From af026a8526fc13923e3fe54041bcc82592e2c245 Mon Sep 17 00:00:00 2001
From: Johan Peltenburg <johan.peltenburg+code@gmail.com>
Date: Mon, 27 Jul 2026 11:25:46 +0200
Subject: [PATCH 1/2] fix(instrumentation-build): skip empty AnyEvent

Signed-off-by: Johan Peltenburg <johan.peltenburg+code@gmail.com>
---
 crates/instrumentation-build/src/lib.rs | 27 ++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/crates/instrumentation-build/src/lib.rs b/crates/instrumentation-build/src/lib.rs
index 00b67533e..29ef6fb13 100644
--- a/crates/instrumentation-build/src/lib.rs
+++ b/crates/instrumentation-build/src/lib.rs
@@ -97,6 +97,8 @@ pub struct Options {
 
     /// Emit `AnyEvent` and `AnyEvent::from_any`, a decoder from a type-erased
     /// `&dyn Any` back to the concrete `Event<T>`. Carries [`Self::event_derives`].
+    ///
+    /// No aggregate is emitted when the schema declares no events.
     pub any_event: bool,
 }
 
@@ -188,7 +190,10 @@ pub fn generate_str(schema: &Schema, opts: &Options) -> Result<String, GenerateE
     let records = generate_record_types(schema, opts)?;
     let events = generate_event_types(schema, opts)?;
     let runtime = generate_runtime_types(schema)?;
-    let any_event = if opts.any_event {
+    let has_events = schema
+        .entities()
+        .any(|entity| entity.events().next().is_some());
+    let any_event = if opts.any_event && has_events {
         any_event::generate_any_event(schema, opts)?
     } else {
         quote! {}
@@ -210,3 +215,23 @@ fn ensure_unqualified_type_paths(schema: &Schema) -> Result<(), GenerateError> {
         None => Ok(()),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use quent_schema::builder::SchemaBuilder;
+    use quent_schema::test_utils::ident;
+
+    #[test]
+    fn skips_any_event_without_events() {
+        let schema = SchemaBuilder::new(ident("Demo")).build().unwrap();
+        let options = Options {
+            any_event: true,
+            ..Options::default()
+        };
+
+        let source = generate_str(&schema, &options).unwrap();
+
+        assert!(!source.contains("enum AnyEvent"));
+    }
+}

From c577e3e033e5a5dd3279c08daab651dd880ac9dd Mon Sep 17 00:00:00 2001
From: Johan Peltenburg <johan.peltenburg+code@gmail.com>
Date: Mon, 27 Jul 2026 11:53:46 +0200
Subject: [PATCH 2/2] refactor(instrumentation-build): handle empty AnyEvent
 locally

Signed-off-by: Johan Peltenburg <johan.peltenburg+code@gmail.com>
---
 crates/instrumentation-build/src/any_event.rs | 17 +++++++++++--
 crates/instrumentation-build/src/lib.rs       | 25 +------------------
 2 files changed, 16 insertions(+), 26 deletions(-)

diff --git a/crates/instrumentation-build/src/any_event.rs b/crates/instrumentation-build/src/any_event.rs
index eaccbb826..3cc58734b 100644
--- a/crates/instrumentation-build/src/any_event.rs
+++ b/crates/instrumentation-build/src/any_event.rs
@@ -23,8 +23,6 @@ pub(crate) fn generate_any_event(
     schema: &Schema,
     opts: &Options,
 ) -> Result<TokenStream, GenerateError> {
-    let derives = derive_attr(opts.event_derives)?;
-
     let variants: Vec<(Ident, Ident)> = schema
         .entities()
         .map(|entity| {
@@ -35,7 +33,11 @@ pub(crate) fn generate_any_event(
             )
         })
         .collect();
+    if variants.is_empty() {
+        return Ok(quote! {});
+    }
 
+    let derives = derive_attr(opts.event_derives)?;
     let decls = variants.iter().map(|(variant, event)| {
         quote! { #variant(&'a ::quent_instrumentation::Event<#event>) }
     });
@@ -118,4 +120,15 @@ mod tests {
             pretty(expected)
         );
     }
+
+    #[test]
+    fn emits_nothing_without_entities() {
+        let schema = SchemaBuilder::new(ident("Demo")).build().unwrap();
+
+        assert!(
+            generate_any_event(&schema, &Options::default())
+                .unwrap()
+                .is_empty()
+        );
+    }
 }
diff --git a/crates/instrumentation-build/src/lib.rs b/crates/instrumentation-build/src/lib.rs
index 29ef6fb13..eeabbdd2d 100644
--- a/crates/instrumentation-build/src/lib.rs
+++ b/crates/instrumentation-build/src/lib.rs
@@ -190,10 +190,7 @@ pub fn generate_str(schema: &Schema, opts: &Options) -> Result<String, GenerateE
     let records = generate_record_types(schema, opts)?;
     let events = generate_event_types(schema, opts)?;
     let runtime = generate_runtime_types(schema)?;
-    let has_events = schema
-        .entities()
-        .any(|entity| entity.events().next().is_some());
-    let any_event = if opts.any_event && has_events {
+    let any_event = if opts.any_event {
         any_event::generate_any_event(schema, opts)?
     } else {
         quote! {}
@@ -215,23 +212,3 @@ fn ensure_unqualified_type_paths(schema: &Schema) -> Result<(), GenerateError> {
         None => Ok(()),
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use quent_schema::builder::SchemaBuilder;
-    use quent_schema::test_utils::ident;
-
-    #[test]
-    fn skips_any_event_without_events() {
-        let schema = SchemaBuilder::new(ident("Demo")).build().unwrap();
-        let options = Options {
-            any_event: true,
-            ..Options::default()
-        };
-
-        let source = generate_str(&schema, &options).unwrap();
-
-        assert!(!source.contains("enum AnyEvent"));
-    }
-}