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go/internal/lsp/cache/modfiles.go
Rohan Challa 62a9628863 internal/lsp: use the -modfile flag to update a different go.mod file
In the upcoming Go 1.14 release, there is an introduction of the -modfile
flag which allows a user to run a go command but choose where to direct the
go.mod file updates. The information about this can be found here: golang/go#34506.

This change starts setting up the infrastructure to handle the seperate modfile
rather than keep changing a user's go.mod file. To support versions of Go that are
not 1.14, we run a modified "go list" command that checks the release tags to see
if 1.14 is contained.

Updates golang/go#31999

Change-Id: Icb71b6402ec4fa07e5f6f1a63954c25520e860b0
Reviewed-on: https://go-review.googlesource.com/c/tools/+/211538
Run-TryBot: Rohan Challa <rohan@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
2019-12-17 22:15:16 +00:00

67 lines
1.9 KiB
Go

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cache
import (
"context"
"io"
"io/ioutil"
"os"
"strings"
"golang.org/x/tools/internal/lsp/source"
errors "golang.org/x/xerrors"
)
// Borrowed from (internal/imports/mod.go:620)
// This function will return the main go.mod file for this folder if it exists and whether the -modfile
// flag exists for this version of go.
func modfileFlagExists(ctx context.Context, folder string, env []string) (string, bool, error) {
const format = `{{.GoMod}}
{{range context.ReleaseTags}}{{if eq . "go1.14"}}{{.}}{{end}}{{end}}
`
stdout, err := source.InvokeGo(ctx, folder, env, "list", "-m", "-f", format)
if err != nil {
return "", false, err
}
lines := strings.Split(stdout.String(), "\n")
if len(lines) < 2 {
return "", false, errors.Errorf("unexpected stdout: %q", stdout)
}
return lines[0], lines[1] == "go1.14", nil
}
// The function getModfiles will return the go.mod files associated with the directory that is passed in.
func getModfiles(ctx context.Context, folder string, env []string) (*modfiles, error) {
modfile, flagExists, err := modfileFlagExists(ctx, folder, env)
if err != nil {
return nil, err
}
if !flagExists {
return nil, nil
}
if modfile == "" || modfile == os.DevNull {
return nil, errors.Errorf("go env GOMOD cannot detect a go.mod file in this folder")
}
f, err := ioutil.TempFile("", "go.*.mod")
if err != nil {
return nil, err
}
defer f.Close()
// Copy the current go.mod file into the temporary go.mod file.
origFile, err := os.Open(modfile)
if err != nil {
return nil, err
}
defer origFile.Close()
if _, err := io.Copy(f, origFile); err != nil {
return nil, err
}
if err := f.Close(); err != nil {
return nil, err
}
return &modfiles{real: modfile, temp: f.Name()}, nil
}