Don't require file to exist in container for copy operation to comple…

…te successfully

<layers>/generated/build isn't guaranteed to exist

Signed-off-by: Natalie Arellano <narellano@vmware.com>

acceptance/assertions/lifecycle_output.go

@@ -73,7 +73,10 @@ func (l LifecycleOutputAssertionManager) IncludesSeparatePhases() {
 func (l LifecycleOutputAssertionManager) IncludesSeparatePhasesWithExtension() {
 	l.testObject.Helper()
 
-	l.assert.ContainsAll(l.output, "[detector]", "[analyzer]", "[extender]", "[exporter]")
+	// Earlier pack versions print `[extender]`, later pack versions print `[extender (build)]`.
+	// Removing the `]` for the extend phase allows us to navigate compat suite complexity without undo headache.
+	// When previous pack is old enough, we can make the matcher more precise.
+	l.assert.ContainsAll(l.output, "[detector]", "[analyzer]", "[extender", "[exporter]")
 }
 
 func (l LifecycleOutputAssertionManager) IncludesLifecycleImageTag(tag string) {

acceptance/testdata/mock_buildpacks/0.2/read-env-extension/bin/generate

@@ -1,3 +1,14 @@
 #!/usr/bin/env bash
 
 echo "---> Generate: Read Env Extension"
+
+# 1. GET ARGS
+output_dir=$CNB_OUTPUT_DIR
+
+# 2. GENERATE build.Dockerfile
+cat >> "${output_dir}/build.Dockerfile" <<EOL
+ARG base_image
+FROM \${base_image}
+
+RUN echo "Hello World"
+EOL

go.mod

@@ -32,6 +32,7 @@ require (
 	golang.org/x/crypto v0.7.0
 	golang.org/x/mod v0.10.0
 	golang.org/x/oauth2 v0.6.0
+	golang.org/x/sync v0.1.0
 	golang.org/x/term v0.7.0
 	golang.org/x/text v0.8.0
 	gopkg.in/yaml.v3 v3.0.1
@@ -113,7 +114,6 @@ require (
 	github.com/vbatts/tar-split v0.11.2 // indirect
 	github.com/xanzy/ssh-agent v0.3.3 // indirect
 	golang.org/x/net v0.8.0 // indirect
-	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/sys v0.7.0 // indirect
 	golang.org/x/tools v0.7.0 // indirect
 	google.golang.org/appengine v1.6.7 // indirect

internal/build/container_ops.go

@@ -12,6 +12,7 @@ import (
 	"github.com/buildpacks/lifecycle/platform"
 	"github.com/docker/docker/api/types"
 	dcontainer "github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/errdefs"
 	darchive "github.com/docker/docker/pkg/archive"
 	"github.com/pkg/errors"
 
@@ -42,6 +43,30 @@ func CopyOut(handler func(closer io.ReadCloser) error, srcs ...string) Container
 	}
 }
 
+// CopyOutErr copies container directories to a handler function. The handler is responsible for closing the Reader.
+// CopyOutErr differs from CopyOut in that it does not require the source files to exist in the container
+// in order to exit without error.
+func CopyOutErr(handler func(closer io.ReadCloser) error, srcs ...string) ContainerOperation {
+	return func(ctrClient DockerClient, ctx context.Context, containerID string, stdout, stderr io.Writer) error {
+		for _, src := range srcs {
+			reader, _, err := ctrClient.CopyFromContainer(ctx, containerID, src)
+			if err != nil {
+				if errdefs.IsNotFound(err) {
+					continue
+				}
+				return err
+			}
+
+			err = handler(reader)
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	}
+}
+
 func CopyOutTo(src, dest string) ContainerOperation {
 	return CopyOut(func(reader io.ReadCloser) error {
 		info := darchive.CopyInfo{
@@ -54,6 +79,18 @@ func CopyOutTo(src, dest string) ContainerOperation {
 	}, src)
 }
 
+func CopyOutToErr(src, dest string) ContainerOperation {
+	return CopyOutErr(func(reader io.ReadCloser) error {
+		info := darchive.CopyInfo{
+			Path:  src,
+			IsDir: true,
+		}
+
+		defer reader.Close()
+		return darchive.CopyTo(reader, info, dest)
+	}, src)
+}
+
 // CopyDir copies a local directory (src) to the destination on the container while filtering files and changing it's UID/GID.
 // if includeRoot is set the UID/GID will be set on the dst directory.
 func CopyDir(src, dst string, uid, gid int, os string, includeRoot bool, fileFilter func(string) bool) ContainerOperation {

internal/build/lifecycle_execution.go

@@ -407,9 +407,9 @@ func (l *LifecycleExecution) Detect(ctx context.Context, phaseFactory PhaseFacto
 		),
 		WithFlags(flags...),
 		If(l.hasExtensions(), WithPostContainerRunOperations(
-			CopyOutTo(filepath.Join(l.mountPaths.layersDir(), "analyzed.toml"), l.TmpDir))),
+			CopyOutToErr(filepath.Join(l.mountPaths.layersDir(), "analyzed.toml"), l.TmpDir))),
 		If(l.hasExtensions(), WithPostContainerRunOperations(
-			CopyOutTo(filepath.Join(l.mountPaths.layersDir(), "generated", "build"), l.TmpDir))),
+			CopyOutToErr(filepath.Join(l.mountPaths.layersDir(), "generated", "build"), l.TmpDir))),
 		envOp,
 	)