Background fillthreads are used when we want to populate a buffer from an
external command. The most common is command substitution.
Prior to this commit, fish would spin up a fillthread whenever required.
This ended up being quite expensive.
Switch to using the iothread pool instead. This enables reusing the same
thread(s), which prevents needing to spawn new threads. This shows a big
perf win on the alias benchmark (766 -> 378 ms).
This reintroduces commits 22230a1a0d
and 9d7d70c204, now with the bug fixed.
The problem was when there was one thread waiting in the pool. We enqueue
an item onto the pool and attempt to wake up the thread. But before the
thread runs, we enqueue another item - this second enqueue will see the
thread waiting and attempt to wake it up as well. If the two work items
were dependent (reader/writer) then we would have a deadlock.
The fix is to check if the number of waiting threads is at least as large
as the queue. If the number of enqueued items exceeds the number of waiting
threads, then spawn a new thread always.
This added the function offset *again*, but it's already included in
the line for the current file.
And yes, I have explicitly tested a function file with a function
defined at a later line.
Fixes#6350
Since #6287, bare variable assignments do not parse, which broke
the "Unsupported use of '='" error message.
This commit catches parse errors that occur on bare variable assignments.
When a statement node fails to parse, then we check if there is at least one
prefixing variable assignment. If so, we emit the old error message.
See also #6347
This adds initial support for statements with prefixed variable assignments.
Statments like this are supported:
a=1 b=$a echo $b # outputs 1
Just like in other shells, the left-hand side of each assignment must
be a valid variable identifier (no quoting/escaping). Array indexing
(PATH[1]=/bin ls $PATH) is *not* yet supported, but can be added fairly
easily.
The right hand side may be any valid string token, like a command
substitution, or a brace expansion.
Since `a=* foo` is equivalent to `begin set -lx a *; foo; end`,
the assignment, like `set`, uses nullglob behavior, e.g. below command
can safely be used to check if a directory is empty.
x=/nothing/{,.}* test (count $x) -eq 0
Generic file completion is done after the equal sign, so for example
pressing tab after something like `HOME=/` completes files in the
root directory
Subcommand completion works, so something like
`GIT_DIR=repo.git and command git ` correctly calls git completions
(but the git completion does not use the variable as of now).
The variable assignment is highlighted like an argument.
Closes#6048
