From 5ae17cd01f8a44c3699db63c4804b0840188ab44 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Thu, 31 Mar 2022 19:35:45 +0300
Subject: [PATCH 01/18] seal_code_hash() added

---
 crates/env/src/api.rs                    | 10 ++++++++++
 crates/env/src/backend.rs                | 14 ++++++++++++++
 crates/env/src/engine/off_chain/impls.rs | 11 +++++++++++
 crates/env/src/engine/on_chain/ext.rs    |  7 +++++++
 crates/env/src/engine/on_chain/impls.rs  |  9 +++++++++
 crates/lang/src/env_access.rs            |  7 +++++++
 6 files changed, 58 insertions(+)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index fb96c44e87..516506b7ba 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -514,6 +514,16 @@ where
     })
 }
 
+///
+pub fn code_hash<E>(account: &E::AccountId, output: &mut E::Hash) -> Result<()>
+where
+    E: Environment,
+{
+    <EnvInstance as OnInstance>::on_instance(|instance| {
+        instance.code_hash::<E>(account, output)
+    })
+}
+
 /// Checks whether the caller of the current contract is the origin of the whole call stack.
 ///
 /// Prefer this over [`is_contract`] when checking whether your contract is being called by
diff --git a/crates/env/src/backend.rs b/crates/env/src/backend.rs
index cb7b7723a9..2b30c3f554 100644
--- a/crates/env/src/backend.rs
+++ b/crates/env/src/backend.rs
@@ -447,4 +447,18 @@ pub trait TypedEnvBackend: EnvBackend {
     fn caller_is_origin<E>(&mut self) -> bool
     where
         E: Environment;
+
+    /// Reads the code hash of the contract for the given `account`,
+    /// and stores the result in `output`.
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`code_hash`][`crate::code_hash`]
+    fn code_hash<E>(
+        &mut self,
+        account: &E::AccountId,
+        output: &mut E::Hash,
+    ) -> Result<()>
+    where
+        E: Environment;
 }
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index 7c302b16d2..26b33d161e 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -486,4 +486,15 @@ impl TypedEnvBackend for EnvInstance {
     {
         unimplemented!("off-chain environment does not support cross-contract calls")
     }
+
+    fn code_hash<E>(
+        &mut self,
+        _account: &E::AccountId,
+        _output: &mut E::Hash,
+    ) -> Result<()>
+    where
+        E: Environment,
+    {
+        unimplemented!("off-chain environment does not support contract instantiation")
+    }
 }
diff --git a/crates/env/src/engine/on_chain/ext.rs b/crates/env/src/engine/on_chain/ext.rs
index f35cae20da..e147ca78b3 100644
--- a/crates/env/src/engine/on_chain/ext.rs
+++ b/crates/env/src/engine/on_chain/ext.rs
@@ -676,3 +676,10 @@ pub fn caller_is_origin() -> bool {
     let ret_val = unsafe { sys::seal_caller_is_origin() };
     ret_val.into_bool()
 }
+
+pub fn code_hash(account_id: &[u8], output: &mut &mut [u8]) -> Result {
+    let ret_val = unsafe {
+        sys::seal_code_hash(Ptr32::from_slice(account_id), Ptr32Mut::from_slice(output))
+    };
+    ret_code.into()
+}
diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index da6a54bba8..a11bc8f986 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -512,4 +512,13 @@ impl TypedEnvBackend for EnvInstance {
     {
         ext::caller_is_origin()
     }
+
+    fn code_hash<E>(&mut self, account_id: &E::AccountId, output: E::Hash) -> Result<()>
+    where
+        E: Environment,
+    {
+        let mut scope = self.scoped_buffer();
+        let enc_account_id = scope.take_encoded(account_id);
+        ext::code_hash(enc_account_id, output).map_err(Into::into)
+    }
 }
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index ede514f098..34715c4e77 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -25,6 +25,7 @@ use ink_env::{
         CryptoHash,
         HashOutput,
     },
+    Clear,
     Environment,
     Error,
     Result,
@@ -901,4 +902,10 @@ where
     pub fn caller_is_origin(self) -> bool {
         ink_env::caller_is_origin::<E>()
     }
+
+    ///
+    pub fn code_hash(self, account_id: &E::AccountId) -> Result<E::Hash> {
+        let mut output = <E as Environment>::Hash::clear();
+        ink_env::code_hash::<E>(account_id, &mut output).map(|_| output.into())
+    }
 }

From c977acc7ba2e9e204dcc39597ef8f154412cc0de Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Thu, 31 Mar 2022 19:48:59 +0300
Subject: [PATCH 02/18] +docs

---
 crates/env/src/api.rs         |  2 +-
 crates/env/src/backend.rs     |  2 +-
 crates/lang/src/env_access.rs | 27 +++++++++++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index 516506b7ba..74f1ef9877 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -514,7 +514,7 @@ where
     })
 }
 
-///
+/// Retrieves the code hash of a contract living at specified account
 pub fn code_hash<E>(account: &E::AccountId, output: &mut E::Hash) -> Result<()>
 where
     E: Environment,
diff --git a/crates/env/src/backend.rs b/crates/env/src/backend.rs
index 2b30c3f554..4bbbed7199 100644
--- a/crates/env/src/backend.rs
+++ b/crates/env/src/backend.rs
@@ -448,7 +448,7 @@ pub trait TypedEnvBackend: EnvBackend {
     where
         E: Environment;
 
-    /// Reads the code hash of the contract for the given `account`,
+    /// Retrieves the code hash of the contract for the given `account`,
     /// and stores the result in `output`.
     ///
     /// # Note
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index 34715c4e77..83e235d797 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -903,7 +903,34 @@ where
         ink_env::caller_is_origin::<E>()
     }
 
