python: tests and plug a reference leak in the exception throwing code

extra/python/python-tests.factor

@@ -17,8 +17,10 @@ IN: python
 [ t ] [ Py_IsInitialized ] py-test
 
 ! py-importing
-[ { "ImportError" "No module named kolobi" } ] [
-    [ "kolobi" py-import ] [ [ type>> ] [ message>> ] bi 2array ] recover
+[ { "ImportError" "No module named kolobi" f } ] [
+    [ "kolobi" py-import ] [
+        [ type>> ] [ message>> ] [ traceback>> ] tri 3array
+    ] recover
 ] py-test
 
 ! setattr

extra/python/syntax/syntax-tests.factor

@@ -1,7 +1,7 @@
-USING: arrays assocs destructors fry io.files.temp kernel math
-namespaces python python.ffi python.objects sequences sets
-splitting tools.test unicode.categories ;
-IN: python.syntax
+USING: accessors arrays assocs continuations destructors fry io.files.temp
+kernel math namespaces python python.ffi python.objects python.syntax
+sequences sets splitting tools.test unicode.categories ;
+IN: python.syntax.tests
 
 : py-test ( result quot -- )
     '[ _ with-destructors ] unit-test ; inline
@@ -13,7 +13,7 @@ PY-FROM: os =>
 
 [ t ] [ getpid py> integer? ] unit-test
 
-! ! Automatic tuple unpacking
+! Automatic tuple unpacking
 PY-FROM: os.path =>
     basename ( x -- x' )
     splitext ( x -- base ext ) ;
@@ -153,3 +153,16 @@ PY-METHODS: ArgumentParser =>
 
 ! Can you pass a callback written in factor to a python function?
 PY-FROM: wsgiref.simple_server => make_server ( iface port callback -- httpd ) ;
+
+{ t } [
+    [ 987 >py basename ] [ traceback>> ] recover length 0 >
+] unit-test
+
+! Test if exceptions leak references. If so, the test will leak a few
+! hundred megs of memory. Enough to be noticed but not to slow down
+! the tests too much.
+{ } [
+    100000 [
+        [ [ 987 >py basename drop ] ignore-errors ] with-destructors
+    ] times
+] unit-test

extra/python/throwing/throwing.factor

@@ -1,4 +1,4 @@
-USING: arrays kernel python python.syntax sequences ;
+USING: arrays kernel python python.ffi python.syntax sequences ;
 IN: python.throwing
 
 ERROR: python-error type message traceback ;
@@ -10,5 +10,9 @@ PY-METHODS: obj =>
     __str__ ( o -- str ) ;
 
 : throw-error ( ptype pvalue ptraceback -- )
-    [ $__name__ py> ] [ __str__ py> ] [ [ format_tb py> ] [ f ] if* ] tri*
-    python-error ;
+    [
+        [ $__name__ py> ]
+        [ __str__ py> ]
+        [ [ format_tb py> ] [ f ] if* ] tri*
+    ] 3keep
+    [ Py_DecRef ] tri@ python-error ;