Fix failure on file-5.15. That has a bug and/or change in behvior

where the first call to magic_load results in magic_error returning a
string even though there was no error.  Fixed by being more precise
about checking the return values (either nul or -1 depending on
function) rather than relying on magic_error.

1 files changed, 14 insertions, 7 deletions

diff --git a/magic.py b/magic.py
index ab1fd63..c3ece14 100644
--- a/magic.py
+++ b/magic.py
@@ -162,13 +162,21 @@ if not libmagic or not libmagic._name:
 
 magic_t = ctypes.c_void_p
 
-def errorcheck(result, func, args):
-    err = magic_error(args[0])
-    if err is not None:
+def errorcheck_null(result, func, args):
+    if result is None:
+        err = magic_error(args[0])
         raise MagicException(err)
     else:
         return result
 
+def errorcheck_negative_one(result, func, args):
+    if result is -1:
+        err = magic_error(args[0])
+        raise MagicException(err)
+    else:
+        return result
+    
+
 def coerce_filename(filename):
     if filename is None:
         return None
@@ -193,7 +201,7 @@ magic_errno.argtypes = [magic_t]
 _magic_file = libmagic.magic_file
 _magic_file.restype = c_char_p
 _magic_file.argtypes = [magic_t, c_char_p]
-_magic_file.errcheck = errorcheck
+_magic_file.errcheck = errorcheck_null
 
 def magic_file(cookie, filename):
     return _magic_file(cookie, coerce_filename(filename))
@@ -201,8 +209,7 @@ def magic_file(cookie, filename):
 _magic_buffer = libmagic.magic_buffer
 _magic_buffer.restype = c_char_p
 _magic_buffer.argtypes = [magic_t, c_void_p, c_size_t]
-_magic_buffer.errcheck = errorcheck
-
+_magic_buffer.errcheck = errorcheck_null
 
 def magic_buffer(cookie, buf):
     return _magic_buffer(cookie, buf, len(buf))
@@ -211,7 +218,7 @@ def magic_buffer(cookie, buf):
 _magic_load = libmagic.magic_load
 _magic_load.restype = c_int
 _magic_load.argtypes = [magic_t, c_char_p]
-_magic_load.errcheck = errorcheck
+_magic_load.errcheck = errorcheck_negative_one
 
 def magic_load(cookie, filename):
     return _magic_load(cookie, coerce_filename(filename))