env-file has quoting problems

[EvanCarroll]

• This is a bug report
• This is a feature request
• I searched existing issues before opening this one

Expected behavior

That env-file works the same way as the shell

echo 'FOO="bar"' > .env

set -o allexport
. ./.env
set +o allexport

echo $FOO # returns "bar"

Actual behavior

Quotes are interpreted literally rather as quote characters. If you

$ echo 'FOO="bar"' > .env

Then the $FOO inside the container is set to "bar" (with quotes) rather than bar.

Steps to reproduce the behavior

$ echo 'FOO="bar"' > .env
$ docker run --rm --env-file .env $IMG sh -c 'echo $FOO'
"bar"

See also containers/podman#9446

[thaJeztah]

First of all, note that the .env file (as used by compose) has different semantics than --env-file. For example (if I'm not mistaken) .env files "ignore" export xx lines, so there might always be some discrepancy.

As to handling of quotes; if I remember correctly, the original implementation (moby/moby#4174) both matched the behavior of ENV (in the Dockerfile syntax), which at that time did not handle quoting (everything after = was taken as literal value, including quotes).

There was some discussion around quoting on the original PR (also related to wether or not newlines should be expanded (similar to echo -e "string\nwith\nnewlines")), but it was decided to limit the format to a line-based format, only using = to separate "name" from "value".

That said, it's a long time since that pull requests, and there have been other requests to allow more flexibility (moby/moby#12997), but there was a fear of introducing feature-creep; what's mostly needed for changes to happen in this area is a proposal / design to see if it's possible to change while remaining backward compatible; moby/moby#12997 (comment)

[EvanCarroll]

I would argue that simply not providing quoting will be very confusing as it violates all industry expectations of "env file" (or more specifically a "dot env" file). I don't know if there is a spec ,the idea comes from 12 Factor App, but all of the implementations function differently. If compose has different semantics for it's .env file, I would wonder why they're not implemented in the same fashion.

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