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f87c222f14
The go/format.Node function fails silently on malformed ASTs, even
though it writes out an invalid tree containing the strings "BadExpr"
and "BadStmt". We fix this by checking for *ast.Bad{Expr,Decl,Stmt}
before running the function. Ultimately, this should be fixed upstream
and just return an error from format.Node.
Change-Id: I2ba25551f0e97c0321d8e757de67360af44044d7
Reviewed-on: https://go-review.googlesource.com/c/149613
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
60 lines
1.6 KiB
Go
60 lines
1.6 KiB
Go
// Copyright 2018 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 source
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import (
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"bytes"
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"context"
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"fmt"
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"go/ast"
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"go/format"
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"golang.org/x/tools/go/ast/astutil"
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)
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// Format formats a document with a given range.
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func Format(ctx context.Context, f *File, rng Range) ([]TextEdit, error) {
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fAST, err := f.GetAST()
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if err != nil {
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return nil, err
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}
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path, exact := astutil.PathEnclosingInterval(fAST, rng.Start, rng.End)
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if !exact || len(path) == 0 {
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return nil, fmt.Errorf("no exact AST node matching the specified range")
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}
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node := path[0]
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// format.Node can fail when the AST contains a bad expression or
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// statement. For now, we preemptively check for one.
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// TODO(rstambler): This should really return an error from format.Node.
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var isBad bool
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ast.Inspect(node, func(n ast.Node) bool {
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switch n.(type) {
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case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt:
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isBad = true
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return false
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default:
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return true
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}
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})
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if isBad {
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return nil, fmt.Errorf("unable to format file due to a badly formatted AST")
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}
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// format.Node changes slightly from one release to another, so the version
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// of Go used to build the LSP server will determine how it formats code.
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// This should be acceptable for all users, who likely be prompted to rebuild
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// the LSP server on each Go release.
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buf := &bytes.Buffer{}
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if err := format.Node(buf, f.view.Config.Fset, node); err != nil {
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return nil, err
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}
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// TODO(rstambler): Compute text edits instead of replacing whole file.
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return []TextEdit{
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{
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Range: rng,
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NewText: buf.String(),
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},
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}, nil
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}
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