+    /// Returns the code hash of the contract living at the given `account`.
     ///
+    /// # Example
+    ///
+    /// ```
+    /// # use ink_lang as ink;
+    /// # #[ink::contract]
+    /// # pub mod my_contract {
+    /// #     #[ink(storage)]
+    /// #     pub struct MyContract { }
+    /// #
+    /// #     impl MyContract {
+    /// #         #[ink(constructor)]
+    /// #         pub fn new() -> Self {
+    /// #             Self {}
+    /// #         }
+    /// #
+    /// #[ink(message)]
+    /// pub fn code_hash(&mut self, account_id: AccountId) -> Result<Hash> {
+    ///     self.env().code_hash(&account_id)
+    /// }
+    /// #    }
+    /// # }
+    /// ```
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`ink_env::code_hash`]
     pub fn code_hash(self, account_id: &E::AccountId) -> Result<E::Hash> {
         let mut output = <E as Environment>::Hash::clear();
         ink_env::code_hash::<E>(account_id, &mut output).map(|_| output.into())

From c0744f9df0d89529179580fe7f395e309f21af8e Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Thu, 31 Mar 2022 20:13:53 +0300
Subject: [PATCH 03/18] seal_own_code_hash() added

---
 crates/env/src/api.rs                    | 10 +++++++
 crates/env/src/backend.rs                |  9 +++++++
 crates/env/src/engine/off_chain/impls.rs |  7 +++++
 crates/env/src/engine/on_chain/ext.rs    |  5 ++++
 crates/env/src/engine/on_chain/impls.rs  |  7 +++++
 crates/lang/src/env_access.rs            | 33 ++++++++++++++++++++++++
 6 files changed, 71 insertions(+)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index 74f1ef9877..de9427b42b 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -524,6 +524,16 @@ where
     })
 }
 
+/// Retrieves the code hash of the currently executing contract.
+pub fn own_code_hash<E>(output: &mut E::Hash) -> Result<()>
+where
+    E: Environment,
+{
+    <EnvInstance as OnInstance>::on_instance(|instance| {
+        instance.own_code_hash::<E>(output)
+    })
+}
+
 /// Checks whether the caller of the current contract is the origin of the whole call stack.
 ///
 /// Prefer this over [`is_contract`] when checking whether your contract is being called by
diff --git a/crates/env/src/backend.rs b/crates/env/src/backend.rs
index 4bbbed7199..36df2f1077 100644
--- a/crates/env/src/backend.rs
+++ b/crates/env/src/backend.rs
@@ -461,4 +461,13 @@ pub trait TypedEnvBackend: EnvBackend {
     ) -> Result<()>
     where
         E: Environment;
+
+    /// Retrieves the code hash of the currently executing contract.
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`own_code_hash`][`crate::own_code_hash`]
+    fn own_code_hash<E>(&mut self, output: &mut E::Hash) -> Result<()>
+    where
+        E: Environment;
 }
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index 26b33d161e..bb60ba3077 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -497,4 +497,11 @@ impl TypedEnvBackend for EnvInstance {
     {
         unimplemented!("off-chain environment does not support contract instantiation")
     }
+
+    fn own_code_hash<E>(&mut self, _output: &mut E::Hash) -> Result<()>
+    where
+        E: Environment,
+    {
+        unimplemented!("off-chain environment does not support contract instantiation")
+    }
 }
diff --git a/crates/env/src/engine/on_chain/ext.rs b/crates/env/src/engine/on_chain/ext.rs
index e147ca78b3..606fab6cb7 100644
--- a/crates/env/src/engine/on_chain/ext.rs
+++ b/crates/env/src/engine/on_chain/ext.rs
@@ -683,3 +683,8 @@ pub fn code_hash(account_id: &[u8], output: &mut &mut [u8]) -> Result {
     };
     ret_code.into()
 }
+
+pub fn own_code_hash(output: &mut &mut [u8]) -> Result {
+    let ret_val = unsafe { sys::seal_own_code_hash(Ptr32Mut::from_slice(output)) };
+    ret_code.into()
+}
diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index a11bc8f986..aacd59d8a4 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -521,4 +521,11 @@ impl TypedEnvBackend for EnvInstance {
         let enc_account_id = scope.take_encoded(account_id);
         ext::code_hash(enc_account_id, output).map_err(Into::into)
     }
+
+    fn own_code_hash<E>(&mut self, output: E::Hash) -> Result<()>
+    where
+        E: Environment,
+    {
+        ext::own_code_hash(output).map_err(Into::into)
+    }
 }
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index 83e235d797..5a9a5985d8 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -935,4 +935,37 @@ where
         let mut output = <E as Environment>::Hash::clear();
         ink_env::code_hash::<E>(account_id, &mut output).map(|_| output.into())
     }
+
+    /// Returns the code hash of the contract living at the given `account`.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use ink_lang as ink;
+    /// # #[ink::contract]
+    /// # pub mod my_contract {
+    /// #     #[ink(storage)]
+    /// #     pub struct MyContract { }
+    /// #
+    /// #     impl MyContract {
+    /// #         #[ink(constructor)]
+    /// #         pub fn new() -> Self {
+    /// #             Self {}
+    /// #         }
+    /// #
+    /// #[ink(message)]
+    /// pub fn own_code_hash(&mut self) -> Result<Hash> {
+    ///     self.env().own_code_hash()
+    /// }
+    /// #    }
+    /// # }
+    /// ```
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`ink_env::own_code_hash`]
+    pub fn own_code_hash(self) -> Result<E::Hash> {
+        let mut output = <E as Environment>::Hash::clear();
+        ink_env::own_code_hash::<E>(&mut output).map(|_| output.into())
+    }
 }

