From ad04e49c43b3ddbc588924065158327af5213683 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juli=C3=A1n=20Pinz=C3=B3n=20Eslava?= <julian@buildkite.com>
Date: Thu, 19 Feb 2026 13:23:30 +1100
Subject: [PATCH] Fix ERB expression compilation when code contains a heredoc

When an ERB output tag wraps code in parentheses and that code contains
a heredoc (e.g. `method_call <<~GRAPHQL, variables`), the closing
parenthesis must appear on its own line after the heredoc terminator.
Without this, the compiled Ruby is syntactically invalid.

Always insert a newline before the closing parenthesis unconditionally,
since Ruby ignores trailing newlines in expressions.

Includes a snapshot test for the compiled output.

Co-authored-by: Amp <amp@ampcode.com>
Amp-Thread-ID: https://ampcode.com/threads/T-019c7333-8beb-715a-9183-8434cd5fb15a
---
 lib/reactionview/template/handlers/herb/herb.rb     |  2 +-
 ...on_compiled_40e3b949384b06dd58f462a17aa0827b.txt |  3 ++-
 ...ut_compiled_ce838ee50a8780e359b0426fe5b6bfb4.txt |  4 +++-
 ...es_compiled_ca45577d00c738a24540dfeb3f7885ef.txt |  3 ++-
 ...ns_compiled_082a93002fba858b87a75785cd88a2b7.txt |  4 +++-
 ...on_compiled_8fc34c93947921e6cf438e5adfc691d7.txt |  3 ++-
 ...er_compiled_9d7872dac3cef10a2a63f61404a4b051.txt |  3 ++-
 ...to_compiled_351531c91827e79a1a9ab2f324c18ce9.txt |  3 ++-
 ...rs_compiled_3a9949064612857244b6b8987a2b6dc3.txt |  9 ++++++---
 ...by_compiled_ffc55de9e7891578a81f0a2b0c1346a5.txt |  8 ++++++++
 test/template/handlers/herb_test.rb                 | 13 +++++++++++++
 11 files changed, 44 insertions(+), 11 deletions(-)
 create mode 100644 test/snapshots/herb/template_handler_test/test_0029_heredoc_with_trailing_arguments_compiles_to_valid_Ruby_compiled_ffc55de9e7891578a81f0a2b0c1346a5.txt

diff --git a/lib/reactionview/template/handlers/herb/herb.rb b/lib/reactionview/template/handlers/herb/herb.rb
index d117265..c8f8452 100644
--- a/lib/reactionview/template/handlers/herb/herb.rb
+++ b/lib/reactionview/template/handlers/herb/herb.rb
@@ -66,7 +66,7 @@ def add_rails_expression(indicator, code, wrap_parentheses:)
                       end
 
