From a3db716c0afd72219f39aae53967953f52e00511 Mon Sep 17 00:00:00 2001
From: Joel Longtine <joel@dagger.io>
Date: Fri, 7 Jan 2022 16:21:06 -0700
Subject: [PATCH] Ensure we can Marshall #Scratch as CUE

Signed-off-by: Joel Longtine <joel@dagger.io>
---
 plan/task/build.go                            | 19 ++++++++------
 plancontext/fs.go                             | 10 ++++++--
 tests/tasks.bats                              |  2 ++
 tests/tasks/scratch/scratch_build_scratch.cue | 25 +++++++++++++++++++
 tests/tasks/scratch/scratch_writefile.cue     | 23 +++++++++++++++++
 5 files changed, 70 insertions(+), 9 deletions(-)
 create mode 100644 tests/tasks/scratch/scratch_build_scratch.cue
 create mode 100644 tests/tasks/scratch/scratch_writefile.cue

diff --git a/plan/task/build.go b/plan/task/build.go
index 503c6d5f..94228600 100644
--- a/plan/task/build.go
+++ b/plan/task/build.go
@@ -115,14 +115,19 @@ func (t *buildTask) dockerfile(ctx context.Context, pctx *plancontext.Context, s
 		return nil, err
 	}
 
-	st, err := ref.ToState()
-	if err != nil {
-		return nil, err
-	}
+	var solvedRef bkgw.Reference
+	if ref != nil {
+		st, err := ref.ToState()
+		if err != nil {
+			return nil, err
+		}
 
-	solvedRef, err := s.Solve(ctx, st, pctx.Platform.Get())
-	if err != nil {
-		return nil, err
+		solvedRef, err = s.Solve(ctx, st, pctx.Platform.Get())
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		solvedRef = ref
 	}
 
 	// Image metadata
diff --git a/plancontext/fs.go b/plancontext/fs.go
index a0b712fd..c4adb419 100644
--- a/plancontext/fs.go
+++ b/plancontext/fs.go
@@ -42,8 +42,14 @@ func (fs *FS) State() (llb.State, error) {
 
 func (fs *FS) MarshalCUE() *compiler.Value {
 	v := compiler.NewValue()
-	if err := v.FillPath(fsIDPath, fs.id); err != nil {
-		panic(err)
+	if fs.result == nil {
+		if err := v.FillPath(fsIDPath, nil); err != nil {
+			panic(err)
+		}
+	} else {
+		if err := v.FillPath(fsIDPath, fs.id); err != nil {
+			panic(err)
+		}
 	}
 	return v
 }
diff --git a/tests/tasks.bats b/tests/tasks.bats
index c93a408e..79b98601 100644
--- a/tests/tasks.bats
+++ b/tests/tasks.bats
@@ -92,6 +92,8 @@ setup() {
 @test "task: #Scratch" {
     cd "$TESTDIR"/tasks/scratch
     "$DAGGER" --europa up ./scratch.cue -l debug
+    "$DAGGER" --europa up ./scratch_build_scratch.cue -l debug
+    "$DAGGER" --europa up ./scratch_writefile.cue -l debug
 }
 
 @test "task: #Subdir" {
diff --git a/tests/tasks/scratch/scratch_build_scratch.cue b/tests/tasks/scratch/scratch_build_scratch.cue
new file mode 100644
index 00000000..ec89f6aa
--- /dev/null
+++ b/tests/tasks/scratch/scratch_build_scratch.cue
@@ -0,0 +1,25 @@
+package main
+
+import (
+	"alpha.dagger.io/europa/dagger/engine"
+)
+
+engine.#Plan & {
+	actions: {
+		write: engine.#WriteFile & {
+			input:       engine.#Scratch
+			path:        "/.dockerignore"
+			contents:    "Dockerfile"
+			permissions: 700
+		}
+
+		build: engine.#Build & {
+			source: write.output
+			dockerfile: contents: """
+				FROM scratch
+				"""
+			// Assert that output is engine.#Scratch
+			output: engine.#Scratch
+		}
+	}
+}
diff --git a/tests/tasks/scratch/scratch_writefile.cue b/tests/tasks/scratch/scratch_writefile.cue
new file mode 100644
index 00000000..6ac4c12f
--- /dev/null
+++ b/tests/tasks/scratch/scratch_writefile.cue
@@ -0,0 +1,23 @@
+package main
+
+import (
+	"alpha.dagger.io/europa/dagger/engine"
+)
+
+engine.#Plan & {
+	actions: {
+		write: engine.#WriteFile & {
+			input:       engine.#Scratch
+			path:        "/testing"
+			contents:    "1,2,3"
+			permissions: 700
+		}
+		readfile: engine.#ReadFile & {
+			input: write.output
+			path:  "/testing"
+		} & {
+			// assert result
+			contents: "1,2,3"
+		}
+	}
+}