From 99ef061e647dfb7e5fcf1a44be9d86058827ac10 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Thu, 31 Mar 2022 20:37:20 +0300
Subject: [PATCH 04/18] ci errors fixes

---
 crates/env/src/engine/on_chain/ext.rs | 11 +++++++++++
 crates/lang/src/env_access.rs         |  2 +-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/crates/env/src/engine/on_chain/ext.rs b/crates/env/src/engine/on_chain/ext.rs
index 606fab6cb7..2900b0ce98 100644
--- a/crates/env/src/engine/on_chain/ext.rs
+++ b/crates/env/src/engine/on_chain/ext.rs
@@ -347,6 +347,17 @@ mod sys {
             message_hash_ptr: Ptr32<[u8]>,
             output_ptr: Ptr32Mut<[u8]>,
         ) -> ReturnCode;
+
+        pub fn seal_code_hash(
+            account_id_ptr: Ptr32<[u8]>,
+            output_ptr: Ptr32Mut<[u8]>,
+            output_len_ptr: Ptr32Mut<u32>,
+        ) -> ReturnCode;
+
+        pub fn seal_own_code_hash(
+            output_ptr: Ptr32Mut<[u8]>,
+            output_len_ptr: Ptr32Mut<u32>,
+        ) -> ReturnCode;
     }
 }
 
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index 5a9a5985d8..78dfd78082 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -966,6 +966,6 @@ where
     /// For more details visit: [`ink_env::own_code_hash`]
     pub fn own_code_hash(self) -> Result<E::Hash> {
         let mut output = <E as Environment>::Hash::clear();
-        ink_env::own_code_hash::<E>(&mut output).map(|_| output.into())
+        ink_env::own_code_hash::<E>(&mut output).map(|_| output)
     }
 }

From f9769dc8daaa4d3a90687b4afc5f6e8fb372123b Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Thu, 31 Mar 2022 21:16:45 +0300
Subject: [PATCH 05/18] more ci fixes

---
 crates/env/src/engine/on_chain/ext.rs   | 23 +++++++++++++++++------
 crates/env/src/engine/on_chain/impls.rs |  8 ++++++--
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/crates/env/src/engine/on_chain/ext.rs b/crates/env/src/engine/on_chain/ext.rs
index 2900b0ce98..bd4cec323a 100644
--- a/crates/env/src/engine/on_chain/ext.rs
+++ b/crates/env/src/engine/on_chain/ext.rs
@@ -688,14 +688,25 @@ pub fn caller_is_origin() -> bool {
     ret_val.into_bool()
 }
 
-pub fn code_hash(account_id: &[u8], output: &mut &mut [u8]) -> Result {
+pub fn code_hash(account_id: &[u8], output: &mut [u8]) -> Result {
+    let mut output_len = output.len() as u32;
     let ret_val = unsafe {
-        sys::seal_code_hash(Ptr32::from_slice(account_id), Ptr32Mut::from_slice(output))
+        sys::seal_code_hash(
+            Ptr32::from_slice(account_id),
+            Ptr32Mut::from_slice(output),
+            Ptr32Mut::from_ref(&mut output_len),
+        )
     };
-    ret_code.into()
+    ret_val.into()
 }
 
-pub fn own_code_hash(output: &mut &mut [u8]) -> Result {
-    let ret_val = unsafe { sys::seal_own_code_hash(Ptr32Mut::from_slice(output)) };
-    ret_code.into()
+pub fn own_code_hash(output: &mut [u8]) -> Result {
+    let mut output_len = output.len() as u32;
+    let ret_val = unsafe {
+        sys::seal_own_code_hash(
+            Ptr32Mut::from_slice(output),
+            Ptr32Mut::from_ref(&mut output_len),
+        )
+    };
+    ret_val.into()
 }
diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index aacd59d8a4..2ad894ca48 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -513,7 +513,11 @@ impl TypedEnvBackend for EnvInstance {
         ext::caller_is_origin()
     }
 
-    fn code_hash<E>(&mut self, account_id: &E::AccountId, output: E::Hash) -> Result<()>
+    fn code_hash<E>(
+        &mut self,
+        account_id: &E::AccountId,
+        output: &mut E::Hash,
+    ) -> Result<()>
     where
         E: Environment,
     {
@@ -522,7 +526,7 @@ impl TypedEnvBackend for EnvInstance {
         ext::code_hash(enc_account_id, output).map_err(Into::into)
     }
 
-    fn own_code_hash<E>(&mut self, output: E::Hash) -> Result<()>
+    fn own_code_hash<E>(&mut self, output: &mut E::Hash) -> Result<()>
     where
         E: Environment,
     {

From 2e019bf4a4bac0288a211e14bc0133e6a16a91a4 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Thu, 31 Mar 2022 21:28:27 +0300
Subject: [PATCH 06/18] more ci fixes

---
 crates/env/src/engine/on_chain/impls.rs | 4 ++--
 crates/lang/src/env_access.rs           | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index 2ad894ca48..1fdca85770 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -523,13 +523,13 @@ impl TypedEnvBackend for EnvInstance {
     {
         let mut scope = self.scoped_buffer();
         let enc_account_id = scope.take_encoded(account_id);
-        ext::code_hash(enc_account_id, output).map_err(Into::into)
+        ext::code_hash(enc_account_id, output.as_mut()).map_err(Into::into)
     }
 
     fn own_code_hash<E>(&mut self, output: &mut E::Hash) -> Result<()>
     where
         E: Environment,
     {
-        ext::own_code_hash(output).map_err(Into::into)
+        ext::own_code_hash(output.as_mut()).map_err(Into::into)
     }
 }
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index 78dfd78082..6f275bc06c 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -933,7 +933,7 @@ where
     /// For more details visit: [`ink_env::code_hash`]
     pub fn code_hash(self, account_id: &E::AccountId) -> Result<E::Hash> {
         let mut output = <E as Environment>::Hash::clear();
-        ink_env::code_hash::<E>(account_id, &mut output).map(|_| output.into())
+        ink_env::code_hash::<E>(account_id, &mut output).map(|_| output)
     }
 
     /// Returns the code hash of the contract living at the given `account`.