               if wrap_parentheses
-                @src << "(" << code << ")"
+                @src << "(" << code << "\n)"
               else
                 @src << " " << code
               end
diff --git a/test/snapshots/herb/template_handler_test/test_0003_template_with_expression_compiled_40e3b949384b06dd58f462a17aa0827b.txt b/test/snapshots/herb/template_handler_test/test_0003_template_with_expression_compiled_40e3b949384b06dd58f462a17aa0827b.txt
index 3835b27..af46782 100644
--- a/test/snapshots/herb/template_handler_test/test_0003_template_with_expression_compiled_40e3b949384b06dd58f462a17aa0827b.txt
+++ b/test/snapshots/herb/template_handler_test/test_0003_template_with_expression_compiled_40e3b949384b06dd58f462a17aa0827b.txt
@@ -1,2 +1,3 @@
- @output_buffer.safe_append='<h1>Hello '.freeze; @output_buffer.append=(@name); @output_buffer.safe_append='</h1>'.freeze;
+ @output_buffer.safe_append='<h1>Hello '.freeze; @output_buffer.append=(@name
+); @output_buffer.safe_append='</h1>'.freeze;
 @output_buffer
\ No newline at end of file
diff --git a/test/snapshots/herb/template_handler_test/test_0005_raw_and_regular_output_compiled_ce838ee50a8780e359b0426fe5b6bfb4.txt b/test/snapshots/herb/template_handler_test/test_0005_raw_and_regular_output_compiled_ce838ee50a8780e359b0426fe5b6bfb4.txt
index 6caf279..5c02636 100644
--- a/test/snapshots/herb/template_handler_test/test_0005_raw_and_regular_output_compiled_ce838ee50a8780e359b0426fe5b6bfb4.txt
+++ b/test/snapshots/herb/template_handler_test/test_0005_raw_and_regular_output_compiled_ce838ee50a8780e359b0426fe5b6bfb4.txt
@@ -1,2 +1,4 @@
- @output_buffer.append=(@html); @output_buffer.append=(raw @safe_html);
+ @output_buffer.append=(@html
+); @output_buffer.append=(raw @safe_html
+);
 @output_buffer
\ No newline at end of file
diff --git a/test/snapshots/herb/template_handler_test/test_0006_template_with_newlines_compiled_ca45577d00c738a24540dfeb3f7885ef.txt b/test/snapshots/herb/template_handler_test/test_0006_template_with_newlines_compiled_ca45577d00c738a24540dfeb3f7885ef.txt
index 32fd006..dc3a160 100644
--- a/test/snapshots/herb/template_handler_test/test_0006_template_with_newlines_compiled_ca45577d00c738a24540dfeb3f7885ef.txt
+++ b/test/snapshots/herb/template_handler_test/test_0006_template_with_newlines_compiled_ca45577d00c738a24540dfeb3f7885ef.txt
@@ -1,4 +1,5 @@
  @output_buffer.safe_append='<div>
-'.freeze; @output_buffer.append=(@content); @output_buffer.safe_append='
+'.freeze; @output_buffer.append=(@content
+); @output_buffer.safe_append='
 </div>'.freeze;
 @output_buffer
\ No newline at end of file
diff --git a/test/snapshots/herb/template_handler_test/test_0007_multiple_expressions_compiled_082a93002fba858b87a75785cd88a2b7.txt b/test/snapshots/herb/template_handler_test/test_0007_multiple_expressions_compiled_082a93002fba858b87a75785cd88a2b7.txt
index f1afa87..5b2fc28 100644
--- a/test/snapshots/herb/template_handler_test/test_0007_multiple_expressions_compiled_082a93002fba858b87a75785cd88a2b7.txt
+++ b/test/snapshots/herb/template_handler_test/test_0007_multiple_expressions_compiled_082a93002fba858b87a75785cd88a2b7.txt
@@ -1,2 +1,4 @@
- @output_buffer.safe_append='<h1>Hello '.freeze; @output_buffer.append=(@name); @output_buffer.safe_append='!</h1><p>'.freeze; @output_buffer.append=(@message); @output_buffer.safe_append='</p>'.freeze;
+ @output_buffer.safe_append='<h1>Hello '.freeze; @output_buffer.append=(@name
+); @output_buffer.safe_append='!</h1><p>'.freeze; @output_buffer.append=(@message
+); @output_buffer.safe_append='</p>'.freeze;
 @output_buffer
\ No newline at end of file
diff --git a/test/snapshots/herb/template_handler_test/test_0008_xss_protection_compiled_8fc34c93947921e6cf438e5adfc691d7.txt b/test/snapshots/herb/template_handler_test/test_0008_xss_protection_compiled_8fc34c93947921e6cf438e5adfc691d7.txt
index 0b73dcd..5c2e409 100644
--- a/test/snapshots/herb/template_handler_test/test_0008_xss_protection_compiled_8fc34c93947921e6cf438e5adfc691d7.txt
+++ b/test/snapshots/herb/template_handler_test/test_0008_xss_protection_compiled_8fc34c93947921e6cf438e5adfc691d7.txt
@@ -1,2 +1,3 @@
- @output_buffer.safe_append='<div>'.freeze; @output_buffer.append=(@unsafe_content); @output_buffer.safe_append='</div>'.freeze;
+ @output_buffer.safe_append='<div>'.freeze; @output_buffer.append=(@unsafe_content
+); @output_buffer.safe_append='</div>'.freeze;
 @output_buffer
\ No newline at end of file
diff --git a/test/snapshots/herb/template_handler_test/test_0009_content_tag_helper_compiled_9d7872dac3cef10a2a63f61404a4b051.txt b/test/snapshots/herb/template_handler_test/test_0009_content_tag_helper_compiled_9d7872dac3cef10a2a63f61404a4b051.txt
index e819f9c..1a0f57f 100644
--- a/test/snapshots/herb/template_handler_test/test_0009_content_tag_helper_compiled_9d7872dac3cef10a2a63f61404a4b051.txt
+++ b/test/snapshots/herb/template_handler_test/test_0009_content_tag_helper_compiled_9d7872dac3cef10a2a63f61404a4b051.txt
@@ -1,2 +1,3 @@
- @output_buffer.append=(content_tag :div, "Hello", class: "greeting");
+ @output_buffer.append=(content_tag :div, "Hello", class: "greeting"
+);
 @output_buffer
\ No newline at end of file
diff --git a/test/snapshots/herb/template_handler_test/test_0010_user_card_with_conditional_and_link_to_compiled_351531c91827e79a1a9ab2f324c18ce9.txt b/test/snapshots/herb/template_handler_test/test_0010_user_card_with_conditional_and_link_to_compiled_351531c91827e79a1a9ab2f324c18ce9.txt
index d517164..7ef0940 100644
--- a/test/snapshots/herb/template_handler_test/test_0010_user_card_with_conditional_and_link_to_compiled_351531c91827e79a1a9ab2f324c18ce9.txt
+++ b/test/snapshots/herb/template_handler_test/test_0010_user_card_with_conditional_and_link_to_compiled_351531c91827e79a1a9ab2f324c18ce9.txt
@@ -1,5 +1,6 @@
  @output_buffer.safe_append='<div class="user-card">
-  <h2>'.freeze; @output_buffer.append=(@user[:name]); @output_buffer.safe_append='</h2>
+  <h2>'.freeze; @output_buffer.append=(@user[:name]
+); @output_buffer.safe_append='</h2>
 '.freeze;   if @user[:verified] 
  @output_buffer.safe_append='    <span class="badge">Verified</span>
 '.freeze;   end 
diff --git a/test/snapshots/herb/template_handler_test/test_0011_complex_layout_with_helpers_compiled_3a9949064612857244b6b8987a2b6dc3.txt b/test/snapshots/herb/template_handler_test/test_0011_complex_layout_with_helpers_compiled_3a9949064612857244b6b8987a2b6dc3.txt
index 80b6784..0cae96f 100644
--- a/test/snapshots/herb/template_handler_test/test_0011_complex_layout_with_helpers_compiled_3a9949064612857244b6b8987a2b6dc3.txt
+++ b/test/snapshots/herb/template_handler_test/test_0011_complex_layout_with_helpers_compiled_3a9949064612857244b6b8987a2b6dc3.txt
@@ -1,13 +1,16 @@
  @output_buffer.safe_append='<div class="container py-8">
-  <h1 class="title">'.freeze; @output_buffer.append=(title "Events by Country"); @output_buffer.safe_append='</h1>
+  <h1 class="title">'.freeze; @output_buffer.append=(title "Events by Country"
+); @output_buffer.safe_append='</h1>
 
