Description:
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The function php_mimepart_process_line() checks if the count of children have 
exceeded MAXPARTS and issue a PHP warning + return FAILURE. The 
php_mimepart_parse() which calls the line processing not obeys the returned 
value and call it again and again for the rest of the lines, resulting another 
PHP warning for each additional line. (if you've got 10000 additional line, then 
it will be 10000 additional warning)

Second, the php_mimepart_parse() return SUCCESS even when we cant parse all of 
the lines, which will result the mailparse_msg_parse_file() not returning false 
but a resource containing a partial email.

Third, the mailparse_msg_parse_file() leaks memory if the php_mimepart_parse() 
would return FAILURE as it not clears out the already allocated object and not 
returning it either. Since the php_mimepart_parse() never returned failure (see 
second point) it never actually came up before.

Additionally mailparse_mimemessage() not obeying the returned value from 
php_mimepart_parse() at all, but that's in the mailmessage object which is not 
documented and seemingly otdated/unfinished anyway.


Test script:
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// $filename has more than 300 mime parts
$resource = mailparse_msg_parse_file($filename);


Expected result:
----------------
one warning exceeding MAXPARTS, and the $resource should be false, no memory leak 
happening

Actual result:
--------------
lot's of 'exceeding MAXPARTS' warnings, a resource returned pointing to a half 
parsed email