go/parser: emits invalid ast.ImportSpec when missing end quote of import path #6748
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Owner changed to @griesemer. Status changed to Accepted. |
I cannot reproduce an ast.ImportSpec with nil Path with your example. Specifically, for:
$ cat x.go
package main
import (
"fmt
)
var _ = fmt.Println
func main() {
}
I get a "correctly" looking AST given the error:
$ gotype -ast x.go
0 *ast.File {
1 . Package: x.go:1:1
2 . Name: *ast.Ident {
3 . . NamePos: x.go:1:9
4 . . Name: "main"
5 . }
6 . Decls: []ast.Decl (len = 1) {
7 . . 0: *ast.GenDecl {
8 . . . TokPos: x.go:3:1
9 . . . Tok: import
10 . . . Lparen: x.go:3:8
11 . . . Specs: []ast.Spec (len = 2) {
12 . . . . 0: *ast.ImportSpec {
13 . . . . . Path: *ast.BasicLit {
14 . . . . . . ValuePos: x.go:4:5
15 . . . . . . Kind: STRING
16 . . . . . . Value: "\"fmt\n)"
17 . . . . . }
18 . . . . . EndPos: -
19 . . . . }
20 . . . . 1: *ast.ImportSpec {
21 . . . . . Path: *ast.BasicLit {
22 . . . . . . ValuePos: x.go:7:1
23 . . . . . . Kind: STRING
24 . . . . . . Value: ""
25 . . . . . }
26 . . . . . EndPos: -
27 . . . . }
28 . . . }
29 . . . Rparen: x.go:10:3
30 . . }
31 . }
32 . Scope: *ast.Scope {
33 . . Objects: map[string]*ast.Object (len = 0) {}
34 . }
35 . Imports: []*ast.ImportSpec (len = 2) {
36 . . 0: *(obj @ 12)
37 . . 1: *(obj @ 20)
38 . }
39 }
x.go:4:5: string not terminated
x.go:7:1: expected 'STRING', found 'var'
x.go:10:3: expected ')', found 'EOF'
The AST does contain 2 imports specs (line 12, line 20) due to the error which leads to
a synchronization problem. But both of them have a non-nil Path (line 13, line 21, with
position information).
Inspecting the parser source (go/parser/parser.go:2136 ff) shows that the only place in
the entire parser where an ast.ImportSpec node is created is on line 2164, and that
ImportSpec node always has a non-nil ast.BasicLit (line 2167); i.e., the ImportSpec.Path
cannot be nil by construction (if constructed with the parser). Finally, the
parseImportSpec function always returns a non-nil ImportSpec, equally by construction.
If you can reproduce this, please provide the complete code to reproduce. The error may
be elsewhere.
Related to this (but not causing a problem here) is issue #7091.
Status changed to WaitingForReply. |
This issue was closed.
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by jessevdk:
I've been using ast/parser and friends to parse some go sources. I've come across a nil dereference panic when processing a file containing errors. Specifically, I've tried to parse something like the following: import ( "fmt ) var _ = fmt.Println func main() { } The problem which occurs is that the resulting AST contains an ast.ImportSpec node with a Path set to nil. This is ok, but s.Pos() will try to dereference the nil pointer when called. It would be nice if the ImportSpec node would still be able to report a valid Pos. This also affects go.tools/types which does not check for Path being nil.The text was updated successfully, but these errors were encountered: