From 9085aa537c56731d7fd1d25ca158f25e7adad4b6 Mon Sep 17 00:00:00 2001
From: Wleeaf <179125857+wleeaf@users.noreply.github.com>
Date: Sun, 25 Oct 2026 16:36:32 +0000
Subject: [PATCH] [fix] Keep parens on `raise` calls ending in an omitted hash
 value

`raise(Error, cause:)` was formatted as `raise Error, cause:`. Without
parens, Ruby takes whatever follows an omitted value as that value, so
the next line became the `cause:` argument, and a trailing modifier
(`raise Error, cause: if x`) became a syntax error.
---
 fixtures/small/raise_omitted_hash_value_actual.rb   | 10 ++++++++++
 fixtures/small/raise_omitted_hash_value_expected.rb | 10 ++++++++++
 librubyfmt/src/format_prism.rs                      | 13 +++++++++++++
 3 files changed, 33 insertions(+)
 create mode 100644 fixtures/small/raise_omitted_hash_value_actual.rb
 create mode 100644 fixtures/small/raise_omitted_hash_value_expected.rb

diff --git a/fixtures/small/raise_omitted_hash_value_actual.rb b/fixtures/small/raise_omitted_hash_value_actual.rb
new file mode 100644
index 00000000..39a9396f
--- /dev/null
+++ b/fixtures/small/raise_omitted_hash_value_actual.rb
@@ -0,0 +1,10 @@
+def boom(cause)
+  raise(ArgumentError, "message", cause:)
+end
+
+def retry_with(cause)
+  raise(RetryError, cause:)
+  cleanup
+end
+
+raise(Error, cause:) if cause
diff --git a/fixtures/small/raise_omitted_hash_value_expected.rb b/fixtures/small/raise_omitted_hash_value_expected.rb
new file mode 100644
index 00000000..39a9396f
--- /dev/null
+++ b/fixtures/small/raise_omitted_hash_value_expected.rb
@@ -0,0 +1,10 @@
+def boom(cause)
+  raise(ArgumentError, "message", cause:)
+end
+
+def retry_with(cause)
+  raise(RetryError, cause:)
+  cleanup
+end
+
+raise(Error, cause:) if cause
diff --git a/librubyfmt/src/format_prism.rs b/librubyfmt/src/format_prism.rs
index b4bf7ee7..d70aa43e 100644
--- a/librubyfmt/src/format_prism.rs
+++ b/librubyfmt/src/format_prism.rs
@@ -1766,6 +1766,19 @@ fn use_parens_for_call_node<'src>(
             return true;
         }
 
+        // Without parens, an omitted value at the end of the arguments
+        // (`raise Foo, cause:`) would take whatever comes next as its value
+        if call_node
+            .arguments()
+            .and_then(|arguments| arguments.arguments().last())
+            .and_then(|arg| arg.as_keyword_hash_node())
+            .and_then(|hash| hash.elements().last())
+            .and_then(|element| element.as_assoc_node())
+            .is_some_and(|assoc| assoc.value().as_implicit_node().is_some())
+        {
+            return true;
+        }
+
         if let Some(arguments) = call_node.arguments()
             && arguments.arguments().iter().any(|arg| {
                 arg.as_splat_node().is_some() || arg.as_forwarding_arguments_node().is_some()