If a function process is deferred, allow it to be unbuffered.
This permits certain simple cases where functions are piped to external
commands to execute without buffering.
This is a somewhat-hacky stopgap measure that can't really be extended
to more general concurrent processes. However it is overall an improvement
in user experience that might help flush out some bugs too.
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
