PSelecter test fails on aarch64

[saraedum]

This doctest of PSelecter fails on aarch64 (at least when running with qemu:)

        >>> from cysignals import AlarmInterrupt
        >>> from cysignals.pselect import PSelecter
        >>> import os, signal, time
        >>> with PSelecter([signal.SIGHUP, signal.SIGALRM]) as sel:
        ...     os.kill(os.getpid(), signal.SIGALRM)
        ...     time.sleep(0.5)  # Simply sleep, no interrupt detected
        ...     try:
        ...         _ = sel.sleep(1)  # Interrupt seen here
        ...     except AlarmInterrupt:
        ...         print("Interrupt OK")
        Interrupt OK

Namely, this throws an AlarmInterrupt, I guess before the try block.

The verbose output from a CI run is:

2021-12-02T06:49:33.4949218Z Trying:
2021-12-02T06:49:33.4949643Z     with PSelecter([signal.SIGHUP, signal.SIGALRM]) as sel:
2021-12-02T06:49:33.4950099Z         os.kill(os.getpid(), signal.SIGALRM)
2021-12-02T06:49:33.4950538Z         time.sleep(0.5)  # Simply sleep, no interrupt detected
2021-12-02T06:49:33.4950925Z         try:
2021-12-02T06:49:33.4951310Z             _ = sel.sleep(1)  # Interrupt seen here
2021-12-02T06:49:33.4951710Z         except AlarmInterrupt:
2021-12-02T06:49:33.4952107Z             print("Interrupt OK")
2021-12-02T06:49:33.4952465Z Expecting:
2021-12-02T06:49:33.4952785Z     Interrupt OK
2021-12-02T06:49:34.0024344Z Test src/cysignals/pselect.pyx failed with a <class 'cysignals.signals.AlarmInterrupt'> error: 

The full CI run is here.

This is from a mildly patched cysignals 1.11.0, for packaging for conda-forge, see conda-forge/cysignals-feedstock#35.

The patches applied were:

• a patch to make cross-compilation work:

 configure.ac | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/configure.ac b/configure.ac
index 2910f9b..07f81a0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -55,6 +55,9 @@ AC_RUN_IFELSE([AC_LANG_PROGRAM([[]], [[asm("leal (%eax), %eax; emms");]])],
     ,
     dnl NO
     [AC_MSG_RESULT([no])]
+    ,
+    dnl NO, cross compiling.
+    [AC_MSG_RESULT([no])]
 )

 AC_MSG_CHECKING([whether setjmp() saves the signal mask])
@@ -84,6 +87,9 @@ AC_RUN_IFELSE([AC_LANG_PROGRAM(
     ,
     dnl NO
     [AC_MSG_RESULT([no])]
+    ,
+    dnl NO, cross compiling.
+    [AC_MSG_RESULT([no])]
 )

 AC_MSG_CHECKING([for GNU libc])
@@ -132,6 +138,9 @@ AC_RUN_IFELSE([AC_LANG_SOURCE(
     ,
     dnl NO
     [AC_MSG_RESULT([no])]
+    ,
+    dnl NO, cross compiling.
+    [AC_MSG_RESULT([no])]
 )

 dnl Check for atomic operations

• a patch to ignore some additional output that happens in qemu builds:

--- a/src/cysignals/tests.pyx
+++ b/src/cysignals/tests.pyx
@@ -613,7 +613,7 @@ def unguarded_dereference_null_pointer():
         This probably occurred because a *compiled* module has a bug
         in it and is not properly wrapped with sig_on(), sig_off().
         Python will now terminate.
-        ------------------------------------------------------------------------
+        ...

     The same but with ``CYSIGNALS_CRASH_QUIET`` set. This will crash
     Python silently::
@@ -656,7 +656,7 @@ def unguarded_abort():
         This probably occurred because a *compiled* module has a bug
         in it and is not properly wrapped with sig_on(), sig_off().
         Python will now terminate.
-        ------------------------------------------------------------------------
+        ...

     """
     with nogil:
@@ -691,7 +691,7 @@ def unguarded_stack_overflow():
         This probably occurred because a *compiled* module has a bug
         in it and is not properly wrapped with sig_on(), sig_off().
         Python will now terminate.
-        ------------------------------------------------------------------------
+        ...

     """
     with nogil:
@@ -734,7 +734,7 @@ def test_bad_str(long delay=DEFAULT_DELAY):
         This probably occurred because a *compiled* module has a bug
         in it and is not properly wrapped with sig_on(), sig_off().
         Python will now terminate.
-        ------------------------------------------------------------------------
+        ...

     """
     cdef char* s = <char*>(16)
diff --git a/src/cysignals/tests.pyx b/src/cysignals/tests.pyx
index 0673ffa..6a8156d 100644
--- a/src/cysignals/tests.pyx
+++ b/src/cysignals/tests.pyx
@@ -615,14 +615,6 @@ def unguarded_dereference_null_pointer():
         Python will now terminate.
         ------------------------------------------------------------------------

-    The same but with ``CYSIGNALS_CRASH_QUIET`` set. This will crash
-    Python silently::
-
-        >>> import os
-        >>> env = dict(os.environ)
-        >>> env["CYSIGNALS_CRASH_QUIET"] = ""
-        >>> subpython_err('from cysignals.tests import *; unguarded_dereference_null_pointer()', env=env)
-
     """
     with nogil:
         dereference_null_pointer()

• a patch to produce more verbose output when testing

--- a/rundoctests.py
+++ b/rundoctests.py
@@ -63,13 +63,15 @@ def testfile(file):
         if sys.platform == 'darwin':
             from cysignals.signals import _setup_alt_stack
             _setup_alt_stack()
-        failures, _ = doctest.testfile(file, module_relative=False,
+        failures, _ = doctest.testfile(file, module_relative=False, verbose=True,
                                        optionflags=flags, parser=parser)
         if not failures:
+            print(f"Test {file} passed.")
             os._exit(0)
     except BaseException as E:
-        print(E)
+        print(f"Test {file} failed with a {type(E)} error: {E}")
     finally:
+        print(f"Test {file} failed.")
         os._exit(23)