From 5037e148fc3e72c657aa7a13146a1147ccb6f8a6 Mon Sep 17 00:00:00 2001
From: Peter Solnica <peter@solnica.online>
Date: Tue, 6 Oct 2026 11:59:44 +0000
Subject: [PATCH] fix(transport): log directly sent envelopes in DebugTransport

---
 .../lib/sentry/transport/debug_transport.rb   | 13 +++++++--
 .../sentry/transport/debug_transport_spec.rb  | 27 +++++++++++++++++++
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/sentry-ruby/lib/sentry/transport/debug_transport.rb b/sentry-ruby/lib/sentry/transport/debug_transport.rb
index 58d3ffb3e..5771a9004 100644
--- a/sentry-ruby/lib/sentry/transport/debug_transport.rb
+++ b/sentry-ruby/lib/sentry/transport/debug_transport.rb
@@ -27,6 +27,11 @@ def send_event(event)
       backend.send_event(event)
     end
 
+    def send_envelope(envelope)
+      log_envelope(envelope)
+      backend.send_envelope(envelope)
+    end
+
     def log_envelope(envelope)
       envelope_json = {
         timestamp: Time.now.utc.iso8601,
@@ -36,13 +41,13 @@ def log_envelope(envelope)
         end
       }
 
-      File.open(log_file, "a") { |file| file << JSON.dump(envelope_json) << "\n" }
+      File.open(log_file, "a") { |file| file.write("#{JSON.dump(envelope_json)}\n") }
     end
 
     def logged_envelopes
       return [] unless File.exist?(log_file)
 
-      File.readlines(log_file).map do |line|
+      File.readlines(log_file).select { |line| fully_written?(line) }.map do |line|
         JSON.parse(line)
       end
     end
@@ -54,6 +59,10 @@ def clear
 
     private
 
+    def fully_written?(line)
+      line.end_with?("\n")
+    end
+
     def initialize_backend(configuration)
       backend = configuration.dsn.local? ? DummyTransport : HTTPTransport
       backend.new(configuration)
diff --git a/sentry-ruby/spec/sentry/transport/debug_transport_spec.rb b/sentry-ruby/spec/sentry/transport/debug_transport_spec.rb
index 90b283ff3..21f4de1c6 100644
--- a/sentry-ruby/spec/sentry/transport/debug_transport_spec.rb
+++ b/sentry-ruby/spec/sentry/transport/debug_transport_spec.rb
@@ -22,6 +22,12 @@
   context "with local DSN for testing" do
     let(:dsn) { Sentry::TestHelper::DUMMY_DSN }
 
+    def build_envelope(body)
+      Sentry::Envelope.new(sent_at: Sentry.utc_now.iso8601).tap do |envelope|
+        envelope.add_item({ type: "log" }, { items: [{ body: body }] })
+      end
+    end
+
     describe ".capture_exception with debug transport" do
       it "logs envelope data and stores an event internally" do
         Sentry.capture_exception(error)
@@ -37,6 +43,27 @@
         expect(payload["exception"]["values"].first["value"]).to include("test error")
       end
     end
+
+    describe "#send_envelope" do
+      it "logs the envelope and passes it on to the backend" do
+        transport.send_envelope(build_envelope("hello"))
+
+        expect(transport.backend.envelopes.count).to be(1)
+        expect(transport.logged_envelopes.last.dig("items", 0, "payload", "items", 0, "body")).to eq("hello")
+      end
+    end
+
+    describe "#logged_envelopes" do
+      it "skips a last line that is still being written" do
+        transport.clear
+        transport.send_envelope(build_envelope("complete"))
+        File.open(transport.log_file, "a") { |file| file.write('{"timestamp":"2026-10-06T09:08:2') }
+
+        bodies = transport.logged_envelopes.map { |envelope| envelope.dig("items", 0, "payload", "items", 0, "body") }
+
+        expect(bodies).to eq(["complete"])
+      end
+    end
   end
 
   context "with a real DSN for testing" do