From 395289bb05012c9ef441ea7a3ea5ba47e1ea6cfa Mon Sep 17 00:00:00 2001
From: Koby <kobyhall@proton.me>
Date: Fri, 13 Oct 2023 18:31:30 +0200
Subject: [PATCH 1/7] chore: warn if backend version mismatch

---
 tooling/backend_interface/src/cli/mod.rs      |  2 ++
 tooling/backend_interface/src/cli/version.rs  | 28 +++++++++++++++++++
 tooling/backend_interface/src/lib.rs          | 11 ++++++++
 tooling/backend_interface/src/proof_system.rs |  3 ++
 tooling/bb_abstraction_leaks/build.rs         |  1 +
 tooling/bb_abstraction_leaks/src/lib.rs       |  1 +
 6 files changed, 46 insertions(+)
 create mode 100644 tooling/backend_interface/src/cli/version.rs

diff --git a/tooling/backend_interface/src/cli/mod.rs b/tooling/backend_interface/src/cli/mod.rs
index 848c5e11e81..4bed573c9ec 100644
--- a/tooling/backend_interface/src/cli/mod.rs
+++ b/tooling/backend_interface/src/cli/mod.rs
@@ -6,6 +6,7 @@ mod info;
 mod prove;
 mod verify;
 mod write_vk;
+mod version;
 
 pub(crate) use contract::ContractCommand;
 pub(crate) use gates::GatesCommand;
@@ -13,6 +14,7 @@ pub(crate) use info::InfoCommand;
 pub(crate) use prove::ProveCommand;
 pub(crate) use verify::VerifyCommand;
 pub(crate) use write_vk::WriteVkCommand;
+pub(crate) use version::VersionCommand;
 
 #[test]
 fn no_command_provided_works() -> Result<(), crate::BackendError> {
diff --git a/tooling/backend_interface/src/cli/version.rs b/tooling/backend_interface/src/cli/version.rs
new file mode 100644
index 00000000000..3de8062c2e0
--- /dev/null
+++ b/tooling/backend_interface/src/cli/version.rs
@@ -0,0 +1,28 @@
+use std::path::Path;
+
+use crate::BackendError;
+
+use super::string_from_stderr;
+
+/// VersionCommand will call the backend binary
+/// to query installed version.
+pub(crate) struct VersionCommand {}
+
+impl VersionCommand {
+    pub(crate) fn run(self, binary_path: &Path) -> Result<String, BackendError> {
+        let mut command = std::process::Command::new(binary_path);
+
+        command
+            .arg("--version");
+
+        let output = command.output()?;
+        if output.status.success() {
+            match String::from_utf8(output.stdout) {
+                Ok(result) => Ok(result),
+                Err(_) => Err(BackendError::CommandFailed("Unexpected output from --version check.".to_owned())),
+            }
+        } else {
+            Err(BackendError::CommandFailed(string_from_stderr(&output.stderr)))
+        }
+    }
+}
diff --git a/tooling/backend_interface/src/lib.rs b/tooling/backend_interface/src/lib.rs
index d6a9cd0d293..afb42230d8d 100644
--- a/tooling/backend_interface/src/lib.rs
+++ b/tooling/backend_interface/src/lib.rs
@@ -10,6 +10,8 @@ mod smart_contract;
 
 use acvm::acir::circuit::Opcode;
 use bb_abstraction_leaks::ACVM_BACKEND_BARRETENBERG;
+use bb_abstraction_leaks::BB_VERSION;
+use cli::VersionCommand;
 pub use download::download_backend;
 
 const BACKENDS_DIR: &str = ".nargo/backends";
@@ -104,6 +106,15 @@ impl Backend {
     fn crs_directory(&self) -> PathBuf {
         self.backend_directory().join("crs")
     }
+
+    fn assert_correct_version(&self) -> Result<String, BackendError> {
+        let binary_path = self.binary_path();
+        let version_string = VersionCommand{}.run(binary_path)?;
+        if version_string.as_str() != BB_VERSION {
+            println!("WARNING!: Configured backend version `{:}` is different from expected `{:}`", version_string, BB_VERSION);
+        }
+        Ok(version_string)
+    }
 }
 
 pub struct BackendOpcodeSupport {
diff --git a/tooling/backend_interface/src/proof_system.rs b/tooling/backend_interface/src/proof_system.rs
index ffdb7531ed1..fde3fd20a28 100644
--- a/tooling/backend_interface/src/proof_system.rs
+++ b/tooling/backend_interface/src/proof_system.rs
@@ -39,6 +39,8 @@ impl Backend {
     ) -> Result<Vec<u8>, BackendError> {
         let binary_path = self.assert_binary_exists()?;
 