-  '.freeze; @output_buffer.append=(ui_button "View all cities", url: cities_path, kind: :secondary); @output_buffer.safe_append='
+  '.freeze; @output_buffer.append=(ui_button "View all cities", url: cities_path, kind: :secondary
+); @output_buffer.safe_append='
 
 '.freeze;   if @show_countries 
  @output_buffer.safe_append='    <h2>Countries</h2>
     '.freeze; @output_buffer.append= link_to country_path("switzerland"), id: "country-ch", class: "event-item" do; @output_buffer.safe_append='
       <span class="event-name">🇨🇭 Switzerland</span>
-      '.freeze; @output_buffer.append=(ui_badge(5, kind: :secondary, class: "event-count")); @output_buffer.safe_append='
+      '.freeze; @output_buffer.append=(ui_badge(5, kind: :secondary, class: "event-count")
+); @output_buffer.safe_append='
 '.freeze;     end 
    end 
  @output_buffer.safe_append='</div>
diff --git a/test/snapshots/herb/template_handler_test/test_0029_heredoc_with_trailing_arguments_compiles_to_valid_Ruby_compiled_ffc55de9e7891578a81f0a2b0c1346a5.txt b/test/snapshots/herb/template_handler_test/test_0029_heredoc_with_trailing_arguments_compiles_to_valid_Ruby_compiled_ffc55de9e7891578a81f0a2b0c1346a5.txt
new file mode 100644
index 0000000..12e6535
--- /dev/null
+++ b/test/snapshots/herb/template_handler_test/test_0029_heredoc_with_trailing_arguments_compiles_to_valid_Ruby_compiled_ffc55de9e7891578a81f0a2b0c1346a5.txt
@@ -0,0 +1,8 @@
+ @output_buffer.append=(method_call <<~GRAPHQL, variables
+  query {
+    field
+  }
+GRAPHQL
+);
+ @output_buffer.safe_append='
+'.freeze;@output_buffer
\ No newline at end of file
diff --git a/test/template/handlers/herb_test.rb b/test/template/handlers/herb_test.rb
index 0b973f3..b6a3149 100644
--- a/test/template/handlers/herb_test.rb
+++ b/test/template/handlers/herb_test.rb
@@ -342,4 +342,17 @@ def @view_context.ui_badge(count, **_options)
     assert_compiled_snapshot(template)
     assert_evaluated_snapshot(template, ivars: { config: { key: "value" } })
   end
+
+  test "heredoc with trailing arguments compiles to valid Ruby" do
+    template = <<~ERB
+      <%= method_call <<~GRAPHQL, variables
+        query {
+          field
+        }
+      GRAPHQL
+      %>
+    ERB
+
+    assert_compiled_snapshot(template)
+  end
 end