[lmm]

The problem is that Bash is using the same channel for two quite different things - values and functions. It's doing that because the channel is a string; if there were a proper protocol for passing environment to subprocesses, that protocol would make a distinction between the two.

[icebraining]

if there were a proper protocol for passing environment to subprocesses, that protocol would make a distinction between the two.

TCP is a binary protocol, how does it distinguish between executable and plain text formats? Answer: it doesn't, because TCP doesn't know or care about that, that's left to the layers above to handle.

Likewise, environment variables don't know or care about "functions", that's a concept that doesn't enter into the protocol, since it's not a shell specific protocol. All it transmits are keys and values, which are generic blobs of data. That bash uses the protocol to transmit code mixed up with data is no more the protocol's fault than the fact that TCP was used to transmit those same functions on HTTP requests.

[dllthomas]

In principle, a distinguishing protocol could be embedded within the undistinguished one. If the actual environment variables were preceded with a sequence indicating the type of the contents in all cases, this would not be an issue.