app: do not catch exceptions in init_card

The function init_card catches all exceptions and then returns None
objects for card or rs in case of an error. This does not fit in the
style we pursue in pySim. This is in particular true for library
functions. We want those functions to raise exceptions when something is
wrong, so that we can catch the exception at top level. Let's fix this
for init_card now.

Related: OS#6271
Change-Id: I581125d8273ef024f6dbf3a5db6116be15c5c95d
---
M pySim/app.py
1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/pySim/app.py b/pySim/app.py
index 1711a1c..b0df85f 100644
--- a/pySim/app.py
+++ b/pySim/app.py
@@ -55,14 +55,7 @@
     # Wait up to three seconds for a card in reader and try to detect
     # the card type.
     print("Waiting for card...")
-    try:
-        sl.wait_for_card(3)
-    except NoCardError:
-        print("No card detected!")
-        return None, None
-    except:
-        print("Card not readable!")
-        return None, None
+    sl.wait_for_card(3)
 
     generic_card = False
     card = card_detect(scc)
@@ -73,6 +66,10 @@
 
     profile = CardProfile.pick(scc)
     if profile is None:
+        # It is not an unrecoverable error in case profile detection fails. It
+        # just means that pySim was unable to recognize the card profile. This
+        # may happen in particular with unprovisioned cards that do not have
+        # any files on them yet.
         print("Unsupported card type!")
         return None, card
 

