cmd/doc: strange formatting on inline comment in struct with unexported field

[dsnet]

Using go1.5

Consider this Go package:

package foo

type Reader struct {
    InputOffset  int64 // Total number of bytes read from underlying io.Reader.
    OutputOffset int64 // Total number of bytes emitted from Read.
    hidden       int
}

Currently I see:

$ go doc Reader
type Reader struct {
    InputOffset  int64 // Total number of bytes read from underlying io.Reader.
    OutputOffset int64
                // Total number of bytes emitted from Read.
    // Has unexported fields.
}

I expect to see:

$ go doc Reader
type Reader struct {
    InputOffset  int64 // Total number of bytes read from underlying io.Reader.
    OutputOffset int64 // Total number of bytes emitted from Read.
    // Has unexported fields.
}

---

On a slightly related note, if you just comment out "hidden", but don't delete it, an extra newline is unnecessarily printed:

$ go doc Reader
type Reader struct {
    InputOffset  int64 // Total number of bytes read from underlying io.Reader.
    OutputOffset int64 // Total number of bytes emitted from Read.

}

@robpike

[robpike]

This is how the go/doc package (not cmd/doc) folds lines. The issue is triggered by Output being one byte longer than Input, reaching a threshold.

Working as intended.

[dsnet]

I don't think it has to do with Output being one byte longer. The still occurs with this trivial package:

package foo

type A struct {
    A int // A
    B int // B
    c int
}

Actually, I believe the bug is from the go/doc package. I traced the issue to the fact that the NamePos is not being set. See CL/16286.

[gopherbot]

CL https://golang.org/cl/16286 mentions this issue.