+        self.assert_correct_version()?;
+
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory = temp_directory.path().to_path_buf();
 
@@ -78,6 +80,7 @@ impl Backend {
         is_recursive: bool,
     ) -> Result<bool, BackendError> {
         let binary_path = self.assert_binary_exists()?;
+        self.assert_correct_version()?;
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory = temp_directory.path().to_path_buf();
diff --git a/tooling/bb_abstraction_leaks/build.rs b/tooling/bb_abstraction_leaks/build.rs
index baf3cfdf6a6..1ae5a28f5a8 100644
--- a/tooling/bb_abstraction_leaks/build.rs
+++ b/tooling/bb_abstraction_leaks/build.rs
@@ -35,6 +35,7 @@ fn main() -> Result<(), String> {
     };
 
     println!("cargo:rustc-env=BB_BINARY_URL={}", get_bb_download_url(arch, os));
+    println!("cargo:rustc-env=BB_VERSION={}", VERSION);
 
     Ok(())
 }
diff --git a/tooling/bb_abstraction_leaks/src/lib.rs b/tooling/bb_abstraction_leaks/src/lib.rs
index 799e14c36f0..e0fdc467c53 100644
--- a/tooling/bb_abstraction_leaks/src/lib.rs
+++ b/tooling/bb_abstraction_leaks/src/lib.rs
@@ -5,6 +5,7 @@ use acvm::FieldElement;
 
 pub const ACVM_BACKEND_BARRETENBERG: &str = "acvm-backend-barretenberg";
 pub const BB_DOWNLOAD_URL: &str = env!("BB_BINARY_URL");
+pub const BB_VERSION: &str = env!("BB_VERSION");
 
 /// Embed the Solidity verifier file
 const ULTRA_VERIFIER_CONTRACT: &str = include_str!("contract.sol");

From d8749cc8ca1ae366d344fd55c69b1d2272ae15c4 Mon Sep 17 00:00:00 2001
From: Koby <kobyhall@proton.me>
Date: Fri, 13 Oct 2023 18:42:47 +0200
Subject: [PATCH 2/7] chore: add smart contract assert

---
 tooling/backend_interface/src/smart_contract.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tooling/backend_interface/src/smart_contract.rs b/tooling/backend_interface/src/smart_contract.rs
index 5f56557cad4..c7dbe3713d0 100644
--- a/tooling/backend_interface/src/smart_contract.rs
+++ b/tooling/backend_interface/src/smart_contract.rs
@@ -10,6 +10,8 @@ impl Backend {
     pub fn eth_contract(&self, circuit: &Circuit) -> Result<String, BackendError> {
         let binary_path = self.assert_binary_exists()?;
 
+        self.assert_correct_version()?;
+
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory_path = temp_directory.path().to_path_buf();
 

From 9ca358d90019c7dd555112cc19ba726c113808d7 Mon Sep 17 00:00:00 2001
From: Koby <kobyhall@proton.me>
Date: Fri, 13 Oct 2023 19:46:35 +0200
Subject: [PATCH 3/7] chore: assert version on ly on barretenberg backends

---
 tooling/backend_interface/src/cli/mod.rs        |  4 ++--
 tooling/backend_interface/src/cli/version.rs    |  7 ++++---
 tooling/backend_interface/src/lib.rs            | 14 +++++++++-----
 tooling/backend_interface/src/proof_system.rs   |  4 ++--
 tooling/backend_interface/src/smart_contract.rs |  2 +-
 tooling/bb_abstraction_leaks/src/lib.rs         |  1 +
 6 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/tooling/backend_interface/src/cli/mod.rs b/tooling/backend_interface/src/cli/mod.rs
index 4bed573c9ec..d1eebb1ba8e 100644
--- a/tooling/backend_interface/src/cli/mod.rs
+++ b/tooling/backend_interface/src/cli/mod.rs
@@ -5,16 +5,16 @@ mod gates;
 mod info;
 mod prove;
 mod verify;
-mod write_vk;
 mod version;
+mod write_vk;
 
 pub(crate) use contract::ContractCommand;
 pub(crate) use gates::GatesCommand;
 pub(crate) use info::InfoCommand;
 pub(crate) use prove::ProveCommand;
 pub(crate) use verify::VerifyCommand;
-pub(crate) use write_vk::WriteVkCommand;
 pub(crate) use version::VersionCommand;
+pub(crate) use write_vk::WriteVkCommand;
 
