`apply-partially` and hash tables

[Joost Kremers <joostkremers@fastmail.fm>]

Hi list,

A question that just came up: if I use `apply-partially` to create a
function that has a hash table as one of its fixed arguments, and then at
some later point add data to said hash table, it seems that this data is
visible to subsequent calls to the partially applied function:

```
(let* ((s #s(hash-table test equal data ("MGrt" "Mouton De Gruyter"
                                         "OTS" "Utrecht School of Linguistics UiL-OTS")))
       (fn (apply-partially #'parsebib--expand-strings s)))
  (puthash "BW" "Oxford: Blackwell Publishers" s)
  (funcall fn "BW"))
"Oxford: Blackwell Publishers"
```

`parsebib--expand-strings` is a function that (among other things) does a
hash table look-up. The entry ("BW" "Oxford: Blackwell Publishers") is
added to the hash table after the function is created, but it can obviously
still be found by it.

So my question: is this intended behaviour, something that I can rely on to
continue to work, or is this an artefact of the implementation that may
change at any time in the future?

TIA

-- 
Joost Kremers
Life has its moments