gqlgen: Generate imports wrong package and gives error

hey guys, any update on this ?

Bump. This is a genuine issue and none of the mentioned fixes are really satisfactory. I’m happy to work on a PR if someone can tell me it’s okay to make a configuration option for replacing packages Alternatively, would be nice to know why golang.org/x/tools/imports was made to not touch imports and a custom implementation was made instead. I’ll mention @vektah who is the author for the commit breml mentioned. Hopefully we can get this moving 🙂

An alternative to @duckbrain his solution it to use gofmt to update the imports. Just run the following at the root of your project after you (re-)generated the files:

gofmt -w -d -r '"errors" -> "github.com/pkg/errors"' **/*.go

As a hacky workaround until this gets fixed, I created a plugin to remove the line and re-run goimports after it generates the errant file.

package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strings"

	"github.com/99designs/gqlgen/api"
	"github.com/99designs/gqlgen/codegen"
	"github.com/99designs/gqlgen/codegen/config"
)

type ImportsPlugin struct {
}

func (ImportsPlugin) Name() string {
	return "Imports"
}
func (ImportsPlugin) GenerateCode(cfg *codegen.Data) error {
	dir := cfg.Config.Resolver.Dir()

	badLineRegexp := regexp.MustCompile(`\n\s*"errors"\n`)

	return filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if !strings.HasSuffix(info.Name(), ".resolvers.go") {
			return nil
		}
		f, err := ioutil.ReadFile(path)
		if err != nil {
			return err
		}
		if !badLineRegexp.Match(f) {
			return nil
		}
		n := badLineRegexp.ReplaceAll(f, []byte("\n"))
		err = ioutil.WriteFile(path, n, os.ModePerm)
		if err != nil {
			return err
		}
		c := exec.Command("go", "run", "golang.org/x/tools/cmd/goimports", "-w", path)
		c.Stdout = os.Stdout
		c.Stderr = os.Stderr
		return c.Run()
	})
}

func main() {
	cfg, err := config.LoadConfigFromDefaultLocations()
	if err != nil {
		fmt.Fprintln(os.Stderr, "failed to load config", err.Error())
		os.Exit(2)
	}

	err = api.Generate(cfg,
		api.AddPlugin(ImportsPlugin{}),
	)
	if err != nil {
		fmt.Fprintln(os.Stderr, err.Error())
		os.Exit(3)
	}
}

@pjvds many users may not want to use “github.com/pkg/errors” and GQLGen has no way of knowing that github.com/pkg/errors is a drop-in replacement for errors. @j0hnsmith’s workaround seems pretty reasonable to me.

The general problem is GQLGen may request an import who’s name conflicts with an existing import. The best way I could think to solve the problem is add a configuration option to map imports to a replacement, kind of like a replace directive in go.mod, but it replaces the generated import. It would be up to the user to ensure the replaced package is compatible with GQLGen’s usage of it.

See: https://github.com/99designs/gqlgen/blob/5ad012e3d7be1127706b9c8a3da0378df3a98ec1/codegen/templates/import.go#L43 where the import is handled.

Alternatively the specific problem was introduced by the resolvers template moving from panic("not implemented") to panic(errors.Errorf("not implemented")).

it seems that adding an alias to the import makes gqlgen ignore it, I use that as a workaround

Adding an alias seems to make said aliased imports get removed entirely, in my case.

Edit: Spoke too soon, seems to work for some packages but not others. "github.com/99designs/gqlgen/graphql" for example, if aliased, gets removed.

I wonder why gqlgen does insertions and deletions of the imports on its own in contrast to relying on golang.org/x/tools/imports, which is purely made for this purpose, used with great success in most IDE/editors and is maintained by the Go maintainers.

The pruning happens in https://github.com/99designs/gqlgen/blob/master/internal/imports/prune.go and while golang.org/x/tools/imports is used, it is forced to not touch the imports (see: https://github.com/99designs/gqlgen/blob/master/internal/imports/prune.go#L46). The respective commit (https://github.com/99designs/gqlgen/commit/732be3959b402bbd3b864c5f40f475640f1334c5) states “Don’t let goimports guess import paths” in the commit message, but does not give a reason for this decision nor a reference to an issue.

Wouldn’t this issue be resolved, if the line {{ reserveImport "errors" }} (https://github.com/99designs/gqlgen/blob/master/plugin/resolvergen/resolver.gotpl#L7) is removed and golang.org/x/tools/imports would not be be limited to formatting only?

https://github.com/99designs/gqlgen/blob/master/plugin/resolvergen/resolver.gotpl#L7

del this will resolve this issue. Why add lines:

{{ reserveImport "context"  }}
{{ reserveImport "fmt"  }}
{{ reserveImport "io"  }}
{{ reserveImport "strconv"  }}
{{ reserveImport "time"  }}
{{ reserveImport "sync"  }}
{{ reserveImport "errors"  }}
{{ reserveImport "bytes"  }}

fmt aliase f

after gqlgen generate， f was deleted

Running gofmt doesn’t fix the imports for me 😦