bug: Fix STDIN/STDOUT buffer issue on code generation with code forma…

…tters There was a problem that it cannot generate code If the input size is too big, because of the buffer of the OS. This commit fixes that problem by using `exec.Cmd#StdinPipe()` and removes some redundant/unsophisticated code. As far as I checked, this problem appeared on only Linux. Signed-off-by: moznion <[email protected]>
moznion · Feb 22, 2021 · 07420ca · 07420ca
1 parent 78541c0
commit 07420ca
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Showing 4 changed files with 46 additions and 11 deletions.
diff --git a/generator/root.go b/generator/root.go
@@ -132,25 +132,29 @@ func (g *Root) applyGoimports(generatedCode string) (string, error) {
 }
 
 func applyCodeFormatter(generatedCode string, formatterCmdName string, formatterOpts ...string) (string, error) {
-	echoCmd := exec.Command("echo", generatedCode)
 	formatterCmd := exec.Command(formatterCmdName, formatterOpts...)
-
-	r, w := io.Pipe()
-	echoCmd.Stdout = w
-	formatterCmd.Stdin = r
+	stdinPipe, _ := formatterCmd.StdinPipe()
 
 	var out, errout bytes.Buffer
 	formatterCmd.Stdout = &out
 	formatterCmd.Stderr = &errout
 
-	echoCmd.Start()
-	if err := formatterCmd.Start(); err != nil {
+	err := formatterCmd.Start()
+	if err != nil {
 		cmds := []string{formatterCmdName}
 		return "", errmsg.CodeFormatterError(strings.Join(append(cmds, formatterOpts...), " "), errout.String(), err)
 	}
-	echoCmd.Wait()
-	w.Close()
-	err := formatterCmd.Wait()
+
+	_, err = io.WriteString(stdinPipe, generatedCode)
+	if err != nil {
+		return "", err
+	}
+	err = stdinPipe.Close()
+	if err != nil {
+		return "", err
+	}
+
+	err = formatterCmd.Wait()
 	if err != nil {
 		cmds := []string{formatterCmdName}
 		return "", errmsg.CodeFormatterError(strings.Join(append(cmds, formatterOpts...), " "), errout.String(), err)

diff --git a/generator/root_test.go b/generator/root_test.go
@@ -1,12 +1,12 @@
 package generator
 
 import (
+	"fmt"
 	"regexp"
 	"strings"
 	"testing"
 
 	"github.com/moznion/gowrtr/internal/errmsg"
-
 	"github.com/stretchr/testify/assert"
 )
 
@@ -517,3 +517,31 @@ func TestShouldGenerateCodeRaiseErrorWhenCodeFormatterIsExited(t *testing.T) {
 		assert.Regexp(t, regexp.MustCompile(`^\[GOWRTR-13\] code formatter raises error: command='not-existed-cmd'.+`), err.Error())
 	}
 }
+
+// to check STDIN buffer behavior with code formatter
+func TestMassiveAmountCode(t *testing.T) {
+	generator := NewRoot(
+		NewComment(" THIS CODE WAS AUTO GENERATED"),
+		NewNewline(),
+		NewPackage("mypkg"),
+		NewNewline(),
+		NewImport("fmt"),
+		NewNewline(),
+	)
+
+	for i := 0; i <= 1000; i++ {
+		generator = generator.AddStatements(
+			NewFunc(
+				nil,
+				NewFuncSignature(fmt.Sprintf("f%d", i)),
+				NewRawStatement(
+					`fmt.Println("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@")`,
+				).WithNewline(true),
+			),
+		)
+	}
+
+	generated, err := generator.Gofmt().Generate(0)
+	assert.NoError(t, err)
+	assert.NotEmpty(t, generated)
+}
diff --git a/go.mod b/go.mod
@@ -3,6 +3,7 @@ module github.com/moznion/gowrtr
 go 1.14
 
 require (
+	github.com/iancoleman/strcase v0.1.3 // indirect
 	github.com/moznion/go-errgen v1.8.1
 	github.com/pkg/errors v0.9.1
 	github.com/stretchr/testify v1.6.0

diff --git a/go.sum b/go.sum
@@ -2,6 +2,8 @@ github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/iancoleman/strcase v0.0.0-20180726023541-3605ed457bf7 h1:ux/56T2xqZO/3cP1I2F86qpeoYPCOzk+KF/UH/Ar+lk=
 github.com/iancoleman/strcase v0.0.0-20180726023541-3605ed457bf7/go.mod h1:SK73tn/9oHe+/Y0h39VT4UCxmurVJkR5NA7kMEAOgSE=
+github.com/iancoleman/strcase v0.1.3 h1:dJBk1m2/qjL1twPLf68JND55vvivMupZ4wIzE8CTdBw=
+github.com/iancoleman/strcase v0.1.3/go.mod h1:SK73tn/9oHe+/Y0h39VT4UCxmurVJkR5NA7kMEAOgSE=
 github.com/moznion/go-errgen v1.3.1/go.mod h1:+BkSRLNc98WWAJmdtxYcxxucQ7sl8m4sroepmHio33Y=
 github.com/moznion/go-errgen v1.8.1 h1:jxaMIi1WiX/N9xnOecBN3ZQUhbBgnrvedSjNmU7EXFo=
 github.com/moznion/go-errgen v1.8.1/go.mod h1:3mE7v+d7czyIqbfd3jOK/wLgRn5lTOtNRNEeCHXHaCk=