fix for start_erl.data - old release getting started after deployment

[delta1]

Summary of changes

This is a simple change to fix the issue in #693 - where the start_erl.data file in releases/ does not get copied into the mutable dir when the directory already exists.

It is a slightly better fix than #703 since it checks if the start_erl.data file in releases dir is newer than the var version first, instead of blindly copying it every single time.

Checklist

• [ n/a] New functions have typespecs, changed functions were updated
• [ n/a] Same for documentation, including moduledocs
• [?] Tests were added or updated to cover changes - not sure how to test this change, please advise
• Commits were squashed into a single coherent commit

Licensing/Copyright

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(the "Contribution"). My Contribution is licensed under the MIT License.

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[delta1]

@bitwalker ?

[aselder]

@bitwalker Can we get this merged? This is a fix for a serious issue.

[tmartin8080]

As a temp workaround for edeliver, added this hook to the .deliver/config.

post_extract_release_archive() {
  status "Copying new release version start_erl.data file"
  __sync_remote "
    [ -f ~/.profile ] && source ~/.profile
    set -e
    if [ -f /home/deploy/apps/phxroad/var/start_erl.data ]; then
      rm /home/deploy/apps/phxroad/var/start_erl.data
    fi
  "
}

Thanks for the PR @delta1

[noozo]

If you happen to be using bootleg instead, here's a similar fix: labzero/bootleg#313

[Scarysize]

Nice fix. Would be awesome to have a new patch release for the distillery package!

[Ninigi]

@bitwalker thank you so much for making most of Elixir deployment a breeze. This PR has been merged for a few months now, but I still have to deal with this issue on every single project. Can we get a hex release please? I would prefer broken distillery (which I know might be broken) over playing Groundhog Day. (and no, I do not want to install from master, that is even worse than dealing with the same problem over and over again.)

[delta1]

@Ninigi save your sanity by just forking and then referencing your fork in mix.exs so you have full control

{:distillery, github: "user/distillery", ref: "1234hash"} # or branch: or tag:

Docs: https://hexdocs.pm/mix/Mix.Tasks.Deps.html#module-git-options-git