Install builder cannot replace a currently executing binary on Linux - close #112

build_tests/install_running_exe/Rsconscript

@@ -0,0 +1,6 @@
+build do
+  Environment.new do |env|
+    env.Program("program.exe", "program.c")
+    env.Install("install/program.exe", "program.exe")
+  end
+end

build_tests/install_running_exe/program.c

@@ -0,0 +1,8 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int main(int argc, char * argv[])
+{
+    sleep(2);
+    return 0;
+}

lib/rscons/builders/copy.rb

@@ -57,6 +57,7 @@ module Rscons
                 printed_message = true
               end
               @cache.mkdir_p(File.dirname(dest), install: @install_builder)
+              FileUtils.rm_f(dest)
               FileUtils.cp(src, dest, :preserve => true)
             end
             @cache.register_build(dest, :Copy, [src], @env, install: @install_builder)

spec/build_tests_spec.rb

@@ -337,6 +337,20 @@ EOF
     expect(result.stderr).to match /Could not find a registered build target "foo"/
   end
 
+  it "allows replacing a running executable when performing an 'install' operation" do
+    test_dir("install_running_exe")
+    result = run_rscons(op: "install")
+    expect(result.stderr).to eq ""
+    fcontents = File.read("program.c", mode: "rb")
+    File.open("program.c", "wb") do |fh|
+      fh.write(fcontents.sub(/2/, '3'))
+    end
+    pid = Process.spawn("install/program.exe")
+    result = run_rscons(op: "install")
+    expect(result.stderr).to eq ""
+    Process.wait(pid)
+  end
+
   context "clean operation" do
     it 'cleans built files' do
       test_dir("simple")