go-fuzz-build: embed support packages in binary?

[josharian]

It'd be nice if we could embed the support packages go-fuzz-build needs into the binary, rather than relying on the go tool being able to find them on disk. See discussion at golang/go#30515 (comment) and the following few comments.

https://go-review.googlesource.com/c/tools/+/172409/ added "package overlay" support to go/packages. This is a reminder issue to experiment with whether it would suffice for embedding our support packages, and if so, to start using it.

[thepudds]

@josharian Is the thinking that this would be the best approach (now that overlays of entire packages are supported):

Use codegen to embed the support package into go-fuzz-build and use go/packages overlays (ugh, plus IIUC this doesn’t work because you can only overlay files, not entire packages)

That is excerpt from your comment at golang/go#30515 (comment)

[josharian]

That’s what I was thinking, yes. I definitely still have an “ugh” reaction to it, but it should be reliable and simple for go-fuzz users.

[thepudds]

Most likely this can be done with the go-bindata-assetfs package, which is already vendored.

Here is a sample go:generate in the current go-fuzz that could be used as a starting point for anyone interested in investigating this.

go-fuzz/go-fuzz/main.go

Lines 23 to 26 in 1810d38

	//go:generate go build github.com/dvyukov/go-fuzz/go-fuzz/vendor/github.com/elazarl/go-bindata-assetfs/go-bindata-assetfs
	//go:generate ./go-bindata-assetfs assets/...
	//go:generate goimports -w bindata_assetfs.go
	//go:generate rm go-bindata-assetfs

[thepudds]

@josharian fyi, I filed #279 to track a potentially related issue.

I suspect you might have been using https://github.com/kevinburke/go-bindata installed locally on your machine in the most recent go generate run in 1e7aea5... does that seem plausible?

If #279 is indeed an issue, do you think it would be OK to treat that as a separate pre-existing issue that does not gate any attempt here (in other words, to rely on a local installation of go-bindata in order to help embed the support packages here), or do you think #279 should be addressed before trying to resolve this issue here?

All that said, #279 might just be me being confused, so maybe it is a non-issue.

[josharian]

No need to gate progress here on #279, although I suspect that in practice you might choose to. Up to you.

Thanks for looking into this.