зеркало из https://github.com/golang/tools.git
90 строки
2.9 KiB
Go
90 строки
2.9 KiB
Go
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// Copyright 2024 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package typesinternal
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import (
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"go/types"
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"golang.org/x/tools/internal/stdlib"
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"golang.org/x/tools/internal/versions"
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)
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// TooNewStdSymbols computes the set of package-level symbols
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// exported by pkg that are not available at the specified version.
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// The result maps each symbol to its minimum version.
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//
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// The pkg is allowed to contain type errors.
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func TooNewStdSymbols(pkg *types.Package, version string) map[types.Object]string {
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disallowed := make(map[types.Object]string)
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// Pass 1: package-level symbols.
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symbols := stdlib.PackageSymbols[pkg.Path()]
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for _, sym := range symbols {
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symver := sym.Version.String()
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if versions.Before(version, symver) {
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switch sym.Kind {
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case stdlib.Func, stdlib.Var, stdlib.Const, stdlib.Type:
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disallowed[pkg.Scope().Lookup(sym.Name)] = symver
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}
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}
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}
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// Pass 2: fields and methods.
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//
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// We allow fields and methods if their associated type is
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// disallowed, as otherwise we would report false positives
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// for compatibility shims. Consider:
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//
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// //go:build go1.22
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// type T struct { F std.Real } // correct new API
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//
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// //go:build !go1.22
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// type T struct { F fake } // shim
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// type fake struct { ... }
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// func (fake) M () {}
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//
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// These alternative declarations of T use either the std.Real
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// type, introduced in go1.22, or a fake type, for the field
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// F. (The fakery could be arbitrarily deep, involving more
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// nested fields and methods than are shown here.) Clients
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// that use the compatibility shim T will compile with any
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// version of go, whether older or newer than go1.22, but only
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// the newer version will use the std.Real implementation.
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//
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// Now consider a reference to method M in new(T).F.M() in a
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// module that requires a minimum of go1.21. The analysis may
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// occur using a version of Go higher than 1.21, selecting the
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// first version of T, so the method M is Real.M. This would
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// spuriously cause the analyzer to report a reference to a
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// too-new symbol even though this expression compiles just
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// fine (with the fake implementation) using go1.21.
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for _, sym := range symbols {
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symVersion := sym.Version.String()
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if !versions.Before(version, symVersion) {
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continue // allowed
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}
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var obj types.Object
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switch sym.Kind {
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case stdlib.Field:
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typename, name := sym.SplitField()
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if t := pkg.Scope().Lookup(typename); t != nil && disallowed[t] == "" {
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obj, _, _ = types.LookupFieldOrMethod(t.Type(), false, pkg, name)
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}
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case stdlib.Method:
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ptr, recvname, name := sym.SplitMethod()
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if t := pkg.Scope().Lookup(recvname); t != nil && disallowed[t] == "" {
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obj, _, _ = types.LookupFieldOrMethod(t.Type(), ptr, pkg, name)
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}
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}
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if obj != nil {
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disallowed[obj] = symVersion
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}
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}
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return disallowed
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}
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