 #[test]
 fn no_command_provided_works() -> Result<(), crate::BackendError> {
diff --git a/tooling/backend_interface/src/cli/version.rs b/tooling/backend_interface/src/cli/version.rs
index 3de8062c2e0..29c434ac5d8 100644
--- a/tooling/backend_interface/src/cli/version.rs
+++ b/tooling/backend_interface/src/cli/version.rs
@@ -12,14 +12,15 @@ impl VersionCommand {
     pub(crate) fn run(self, binary_path: &Path) -> Result<String, BackendError> {
         let mut command = std::process::Command::new(binary_path);
 
-        command
-            .arg("--version");
+        command.arg("--version");
 
         let output = command.output()?;
         if output.status.success() {
             match String::from_utf8(output.stdout) {
                 Ok(result) => Ok(result),
-                Err(_) => Err(BackendError::CommandFailed("Unexpected output from --version check.".to_owned())),
+                Err(_) => Err(BackendError::CommandFailed(
+                    "Unexpected output from --version check.".to_owned(),
+                )),
             }
         } else {
             Err(BackendError::CommandFailed(string_from_stderr(&output.stderr)))
diff --git a/tooling/backend_interface/src/lib.rs b/tooling/backend_interface/src/lib.rs
index afb42230d8d..a1132a59fd9 100644
--- a/tooling/backend_interface/src/lib.rs
+++ b/tooling/backend_interface/src/lib.rs
@@ -10,6 +10,7 @@ mod smart_contract;
 
 use acvm::acir::circuit::Opcode;
 use bb_abstraction_leaks::ACVM_BACKEND_BARRETENBERG;
+use bb_abstraction_leaks::BACKEND_BARRETENBERG_SEARCH_STR;
 use bb_abstraction_leaks::BB_VERSION;
 use cli::VersionCommand;
 pub use download::download_backend;
@@ -107,13 +108,16 @@ impl Backend {
         self.backend_directory().join("crs")
     }
 
-    fn assert_correct_version(&self) -> Result<String, BackendError> {
+    fn assert_correct_version(&self) {
         let binary_path = self.binary_path();
-        let version_string = VersionCommand{}.run(binary_path)?;
-        if version_string.as_str() != BB_VERSION {
-            println!("WARNING!: Configured backend version `{:}` is different from expected `{:}`", version_string, BB_VERSION);
+        if binary_path.to_string_lossy().contains(BACKEND_BARRETENBERG_SEARCH_STR) {
+            let version_result = VersionCommand {}.run(binary_path);
+            if let Ok(version_string) = version_result {
+                if version_string.as_str() != BB_VERSION {
+                    println!("WARNING!: Configured backend version `{:}` is different from expected `{:}`", version_string, BB_VERSION);
+                }
+            }
         }
-        Ok(version_string)
     }
 }
 
diff --git a/tooling/backend_interface/src/proof_system.rs b/tooling/backend_interface/src/proof_system.rs
index fde3fd20a28..7553874a8d7 100644
--- a/tooling/backend_interface/src/proof_system.rs
+++ b/tooling/backend_interface/src/proof_system.rs
@@ -39,7 +39,7 @@ impl Backend {
     ) -> Result<Vec<u8>, BackendError> {
         let binary_path = self.assert_binary_exists()?;
 
-        self.assert_correct_version()?;
+        self.assert_correct_version();
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory = temp_directory.path().to_path_buf();
@@ -80,7 +80,7 @@ impl Backend {
         is_recursive: bool,
     ) -> Result<bool, BackendError> {
         let binary_path = self.assert_binary_exists()?;
-        self.assert_correct_version()?;
+        self.assert_correct_version();
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory = temp_directory.path().to_path_buf();
diff --git a/tooling/backend_interface/src/smart_contract.rs b/tooling/backend_interface/src/smart_contract.rs
index c7dbe3713d0..f1e55310f2e 100644
--- a/tooling/backend_interface/src/smart_contract.rs
+++ b/tooling/backend_interface/src/smart_contract.rs
@@ -10,7 +10,7 @@ impl Backend {
     pub fn eth_contract(&self, circuit: &Circuit) -> Result<String, BackendError> {
         let binary_path = self.assert_binary_exists()?;
 
