feat: add http.NoBody (#34)

feat: add http.NoBody

pkg/analyzer/analyzer.go

@@ -20,6 +20,7 @@ const (
 	CryptoHashFlag     = "crypto-hash"
 	HTTPMethodFlag     = "http-method"
 	HTTPStatusCodeFlag = "http-status-code"
+	HTTPNoBodyFlag     = "http-no-body"
 	DefaultRPCPathFlag = "default-rpc-path"
 )
 
@@ -38,6 +39,7 @@ func flags() flag.FlagSet {
 	flags := flag.NewFlagSet("", flag.ExitOnError)
 	flags.Bool(HTTPMethodFlag, true, "suggest the use of http.MethodXX")
 	flags.Bool(HTTPStatusCodeFlag, true, "suggest the use of http.StatusXX")
+	flags.Bool(HTTPNoBodyFlag, false, "suggest the use of http.NoBody")
 	flags.Bool(TimeWeekdayFlag, false, "suggest the use of time.Weekday")
 	flags.Bool(TimeMonthFlag, false, "suggest the use of time.Month")
 	flags.Bool(TimeLayoutFlag, false, "suggest the use of time.Layout")
@@ -74,21 +76,29 @@ func run(pass *analysis.Pass) (interface{}, error) {
 				}
 
 			case "NewRequest":
-				if !lookupFlag(pass, HTTPMethodFlag) {
-					return
+				if lookupFlag(pass, HTTPMethodFlag) {
+					if basicLit := getBasicLitFromArgs(n.Args, 3, 0, token.STRING); basicLit != nil {
+						checkHTTPMethod(pass, basicLit)
+					}
 				}
 
-				if basicLit := getBasicLitFromArgs(n.Args, 3, 0, token.STRING); basicLit != nil {
-					checkHTTPMethod(pass, basicLit)
+				if lookupFlag(pass, HTTPNoBodyFlag) {
+					if ident := getIdentFromArgs(n.Args, 3, 2); ident != nil {
+						checkHTTPNoBody(pass, ident)
+					}
 				}
 
 			case "NewRequestWithContext":
-				if !lookupFlag(pass, HTTPMethodFlag) {
-					return
+				if lookupFlag(pass, HTTPMethodFlag) {
+					if basicLit := getBasicLitFromArgs(n.Args, 4, 1, token.STRING); basicLit != nil {
+						checkHTTPMethod(pass, basicLit)
+					}
 				}
 
-				if basicLit := getBasicLitFromArgs(n.Args, 4, 1, token.STRING); basicLit != nil {
-					checkHTTPMethod(pass, basicLit)
+				if lookupFlag(pass, HTTPNoBodyFlag) {
+					if ident := getIdentFromArgs(n.Args, 4, 3); ident != nil {
+						checkHTTPNoBody(pass, ident)
+					}
 				}
 			}
 
@@ -173,6 +183,14 @@ func checkHTTPStatusCode(pass *analysis.Pass, basicLit *ast.BasicLit) {
 	}
 }
 
+func checkHTTPNoBody(pass *analysis.Pass, ident *ast.Ident) {
+	currentVal := ident.Name
+
+	if newVal, ok := mapping.HTTPNoBody[currentVal]; ok {
+		report(pass, ident.Pos(), currentVal, newVal)
+	}
+}
+
 func checkTimeWeekday(pass *analysis.Pass, pos token.Pos, currentVal string) {
 	if newVal, ok := mapping.TimeWeekday[currentVal]; ok {
 		report(pass, pos, currentVal, newVal)
@@ -226,6 +244,24 @@ func getBasicLitFromArgs(args []ast.Expr, count, idx int, typ token.Token) *ast.
 	return basicLit
 }
 
