Fix#5133 changed builtins to acquire the terminal, but this regressed
caused fish to be stopped when running in background via `sudo fish`.
Fix this by only acquiring the terminal if the terminal was owned by the
builtin's pgroup.
Fixes#5147
When running a builtin, if we are an interactive shell and stdin is a tty,
then acquire ownership of the terminal via tcgetpgrp() before running the
builtin, and set it back after.
Fixes#4540
The order of this list does not need to be strictly maintained any
longer.
Benchmarked with `hyperfine` as follows, where `bench1` is the existing
approach of binary search and `bench2` is the new unordered_set code,
(executed under bash because fish would always return non-zero). The
benchmark code checks each argv to see if it is a builtin keyword (both
return the same result):
```
hyperfine './bench1 $(shuf /usr/share/dict/words)' './bench2 $(shuf /usr/share/dict/words)'
Benchmark #1: ./bench1 $(shuf /usr/share/dict/words)
Time (mean ± σ): 68.4 ms ± 3.0 ms [User: 28.8 ms, System: 38.9 ms]
Range (min … max): 60.4 ms … 75.4 ms
Benchmark #2: ./bench2 $(shuf /usr/share/dict/words)
Time (mean ± σ): 61.4 ms ± 2.3 ms [User: 23.1 ms, System: 39.8 ms]
Range (min … max): 58.1 ms … 67.1 ms
Summary
'./bench2 $(shuf /usr/share/dict/words)' ran
1.11x faster than './bench1 $(shuf /usr/share/dict/words)'
```
This is the second baby step in resolving #3157. Implement a bare minimum
builtin `math` command. This is solely to ensure that fish can be built
and run in the Travis build environments. This is okay since anyone running
`builtin math` today is already getting an error response.
Also, more work is needed to support bare var references, multiple result
values, etc.
Also stop special-casing `printf` as if it were a syntactical keyword
with respect to handling `printf --help`. It should use the same pattern
as every other builtin command.
We've needed a fishy way to parse flags and arguments given to scripts
and functions for a very long time. In particular a manner that provides
the same behavior implemented by builtin commands. The long term goal is
to support DocOpt. But since it is unclear when that will happen so this
implements a `argparse` command. So named as homage to the excellent
Python module of the same name.
Fixes#4190
The count command should not treat any flag specially. Not even `-h` and
`--help`. It should simply return a count of the number of arguments it
received.
Fixes#4189
This implements `status is-breakpoint` that returns true if the current
shell prompt is displayed in the context of a `breakpoint` command.
This also fixes several bugs. Most notably making `breakpoint` a no-op if
the shell isn't interactive. Also, typing `breakpoint` at an interactive
prompt should be an error rather than creating a new nested debugging
context.
Partial fix for #1310
