Avoid a double free with generated Python libraries (#26228)

[reviewed by @dlongnecke-cray]

We were encountering a problem when chpl_library_finalize was getting
called multiple times - exiting the Python program would result in:

```
Assertion failed: (data && data->bundle), function chpl_task_getInfoChapel, file chpl-tasks-impl-fns.h, line 140.
```

because our generated `__init__.py` file added an `atexit` call to clean
up the runtime, but code could invoke an explicit cleanup call as well.
This would cause problems if the generated library was imported via the
local directory structure instead of the PYTHONPATH, as the
`__init__.py` would apply to the outer directory being referenced and
thus would get registered as part of the `import` to get the inner
library. Removing the explicit clean up in user code would help, but we
shouldn't be sensitive to how the user got access to our exported
functions, nor if they feel like making the explicit cleanup call
themselves.

This may also help in cases where multiple Chapel libraries are used in
a Python program.

Add a test locking in the behavior I was seeing with an unusual import
path and that it has been fixed

Passed a local run of all the Python single locale interop tests, and a
normal paratest with a fresh checkout (to make sure I didn't break C
interoperability)

runtime/src/chpl-init.c

@@ -441,13 +441,23 @@ void chpl_library_init(int argc, char* argv[]) {
 // we may have initialized
 extern void chpl_deinitModules(void);
 
+bool lib_deinited = false;
+
 //
 // A wrapper around chplexit.c:chpl_finalize(...), sole purpose is
 // to provide a "chpl_library_*" interface for the Chapel "library-user".
 void chpl_library_finalize(void) {
   if (!lib_inited) {
     return;
   }
+
+  if (lib_deinited) {
+    // Nothing to do, we've already been cleaned up
+    return;
+  } else {
+    lib_deinited = true;
+  }
+
   chpl_libraryModuleLevelCleanup();
   chpl_deinitModules();
   chpl_finalize(0, 1);

test/interop/python/unusualDirStructure/.gitignore

@@ -0,0 +1 @@
+myLoc/*

test/interop/python/unusualDirStructure/COMPOPTS

@@ -0,0 +1 @@
+--library --library-python

test/interop/python/unusualDirStructure/PREDIFF

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+# Remove clang/gcc unused argument warning
+cat $2 | sed '/^clang: warning: argument unused/d' | \
+sed '/warning: unrecognized command line option/d' | \
+sed '/warning: code will never be executed/d' | \
+# Remove warning about the object file being made for a different OSX version
+sed '/^ld: warning: object file/d' | \
+# Remove warning about .a's being built for a different architecture
+sed '/ignoring file/d' | \
+# Remove numpy version deprecation warning (Cython is responsible for this)
+sed '/arrayobject.h:[0-9]*/d' | \
+sed '/ndarraytypes.h:[0-9]*/d' | \
+sed '/Using deprecated NumPy API/d' | \
+sed '/^ *\^/d' | \
+sed '/^1 warning generated./d' | \
+sed '/^[2-9] warnings generated./d' | \
+sed '/^[ ]*$/d' | \
+sed '/^[ ]*[0-9]* | /d' | \
+sed '/^ *|/d' | \
+# avoid sporadic ld: warning errors (I'm sometimes seeing just that on a line,
+# or just multiple copies of it)
+sed '/^ld: warning/d' > $2.tmp
+cat $2.tmp > $2
+rm $2.tmp

test/interop/python/unusualDirStructure/SKIPIF

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+if [[ $CHPL_COMM != none ]] ; then
+  echo True
+elif [[ $CHPL_TARGET_PLATFORM != darwin && $CHPL_LIB_PIC != pic ]] ; then
+  echo True
+elif command -v python3 >/dev/null; then
+  # Python3 is required for building with Cython (we would need to change our
+  # output of certain types and that isn't particularly worth it)
+  # The script skipif_helper.py checks that cython and numpy are installed
+  python3 skipif_helper.py
+else
+  echo True
+fi

test/interop/python/unusualDirStructure/skipif_helper.py

@@ -0,0 +1,14 @@
+import os
+
+try:
+  # numpy and cython are required for building Python modules
+  import numpy
+  import cython
+
+  compiler = os.environ['CHPL_TARGET_COMPILER']
+  if (compiler.startswith("cray-prgenv") and compiler != "cray-prgenv-gnu"):
+    print(True)
+  else:
+    print(False)
+except ImportError:
+  print(True)

test/interop/python/unusualDirStructure/testing.chpl

@@ -0,0 +1,30 @@
+// Chapel file that exports a variety of functions for use with Python
+export proc foo() {
+  writeln("I do nothing");
+}
+
+export proc takesAndReturns(x: int): int {
+  writeln("arg was: ", x, ", return is: ", (x + 1));
+  return x + 1;
+}
+
+export proc parallelProg(numTasksToRun: int) {
+  coforall i in 1..numTasksToRun {
+    writeln("In task ", i);
+  }
+}
+
+export proc threadring(passes: int, tasks: int) {
+  var mailbox: [1..tasks] sync int;
+  mailbox[1].writeEF(0);
+  proc passTokens(tid) {
+    do {
+      const numPasses = mailbox[tid].readFE();
+      mailbox[tid%tasks+1].writeEF(numPasses+1);
+      if numPasses == passes then
+        writeln(tid);
+    } while (numPasses < passes);
+  }
+  coforall tid in 1..tasks do
+    passTokens(tid);
+}

test/interop/python/unusualDirStructure/testing.cleanfiles

@@ -0,0 +1 @@
+myLoc/*

test/interop/python/unusualDirStructure/testing.compopts

@@ -0,0 +1 @@
+--library-dir=myLoc

test/interop/python/unusualDirStructure/testing.good

@@ -0,0 +1,3 @@
+I do nothing
+arg was: 3, return is: 4
+21

test/interop/python/unusualDirStructure/testing.prediff

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+sed '/from testing.c:[0-9]*/d' $2 > $2.tmp
+sed '/^ *$/d' $2.tmp > $2
+rm $2.tmp
+export PYTHONPATH=myLoc/
+# intentionally include any error output from running the Python file
+# (tbh, I should be doing that anyways...)
+python3 use_testing.py >> $2 2>&1

test/interop/python/unusualDirStructure/use_testing.py

@@ -0,0 +1,9 @@
+# import via the current working directory, since we have an `__init__.py` there
+import myLoc.testing as testing
+
+testing.chpl_setup()
+testing.foo()
+x = 3
+y = testing.takesAndReturns(x)
+testing.threadring(1000, 98)
+testing.chpl_cleanup()