pkt-line and LF terminated lines of data

From: dwh@linuxprogrammer.org <dwh@linuxprogrammer.org>
Date: Apr 28, 2021, 22:22 UTC
Message-ID: <20210428222219.GA982@localhost>

I was just reading the Documentation/technical/protocol-common.txt description of the pkt-line format. One detail that is left out is how a receiver of pkt-line encoded data determines if a line is binary data or contains non-binary data.

The documentation says:

> A non-binary line SHOULD BE terminated by an LF, which if present MUST
> be included in the total length. Receivers MUST treat pkt-lines with
> non-binary data the same whether or not they contain the trailing LF
> (stripping the LF if present, and not complaining when it is missing).

It seems like a pkt-line with binary data could easily end with 0x0a (LF) and a receiver would strip it off even though that is a legitimate byte in the binary stream. I don't think receivers should be trying to determine if the pkt-line is binary or non-binary and never strip off any 0x0a bytes at the end of a pkt-line.

The client code that relies on the pkt-line receiver is where the logic should reside that figures out what to do with strings that end with LF. The pkt-line receiver just parses the pkg-line length, reads the correct number of bytes and passes them along for further processing.

What am I missing? What should be added to this documentation that gives more detail on when/why/how a pkt-line would be determined to be non-binary and the LF stripping would occur?

Cheers! Dave