Add testcase for os/shell to test/suite-ev.janet
While we may not want to completely deprecate os/shell, we should at
least try to redirect users to better and safer interfaces like
os/execute.
I encountered this issue with `janet -e '(os/shell "echo")'` on Mac, system malloc lib will complain as follows:
```
janet(42817,0x7ff854547780) malloc: *** error for object 0x60000000b730: pointer being freed was not allocated
janet(42817,0x7ff854547780) malloc: *** set a breakpoint in malloc_error_break to debug
```
So I followed the suggestion and here's the backtrace:
```
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
* frame #0: 0x00007ff810cb6883 libsystem_malloc.dylib`malloc_error_break
frame #1: 0x00007ff810ca76d3 libsystem_malloc.dylib`malloc_vreport + 761
frame #2: 0x00007ff810caab31 libsystem_malloc.dylib`malloc_report + 151
frame #3: 0x0000000100025402 janet`janet_ev_default_threaded_callback(return_value=JanetEVGenericMessage @ 0x00007ff7bfefad90) at ev.c:2412:13 [opt]
frame #4: 0x0000000100024b1f janet`janet_loop1_impl [inlined] janet_ev_handle_selfpipe at ev.c:1643:13 [opt]
frame #5: 0x0000000100024ac9 janet`janet_loop1_impl(has_timeout=<unavailable>, timeout=0) at ev.c:2028:13 [opt]
frame #6: 0x0000000100024714 janet`janet_loop1 at ev.c:1588:13 [opt]
frame #7: 0x00000001000497f5 janet`janet_loop_fiber at ev.c:1609:41 [opt]
frame #8: 0x00000001000497b3 janet`janet_loop_fiber(fiber=0x0000600002903790) at run.c:150:5 [opt]
frame #9: 0x0000000100075266 janet`main(argc=<unavailable>, argv=0x00007ff7bfeff210) at shell.c:1284:14 [opt]
frame #10: 0x00007ff810b1041f dyld`start + 1903
```
Found out that it's actually a missing break in the code which leads to double free.
BTW, I'm thinking that if we can implement a debug allocator to be used in the test, so maybe this kind of bugs can be captured earlier.
Change-Id: I74d324b70b39ddc7d6f509b0382e2be36a6a6964
Signed-off-by: Tw <tw19881113@gmail.com>
on 32 bit systems in some cases.
Since most internal arrays in Janet have 32 bit limits, this is is not
hit in practice on 64 bit systems, except in cases of user input. Apply
a fix more generally to simply avoid the issue by coding "defensively".
Some applications are not strictly needed.
Also match shell convention, with strict searching from left to right
instead of right to left by default. The _first_ element will be bound
to (dyn *syspath*), not the last.
Potentially breaking change for complicated, custom setups
Flag collisions was causing some unexpected behavior in some situations.
Removing the source of collisions resolve odd cancelation behavior in
the ev/ module where multiple calls to ev/cancel on the same fiber would
mess with the internal fiber flags and cause bad behavior and the wrong
error message return (but still otherwise behave correctly, so unless
you were parsing the returned error messages, things likely worked).
Also leave comments and test to avoid regressions.
Rather than needing to create wrapper scripts for utilities, `janet -t
mylib <args...>` can be a simple, if somewhat awkward, alternative for
portable command line tooling. Also use spork/fmt on boot.janet.
Passing in the wrong number of keyword arguments could be problematic
and cause compialtion issues. Handle that more gracefully and at least
be clean in valgrind.
Calvin Rose