From da094122f9902319aefbb9821fdc6cefea80bb8d Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Fri, 1 Apr 2022 14:46:05 +0300
Subject: [PATCH 07/18] refactored on what to return

---
 crates/env/src/api.rs                    | 12 ++++--------
 crates/env/src/backend.rs                |  8 ++------
 crates/env/src/engine/off_chain/impls.rs |  8 ++------
 crates/env/src/engine/on_chain/impls.rs  | 18 ++++++++++--------
 crates/lang/src/env_access.rs            | 15 ++++++---------
 5 files changed, 24 insertions(+), 37 deletions(-)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index de9427b42b..7c32657c74 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -515,23 +515,19 @@ where
 }
 
 /// Retrieves the code hash of a contract living at specified account
-pub fn code_hash<E>(account: &E::AccountId, output: &mut E::Hash) -> Result<()>
+pub fn code_hash<E>(account: &E::AccountId) -> Result<E::Hash>
 where
     E: Environment,
 {
-    <EnvInstance as OnInstance>::on_instance(|instance| {
-        instance.code_hash::<E>(account, output)
-    })
+    <EnvInstance as OnInstance>::on_instance(|instance| instance.code_hash::<E>(account))
 }
 
 /// Retrieves the code hash of the currently executing contract.
-pub fn own_code_hash<E>(output: &mut E::Hash) -> Result<()>
+pub fn own_code_hash<E>() -> Result<E::Hash>
 where
     E: Environment,
 {
-    <EnvInstance as OnInstance>::on_instance(|instance| {
-        instance.own_code_hash::<E>(output)
-    })
+    <EnvInstance as OnInstance>::on_instance(|instance| instance.own_code_hash::<E>())
 }
 
 /// Checks whether the caller of the current contract is the origin of the whole call stack.
diff --git a/crates/env/src/backend.rs b/crates/env/src/backend.rs
index 36df2f1077..fb9cd404d2 100644
--- a/crates/env/src/backend.rs
+++ b/crates/env/src/backend.rs
@@ -454,11 +454,7 @@ pub trait TypedEnvBackend: EnvBackend {
     /// # Note
     ///
     /// For more details visit: [`code_hash`][`crate::code_hash`]
-    fn code_hash<E>(
-        &mut self,
-        account: &E::AccountId,
-        output: &mut E::Hash,
-    ) -> Result<()>
+    fn code_hash<E>(&mut self, account: &E::AccountId) -> Result<E::Hash>
     where
         E: Environment;
 
@@ -467,7 +463,7 @@ pub trait TypedEnvBackend: EnvBackend {
     /// # Note
     ///
     /// For more details visit: [`own_code_hash`][`crate::own_code_hash`]
-    fn own_code_hash<E>(&mut self, output: &mut E::Hash) -> Result<()>
+    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
     where
         E: Environment;
 }
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index bb60ba3077..f6be219f8e 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -487,18 +487,14 @@ impl TypedEnvBackend for EnvInstance {
         unimplemented!("off-chain environment does not support cross-contract calls")
     }
 
-    fn code_hash<E>(
-        &mut self,
-        _account: &E::AccountId,
-        _output: &mut E::Hash,
-    ) -> Result<()>
+    fn code_hash<E>(&mut self, _account: &E::AccountId) -> Result<E::Hash>
     where
         E: Environment,
     {
         unimplemented!("off-chain environment does not support contract instantiation")
     }
 
-    fn own_code_hash<E>(&mut self, _output: &mut E::Hash) -> Result<()>
+    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
     where
         E: Environment,
     {
diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index 1fdca85770..978aab8543 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -513,23 +513,25 @@ impl TypedEnvBackend for EnvInstance {
         ext::caller_is_origin()
     }
 
-    fn code_hash<E>(
-        &mut self,
-        account_id: &E::AccountId,
-        output: &mut E::Hash,
-    ) -> Result<()>
+    fn code_hash<E>(&mut self, account_id: &E::AccountId) -> Result<E::Hash>
     where
         E: Environment,
     {
         let mut scope = self.scoped_buffer();
         let enc_account_id = scope.take_encoded(account_id);
-        ext::code_hash(enc_account_id, output.as_mut()).map_err(Into::into)
+        let mut output = <E as Environment>::Hash::clear();
+        ext::code_hash(enc_account_id, output.as_mut())
+            .map(|_| output)
+            .map_err(Into::into)
     }
 
-    fn own_code_hash<E>(&mut self, output: &mut E::Hash) -> Result<()>
+    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
     where
         E: Environment,
     {
-        ext::own_code_hash(output.as_mut()).map_err(Into::into)
+        let mut output = <E as Environment>::Hash::clear();
+        ext::own_code_hash(output.as_mut())
+            .map(|_| output)
+            .map_err(Into::into)
     }
 }
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index 6f275bc06c..a2362f0518 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -25,7 +25,6 @@ use ink_env::{
         CryptoHash,
         HashOutput,
     },
-    Clear,
     Environment,
     Error,
     Result,
@@ -921,8 +920,8 @@ where
     /// #         }
     /// #
     /// #[ink(message)]
-    /// pub fn code_hash(&mut self, account_id: AccountId) -> Result<Hash> {
-    ///     self.env().code_hash(&account_id)
+    /// pub fn code_hash(&mut self, account_id: AccountId) -> Option<Hash> {
+    ///     self.env().code_hash(&account_id).ok()
     /// }
     /// #    }
     /// # }
@@ -932,8 +931,7 @@ where
     ///
     /// For more details visit: [`ink_env::code_hash`]
     pub fn code_hash(self, account_id: &E::AccountId) -> Result<E::Hash> {
-        let mut output = <E as Environment>::Hash::clear();
-        ink_env::code_hash::<E>(account_id, &mut output).map(|_| output)
+        ink_env::code_hash::<E>(account_id)
     }
 
