fix(core)!: conditionally override exit code in ExitCodeSetup

2 files changed, 11 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e85058c..49b1f35 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -211,6 +211,8 @@ None
 
     All examples, docs, and test cases across the repository have been updated to use `.into()` where packed types are returned from chain functions.
 
+3. **[`core`]** **[`ExitCodeSetup`]** Updated `ExitCodeSetup` to only override the exit code when `ResExitCode` has been modified (i.e., `exit_code != 0`). Previously, it unconditionally overrode the exit code, which could interfere with exit codes set by other hooks or the program's default exit flow. The `on_finish` hook now returns `ProgramControlUnit::OverrideExitCode(...)` only when the exit code is non-zero, and `ProgramControls::Empty` otherwise. The import of `ProgramControls` has been added accordingly.
+
 ---
 
 ## Release 0.2.2 (2026-07-10)
diff --git a/mingling/src/setups/exit_code.rs b/mingling/src/setups/exit_code.rs
index 025ed8a..6b8a1ef 100644
--- a/mingling/src/setups/exit_code.rs
+++ b/mingling/src/setups/exit_code.rs
@@ -2,7 +2,7 @@ use std::marker::PhantomData;
 
 use mingling_core::{
     ProgramCollect,
-    hook::{ProgramControlUnit, ProgramHook},
+    hook::{ProgramControlUnit, ProgramControls, ProgramHook},
     setup::ProgramSetup,
     this,
 };
@@ -39,7 +39,14 @@ where
         // Insert hook to override exit code before program ends
         program.with_hook(ProgramHook::empty().on_finish(|_| {
             let this = this::<C>().res_or_default::<ResExitCode>();
-            ProgramControlUnit::OverrideExitCode(this.exit_code)
+            let ec = this.exit_code;
+
+            // Only override when ResExitCode has been modified
+            if ec != 0 {
+                ProgramControlUnit::OverrideExitCode(this.exit_code).into()
+            } else {
+                ProgramControls::Empty
+            }
         }));
     }
 }