+// getIdentFromArgs gets the *ast.Ident of a function argument.
+//
+// Arguments:
+//   - count - expected number of argument in function
+//   - idx - index of the argument to get the *ast.Ident
+func getIdentFromArgs(args []ast.Expr, count, idx int) *ast.Ident {
+	if len(args) != count {
+		return nil
+	}
+
+	ident, ok := args[idx].(*ast.Ident)
+	if !ok {
+		return nil
+	}
+
+	return ident
+}
+
 // getBasicLitFromElts gets the *ast.BasicLit of a struct elements.
 //
 // Arguments:

pkg/analyzer/analyzer_test.go

@@ -33,6 +33,9 @@ func TestUseStdlibVars(t *testing.T) {
 	if err := a.Flags.Set(analyzer.DefaultRPCPathFlag, "true"); err != nil {
 		t.Error(err)
 	}
+	if err := a.Flags.Set(analyzer.HTTPNoBodyFlag, "true"); err != nil {
+		t.Error(err)
+	}
 
 	analysistest.Run(t, analysistest.TestData(), a, pkgs...)
 }

pkg/analyzer/internal/gen.go

@@ -83,6 +83,12 @@ func main() {
 			templateName: "test-issue32.go.tmpl",
 			fileName:     "pkg/analyzer/testdata/src/a/http/issue32.go",
 		},
+		{
+			mapping:      mapping.HTTPNoBody,
+			packageName:  "http_test",
+			templateName: "test-httpnobody.go.tmpl",
+			fileName:     "pkg/analyzer/testdata/src/a/http/nobody.go",
+		},
 	}
 
 	for _, operation := range operations {

pkg/analyzer/internal/mapping/mapping.go

@@ -159,3 +159,7 @@ var TimeLayout = map[string]string{
 	time.StampMicro:  "time.StampMicro",
 	time.StampNano:   "time.StampNano",
 }
+
+var HTTPNoBody = map[string]string{
+	"nil": "http.NoBody",
+}

pkg/analyzer/internal/template/test-httpmethod.go.tmpl

@@ -18,13 +18,13 @@ const (
 
 func _() {
 {{- range $key, $value := .Mapping }}
-	_, _ = http.NewRequest("{{ $key }}", "", nil) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
+	_, _ = http.NewRequest("{{ $key }}", "", http.NoBody) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
 {{- end }}
 }
 
 func _() {
 {{- range $key, $value := .Mapping }}
-	_, _ = http.NewRequestWithContext(nil, "{{ $key }}", "", nil) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
+	_, _ = http.NewRequestWithContext(nil, "{{ $key }}", "", http.NoBody) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
 {{- end }}
 }
 

pkg/analyzer/internal/template/test-httpnobody.go.tmpl

@@ -0,0 +1,17 @@
+// Code generated by usestdlibvars, DO NOT EDIT.
+
+package {{ .PackageName }}
+
+import "net/http"
+
+func _() {
+{{- range $key, $value := .Mapping }}
+	_, _ = http.NewRequest(http.MethodGet, "", {{ $key }}) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
+{{- end }}
+}
+
+func _() {
+{{- range $key, $value := .Mapping }}
+		_, _ = http.NewRequestWithContext(nil, http.MethodGet, "", {{ $key }}) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
+{{- end }}
+}

pkg/analyzer/internal/template/test-issue32.go.tmpl

@@ -18,13 +18,13 @@ const (
 
 func _() {
 {{- range $key, $value := .Mapping }}
-	_, _ = http.NewRequest("{{ lower $key }}", "", nil) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
+	_, _ = http.NewRequest("{{ lower $key }}", "", http.NoBody) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
 {{- end }}
 }
 
 func _() {
 {{- range $key, $value := .Mapping }}
-	_, _ = http.NewRequestWithContext(nil, "{{ lower $key }}", "", nil) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
+	_, _ = http.NewRequestWithContext(nil, "{{ lower $key }}", "", http.NoBody) // want `"{{ quoteMeta $key }}" can be replaced by {{ quoteMeta $value }}`
 {{- end }}
 }