     /// Returns the code hash of the contract living at the given `account`.
@@ -954,8 +952,8 @@ where
     /// #         }
     /// #
     /// #[ink(message)]
-    /// pub fn own_code_hash(&mut self) -> Result<Hash> {
-    ///     self.env().own_code_hash()
+    /// pub fn own_code_hash(&mut self) -> Hash {
+    ///     self.env().own_code_hash().expect("contract should have a code hash")
     /// }
     /// #    }
     /// # }
@@ -965,7 +963,6 @@ where
     ///
     /// For more details visit: [`ink_env::own_code_hash`]
     pub fn own_code_hash(self) -> Result<E::Hash> {
-        let mut output = <E as Environment>::Hash::clear();
-        ink_env::own_code_hash::<E>(&mut output).map(|_| output)
+        ink_env::own_code_hash::<E>()
     }
 }

From 87a0e24afa4adbaa7d19f604dff85bb9cdb20c0e Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Mon, 4 Apr 2022 19:01:20 +0300
Subject: [PATCH 08/18] Apply suggestions from code review
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Michael Müller <mich@elmueller.net>
---
 crates/env/src/api.rs                    | 2 +-
 crates/env/src/backend.rs                | 2 +-
 crates/env/src/engine/off_chain/impls.rs | 4 ++--
 crates/lang/src/env_access.rs            | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index 7c32657c74..ef6a3bbd28 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -514,7 +514,7 @@ where
     })
 }
 
-/// Retrieves the code hash of a contract living at specified account
+/// Retrieves the code hash of the contract at the specified account id.
 pub fn code_hash<E>(account: &E::AccountId) -> Result<E::Hash>
 where
     E: Environment,
diff --git a/crates/env/src/backend.rs b/crates/env/src/backend.rs
index fb9cd404d2..1c36f6ced6 100644
--- a/crates/env/src/backend.rs
+++ b/crates/env/src/backend.rs
@@ -448,7 +448,7 @@ pub trait TypedEnvBackend: EnvBackend {
     where
         E: Environment;
 
-    /// Retrieves the code hash of the contract for the given `account`,
+    /// Retrieves the code hash of the contract at the given `account` id,
     /// and stores the result in `output`.
     ///
     /// # Note
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index f6be219f8e..969d761746 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -491,13 +491,13 @@ impl TypedEnvBackend for EnvInstance {
     where
         E: Environment,
     {
-        unimplemented!("off-chain environment does not support contract instantiation")
+        unimplemented!("off-chain environment does not support `code_hash`")
     }
 
     fn own_code_hash<E>(&mut self) -> Result<E::Hash>
     where
         E: Environment,
     {
-        unimplemented!("off-chain environment does not support contract instantiation")
+        unimplemented!("off-chain environment does not support `own_code_hash`")
     }
 }
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index a2362f0518..80a10a2ee5 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -902,7 +902,7 @@ where
         ink_env::caller_is_origin::<E>()
     }
 
-    /// Returns the code hash of the contract living at the given `account`.
+    /// Returns the code hash of the contract at the given `account` id.
     ///
     /// # Example
     ///

From b77254c609dc743223728984ed2fb00137a1f0d6 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Wed, 6 Apr 2022 14:46:14 +0300
Subject: [PATCH 09/18] fix: new funcs are in TypedEnvBackend trait

---
 crates/env/src/api.rs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index ef6a3bbd28..931b972588 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -519,7 +519,9 @@ pub fn code_hash<E>(account: &E::AccountId) -> Result<E::Hash>
 where
     E: Environment,
 {
-    <EnvInstance as OnInstance>::on_instance(|instance| instance.code_hash::<E>(account))
+    <EnvInstance as OnInstance>::on_instance(|instance| {
+        TypedEnvBackend::code_hash::<E>(instance, account)
+    })
 }
 
 /// Retrieves the code hash of the currently executing contract.
@@ -527,7 +529,9 @@ pub fn own_code_hash<E>() -> Result<E::Hash>
 where
     E: Environment,
 {
-    <EnvInstance as OnInstance>::on_instance(|instance| instance.own_code_hash::<E>())
+    <EnvInstance as OnInstance>::on_instance(|instance| {
+        TypedEnvBackend::own_code_hash::<E>(instance)
+    })
 }
 
 /// Checks whether the caller of the current contract is the origin of the whole call stack.

