github.com/twelsh-aw/go/src@v0.0.0-20230516233729-a56fe86a7c81/README.vendor (about) 1 Vendoring in std and cmd 2 ======================== 3 4 The Go command maintains copies of external packages needed by the 5 standard library in the src/vendor and src/cmd/vendor directories. 6 7 There are two modules, std and cmd, defined in src/go.mod and 8 src/cmd/go.mod. When a package outside std or cmd is imported 9 by a package inside std or cmd, the import path is interpreted 10 as if it had a "vendor/" prefix. For example, within "crypto/tls", 11 an import of "golang.org/x/crypto/cryptobyte" resolves to 12 "vendor/golang.org/x/crypto/cryptobyte". When a package with the 13 same path is imported from a package outside std or cmd, it will 14 be resolved normally. Consequently, a binary may be built with two 15 copies of a package at different versions if the package is 16 imported normally and vendored by the standard library. 17 18 Vendored packages are internally renamed with a "vendor/" prefix 19 to preserve the invariant that all packages have distinct paths. 20 This is necessary to avoid compiler and linker conflicts. Adding 21 a "vendor/" prefix also maintains the invariant that standard 22 library packages begin with a dotless path element. 23 24 The module requirements of std and cmd do not influence version 25 selection in other modules. They are only considered when running 26 module commands like 'go get' and 'go mod vendor' from a directory 27 in GOROOT/src. 28 29 Maintaining vendor directories 30 ============================== 31 32 Before updating vendor directories, ensure that module mode is enabled. 33 Make sure that GO111MODULE is not set in the environment, or that it is 34 set to 'on' or 'auto'. 35 36 Requirements may be added, updated, and removed with 'go get'. 37 The vendor directory may be updated with 'go mod vendor'. 38 A typical sequence might be: 39 40 cd src 41 go get golang.org/x/net@latest 42 go mod tidy 43 go mod vendor 44 45 Use caution when passing '-u' to 'go get'. The '-u' flag updates 46 modules providing all transitively imported packages, not only 47 the module providing the target package. 48 49 Note that 'go mod vendor' only copies packages that are transitively 50 imported by packages in the current module. If a new package is needed, 51 it should be imported before running 'go mod vendor'.