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Massive file generated do to recursion with no errors #70

novaterata opened this issue Jul 1, 2019 · 2 comments


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commented Jul 1, 2019

This bug is kind of hilarious, so we have an html file template that we include in our bin with vfsgen in a package called assets, but because go generate puts the assets_vfsdata.go in the root directory, we move it into assets folder after it's generated. After repeating this process with the assets_vfsdata.go in there, the generated assets_vfsdata.go was ~1.8GB!! with no errors of any kind reported. Of course I changed the directory structure to prevent this, but I found it very interesting that this is possible without a stack overflow of some kind.

File system:
./assets/assets_vfsdata.go // after initial generation and copying from ./assets_vfsdata.go

`// +build ignore

package main

import (



func main() {
var fs http.FileSystem = http.Dir("./assets")

err := vfsgen.Generate(fs, vfsgen.Options{
	PackageName:  "assets",
	BuildTags:    "!dev",
	VariableName: "Assets",
if err != nil {


I switched to http.Dir("./assets/src")
and moved report-template.html into ./assets/src to fix this, but I was pretty surprised that it was even possible


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commented Jul 1, 2019

I'm not sure if the file is huge the second iteration, or if it doubles in size each iteration until reaching some limit


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commented Aug 12, 2019

Thanks for sharing this scenario that you've encountered.

vfsgen is a simple tool that operates on whatever arbitrary input you provide it. I'm not sure if it's viable to detect that its own output is a part of the input, at least not in the general case.

Right now, I can't think of anything that can be done to improve the situation here. Let me know if you have suggestions.

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