cmd/check: Make parsing cleaner by leveraging 'mod'

cmd/check/go_version.go

@@ -7,6 +7,7 @@ import (
 
 	version "github.com/hashicorp/go-version"
 	"github.com/hashicorp/tf-sdk-migrator/util"
+	"github.com/radeksimko/mod/modfile"
 )
 
 // .go-version file contains the Go version as a string, followed by \n
@@ -27,22 +28,22 @@ func ReadGoVersionFromGoVersionFile(providerPath string) (*version.Version, erro
 // the "go" directive sets the expected language version
 // see https://tip.golang.org/cmd/go/#hdr-The_go_mod_file
 func ReadGoVersionFromGoModFile(providerPath string) (*version.Version, error) {
-	content, err := ioutil.ReadFile(providerPath + "/go.mod")
+	path := providerPath + "/go.mod"
+	content, err := ioutil.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}
 
-	lines := strings.Split(string(content), "\n")
-
-	goLine := util.SearchLinesPrefix(lines, "go ", 0)
-	if goLine == -1 {
-		return nil, errors.New("no 'go' directive in go.mod")
+	pf, err := modfile.Parse(path, content, nil)
+	if err != nil {
+		return nil, err
 	}
 
-	v := strings.TrimLeft(lines[goLine], "go ")
-	v = strings.TrimSpace(v)
+	if pf.Go == nil {
+		return nil, errors.New("go statement not found")
+	}
 
-	return version.NewVersion(v)
+	return version.NewVersion(pf.Go.Version)
 }
 
 func ReadGoVersionFromTravisConfig(providerPath string) (*version.Version, error) {

cmd/check/sdk_version.go

@@ -1,31 +1,41 @@
 package check
 
 import (
-	"errors"
+	"fmt"
 	"io/ioutil"
-	"strings"
 
-	"github.com/hashicorp/go-multierror"
 	version "github.com/hashicorp/go-version"
-	"github.com/hashicorp/tf-sdk-migrator/util"
+	"github.com/radeksimko/mod/modfile"
+	"github.com/radeksimko/mod/module"
 )
 
 func ReadSDKVersionFromGoModFile(providerPath string) (*version.Version, error) {
-	content, err := ioutil.ReadFile(providerPath + "/go.mod")
+	path := providerPath + "/go.mod"
+	content, err := ioutil.ReadFile(path)
 	if err != nil {
-		return nil, multierror.Append(err, errors.New("could not read go.mod file for provider "+providerPath))
+		return nil, fmt.Errorf("could not read go.mod file for provider %s", providerPath)
 	}
 
-	lines := strings.Split(string(content), "\n")
+	pf, err := modfile.Parse(path, content, nil)
+	if err != nil {
+		return nil, err
+	}
 
-	terraformPackageLine := util.SearchLines(lines, terraformDependencyPath+" ", 0)
-	if terraformPackageLine == -1 {
-		return nil, errors.New("could not find github/hashicorp/terraform dependency for provider " + providerPath)
+	mv, err := findMatchingRequireStmt(pf.Require, terraformDependencyPath)
+	if err != nil {
+		return nil, err
 	}
 
-	v := strings.TrimSpace(lines[terraformPackageLine])
-	v = strings.TrimLeft(v, "require ")
-	v = strings.TrimLeft(v, terraformDependencyPath+" ")
+	return version.NewVersion(mv.Version)
+}
+
+func findMatchingRequireStmt(requires []*modfile.Require, path string) (module.Version, error) {
+	for _, requireStmt := range requires {
+		mod := requireStmt.Mod
+		if mod.Path == path {
+			return mod, nil
+		}
+	}
 
-	return version.NewVersion(v)
+	return module.Version{}, fmt.Errorf("require statement with path %q not found", path)
 }

cmd/migrate/migrate.go

@@ -16,6 +16,7 @@ import (
 	"github.com/hashicorp/tf-sdk-migrator/cmd/check"
 	"github.com/hashicorp/tf-sdk-migrator/util"
 	"github.com/mitchellh/cli"
+	"github.com/radeksimko/mod/modfile"
 )
 
 const (
@@ -134,16 +135,25 @@ func RewriteGoMod(providerPath string) error {
 		return err
 	}
 
-	lines := strings.Split(string(input), "\n")
+	pf, err := modfile.Parse(goModPath, input, nil)
+	if err != nil {
+		return err
+	}
 
-	// TODO: case where there is only one package in go.mod
-	for i, line := range lines {
-		if strings.HasPrefix(line, "\t"+oldSDKImportPath+" ") {
-			lines[i] = "\t" + newSDKPackagePath + " " + newSDKVersion
-		}
+	err = pf.DropRequire(oldSDKImportPath)
+	if err != nil {
+		return err
 	}
-	output := strings.Join(lines, "\n")
-	err = ioutil.WriteFile(goModPath, []byte(output), 0644)
+
+	pf.AddNewRequire(newSDKPackagePath, newSDKVersion, false)
+
+	pf.Cleanup()
+	formattedOutput, err := pf.Format()
+	if err != nil {
+		return err
+	}
+
+	err = ioutil.WriteFile(goModPath, formattedOutput, 0644)
 	if err != nil {
 		return err
 	}

go.mod

@@ -7,4 +7,5 @@ require (
 	github.com/hashicorp/go-version v1.2.0
 	github.com/mitchellh/cli v1.0.0
 	github.com/radeksimko/go-refs v0.0.0-20190614111518-1b15b5989e59
+	github.com/radeksimko/mod v0.0.0-20190807092412-93f771451dae
 )

go.sum

@@ -20,5 +20,14 @@ github.com/posener/complete v1.1.1 h1:ccV59UEOTzVDnDUEFdT95ZzHVZ+5+158q8+SJb2QV5
 github.com/posener/complete v1.1.1/go.mod h1:em0nMJCgc9GFtwrmVmEMR/ZL6WyhyjMBndrE9hABlRI=
 github.com/radeksimko/go-refs v0.0.0-20190614111518-1b15b5989e59 h1:spSVb40pzPe4JoZLno+/E7Eq5Y0I21DFwdb32g/GN+4=
 github.com/radeksimko/go-refs v0.0.0-20190614111518-1b15b5989e59/go.mod h1:PYFsT0d8q5IGFGbiXhnVA5sQFXxPRNXf7CS/IL90rHY=
+github.com/radeksimko/mod v0.0.0-20190807092412-93f771451dae h1:I7Nl7r9VPplepwIlnEODWuesa2/CurhkwoQGCl4MZj8=
+github.com/radeksimko/mod v0.0.0-20190807092412-93f771451dae/go.mod h1:Q2IM8KSMt66rTOMAXh3BvCD8bYed5rx/ITZ/zNqYakc=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/sys v0.0.0-20180823144017-11551d06cbcc h1:MeuS1UDyZyFH++6vVy44PuufTeFF0d0nfI6XB87YGSk=
 golang.org/x/sys v0.0.0-20180823144017-11551d06cbcc/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=