csecp256k1

commit 75d24657209d68b3c9eb5c17a7c38b2d71cd5a05
parent d612d7115af5f4d0bffc70192e634c7ad7843300
Author: Jared Tobin <jared@jtobin.io>
Date:   Mon, 26 Aug 2024 12:52:23 -0230

lib: w{r}context now returns IO ()

Previously one could do e.g. 'wcontext pure' in order to return the
context itself, which would be invalid outside of the wcontext block.

Diffstat:
M
lib/Crypto/Secp256k1.hs
 | 
22
++++------------------
M
test/Main.hs
 | 
8
++++----

2 files changed, 8 insertions(+), 22 deletions(-)
diff --git a/lib/Crypto/Secp256k1.hs b/lib/Crypto/Secp256k1.hs
@@ -158,22 +158,11 @@ instance Exception Secp256k1Exception
 --   that has /not/ been randomized, and so /doesn't/ offer additional
 --   side-channel attack protection. For that, use 'wrcontext'.
 --
---   Do /not/ attempt to use the created 'Context' value outside
---   of a 'wcontext' or 'wrcontext' block, as the internal
---   bitcoin-core/secp256k1 context will have been destroyed by then.
---   For example, don't be cheeky and do something like:
---
---   > do
---   >   context <- wcontext pure
---   >   derive_pub context seckey
---
---   unless you like segfaults.
---
 --   >>> wcontext $ \tex -> parse_pub tex bytestring
 --   "<bitcoin-core/secp256k1 public key>"
 wcontext
-  :: (Context -> IO a) -- ^ continuation to run in the context
-  -> IO a
+  :: (Context -> IO ()) -- ^ continuation to run in the context
+  -> IO ()
 wcontext = bracket create destroy where
   create = do
     tex <- secp256k1_context_create _SECP256K1_CONTEXT_NONE
@@ -189,15 +178,12 @@ wcontext = bracket create destroy where
 --   Use this function to execute computations that may benefit from
 --   additional side-channel attack protection.
 --
---   As with 'wcontext', do /not/ attempt to use a created 'Context'
---   value outside of the 'wrcontext' block.
---
 --   >>> wrcontext entropy $ \tex -> sign tex sec msg
 --   "<bitcoin-core/secp256k1 signature>"
 wrcontext
   :: BS.ByteString     -- ^ 32 bytes of fresh entropy
-  -> (Context -> IO a) -- ^ continuation to run in the context
-  -> IO a
+  -> (Context -> IO ()) -- ^ continuation to run in the context
+  -> IO ()
 wrcontext enn con
     | BS.length enn /= 32 = throwIO CSecp256k1Error
     | otherwise = bracket create destroy con
diff --git a/test/Main.hs b/test/Main.hs
@@ -129,12 +129,12 @@ parse_xonly_test =
 
 serialize_xonly_test :: TestTree
 serialize_xonly_test =
-  testCase "serialize_xonly (success)" $ do
-    pux <- wcontext $ \tex -> do
+  testCase "serialize_xonly (success)" $
+    wcontext $ \tex -> do
       pub <- parse_pub tex _PUB_COMPRESSED
       key <- xonly tex pub
-      serialize_xonly tex key
-    assertEqual "success" pux _PUB_XONLY
+      pux <- serialize_xonly tex key
+      assertEqual "success" pux _PUB_XONLY
 
 keypair_test :: TestTree
 keypair_test =