parse_index2: fix crash on bad argument type (issue4110) Passing a non-string to parsers.parse_index2() causes Mercurial to crash instead of raising a TypeError (found on Mac OS X 10.8.5, Python 2.7.6): import mercurial.parsers as parsers parsers.parse_index2(0, 0) Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 parsers.so 0x000000010e071c59 _index_clearcaches + 73 (parsers.c:644) 1 parsers.so 0x000000010e06f2d5 index_dealloc + 21 (parsers.c:1767) 2 parsers.so 0x000000010e074e3b parse_index2 + 347 (parsers.c:1891) 3 org.python.python 0x000000010dda8b17 PyEval_EvalFrameEx + 9911 This happens because when arguments of the wrong type are passed to parsers.parse_index2(), indexType's initialization function index_init() in parsers.c leaves the indexObject instance in a state that indexType's destructor function index_dealloc() cannot handle. This patch moves enough of the indexObject initialization code inside index_init() from after the argument validation code to before it. This way, when bad arguments are passed to index_init(), the destructor doesn't crash and the existing code to raise a TypeError works. This patch also adds a test to check that a TypeError is raised.