For a repo github.com/user/package

The directory mod/github.com/user/package@v0.0.0... has permission 0555.
Files inside it can't be deleted.

The permission of directories in mod/github.com/user/package@v0.0.0... is 0755,
Files in mod/github.com/user/package@v0.0.0.../subdir can be deleted.

All files in mod/github.com/user/package@v0.0.0...(including subdirectories) has permission 0400.

This looks like a feature, but currently it is inconsistent.

In my case: https://slexy.org/view/s2deKExjfk

I don't see why it should be the case, I have to either recursively change the permissions,
or use sudo rm -rf $GOPATH/pkg/mod/.

I tested with an outdated go.
The inconsistence has been fixed. All files can't be deleted now.

@rsc discussed this on the mailing list on July 13:

I can't do rm -fr $GOPATH/src/mod because the directory with the @ (in my case golang.org/x/crypto@) is not writable for the user.

Yes, this is really annoying: when I made the directories unwritable I thought that rm -rf would still work on them, and I'm disappointed that it doesn't. Even so, I do think it's important to keep them unwritable to prevent accidental modification. I intend to add 'go clean -modcache' or something like that to blow away that tree for you (chmod + rm), so even though rm -rf fails, there will be an easy command.

go clean -modcache does appear to be implemented in the go1.11 release.

This is, as @mark-rushakoff pointed out, working as intended. The integrity of pkg/mod/** is important. Hence it is not writable.

Is it a reasonable way to ensure data integrity? What is the reasoning behind this? Human error, as in accidental typing of rm -rf $GOPATH/pkg/mod?

You make a fair point which is why Russ commented:

Yes, this is really annoying: when I made the directories unwritable I thought that rm -rf would still work on them, and I'm disappointed that it doesn't.

This minor pain is alleviated by go clean -modcache followed by the rm -rf

go clean -modcache nukes $GOPATH/pkg/mod entirely though, so there's nothing left to rm -rf. :D

$ ls $GOPATH/pkg/mod
cache  github.com  golang.org
$ go clean -modcache
$ ls $GOPATH/pkg/mod
ls: cannot access '/home/bmeh/go/pkg/mod': No such file or directory

Ok, so go clean -modcache covers your case entirely then?

Duplicate of #27161

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