From d19cb9e15477baeea2d642d36a13ac143de1f35a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Agust=C3=ADn=20Borgna?= <agustin.borgna@quantinuum.com>
Date: Thu, 7 Aug 2025 11:11:38 +0200
Subject: [PATCH] feat(hugr-cli): CliError helper

---
 hugr-cli/src/lib.rs      | 14 ++++++++++++++
 hugr-cli/src/mermaid.rs  |  5 ++++-
 hugr-cli/src/validate.rs | 15 ++-------------
 3 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/hugr-cli/src/lib.rs b/hugr-cli/src/lib.rs
index d4c269d811..9e5e74ece8 100644
--- a/hugr-cli/src/lib.rs
+++ b/hugr-cli/src/lib.rs
@@ -136,3 +136,17 @@ pub enum CliError {
         generator: Box<String>,
     },
 }
+
+impl CliError {
+    /// Returns a validation error, with an optional generator.
+    pub fn validation(generator: Option<String>, val_err: PackageValidationError) -> Self {
+        if let Some(g) = generator {
+            Self::ValidateKnownGenerator {
+                inner: val_err,
+                generator: Box::new(g.to_string()),
+            }
+        } else {
+            Self::Validate(val_err)
+        }
+    }
+}
diff --git a/hugr-cli/src/mermaid.rs b/hugr-cli/src/mermaid.rs
index 09cb7b7041..8a7f5121c1 100644
--- a/hugr-cli/src/mermaid.rs
+++ b/hugr-cli/src/mermaid.rs
@@ -44,9 +44,12 @@ impl MermaidArgs {
     /// Write the mermaid diagram for a HUGR envelope.
     pub fn run_print_envelope(&mut self) -> Result<()> {
         let package = self.input_args.get_package()?;
+        let generator = hugr::envelope::get_generator(&package.modules);
 
         if self.validate {
-            package.validate().map_err(CliError::Validate)?;
+            package
+                .validate()
+                .map_err(|val_err| CliError::validation(generator, val_err))?;
         }
 
         for hugr in package.modules {
diff --git a/hugr-cli/src/validate.rs b/hugr-cli/src/validate.rs
index 08253809d7..e82a71a03b 100644
--- a/hugr-cli/src/validate.rs
+++ b/hugr-cli/src/validate.rs
@@ -34,13 +34,13 @@ impl ValArgs {
 
             hugr.validate()
                 .map_err(PackageValidationError::Validation)
-                .map_err(|val_err| wrap_generator(generator, val_err))?;
+                .map_err(|val_err| CliError::validation(generator, val_err))?;
         } else {
             let package = self.input_args.get_package()?;
             let generator = hugr::envelope::get_generator(&package.modules);
             package
                 .validate()
-                .map_err(|val_err| wrap_generator(generator, val_err))?;
+                .map_err(|val_err| CliError::validation(generator, val_err))?;
         };
 
         info!("{VALID_PRINT}");
@@ -48,14 +48,3 @@ impl ValArgs {
         Ok(())
     }
 }
-
-fn wrap_generator(generator: Option<String>, val_err: PackageValidationError) -> CliError {
-    if let Some(g) = generator {
-        CliError::ValidateKnownGenerator {
-            inner: val_err,
-            generator: Box::new(g.to_string()),
-        }
-    } else {
-        CliError::Validate(val_err)
-    }
-}