codekingpro/portable-devtools

1Vendoring in std and cmd2========================3 4The Go command maintains copies of external packages needed by the5standard library in the src/vendor and src/cmd/vendor directories.6 7There are two modules, std and cmd, defined in src/go.mod and8src/cmd/go.mod. When a package outside std or cmd is imported9by a package inside std or cmd, the import path is interpreted10as if it had a "vendor/" prefix. For example, within "crypto/tls",11an import of "golang.org/x/crypto/cryptobyte" resolves to12"vendor/golang.org/x/crypto/cryptobyte". When a package with the13same path is imported from a package outside std or cmd, it will14be resolved normally. Consequently, a binary may be built with two15copies of a package at different versions if the package is16imported normally and vendored by the standard library.17 18Vendored packages are internally renamed with a "vendor/" prefix19to preserve the invariant that all packages have distinct paths.20This is necessary to avoid compiler and linker conflicts. Adding21a "vendor/" prefix also maintains the invariant that standard22library packages begin with a dotless path element.23 24The module requirements of std and cmd do not influence version25selection in other modules. They are only considered when running26module commands like 'go get' and 'go mod vendor' from a directory27in GOROOT/src.28 29Maintaining vendor directories30==============================31 32Before updating vendor directories, ensure that module mode is enabled.33Make sure that GO111MODULE is not set in the environment, or that it is34set to 'on' or 'auto', and if you use a go.work file, set GOWORK=off.35 36Also, ensure that 'go env GOROOT' shows the root of this Go source37tree. Otherwise, the results are undefined. It's recommended to build38Go from source and use that 'go' binary to update its source tree.39 40Requirements may be added, updated, and removed with 'go get'.41The vendor directory may be updated with 'go mod vendor'.42A typical sequence might be:43 44    cd src  # or src/cmd45    go get golang.org/x/net@master46    go mod tidy47    go mod vendor48 49Use caution when passing '-u' to 'go get'. The '-u' flag updates50modules providing all transitively imported packages, not only51the module providing the target package.52 53Note that 'go mod vendor' only copies packages that are transitively54imported by packages in the current module. If a new package is needed,55it should be imported before running 'go mod vendor'.56