If a specific source file should be compiled only when using a newer Go
> toolchain, adding //go:build go1.22 to that source file both ensures that
> only Go 1.22 and newer toolchains will compile the file and also changes
> the language version in that file to Go 1.22.
This file is a generated module that imports all packages provided in
the repository, which replicates an external consumer using our code
as a dependency in go-module mode, and verifies all files in those
packages have the correct "//go:build <go language version>" set.
To test this package:
make shell
make -C ./internal/gocompat/
make: Entering directory '/go/src/github.com/docker/cli/internal/gocompat'
GO111MODULE=off go generate .
GO111MODULE=on go mod tidy
GO111MODULE=on go test -v
# github.com/docker/cli/templates
../../templates/templates.go:13:17: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
# github.com/docker/cli/cli/compose/template
../../cli/compose/template/template.go:98:45: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/template/template.go:105:27: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/template/template.go:141:28: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
# github.com/docker/cli/cli/compose/types
../../cli/compose/types/types.go:53:22: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:86:34: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:105:22: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:137:34: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:211:20: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:343:35: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:442:40: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:469:24: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:490:24: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:587:28: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/types/types.go:442:40: too many errors
# github.com/docker/cli/cli/context/store
../../cli/context/store/storeconfig.go:6:24: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/context/store/store.go:74:12: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/context/store/store.go:75:23: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/context/store/metadatastore.go:43:58: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/context/store/metadatastore.go:48:22: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/context/store/metadatastore.go:80:30: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
# github.com/docker/cli/cli/command/idresolver
../../cli/command/idresolver/idresolver.go:6:2: "github.com/docker/docker/api/types" imported and not used
../../cli/command/idresolver/idresolver.go:7:2: "github.com/docker/docker/api/types/swarm" imported and not used
../../cli/command/idresolver/idresolver.go:9:2: "github.com/pkg/errors" imported and not used
../../cli/command/idresolver/idresolver.go:28:49: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/command/idresolver/idresolver.go:58:53: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
# github.com/docker/cli/cli/compose/schema
../../cli/compose/schema/schema.go:20:46: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/schema/schema.go:27:53: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/schema/schema.go:45:32: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../../cli/compose/schema/schema.go:66:33: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
FAIL gocompat [build failed]
make: *** [Makefile:3: verify] Error 1
make: Leaving directory '/go/src/github.com/docker/cli/internal/gocompat'
[DefaultGoModVersion]: https://github.com/golang/go/blob/58c28ba286dd0e98fe4cca80f5d64bbcb824a685/src/cmd/go/internal/gover/version.go#L15-L24
[2]: https://go.dev/doc/toolchain
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
