From e3ae97ac5ab7740fad8d78794f8f9a134784ad5a Mon Sep 17 00:00:00 2001
From: David Florness <david@florness.com>
Date: Thu, 29 Apr 2021 23:21:26 -0400
Subject: [PATCH] Remove infinite retries for reading proving keys

It seems this was fixed in gnark-crypto v0.4.0 [0]:

    point.SetBytes can now be called concurently with same byte slice input

[0]: https://github.com/ConsenSys/gnark-crypto/releases/tag/v0.4.0
---
 election/msg.go   | 12 ++++--------
 election/voter.go | 15 ++-------------
 2 files changed, 6 insertions(+), 21 deletions(-)

diff --git a/election/msg.go b/election/msg.go
index 41f3a9a..2a44d43 100644
--- a/election/msg.go
+++ b/election/msg.go
@@ -444,7 +444,6 @@ func (elections *ElectionsMap) onKeysMessage(evt *event.Event, client *mautrix.C
 			errorf("couldn't download eval proving key: %s", err)
 			return
 		}
-	tryEvalPk:
 		var buf bytes.Buffer
 		_, err = buf.Write(byts)
 		if err != nil {
@@ -454,9 +453,8 @@ func (elections *ElectionsMap) onKeysMessage(evt *event.Event, client *mautrix.C
 		evalProvingKey = groth16.NewProvingKey(ecc.BLS12_381)
 		_, err = evalProvingKey.ReadFrom(&buf)
 		if err != nil {
-			log.Errorf("couldn't read eval key from downloaded eval proving keys file: %s", err)
-			log.Debug("trying again...")
-			goto tryEvalPk
+			errorf("couldn't read eval key from downloaded eval proving keys file: %s", err)
+			return
 		}
 	}
 
@@ -467,7 +465,6 @@ func (elections *ElectionsMap) onKeysMessage(evt *event.Event, client *mautrix.C
 			errorf("couldn't download sum proving key: %s", err)
 			return
 		}
-	trySumPk:
 		var buf bytes.Buffer
 		_, err = buf.Write(byts)
 		if err != nil {
@@ -477,9 +474,8 @@ func (elections *ElectionsMap) onKeysMessage(evt *event.Event, client *mautrix.C
 		sumProvingKey = groth16.NewProvingKey(ecc.BLS12_381)
 		_, err = sumProvingKey.ReadFrom(&buf)
 		if err != nil {
-			log.Errorf("couldn't read sum key from downloaded sum keys file: %s", err)
-			log.Debug("trying again...")
-			goto trySumPk
+			errorf("couldn't read sum key from downloaded sum keys file: %s", err)
+			return
 		}
 	}
 
diff --git a/election/voter.go b/election/voter.go
index b6423d4..f44b5a7 100644
--- a/election/voter.go
+++ b/election/voter.go
@@ -188,18 +188,7 @@ func (el *Election) SendProvingKeys(client *mautrix.Client, eventStore *EventSto
 		}
 
 		var evalPkBytes bytes.Buffer
-		// TODO: change back to WriteTo.  There seems to be a bug in
-		// gnark/gurvy (or a misunderstanding on my part) where
-		// decompression fails
-		// ignoring ...'s keys msg ($tsSEYHiouPdJlaTqAOG2q_4t9MZa0OGHtJPD95jOvAg) since couldn't read sum key from bytes buffer: invalid compressed coordinate: square root doesn't exist
-		// The file was successfully processed on one side (who
-		// coincidentally was the sender) but not on the other
-		// NOTE: it's plausible this was fixed in gurvy (now gnark-crypto) 0.4.0:
-		//
-		//     point.SetBytes can now be called concurently with same byte slice input
-		//
-		// https://github.com/ConsenSys/gnark-crypto/releases/tag/v0.4.0
-		evalProvingKey.WriteRawTo(&evalPkBytes)
+		evalProvingKey.WriteTo(&evalPkBytes)
 		uploadResp, err := client.UploadMedia(mautrix.ReqUploadMedia{
 			Content:       &evalPkBytes,
 			ContentLength: int64(evalPkBytes.Len()),
@@ -241,7 +230,7 @@ func (el *Election) SendProvingKeys(client *mautrix.Client, eventStore *EventSto
 
 		var sumPkBytes bytes.Buffer
 		// TODO: see above
-		sumProvingKey.WriteRawTo(&sumPkBytes)
+		sumProvingKey.WriteTo(&sumPkBytes)
 		uploadResp, err := client.UploadMedia(mautrix.ReqUploadMedia{
 			Content:       &sumPkBytes,
 			ContentLength: int64(sumPkBytes.Len()),
-- 
2.38.4