fix inference logic

Author: angrychow

lang/golang/parser/utils.go

@@ -18,13 +18,17 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
+	"github.com/cloudwego/abcoder/lang/log"
 	"go/ast"
 	"go/types"
 	"io"
 	"os"
+	"os/exec"
 	"path"
+	"path/filepath"
 	"regexp"
 	"strings"
+	"sync"
 
 	"github.com/Knetic/govaluate"
 	. "github.com/cloudwego/abcoder/lang/uniast"
@@ -49,8 +53,97 @@ func (c cache) Visited(val interface{}) bool {
 	return ok
 }
 
+// PackageCache 缓存 importPath 是否是 system package
+type PackageCache struct {
+	lock  sync.RWMutex
+	cache map[string]bool
+}
+
+func NewPackageCache() *PackageCache {
+	return &PackageCache{
+		cache: make(map[string]bool),
+	}
+}
+
+var (
+	gorootOnce     sync.Once
+	detectedGoRoot string
+	gorootErr      error
+)
+
+// getGoRoot 获取 go root 环境变量。
+func getGoRoot() (string, error) {
+	gorootOnce.Do(func() {
+		cmd := exec.Command("go", "env", "GOROOT")
+		var out bytes.Buffer
+		var stderr bytes.Buffer
+		cmd.Stdout = &out
+		cmd.Stderr = &stderr
+		err := cmd.Run()
+		if err != nil {
+			log.Info("'go env GOROOT' failed: %w, stderr: %s; \n `isSysPkg` will downgrade.", err, stderr.String())
+			gorootErr = fmt.Errorf("'go env GOROOT' failed: %w, stderr: %s", err, stderr.String())
+			return
+		}
+
+		gorootPath := strings.TrimSpace(out.String())
+		if gorootPath == "" {
+			log.Info("'go env GOROOT' returns a empty string \n `isSysPkg` will downgrade.")
+			gorootErr = fmt.Errorf("'go env GOROOT' returns a empty string")
+			return
+		}
+		detectedGoRoot = gorootPath
+	})
+	return detectedGoRoot, gorootErr
+}
+
+// IsStandardPackage 检查一个包是否为标准库，并使用内部缓存。
+func (pc *PackageCache) IsStandardPackage(path string) bool {
+
+	goRoot, err := getGoRoot()
+	// 当前环境找不到 go root，退化到最简单判断
+	if err != nil || goRoot == "" {
+		return !strings.Contains(strings.Split(path, "/")[0], ".")
+	}
+
+	pc.lock.RLock()
+	isStd, found := pc.cache[path]
+	pc.lock.RUnlock()
+
+	if found {
+		return isStd
+	}
+
+	pc.lock.Lock()
+	defer pc.lock.Unlock()
+
+	isStd, found = pc.cache[path]
+	if found {
+		return isStd
+	}
+
+	pkgPath := filepath.Join(goRoot, "src", path)
+	stat, err := os.Stat(pkgPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			isStd = false
+		} else {
+			log.Info("IsStandardPackage: failed to get file stat for %s: %v", pkgPath, err)
+			return false
+		}
+	} else {
+		isStd = stat.IsDir()
+	}
+
+	pc.cache[path] = isStd
+
+	return isStd
+}
+
+var stdlibCache = NewPackageCache()
+
 func isSysPkg(importPath string) bool {
-	return !strings.Contains(strings.Split(importPath, "/")[0], ".")
+	return stdlibCache.IsStandardPackage(importPath)
 }
 
 var (

lang/golang/parser/utils_test.go

@@ -21,6 +21,7 @@ import (
 	"go/token"
 	"go/types"
 	"slices"
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -195,3 +196,69 @@ var f func() (*http.Request, error)`,
 		})
 	}
 }
+
+func resetGlobals() {
+	// 重置 GOROOT 的 sync.Once 和其缓存的变量
+	gorootOnce = sync.Once{}
+	detectedGoRoot = ""
+	gorootErr = nil
+
+	// 重置包缓存
+	stdlibCache = NewPackageCache()
+}
+
+func Test_isSysPkg(t *testing.T) {
+	// 测试在 `go env GOROOT` 可以成功执行时的行为
+	t.Run("Group: Happy Path - GOROOT is found", func(t *testing.T) {
+		resetGlobals()
+
+		testCases := []struct {
+			name       string
+			importPath string
+			want       bool
+		}{
+			{"standard library package", "fmt", true},
+			{"nested standard library package", "net/http", true},
+			{"third-party package", "github.com/google/uuid", false},
+			{"extended library package", "golang.org/x/sync/errgroup", false},
+			{"local-like package name", "myproject/utils", false},
+			{"non-existent package", "non/existent/package", false},
+			{"root-level package with dot", "gopkg.in/yaml.v2", false},
+		}
+
+		for _, tc := range testCases {
+			t.Run(tc.name, func(t *testing.T) {
+				if got := isSysPkg(tc.importPath); got != tc.want {
+					t.Errorf("isSysPkg(%q) = %v, want %v", tc.importPath, got, tc.want)
+				}
+			})
+		}
+	})
+
+	// 测试在 `go env GOROOT` 执行失败时的行为
+	t.Run("Group: Fallback Path - GOROOT is not found", func(t *testing.T) {
+		resetGlobals()
+
+		// 使用 t.Setenv 临时清空 PATH，使得 "go" 命令无法被找到
+		t.Setenv("PATH", "")
+
+		testCases := []struct {
+			name       string
+			importPath string
+			want       bool
+		}{
+			{"standard library package (fallback)", "fmt", true},
+			{"nested standard library package (fallback)", "os/exec", true},
+			{"third-party package (fallback)", "github.com/google/uuid", false},
+			{"local-like package name (fallback)", "myproject/utils", true}, // 在降级模式下，被错误地判断为 true
+		}
+
+		for _, tc := range testCases {
+			t.Run(tc.name, func(t *testing.T) {
+				if got := isSysPkg(tc.importPath); got != tc.want {
+					t.Errorf("isSysPkg(%q) in fallback mode = %v, want %v", tc.importPath, got, tc.want)
+				}
+			})
+		}
+	})
+}