Reuse pmd binary from pmd-dist/target/pmd-bin...zip if available

This is important for speeding up CI builds to avoid rebuilding PMD.

Author: adangel

lib/pmdtester/builders/pmd_report_builder.rb

@@ -49,17 +49,26 @@ def get_pmd_binary_file
 
     # builds pmd on currently checked out branch
     def build_pmd(into_dir:)
-      logger.info "#{@pmd_branch_name}: Building PMD #{@pmd_version}..."
-      package_cmd = './mvnw clean package' \
-                    ' -Dmaven.test.skip=true' \
-                    ' -Dmaven.javadoc.skip=true' \
-                    ' -Dmaven.source.skip=true' \
-                    ' -Dcheckstyle.skip=true'
-      Cmd.execute(package_cmd)
+      # in CI there might have been a build performed already. In that case
+      # we reuse the build result, otherwise we build PMD freshly
+      pmd_dist_target = "pmd-dist/target/pmd-bin-#{@pmd_version}.zip"
+      if File.exist?("#{@local_git_repo}/#{pmd_dist_target}")
+        # that's a warning, because we don't know, whether this build really
+        # belongs to the current branch or whether it's from a previous branch.
+        # In CI, that's not a problem, because the workspace is always fresh.
+        logger.warn "#{@pmd_branch_name}: Reusing already existing #{pmd_dist_target}"
+      else
+        logger.info "#{@pmd_branch_name}: Building PMD #{@pmd_version}..."
+        package_cmd = './mvnw clean package' \
+                      ' -Dmaven.test.skip=true' \
+                      ' -Dmaven.javadoc.skip=true' \
+                      ' -Dmaven.source.skip=true' \
+                      ' -Dcheckstyle.skip=true'
+        Cmd.execute(package_cmd)
+      end
 
       logger.info "#{@pmd_branch_name}: Extracting the zip"
-      Cmd.execute("unzip -qo pmd-dist/target/pmd-bin-#{@pmd_version}.zip" \
-                  ' -d pmd-dist/target/exploded')
+      Cmd.execute("unzip -qo #{pmd_dist_target} -d pmd-dist/target/exploded")
       Cmd.execute("mv pmd-dist/target/exploded/pmd-bin-#{@pmd_version} #{into_dir}")
     end
 

test/test_pmd_report_builder.rb

@@ -7,6 +7,11 @@ class TestPmdReportBuilder < Test::Unit::TestCase
   def setup
     # pmd version that is simulated in tests when pmd should be built
     @pmd_version = '6.10.0-SNAPSHOT'
+
+    # pre-built PMD binary
+    pmd_binary = "target/repositories/pmd/pmd-dist/target/pmd-bin-#{@pmd_version}.zip"
+
+    File.unlink pmd_binary if File.exist? pmd_binary
   end
 
   def test_build_skip
@@ -23,6 +28,31 @@ def test_build_skip
       .build
   end
 
+  # In CI, there is no previous existing distro that can be reused,
+  # that means target/pmd-bin-6.10.0-SNAPSHOT-master-sha1abc does not
+  # exist. However, pmd-dist/target/pmd-bin-6.10.0-SNAPSHOT.zip exists
+  # from a previous build and should be reused.
+  def test_build_skip_ci
+    projects = []
+    argv = %w[-r target/repositories/pmd -b master -p pmd_releases/6.1.0
+              -c config/design.xml -l test/resources/project-test.xml]
+    options = PmdTester::Options.new(argv)
+
+    FileUtils.mkdir_p 'target/repositories/pmd/pmd-dist/target'
+    FileUtils.touch "target/repositories/pmd/pmd-dist/target/pmd-bin-#{@pmd_version}.zip"
+
+    record_expectations('sha1abc', 'sha1abc', false)
+    PmdTester::Cmd.stubs(:execute).with("unzip -qo pmd-dist/target/pmd-bin-#{@pmd_version}.zip" \
+      ' -d pmd-dist/target/exploded').once
+    PmdTester::Cmd.stubs(:execute).with("mv pmd-dist/target/exploded/pmd-bin-#{@pmd_version}" \
+      " #{Dir.getwd}/target/pmd-bin-#{@pmd_version}-master-sha1abc").once
+    record_expectations_after_build
+
+    PmdTester::PmdReportBuilder
+      .new(projects, options, options.base_config, options.base_branch)
+      .build
+  end
+
   def test_build_normal
     projects = []
     argv = %w[-r target/repositories/pmd -b master -p pmd_releases/6.1.0