-        self.assert_correct_version()?;
+        self.assert_correct_version();
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory_path = temp_directory.path().to_path_buf();
diff --git a/tooling/bb_abstraction_leaks/src/lib.rs b/tooling/bb_abstraction_leaks/src/lib.rs
index e0fdc467c53..7f13ade18cf 100644
--- a/tooling/bb_abstraction_leaks/src/lib.rs
+++ b/tooling/bb_abstraction_leaks/src/lib.rs
@@ -3,6 +3,7 @@
 
 use acvm::FieldElement;
 
+pub const BACKEND_BARRETENBERG_SEARCH_STR: &str = "barretenberg";
 pub const ACVM_BACKEND_BARRETENBERG: &str = "acvm-backend-barretenberg";
 pub const BB_DOWNLOAD_URL: &str = env!("BB_BINARY_URL");
 pub const BB_VERSION: &str = env!("BB_VERSION");

From 54616a1ef14aafc68a6513d16ad8b102c801744b Mon Sep 17 00:00:00 2001
From: Tom French <tom@tomfren.ch>
Date: Mon, 16 Oct 2023 09:57:39 +0100
Subject: [PATCH 4/7] chore: nits

---
 tooling/backend_interface/src/cli/version.rs | 2 +-
 tooling/backend_interface/src/lib.rs         | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tooling/backend_interface/src/cli/version.rs b/tooling/backend_interface/src/cli/version.rs
index 29c434ac5d8..83ab72a870e 100644
--- a/tooling/backend_interface/src/cli/version.rs
+++ b/tooling/backend_interface/src/cli/version.rs
@@ -6,7 +6,7 @@ use super::string_from_stderr;
 
 /// VersionCommand will call the backend binary
 /// to query installed version.
-pub(crate) struct VersionCommand {}
+pub(crate) struct VersionCommand;
 
 impl VersionCommand {
     pub(crate) fn run(self, binary_path: &Path) -> Result<String, BackendError> {
diff --git a/tooling/backend_interface/src/lib.rs b/tooling/backend_interface/src/lib.rs
index a1132a59fd9..0968cf03e7d 100644
--- a/tooling/backend_interface/src/lib.rs
+++ b/tooling/backend_interface/src/lib.rs
@@ -111,10 +111,10 @@ impl Backend {
     fn assert_correct_version(&self) {
         let binary_path = self.binary_path();
         if binary_path.to_string_lossy().contains(BACKEND_BARRETENBERG_SEARCH_STR) {
-            let version_result = VersionCommand {}.run(binary_path);
+            let version_result = VersionCommand.run(binary_path);
             if let Ok(version_string) = version_result {
                 if version_string.as_str() != BB_VERSION {
-                    println!("WARNING!: Configured backend version `{:}` is different from expected `{:}`", version_string, BB_VERSION);
+                    println!("WARNING!: Configured backend version `{version_string}` is different from expected `{BB_VERSION}`");
                 }
             }
         }

From 4be4041d1b32388c9935aadc3aa2d36daf75b7e9 Mon Sep 17 00:00:00 2001
From: Koby <kobyhall@proton.me>
Date: Mon, 16 Oct 2023 12:18:50 +0200
Subject: [PATCH 5/7] chore: replace-download correct backend version

---
 tooling/backend_interface/src/lib.rs            | 12 ++++++++----
 tooling/backend_interface/src/proof_system.rs   |  4 ++--
 tooling/backend_interface/src/smart_contract.rs |  2 +-
 tooling/bb_abstraction_leaks/src/lib.rs         |  1 -
 4 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/tooling/backend_interface/src/lib.rs b/tooling/backend_interface/src/lib.rs
index a1132a59fd9..c46a04d9094 100644
--- a/tooling/backend_interface/src/lib.rs
+++ b/tooling/backend_interface/src/lib.rs
@@ -10,7 +10,6 @@ mod smart_contract;
 
 use acvm::acir::circuit::Opcode;
 use bb_abstraction_leaks::ACVM_BACKEND_BARRETENBERG;
-use bb_abstraction_leaks::BACKEND_BARRETENBERG_SEARCH_STR;
 use bb_abstraction_leaks::BB_VERSION;
 use cli::VersionCommand;
 pub use download::download_backend;
@@ -108,16 +107,21 @@ impl Backend {
         self.backend_directory().join("crs")
     }
 
