From bb4657e465b52d4502584cfe214367f1d88368e8 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sun, 27 Feb 2022 16:55:59 -0500
Subject: [PATCH] Process environments created during task execution phase

---
 build_tests/simple/env_in_task.rb |  5 +++++
 lib/rscons/application.rb         | 11 +++++++++++
 lib/rscons/script.rb              | 10 +++++++++-
 spec/build_tests_spec.rb          |  8 ++++++++
 4 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 build_tests/simple/env_in_task.rb

diff --git a/build_tests/simple/env_in_task.rb b/build_tests/simple/env_in_task.rb
new file mode 100644
index 0000000..2600ce0
--- /dev/null
+++ b/build_tests/simple/env_in_task.rb
@@ -0,0 +1,5 @@
+default do
+  env do |env|
+    env.Program('simple.exe', Dir['*.c'])
+  end
+end
diff --git a/lib/rscons/application.rb b/lib/rscons/application.rb
index ab61060..f6d0450 100644
--- a/lib/rscons/application.rb
+++ b/lib/rscons/application.rb
@@ -42,6 +42,16 @@ module Rscons
       @variant_groups = []
     end
 
+    # Return if Rscons is in the task execution phase.
+    #
+    # @api private
+    #
+    # @return [Boolean]
+    #   If Rscons is in the task execution phase.
+    def task_execution_phase?
+      @task_execution_phase
+    end
+
     # Run the application.
     #
     # Execute user-specified tasks.
@@ -77,6 +87,7 @@ module Rscons
         return 0
       end
       apply_task_params(tasks_and_params)
+      @task_execution_phase = true
       if tasks_and_params.empty?
         check_process_environments
         if Task.tasks["default"]
diff --git a/lib/rscons/script.rb b/lib/rscons/script.rb
index 02c8099..e6b811c 100644
--- a/lib/rscons/script.rb
+++ b/lib/rscons/script.rb
@@ -130,13 +130,21 @@ module Rscons
       #
       # If a block is given it is immediately executed and passed the newly
       # created Environment object as an argument.
+      # If the Environment is created in task context, the +process+ method is
+      # immediately called.
+      # Otherwise, the Environment is not processed until the task execution
+      # phase.
       #
       # @yield [env]
       # @yieldparam env [Environment]
       #   The created environment.
       def env(*args, &block)
         Rscons.application.check_configure
-        Environment.new(*args, &block)
+        e = Environment.new(*args, &block)
+        if Rscons.application.task_execution_phase?
+          e.process
+        end
+        e
       end
 
       # Construct a task parameter.
diff --git a/spec/build_tests_spec.rb b/spec/build_tests_spec.rb
index 1fe11a6..43ceb1d 100644
--- a/spec/build_tests_spec.rb
+++ b/spec/build_tests_spec.rb
@@ -195,6 +195,14 @@ EOF
     expect(nr(`./simple.exe`)).to eq "This is a simple C program\n"
   end
 
+  it "processes the environment when created within a task" do
+    test_dir("simple")
+    result = run_rscons(args: %w[-f env_in_task.rb])
+    expect(result.stderr).to eq ""
+    expect(File.exists?("build/e.1/simple.c.o")).to be_truthy
+    expect(nr(`./simple.exe`)).to eq "This is a simple C program\n"
+  end
+
   it "uses the build directory specified with -b" do
     test_dir("simple")
     result = run_rscons(args: %w[-b b])