From 92ca44ff6290f7385179c2dbfe552defcfb5bd35 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Wed, 6 Apr 2022 16:18:43 +0300
Subject: [PATCH 10/18] errors section to code_hash doc + own_code_hash to
 return non-wrapped val

---
 crates/env/src/api.rs                    | 6 +++++-
 crates/env/src/backend.rs                | 2 +-
 crates/env/src/engine/off_chain/impls.rs | 2 +-
 crates/env/src/engine/on_chain/ext.rs    | 5 ++---
 crates/env/src/engine/on_chain/impls.rs  | 7 +++----
 crates/lang/src/env_access.rs            | 4 ++--
 6 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index 931b972588..b6aa6f682b 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -515,6 +515,10 @@ where
 }
 
 /// Retrieves the code hash of the contract at the specified account id.
+///
+/// # Errors
+///
+/// If no code hash found for the specified account id.
 pub fn code_hash<E>(account: &E::AccountId) -> Result<E::Hash>
 where
     E: Environment,
@@ -525,7 +529,7 @@ where
 }
 
 /// Retrieves the code hash of the currently executing contract.
-pub fn own_code_hash<E>() -> Result<E::Hash>
+pub fn own_code_hash<E>() -> E::Hash
 where
     E: Environment,
 {
diff --git a/crates/env/src/backend.rs b/crates/env/src/backend.rs
index 1c36f6ced6..2fa46bb85c 100644
--- a/crates/env/src/backend.rs
+++ b/crates/env/src/backend.rs
@@ -463,7 +463,7 @@ pub trait TypedEnvBackend: EnvBackend {
     /// # Note
     ///
     /// For more details visit: [`own_code_hash`][`crate::own_code_hash`]
-    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
+    fn own_code_hash<E>(&mut self) -> E::Hash
     where
         E: Environment;
 }
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index 969d761746..08cb2d1937 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -494,7 +494,7 @@ impl TypedEnvBackend for EnvInstance {
         unimplemented!("off-chain environment does not support `code_hash`")
     }
 
-    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
+    fn own_code_hash<E>(&mut self) -> E::Hash
     where
         E: Environment,
     {
diff --git a/crates/env/src/engine/on_chain/ext.rs b/crates/env/src/engine/on_chain/ext.rs
index bd4cec323a..80c55d8ff8 100644
--- a/crates/env/src/engine/on_chain/ext.rs
+++ b/crates/env/src/engine/on_chain/ext.rs
@@ -700,13 +700,12 @@ pub fn code_hash(account_id: &[u8], output: &mut [u8]) -> Result {
     ret_val.into()
 }
 
-pub fn own_code_hash(output: &mut [u8]) -> Result {
+pub fn own_code_hash(output: &mut [u8]) {
     let mut output_len = output.len() as u32;
-    let ret_val = unsafe {
+    unsafe {
         sys::seal_own_code_hash(
             Ptr32Mut::from_slice(output),
             Ptr32Mut::from_ref(&mut output_len),
         )
     };
-    ret_val.into()
 }
diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index 978aab8543..ea198dd6a2 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -525,13 +525,12 @@ impl TypedEnvBackend for EnvInstance {
             .map_err(Into::into)
     }
 
-    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
+    fn own_code_hash<E>(&mut self) -> E::Hash
     where
         E: Environment,
     {
         let mut output = <E as Environment>::Hash::clear();
-        ext::own_code_hash(output.as_mut())
-            .map(|_| output)
-            .map_err(Into::into)
+        ext::own_code_hash(output.as_mut());
+        output
     }
 }
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index 80a10a2ee5..3c6c312438 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -953,7 +953,7 @@ where
     /// #
     /// #[ink(message)]
     /// pub fn own_code_hash(&mut self) -> Hash {
-    ///     self.env().own_code_hash().expect("contract should have a code hash")
+    ///     self.env().own_code_hash()
     /// }
     /// #    }
     /// # }
@@ -962,7 +962,7 @@ where
     /// # Note
     ///
     /// For more details visit: [`ink_env::own_code_hash`]
-    pub fn own_code_hash(self) -> Result<E::Hash> {
+    pub fn own_code_hash(self) -> E::Hash {
         ink_env::own_code_hash::<E>()
     }
 }

From 74647effda813a3af2706d844ee567e20572c50d Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Wed, 6 Apr 2022 18:01:58 +0300
Subject: [PATCH 11/18] bug caught and fixed: wrong return val for
 seal_own_code_hash

---
 crates/env/src/engine/on_chain/ext.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/env/src/engine/on_chain/ext.rs b/crates/env/src/engine/on_chain/ext.rs
index 80c55d8ff8..e36b782ec7 100644
--- a/crates/env/src/engine/on_chain/ext.rs
+++ b/crates/env/src/engine/on_chain/ext.rs
@@ -357,7 +357,7 @@ mod sys {
         pub fn seal_own_code_hash(
             output_ptr: Ptr32Mut<[u8]>,
             output_len_ptr: Ptr32Mut<u32>,
-        ) -> ReturnCode;
+        );
     }
 }
 

From 9a25772590b61cf0233b17898317016c2a348d66 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Fri, 8 Apr 2022 14:09:51 +0300
Subject: [PATCH 12/18] Update crates/env/src/api.rs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Michael Müller <mich@elmueller.net>
---
 crates/env/src/api.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index b6aa6f682b..73cb68866f 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -518,7 +518,7 @@ where
 ///
 /// # Errors
 ///
-/// If no code hash found for the specified account id.
+/// Returns `Error::KeyNotFound` if no code hash was found for the specified account id.
 pub fn code_hash<E>(account: &E::AccountId) -> Result<E::Hash>
 where
     E: Environment,

From 1114083d2aa4adb1875b21d132d964634bed23a1 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Fri, 8 Apr 2022 14:16:40 +0300
Subject: [PATCH 13/18] Apply suggestions from code review
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Michael Müller <mich@elmueller.net>
---
 crates/env/src/backend.rs     | 3 +--
 crates/lang/src/env_access.rs | 2 +-
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/crates/env/src/backend.rs b/crates/env/src/backend.rs
index 2fa46bb85c..181884be6e 100644
--- a/crates/env/src/backend.rs
+++ b/crates/env/src/backend.rs
@@ -448,8 +448,7 @@ pub trait TypedEnvBackend: EnvBackend {
     where
         E: Environment;
 
