From 5e60c275b2d8e1191759532f21ff8d0aa5010c94 Mon Sep 17 00:00:00 2001
From: Kris Nuttycombe <kris@nutty.land>
Date: Mon, 22 Apr 2024 12:27:31 -0600
Subject: [PATCH] Allow transparent-only unified addresses and viewing keys.

---
 components/zcash_address/src/kind/unified.rs     | 10 ++--------
 components/zcash_address/src/kind/unified/fvk.rs |  5 +----
 components/zcash_address/src/kind/unified/ivk.rs |  5 +----
 zcash_keys/src/address.rs                        |  5 ++++-
 zcash_keys/src/keys.rs                           |  5 ++++-
 5 files changed, 12 insertions(+), 18 deletions(-)

diff --git a/components/zcash_address/src/kind/unified.rs b/components/zcash_address/src/kind/unified.rs
index 8d7042325..5600ad7a6 100644
--- a/components/zcash_address/src/kind/unified.rs
+++ b/components/zcash_address/src/kind/unified.rs
@@ -561,7 +561,6 @@ pub(crate) mod private {
         ) -> Result<Self, ParseError> {
             assert!(u32::from(Typecode::P2SH) == u32::from(Typecode::P2PKH) + 1);
 
-            let mut only_transparent = true;
             let mut prev_code = None; // less than any Some
             for item in &items {
                 let t = item.typecode();
@@ -576,16 +575,11 @@ pub(crate) mod private {
                     return Err(ParseError::BothP2phkAndP2sh);
                 } else {
                     prev_code = t_code;
-                    only_transparent = only_transparent && item.is_transparent_data_item();
                 }
             }
 
-            if only_transparent {
-                Err(ParseError::OnlyTransparent)
-            } else {
-                // All checks pass!
-                Ok(Self::from_inner(revision, items))
-            }
+            // All checks pass!
+            Ok(Self::from_inner(revision, items))
         }
 
         fn parse_internal<T: Into<Vec<u8>>>(hrp: &str, buf: T) -> Result<Self, ParseError> {
diff --git a/components/zcash_address/src/kind/unified/fvk.rs b/components/zcash_address/src/kind/unified/fvk.rs
index f12adcd96..643f78e40 100644
--- a/components/zcash_address/src/kind/unified/fvk.rs
+++ b/components/zcash_address/src/kind/unified/fvk.rs
@@ -357,9 +357,6 @@ mod tests {
             0xf4, 0xf5, 0x16, 0xef, 0x5c, 0xe0, 0x26, 0xbc, 0x23, 0x73, 0x76, 0x3f, 0x4b,
         ];
 
-        assert_eq!(
-            Ufvk::parse_internal(Ufvk::MAINNET_R0, &encoded[..]),
-            Err(ParseError::OnlyTransparent)
-        );
+        assert_matches!(Ufvk::parse_internal(Ufvk::MAINNET_R0, &encoded[..]), Ok(_));
     }
 }
diff --git a/components/zcash_address/src/kind/unified/ivk.rs b/components/zcash_address/src/kind/unified/ivk.rs
index 5abe1d20b..8d0c5c95e 100644
--- a/components/zcash_address/src/kind/unified/ivk.rs
+++ b/components/zcash_address/src/kind/unified/ivk.rs
@@ -339,9 +339,6 @@ mod tests {
             0xbd, 0xfe, 0xa4, 0xb7, 0x47, 0x20, 0x92, 0x6, 0xf0, 0x0, 0xf9, 0x64,
         ];
 
-        assert_eq!(
-            Uivk::parse_internal(Uivk::MAINNET_R0, &encoded[..]),
-            Err(ParseError::OnlyTransparent)
-        );
+        assert_matches!(Uivk::parse_internal(Uivk::MAINNET_R0, &encoded[..]), Ok(_));
     }
 }
diff --git a/zcash_keys/src/address.rs b/zcash_keys/src/address.rs
index 96353a085..e7b3ae966 100644
--- a/zcash_keys/src/address.rs
+++ b/zcash_keys/src/address.rs
@@ -278,7 +278,10 @@ impl UnifiedAddress {
             .chain(self.expiry_time.map(unified::MetadataItem::ExpiryTime));
 
         let ua = unified::Address::try_from_items(
-            if self.expiry_height().is_some() || self.expiry_time().is_some() {
+            if self.expiry_height().is_some()
+                || self.expiry_time().is_some()
+                || !(self.has_orchard() || self.has_sapling())
+            {
                 Revision::R1
             } else {
                 Revision::R0
diff --git a/zcash_keys/src/keys.rs b/zcash_keys/src/keys.rs
index 1c01c54ad..ddabe2887 100644
--- a/zcash_keys/src/keys.rs
+++ b/zcash_keys/src/keys.rs
@@ -855,7 +855,10 @@ impl UnifiedFullViewingKey {
             .chain(self.expiry_time.map(unified::MetadataItem::ExpiryTime));
 
         zcash_address::unified::Ufvk::try_from_items(
-            if self.expiry_height().is_some() || self.expiry_time().is_some() {
+            if self.expiry_height().is_some()
+                || self.expiry_time().is_some()
+                || !(self.sapling.is_some() || self.orchard.is_some())
+            {
                 Revision::R1
             } else {
                 Revision::R0