From e75ac22ba609062a88f64382ed4cff616ad8e309 Mon Sep 17 00:00:00 2001
From: "Jonathan A. Sternberg" <jonathan.sternberg@docker.com>
Date: Mon, 24 Feb 2025 10:09:02 -0600
Subject: [PATCH] buildflags: skip empty cache entries when parsing

Broken in 11c84973ef104e48eb88a41b5b23d6a559efe868. The section to skip
an empty input was accidentally removed when some code was refactored to
fix a separate issue.

This skips empty cache entries which allows disabling the `cache-from` and
`cache-to` entries from the command line overrides.

Signed-off-by: Jonathan A. Sternberg <jonathan.sternberg@docker.com>
---
 tests/bake.go            | 43 ++++++++++++++++++++++++++++++++++++++++
 util/buildflags/cache.go |  4 ++++
 2 files changed, 47 insertions(+)

diff --git a/tests/bake.go b/tests/bake.go
index f106f21b..4935e115 100644
--- a/tests/bake.go
+++ b/tests/bake.go
@@ -38,6 +38,7 @@ func bakeCmd(sb integration.Sandbox, opts ...cmdOpt) (string, error) {
 var bakeTests = []func(t *testing.T, sb integration.Sandbox){
 	testBakePrint,
 	testBakePrintSensitive,
+	testBakePrintOverrideEmpty,
 	testBakeLocal,
 	testBakeLocalMulti,
 	testBakeRemote,
@@ -286,6 +287,47 @@ RUN echo "Hello ${HELLO}"
 	}
 }
 
+func testBakePrintOverrideEmpty(t *testing.T, sb integration.Sandbox) {
+	dockerfile := []byte(`
+FROM scratch
+COPY foo /foo
+	`)
+	bakefile := []byte(`
+target "default" {
+	cache-to = ["type=gha,mode=min,scope=integration-tests"]
+}
+`)
+	dir := tmpdir(
+		t,
+		fstest.CreateFile("docker-bake.hcl", bakefile, 0600),
+		fstest.CreateFile("Dockerfile", dockerfile, 0600),
+		fstest.CreateFile("foo", []byte("foo"), 0600),
+	)
+
+	cmd := buildxCmd(sb, withDir(dir), withArgs("bake", "--print", "--set", "*.cache-to="))
+	stdout := bytes.Buffer{}
+	stderr := bytes.Buffer{}
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	require.NoError(t, cmd.Run(), stdout.String(), stderr.String())
+
+	require.JSONEq(t, `{
+	"group": {
+		"default": {
+			"targets": [
+				"default"
+			]
+		}
+	},
+	"target": {
+		"default": {
+			"context": ".",
+			"dockerfile": "Dockerfile"
+		}
+	}
+}`, stdout.String())
+}
+
 func testBakeLocal(t *testing.T, sb integration.Sandbox) {
 	dockerfile := []byte(`
 FROM scratch
@@ -871,6 +913,7 @@ target "default" {
 		})
 	}
 }
+
 func testBakeSetNonExistingOutsideNoParallel(t *testing.T, sb integration.Sandbox) {
 	for _, ent := range []bool{true, false} {
 		t.Run(fmt.Sprintf("ent=%v", ent), func(t *testing.T) {
diff --git a/util/buildflags/cache.go b/util/buildflags/cache.go
index e9256900..f9c99034 100644
--- a/util/buildflags/cache.go
+++ b/util/buildflags/cache.go
@@ -175,6 +175,10 @@ func ParseCacheEntry(in []string) (CacheOptions, error) {
 
 	opts := make(CacheOptions, 0, len(in))
 	for _, in := range in {
+		if in == "" {
+			continue
+		}
+
 		if !strings.Contains(in, "=") {
 			// This is ref only format. Each field in the CSV is its own entry.
 			fields, err := csvvalue.Fields(in, nil)