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bug#54486: 29.0.50; Eshell `escaped' string property can "leak" into out
From: |
Jim Porter |
Subject: |
bug#54486: 29.0.50; Eshell `escaped' string property can "leak" into output |
Date: |
Sun, 20 Mar 2022 20:52:43 -0700 |
When using Eshell, it's possible to inadvertently add an `escaped'
string property to strings, resulting in some pretty surprising
behavior. Starting from "emacs -Q --eval '(eshell)'":
~ $ setq var (list "foo" "bar")
("foo" "bar")
~ $ echo $var
("foo" "bar")
~ $ echo $var[0]
foo
~ $ echo $var
(#("foo" 0 3
(escaped t))
"bar")
This happens because when the `$var[0]' argument is parsed in the third
command, the function `eshell-interpolate-variable' wraps the
code-to-be-called with `eshell-escape-arg'. That function adds an
`escaped' property to any string passed into it.
The `escaped' property is used to indicate that the string should be
treated literally (i.e. any special characters like "$" will no longer
have any special meaning in Eshell). That's the right *behavior*, but
ideally, there'd be a way to do so that doesn't involve manipulating the
string like this. Eshell can't know the lifetime of the string, and it
seems like a bad idea in general to go around messing with string
properties just because you referenced that string somehow in Eshell.
I can't think of an obvious fix for this though. Any ideas?
- bug#54486: 29.0.50; Eshell `escaped' string property can "leak" into output,
Jim Porter <=