Add staticcheck tool

vendor/honnef.co/go/tools/staticcheck/sa5008/sa5008.go

@@ -0,0 +1,130 @@
+package sa5008
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+	"strings"
+
+	"honnef.co/go/tools/analysis/code"
+	"honnef.co/go/tools/analysis/lint"
+	"honnef.co/go/tools/analysis/report"
+	"honnef.co/go/tools/staticcheck/fakereflect"
+	"honnef.co/go/tools/staticcheck/fakexml"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+)
+
+var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
+	Analyzer: &analysis.Analyzer{
+		Name:     "SA5008",
+		Run:      run,
+		Requires: []*analysis.Analyzer{inspect.Analyzer},
+	},
+	Doc: &lint.RawDocumentation{
+		Title:    `Invalid struct tag`,
+		Since:    "2019.2",
+		Severity: lint.SeverityWarning,
+		MergeIf:  lint.MergeIfAny,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+func run(pass *analysis.Pass) (any, error) {
+	importsGoFlags := false
+
+	// we use the AST instead of (*types.Package).Imports to work
+	// around vendored packages in GOPATH mode. A vendored package's
+	// path will include the vendoring subtree as a prefix.
+	for _, f := range pass.Files {
+		for _, imp := range f.Imports {
+			v := imp.Path.Value
+			if v[1:len(v)-1] == "github.com/jessevdk/go-flags" {
+				importsGoFlags = true
+				break
+			}
+		}
+	}
+
+	fn := func(node ast.Node) {
+		structNode := node.(*ast.StructType)
+		T := pass.TypesInfo.Types[structNode].Type.(*types.Struct)
+		rt := fakereflect.TypeAndCanAddr{
+			Type: T,
+		}
+		for i, field := range structNode.Fields.List {
+			if field.Tag == nil {
+				continue
+			}
+			tags, err := parseStructTag(field.Tag.Value[1 : len(field.Tag.Value)-1])
+			if err != nil {
+				report.Report(pass, field.Tag, fmt.Sprintf("unparseable struct tag: %s", err))
+				continue
+			}
+			for k, v := range tags {
+				if len(v) > 1 {
+					isGoFlagsTag := importsGoFlags &&
+						(k == "choice" || k == "optional-value" || k == "default")
+					if !isGoFlagsTag {
+						report.Report(pass, field.Tag, fmt.Sprintf("duplicate struct tag %q", k))
+					}
+				}
+
+				switch k {
+				case "json":
+					checkJSONTag(pass, field, v[0])
+				case "xml":
+					if _, err := fakexml.StructFieldInfo(rt.Field(i)); err != nil {
+						report.Report(pass, field.Tag, fmt.Sprintf("invalid XML tag: %s", err))
+					}
+					checkXMLTag(pass, field, v[0])
+				}
+			}
+		}
+	}
+	code.Preorder(pass, fn, (*ast.StructType)(nil))
+	return nil, nil
+}
+
+func checkJSONTag(pass *analysis.Pass, field *ast.Field, tag string) {
+	if pass.Pkg.Path() == "encoding/json" ||
+		pass.Pkg.Path() == "encoding/json_test" ||
+		pass.Pkg.Path() == "encoding/json/v2" ||
+		pass.Pkg.Path() == "encoding/json/v2_test" {
+		// don't flag malformed JSON tags in the encoding/json
+		// package; it knows what it is doing, and it is testing
+		// itself.
+		return
+	}
+	//lint:ignore SA9003 TODO(dh): should we flag empty tags?
+	if len(tag) == 0 {
+	}
+
+	validateJSONTag(pass, field, tag)
+}
+
+func checkXMLTag(pass *analysis.Pass, field *ast.Field, tag string) {
+	//lint:ignore SA9003 TODO(dh): should we flag empty tags?
+	if len(tag) == 0 {
+	}
+	fields := strings.Split(tag, ",")
+	counts := map[string]int{}
+	for _, s := range fields[1:] {
+		switch s {
+		case "attr", "chardata", "cdata", "innerxml", "comment":
+			counts[s]++
+		case "omitempty", "any":
+			counts[s]++
+		case "":
+		default:
+			report.Report(pass, field.Tag, fmt.Sprintf("invalid XML tag: unknown option %q", s))
+		}
+	}
+	for k, v := range counts {
+		if v > 1 {
+			report.Report(pass, field.Tag, fmt.Sprintf("invalid XML tag: duplicate option %q", k))
+		}
+	}
+}