On 20/01/2020 17.44, Wolfgang Denk wrote:
Dear Rasmus Villemoes,
In message 20200108134247.31443-1-rasmus.villemoes@prevas.dk you wrote:
The printenv command already by default hides variables beginning with a dot. It can be useful to take that convention even further, and prevent such variables from ever being stored persistently (and ignored if they happen to exist in stable storage).
This way, one can freely use such variable names in script logic, without worrying about random temporary variables leaking to persistent storage and/or to/from another U-boot "session".
This is not a good idea. The decision whether a variable shall be stored permanently or not, or wheter it is readonly or writable, and other such properties should never based on their name.
Sorry, but what other property of the variable could possibly determine those things, then?
There may
be many good reasons that some .name variable _shall_ be persistent.
Sure, absolutely. Which is why this is entirely opt-in for those who know they won't need that, but do have some semi-complicated script that interacts with various commands that return their output via an environment variable.
Naked-by: Wolfgang Denk wd@denx.de
Ah, now I see how env_flags_varaccess is actually implemented, involving a .flags special variable. OK, then I can certainly see why one would not want that to be excluded from the environment - I just thought the idea behind "printenv" hiding dot-variables by default was that those were considered temporary, and not special in this way.
So, would you accept introducing env_flags_varaccess_temporary, for which I could then add tmp_.*:st ?
Thanks, Rasmus