-    /// Retrieves the code hash of the contract at the given `account` id,
-    /// and stores the result in `output`.
+    /// Retrieves the code hash of the contract at the given `account` id.
     ///
     /// # Note
     ///
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index 3c6c312438..1a78d249e0 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -934,7 +934,7 @@ where
         ink_env::code_hash::<E>(account_id)
     }
 
-    /// Returns the code hash of the contract living at the given `account`.
+    /// Returns the code hash of the contract at the given `account` id.
     ///
     /// # Example
     ///

From 3ec737414a9ba95b44f0f93f72e584bcd78eefdc Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Fri, 8 Apr 2022 14:59:56 +0300
Subject: [PATCH 14/18] own_code_hash to return Result, as there could be
 decoding issues

---
 crates/env/src/api.rs                    |  9 +++++++--
 crates/env/src/backend.rs                |  2 +-
 crates/env/src/engine/off_chain/impls.rs |  2 +-
 crates/env/src/engine/on_chain/ext.rs    |  5 +++--
 crates/env/src/engine/on_chain/impls.rs  | 21 +++++++++++++--------
 crates/lang/src/env_access.rs            |  4 ++--
 6 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/crates/env/src/api.rs b/crates/env/src/api.rs
index 73cb68866f..889d763d24 100644
--- a/crates/env/src/api.rs
+++ b/crates/env/src/api.rs
@@ -518,7 +518,8 @@ where
 ///
 /// # Errors
 ///
-/// Returns `Error::KeyNotFound` if no code hash was found for the specified account id.
+/// - If no code hash was found for the specified account id.
+/// - If the returned value cannot be properly decoded.
 pub fn code_hash<E>(account: &E::AccountId) -> Result<E::Hash>
 where
     E: Environment,
@@ -529,7 +530,11 @@ where
 }
 
 /// Retrieves the code hash of the currently executing contract.
-pub fn own_code_hash<E>() -> E::Hash
+///
+/// # Errors
+///
+/// If the returned value cannot be properly decoded.
+pub fn own_code_hash<E>() -> Result<E::Hash>
 where
     E: Environment,
 {
diff --git a/crates/env/src/backend.rs b/crates/env/src/backend.rs
index 181884be6e..1bbaa4c7e1 100644
--- a/crates/env/src/backend.rs
+++ b/crates/env/src/backend.rs
@@ -462,7 +462,7 @@ pub trait TypedEnvBackend: EnvBackend {
     /// # Note
     ///
     /// For more details visit: [`own_code_hash`][`crate::own_code_hash`]
-    fn own_code_hash<E>(&mut self) -> E::Hash
+    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
     where
         E: Environment;
 }
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index 08cb2d1937..969d761746 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -494,7 +494,7 @@ impl TypedEnvBackend for EnvInstance {
         unimplemented!("off-chain environment does not support `code_hash`")
     }
 
-    fn own_code_hash<E>(&mut self) -> E::Hash
+    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
     where
         E: Environment,
     {
diff --git a/crates/env/src/engine/on_chain/ext.rs b/crates/env/src/engine/on_chain/ext.rs
index e36b782ec7..fa8e0677ad 100644
--- a/crates/env/src/engine/on_chain/ext.rs
+++ b/crates/env/src/engine/on_chain/ext.rs
@@ -700,12 +700,13 @@ pub fn code_hash(account_id: &[u8], output: &mut [u8]) -> Result {
     ret_val.into()
 }
 
-pub fn own_code_hash(output: &mut [u8]) {
+pub fn own_code_hash(output: &mut [u8]) -> Result {
     let mut output_len = output.len() as u32;
-    unsafe {
+    let ret_val = unsafe {
         sys::seal_own_code_hash(
             Ptr32Mut::from_slice(output),
             Ptr32Mut::from_ref(&mut output_len),
         )
     };
+    ret_val.into()
 }
diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index ea198dd6a2..a44f4b68a2 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -518,19 +518,24 @@ impl TypedEnvBackend for EnvInstance {
         E: Environment,
     {
         let mut scope = self.scoped_buffer();
-        let enc_account_id = scope.take_encoded(account_id);
-        let mut output = <E as Environment>::Hash::clear();
-        ext::code_hash(enc_account_id, output.as_mut())
-            .map(|_| output)
+        let mut output = scope.take(32);
+        scope.append_encoded(account_id);
+        let enc_account_id = scope.take_appended();
+
+        ext::code_hash(enc_account_id, output.as_mut());
+        scale::Decode::decode(&mut &output[..])
             .map_err(Into::into)
+            .into()
     }
 
-    fn own_code_hash<E>(&mut self) -> E::Hash
+    fn own_code_hash<E>(&mut self) -> Result<E::Hash>
     where
         E: Environment,
     {
-        let mut output = <E as Environment>::Hash::clear();
-        ext::own_code_hash(output.as_mut());
-        output
+        let output = &mut self.scoped_buffer().take(32);
+        ext::own_code_hash(output);
+        scale::Decode::decode(&mut &output[..])
+            .map_err(Into::into)
+            .into()
     }
 }
diff --git a/crates/lang/src/env_access.rs b/crates/lang/src/env_access.rs
index 1a78d249e0..fa843c6826 100644
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
@@ -953,7 +953,7 @@ where
     /// #
     /// #[ink(message)]
     /// pub fn own_code_hash(&mut self) -> Hash {
-    ///     self.env().own_code_hash()
+    ///     self.env().own_code_hash().expect("contract should have a code hash")
     /// }
     /// #    }
     /// # }
@@ -962,7 +962,7 @@ where
     /// # Note
     ///
     /// For more details visit: [`ink_env::own_code_hash`]
-    pub fn own_code_hash(self) -> E::Hash {
+    pub fn own_code_hash(self) -> Result<E::Hash> {
         ink_env::own_code_hash::<E>()
     }
 }