-    fn assert_correct_version(&self) {
+    fn assert_correct_version(&self) -> Result<&PathBuf, BackendError> {
         let binary_path = self.binary_path();
-        if binary_path.to_string_lossy().contains(BACKEND_BARRETENBERG_SEARCH_STR) {
+        if binary_path.to_string_lossy().contains(ACVM_BACKEND_BARRETENBERG) {
             let version_result = VersionCommand {}.run(binary_path);
             if let Ok(version_string) = version_result {
                 if version_string.as_str() != BB_VERSION {
-                    println!("WARNING!: Configured backend version `{:}` is different from expected `{:}`", version_string, BB_VERSION);
+                    println!("WARNING!: `{:}` version `{:}` is different from expected `{:}`, downloading expected...", ACVM_BACKEND_BARRETENBERG, version_string, BB_VERSION);
+                    // If we're trying to use barretenberg, automatically go and install the correct version.
+                    let bb_url = std::env::var("BB_BINARY_URL")
+                        .unwrap_or_else(|_| bb_abstraction_leaks::BB_DOWNLOAD_URL.to_owned());
+                    download_backend(&bb_url, binary_path)?;
                 }
             }
         }
+        Ok(binary_path)
     }
 }
 
diff --git a/tooling/backend_interface/src/proof_system.rs b/tooling/backend_interface/src/proof_system.rs
index 7553874a8d7..fde3fd20a28 100644
--- a/tooling/backend_interface/src/proof_system.rs
+++ b/tooling/backend_interface/src/proof_system.rs
@@ -39,7 +39,7 @@ impl Backend {
     ) -> Result<Vec<u8>, BackendError> {
         let binary_path = self.assert_binary_exists()?;
 
-        self.assert_correct_version();
+        self.assert_correct_version()?;
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory = temp_directory.path().to_path_buf();
@@ -80,7 +80,7 @@ impl Backend {
         is_recursive: bool,
     ) -> Result<bool, BackendError> {
         let binary_path = self.assert_binary_exists()?;
-        self.assert_correct_version();
+        self.assert_correct_version()?;
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory = temp_directory.path().to_path_buf();
diff --git a/tooling/backend_interface/src/smart_contract.rs b/tooling/backend_interface/src/smart_contract.rs
index f1e55310f2e..c7dbe3713d0 100644
--- a/tooling/backend_interface/src/smart_contract.rs
+++ b/tooling/backend_interface/src/smart_contract.rs
@@ -10,7 +10,7 @@ impl Backend {
     pub fn eth_contract(&self, circuit: &Circuit) -> Result<String, BackendError> {
         let binary_path = self.assert_binary_exists()?;
 
-        self.assert_correct_version();
+        self.assert_correct_version()?;
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory_path = temp_directory.path().to_path_buf();
diff --git a/tooling/bb_abstraction_leaks/src/lib.rs b/tooling/bb_abstraction_leaks/src/lib.rs
index 7f13ade18cf..e0fdc467c53 100644
--- a/tooling/bb_abstraction_leaks/src/lib.rs
+++ b/tooling/bb_abstraction_leaks/src/lib.rs
@@ -3,7 +3,6 @@
 
 use acvm::FieldElement;
 
-pub const BACKEND_BARRETENBERG_SEARCH_STR: &str = "barretenberg";
 pub const ACVM_BACKEND_BARRETENBERG: &str = "acvm-backend-barretenberg";
 pub const BB_DOWNLOAD_URL: &str = env!("BB_BINARY_URL");
 pub const BB_VERSION: &str = env!("BB_VERSION");

From b11aa42e0737256e207f701c5b8ffc53a7c5f267 Mon Sep 17 00:00:00 2001
From: Tom French <tom@tomfren.ch>
Date: Mon, 16 Oct 2023 12:41:36 +0100
Subject: [PATCH 6/7] chore: add handling for case where `bb --version` returns
 an error

