fmt: stack overflow with recursive slice input and formatters %v/%#v

[gopherbot]

by 2852914:

What does 'go version' print?

go version go1.3 linux/amd64

What steps reproduce the problem?

Passing a slice that contains itself to a fmt.* function with either an implicit or
explicit %v formatter will result in an infinite recursion.

http://play.golang.org/p/qjG87yG_LA

What happened?

Infinite recursion inside the printing logic, stack limit reached.

What could have happened instead?

1. The documentation for fmt mentions this recursion caveat, being obvious it could
happen this is just for clarification.
2. The fmt functions need to keep track of what it has printed and not try to print
recursive values.
3. The fmt functions keep track of what it prints and panics (or error) with a more
sensible message when it detects recursion.

[ianlancetaylor]

Comment 1:

Labels changed: added repo-main, release-none.

[robpike]

Comment 2:

Let's go with option 1. It's a rare case that would add significant expense to resolve.

Labels changed: added release-go1.4, documentation, removed release-none.

Owner changed to @robpike.

Status changed to Accepted.

[gopherbot]

Comment 3:

CL https://golang.org/cl/144420043 mentions this issue.

[robpike]

Comment 4:

This issue was closed by revision 892b507.

Status changed to Fixed.