From 764a381570bbcfb1778c5adc51b0eb35dc5fb0c1 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Fri, 8 Apr 2022 17:06:40 +0300
Subject: [PATCH 15/18] bugfix (e2e testing caught)

---
 crates/env/src/engine/on_chain/ext.rs   |  7 +++----
 crates/env/src/engine/on_chain/impls.rs | 14 ++++++--------
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/crates/env/src/engine/on_chain/ext.rs b/crates/env/src/engine/on_chain/ext.rs
index fa8e0677ad..13d63677da 100644
--- a/crates/env/src/engine/on_chain/ext.rs
+++ b/crates/env/src/engine/on_chain/ext.rs
@@ -700,13 +700,12 @@ pub fn code_hash(account_id: &[u8], output: &mut [u8]) -> Result {
     ret_val.into()
 }
 
-pub fn own_code_hash(output: &mut [u8]) -> Result {
+pub fn own_code_hash(output: &mut [u8]) {
     let mut output_len = output.len() as u32;
-    let ret_val = unsafe {
+    unsafe {
         sys::seal_own_code_hash(
             Ptr32Mut::from_slice(output),
             Ptr32Mut::from_ref(&mut output_len),
         )
-    };
-    ret_val.into()
+    }
 }
diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index a44f4b68a2..4923b864f4 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -518,14 +518,13 @@ impl TypedEnvBackend for EnvInstance {
         E: Environment,
     {
         let mut scope = self.scoped_buffer();
-        let mut output = scope.take(32);
+        let output = scope.take(32);
         scope.append_encoded(account_id);
         let enc_account_id = scope.take_appended();
 
-        ext::code_hash(enc_account_id, output.as_mut());
-        scale::Decode::decode(&mut &output[..])
-            .map_err(Into::into)
-            .into()
+        ext::code_hash(enc_account_id, output.as_mut())?;
+        let hash = scale::Decode::decode(&mut &output[..])?;
+        Ok(hash)
     }
 
     fn own_code_hash<E>(&mut self) -> Result<E::Hash>
@@ -534,8 +533,7 @@ impl TypedEnvBackend for EnvInstance {
     {
         let output = &mut self.scoped_buffer().take(32);
         ext::own_code_hash(output);
-        scale::Decode::decode(&mut &output[..])
-            .map_err(Into::into)
-            .into()
+        let hash = scale::Decode::decode(&mut &output[..])?;
+        Ok(hash)
     }
 }

From d1ec5297b750015d44ddc34104c5d8113c4d4da3 Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Fri, 8 Apr 2022 17:13:17 +0300
Subject: [PATCH 16/18] ci fix

---
 crates/env/src/engine/on_chain/impls.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index 4923b864f4..e6611b2367 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -522,7 +522,7 @@ impl TypedEnvBackend for EnvInstance {
         scope.append_encoded(account_id);
         let enc_account_id = scope.take_appended();
 
-        ext::code_hash(enc_account_id, output.as_mut())?;
+        ext::code_hash(enc_account_id, output)?;
         let hash = scale::Decode::decode(&mut &output[..])?;
         Ok(hash)
     }

From 5591d955a5f5a04432415b1b60543db810ff349f Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Fri, 8 Apr 2022 19:32:02 +0300
Subject: [PATCH 17/18] Apply suggestions from code review
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Michael Müller <mich@elmueller.net>
---
 crates/env/src/engine/on_chain/impls.rs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index e6611b2367..26f4386356 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -523,8 +523,7 @@ impl TypedEnvBackend for EnvInstance {
         let enc_account_id = scope.take_appended();
 
         ext::code_hash(enc_account_id, output)?;
-        let hash = scale::Decode::decode(&mut &output[..])?;
-        Ok(hash)
+        scale::Decode::decode(&mut &output[..])
     }
 
     fn own_code_hash<E>(&mut self) -> Result<E::Hash>
@@ -533,7 +532,6 @@ impl TypedEnvBackend for EnvInstance {
     {
         let output = &mut self.scoped_buffer().take(32);
         ext::own_code_hash(output);
-        let hash = scale::Decode::decode(&mut &output[..])?;
-        Ok(hash)
+        scale::Decode::decode(&mut &output[..])
     }
 }

From 12901dc209adc60a588171b3db3caa8c70bc957d Mon Sep 17 00:00:00 2001
From: Alexander Gryaznov <hi@agryaznov.com>
Date: Fri, 8 Apr 2022 19:35:06 +0300
Subject: [PATCH 18/18] Revert "Apply suggestions from code review"

This reverts commit 5591d955a5f5a04432415b1b60543db810ff349f.
---
 crates/env/src/engine/on_chain/impls.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/crates/env/src/engine/on_chain/impls.rs b/crates/env/src/engine/on_chain/impls.rs
index 26f4386356..e6611b2367 100644
--- a/crates/env/src/engine/on_chain/impls.rs
+++ b/crates/env/src/engine/on_chain/impls.rs
@@ -523,7 +523,8 @@ impl TypedEnvBackend for EnvInstance {
         let enc_account_id = scope.take_appended();
 
         ext::code_hash(enc_account_id, output)?;
-        scale::Decode::decode(&mut &output[..])
+        let hash = scale::Decode::decode(&mut &output[..])?;
+        Ok(hash)
     }
 
     fn own_code_hash<E>(&mut self) -> Result<E::Hash>
@@ -532,6 +533,7 @@ impl TypedEnvBackend for EnvInstance {
     {
         let output = &mut self.scoped_buffer().take(32);
         ext::own_code_hash(output);
-        scale::Decode::decode(&mut &output[..])
+        let hash = scale::Decode::decode(&mut &output[..])?;
+        Ok(hash)
     }
 }