---
 tooling/backend_interface/src/lib.rs | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/tooling/backend_interface/src/lib.rs b/tooling/backend_interface/src/lib.rs
index c46a04d9094..6c91c181a92 100644
--- a/tooling/backend_interface/src/lib.rs
+++ b/tooling/backend_interface/src/lib.rs
@@ -110,11 +110,21 @@ impl Backend {
     fn assert_correct_version(&self) -> Result<&PathBuf, BackendError> {
         let binary_path = self.binary_path();
         if binary_path.to_string_lossy().contains(ACVM_BACKEND_BARRETENBERG) {
-            let version_result = VersionCommand {}.run(binary_path);
-            if let Ok(version_string) = version_result {
-                if version_string.as_str() != BB_VERSION {
-                    println!("WARNING!: `{:}` version `{:}` is different from expected `{:}`, downloading expected...", ACVM_BACKEND_BARRETENBERG, version_string, BB_VERSION);
-                    // If we're trying to use barretenberg, automatically go and install the correct version.
+            match VersionCommand.run(binary_path) {
+                // If version matches then do nothing.
+                Ok(version_string) if version_string == BB_VERSION => (),
+
+                // If version doesn't match then download the correct version.
+                Ok(version_string) => {
+                    println!("`{ACVM_BACKEND_BARRETENBERG}` version `{version_string}` is different from expected `{BB_VERSION}`. Downloading expected version...");
+                    let bb_url = std::env::var("BB_BINARY_URL")
+                        .unwrap_or_else(|_| bb_abstraction_leaks::BB_DOWNLOAD_URL.to_owned());
+                    download_backend(&bb_url, binary_path)?;
+                }
+
+                // If `bb` fails to report its version, then attempt to fix it by re-downloading the binary.
+                Err(_) => {
+                    println!("Could not determine version of `{ACVM_BACKEND_BARRETENBERG}`. Downloading expected version...");
                     let bb_url = std::env::var("BB_BINARY_URL")
                         .unwrap_or_else(|_| bb_abstraction_leaks::BB_DOWNLOAD_URL.to_owned());
                     download_backend(&bb_url, binary_path)?;

From 08189232e8eeac2c6edb80c8b5d2a628f3ff57d4 Mon Sep 17 00:00:00 2001
From: Tom French <tom@tomfren.ch>
Date: Mon, 16 Oct 2023 12:50:30 +0100
Subject: [PATCH 7/7] fix: add `assert_correct_version` to methods where it was
 missing

---
 tooling/backend_interface/src/proof_system.rs   | 3 ++-
 tooling/backend_interface/src/smart_contract.rs | 1 -
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tooling/backend_interface/src/proof_system.rs b/tooling/backend_interface/src/proof_system.rs
index fde3fd20a28..cbb4a61be8a 100644
--- a/tooling/backend_interface/src/proof_system.rs
+++ b/tooling/backend_interface/src/proof_system.rs
@@ -13,6 +13,7 @@ use crate::{Backend, BackendError, BackendOpcodeSupport};
 impl Backend {
     pub fn get_exact_circuit_size(&self, circuit: &Circuit) -> Result<u32, BackendError> {
         let binary_path = self.assert_binary_exists()?;
+        self.assert_correct_version()?;
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
         let temp_directory = temp_directory.path().to_path_buf();
@@ -28,6 +29,7 @@ impl Backend {
 
     pub fn get_backend_info(&self) -> Result<(Language, BackendOpcodeSupport), BackendError> {
         let binary_path = self.assert_binary_exists()?;
+        self.assert_correct_version()?;
         InfoCommand { crs_path: self.crs_directory() }.run(binary_path)
     }
 
@@ -38,7 +40,6 @@ impl Backend {
         is_recursive: bool,
     ) -> Result<Vec<u8>, BackendError> {
         let binary_path = self.assert_binary_exists()?;
-
         self.assert_correct_version()?;
 
         let temp_directory = tempdir().expect("could not create a temporary directory");
diff --git a/tooling/backend_interface/src/smart_contract.rs b/tooling/backend_interface/src/smart_contract.rs
index c7dbe3713d0..50afd47287b 100644
--- a/tooling/backend_interface/src/smart_contract.rs
+++ b/tooling/backend_interface/src/smart_contract.rs
@@ -9,7 +9,6 @@ use tempfile::tempdir;
 impl Backend {
     pub fn eth_contract(&self, circuit: &Circuit) -> Result<String, BackendError> {
         let binary_path = self.assert_binary_exists()?;
-
         self.assert_correct_version()?;
 
         let temp_directory = tempdir().expect("could not create a temporary directory");