For some reason, we have two places where a variable can be read-only:
- By key in env.cpp:is_read_only(), which is checked via set*
- By flag on the actual env_var_t, which is checked e.g. in
parse_execution
The latter didn't happen for non-electric variables like hostname,
because they used the default constructor, because they were
constructed via operator[] (or some such C++-iness).
This caused for-loops to crash on an assert if they used a
non-electric read-only var like $hostname or $SHLVL.
Instead, we explicitly set the flag.
We might want to remove one of the two read-only checks, or something?
Fixes#5548.
This previously used /dev/tty to make sure we have `source` connected
to a terminal. Only as it turns out, FreeBSD doesn't have that (https://builds.sr.ht/~faho/job/15308).
So instead, let's just use the expect tests since stdin there is by
definition a terminal.
For things like
source $undefined
or
source (nooutput)
it was quite annoying that it read from tty.
Instead we now require a "-" as the filename to read from the tty.
This does not apply to reading from stdin if it's redirected, so
something | source
still works.
Fixes#2633.
* Hoist `for` loop control var to enclosing scope
It should be possible to reference the last value assigned to a `for`
loop control var when the loop terminates. This makes it easier to detect
if we broke out of the loop among other things. This change makes fish
`for` loops behave like most other shells.
Fixes#1935
* Remove redundant line
Using a read-only variable like `status` as a for loop control variable
has never worked. But without this change you simply get non-sensical
behavior that leaves you scratching your head in puzzlement. This change
replaces the non-sensical behavior with an explicit error message.
Fixes#4342
For example, an argument 12345^ is a real argument, not a redirection
There's no reason to use ^ here instead of >, and it's annoying to git
users.
Fixes#1873
