x/review/git-codereview: do not mail CLs with editor temp files, binaries

[rsc]

Motivated by #23800, git-codereview should probably refuse to mail CLs with editor temp files and binaries.

[mvdan]

How about disallowing non-printable characters in commit messages too? For example, see https://go-review.googlesource.com/c/go/+/97635, which shows on my terminal as:

keep exiting goroutines^P.

[rsc]

OK sure do that too.

[ysmolski]

What kind of binaries should it disallow? We have repositories with images, for instance.

update: I created a patch for the case of temp editor files and non-printable characters.

[gopherbot]

Change https://golang.org/cl/101755 mentions this issue: git-codereview: forbig mailing editor temp files

[ysmolski]

@bradfitz, I have implemented this features and then I read this: #10658

It says that for binaries we should aim for the fix on server side of gerrit. Does my work on this ticket (which does not touch binaries) still relevant?

Thanks.