From b0f2bbb7d51155270c0f31a16b4425e3c5364bc3 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Mon, 17 Jan 2022 18:02:58 -0500
Subject: [PATCH] Support environment variable to set rscons build directory -
 close #145

---
 lib/rscons/application.rb |  3 ++-
 spec/build_tests_spec.rb  | 23 +++++++++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/lib/rscons/application.rb b/lib/rscons/application.rb
index 9ddf3e0..d0050c0 100644
--- a/lib/rscons/application.rb
+++ b/lib/rscons/application.rb
@@ -27,7 +27,8 @@ module Rscons
 
     # Create Application instance.
     def initialize
-      @build_dir = "build"
+      @build_dir = ENV["RSCONS_BUILD_DIR"] || "build"
+      ENV.delete("RSCONS_BUILD_DIR")
       @n_threads = Util.determine_n_threads
       @vars = VarSet.new
       @operations = Set.new
diff --git a/spec/build_tests_spec.rb b/spec/build_tests_spec.rb
index 3ee6e12..4bea9ff 100644
--- a/spec/build_tests_spec.rb
+++ b/spec/build_tests_spec.rb
@@ -208,13 +208,21 @@ EOF
     expect(nr(`./simple.exe`)).to eq "This is a simple C program\n"
   end
 
-  it "builds a C program with one source file in an alternate build directory" do
+  it "uses the build directory specified with -b" do
     test_dir("simple")
     result = run_rscons(rscons_args: %w[-b b])
     expect(result.stderr).to eq ""
     expect(Dir.exist?("build")).to be_falsey
     expect(File.exists?("b/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 by an environment variable" do
+    test_dir("simple")
+    passenv["RSCONS_BUILD_DIR"] = "b2"
+    result = run_rscons
+    expect(result.stderr).to eq ""
+    expect(Dir.exist?("build")).to be_falsey
+    expect(File.exists?("b2/e.1/simple.c.o")).to be_truthy
   end
 
   it "allows specifying a Builder object as the source to another build target" do
@@ -2800,6 +2808,17 @@ EOF
       expect(result.status).to_not eq 0
       expect(result.stdout).to_not match /top configure/
     end
+
+    it "does not pass RSCONS_BUILD_DIR to subsidiary scripts" do
+      test_dir "subsidiary"
+      passenv["RSCONS_BUILD_DIR"] = "buildit"
+      result = run_rscons(op: %W[configure])
+      expect(result.stderr).to eq ""
+      expect(Dir.exist?("build")).to be_falsey
+      expect(Dir.exist?("buildit")).to be_truthy
+      expect(Dir.exist?("sub/build")).to be_truthy
+      expect(Dir.exist?("sub/buildit")).to be_falsey
+    end
   end
 
   context "sh method" do