Operating system counter stores signals as flag set without counter.
So sending two signals to a process may result to one or two signal
handler invocation. Queueing signals inside Idris could give users
false sense of signals being are queue, while they are not.
In particular, test for signal could not work reliably for that
reason.
Also, practically we usually don't need have more than once signal
event.
This is follow-up to #1660. CC @mattpolzin
While the discussion about how to refactor test framework is not
finished (#1654), make this change: move `rm -rf build` in the
beginning of the test. For these reasons:
* it is useful to inspect the contents of the `build` directory
especially after the test failure
* if build crashes mid-test (e.g. process killed), next run should
not be affected by the `build` directory from the previous run
* add `strerror` function
* move `getErrno` to `System.Errno`
* use `strerror` in `Show FileError`
* on node there's no access to `strerror`, so `strerror` just converts the number to string
Convert `App.Control.Exception` interface to an alias to `HasErr`.
Probably `Exception` interface need to be deprecated or removed.
Note similar problem exists with `PrimIO` calling `PrimIO, Exception`,
also need to be fixed.
Fix this scenario:
```
throwBoth : Has [Exception String, Exception Int] es => App es ()
throwOne : Has [Exception Int] es => App es Int
throwOne {es} = handle {err = String} {e = es} throwBoth (\r => pure 1) (\e => pure 3)
```
With this commit it works, before this commit it failed with:
```
Error: While processing right hand side of throwOne. Can't find an implementation for Exception Int (String :: es).
TestException.idr:8:48--8:57
|
8 | throwOne {es} = handle {err = String} {e = es} throwBoth (\r => pure 1) (\e => pure 3)
| ^^^^^^^^^
```
On Unix-like operating systems stdio.h is usually line-buffered. As
putStr uses fputs(3) from stdio.h internally, output will be written to
standard out after a newline character is written to the buffer. Since
the prompt does not contain a newline, it will only be written to
standard output after the user presses return. I encountered this issue
on Alpine Linux which uses musl libc (instead of glibc). However, I
believe this issue is likely also reproducible with glibc. This commit
fixes this issue by flushing standard output after writing the prompt to
it. Surprisingly, `src/Idris/IDEMode/REPL.idr` already does this
correctly, `src/Idris/REPL.idr` does not though.
