Remove the partial external builder output when the copy fails

core/container/externalbuilder/externalbuilder.go

@@ -153,12 +153,14 @@ func (d *Detector) Build(ccid string, mdBytes []byte, codeStream io.Reader) (*In
 	durableReleaseDir := filepath.Join(durablePath, "release")
 	err = CopyDir(logger, buildContext.ReleaseDir, durableReleaseDir)
 	if err != nil {
+		os.RemoveAll(durablePath)
 		return nil, errors.WithMessagef(err, "could not move or copy build context release to persistent location '%s'", durablePath)
 	}
 
 	durableBldDir := filepath.Join(durablePath, "bld")
 	err = CopyDir(logger, buildContext.BldDir, durableBldDir)
 	if err != nil {
+		os.RemoveAll(durablePath)
 		return nil, errors.WithMessagef(err, "could not move or copy build context bld to persistent location '%s'", durablePath)
 	}
 

core/container/externalbuilder/externalbuilder_test.go

@@ -155,6 +155,27 @@ var _ = Describe("externalbuilder", func() {
 					Expect(err).To(MatchError("could not create dir 'path/to/nowhere/fake-package-id' to persist build output: mkdir path/to/nowhere/fake-package-id: no such file or directory"))
 				})
 			})
+
+			Context("when the build output cannot be copied to the durable path", func() {
+				BeforeEach(func() {
+					detector.Builders = externalbuilder.CreateBuilders([]peer.ExternalBuilder{
+						{Path: "testdata/symlinkbuilder", Name: "symlinkbuilder"},
+					}, "mspid")
+				})
+
+				It("removes the partial build output", func() {
+					_, err := detector.Build("fake-package-id", md, codePackage)
+					Expect(err).To(MatchError(ContainSubstring("could not move or copy build context bld to persistent location")))
+					Expect(filepath.Join(durablePath, "fake-package-id")).NotTo(BeAnExistingFile())
+
+					Expect(codePackage.Close()).To(Succeed())
+					codePackage, err = os.Open("testdata/normal_archive.tar.gz")
+					Expect(err).NotTo(HaveOccurred())
+					instance, err := detector.Build("fake-package-id", md, codePackage)
+					Expect(err).To(MatchError(ContainSubstring("could not move or copy build context bld to persistent location")))
+					Expect(instance).To(BeNil())
+				})
+			})
 		})
 
 		Describe("CachedBuild", func() {

core/container/externalbuilder/testdata/symlinkbuilder/bin/build

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+ln -s /etc/hosts "$3/absolute-link"

core/container/externalbuilder/testdata/symlinkbuilder/bin/detect

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+if grep -q "fake-metadata" "$2/metadata.json" ; then
+    exit 0
+fi
+
+exit 1