From dd634fdc6f9aeddc8574daa6719a7f6d05a4dc41 Mon Sep 17 00:00:00 2001
From: "Brian J. Cardiff" <bcardiff@manas.com.ar>
Date: Wed, 22 Feb 2017 13:00:50 -0300
Subject: [PATCH] Playground: refactor instrumentation to allow specs

ensure instrumented code with prelude is able to compile.
---
 .../compiler/crystal/tools/playground_spec.cr | 11 +++++++
 .../crystal/tools/playground/server.cr        | 31 +++++++++++--------
 2 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/spec/compiler/crystal/tools/playground_spec.cr b/spec/compiler/crystal/tools/playground_spec.cr
index 9a763c348d2a..e4c20f8c5c43 100644
--- a/spec/compiler/crystal/tools/playground_spec.cr
+++ b/spec/compiler/crystal/tools/playground_spec.cr
@@ -571,3 +571,14 @@ describe Playground::AgentInstrumentorTransformer do
     CR
   end
 end
+
+private def assert_compile(source)
+  sources = Playground::Session.instrument_and_prelude("", "", 0, source, Logger.new(nil))
+  compiler = Compiler.new
+  compiler.no_codegen = true
+  result = compiler.compile sources, "fake-no-build"
+end
+
+describe Playground::Session do
+  it { assert_compile %(puts "1") }
+end
diff --git a/src/compiler/crystal/tools/playground/server.cr b/src/compiler/crystal/tools/playground/server.cr
index 0518c2cdbafe..b0f46d1f69d0 100644
--- a/src/compiler/crystal/tools/playground/server.cr
+++ b/src/compiler/crystal/tools/playground/server.cr
@@ -13,25 +13,17 @@ module Crystal::Playground
       @tag = 0
     end
 
-    def run(source, tag)
-      @logger.info "Request to run code (session=#{@session_key}, tag=#{tag}).\n#{source}"
-
-      @tag = tag
-      begin
-        ast = Parser.new(source).parse
-      rescue ex : Crystal::Exception
-        send_exception ex, tag
-        return
-      end
+    def self.instrument_and_prelude(session_key, port, tag, source, logger)
+      ast = Parser.new(source).parse
 
       instrumented = Playground::AgentInstrumentorTransformer.transform(ast).to_s
-      @logger.info "Code instrumentation (session=#{@session_key}, tag=#{tag}).\n#{instrumented}"
+      logger.info "Code instrumentation (session=#{session_key}, tag=#{tag}).\n#{instrumented}"
 
       prelude = %(
         require "compiler/crystal/tools/playground/agent"
 
         class Crystal::Playground::Agent
-          @@instance = Crystal::Playground::Agent.new("ws://localhost:#{@port}/agent/#{@session_key}/#{tag}", #{tag})
+          @@instance = Crystal::Playground::Agent.new("ws://localhost:#{port}/agent/#{session_key}/#{tag}", #{tag})
 
           def self.instance
             @@instance
@@ -43,10 +35,23 @@ module Crystal::Playground
         end
         )
 
-      sources = [
+      [
         Compiler::Source.new("playground_prelude", prelude),
         Compiler::Source.new("play", instrumented),
       ]
+    end
+
+    def run(source, tag)
+      @logger.info "Request to run code (session=#{@session_key}, tag=#{tag}).\n#{source}"
+
+      @tag = tag
+      begin
+        sources = self.class.instrument_and_prelude(@session_key, @port, tag, source, @logger)
+      rescue ex : Crystal::Exception
+        send_exception ex, tag
+        return
+      end
+
       output_filename = tempfile "play-#{@session_key}-#{tag}"
       compiler = Compiler.new
       compiler.color = false