Quadlet - fix trailing whitespaces handling

Remove all trailing white spaces from all lines before the line by line
processing
Add test
Exclude the unit file used for the test from whitespace check

Signed-off-by: Ygal Blum <ygal.blum@gmail.com>

.pre-commit-config.yaml

@@ -12,7 +12,7 @@ repos:
       - id: end-of-file-fixer
         exclude: test/buildah-bud/buildah-tests.diff
       - id: trailing-whitespace
-        exclude: test/buildah-bud/buildah-tests.diff|test/e2e/quadlet/remap-keep-id2.container
+        exclude: test/buildah-bud/buildah-tests.diff|test/e2e/quadlet/remap-keep-id2.container|test/e2e/quadlet/line-continuation-whitespace.container
       - id: mixed-line-ending
       - id: check-byte-order-marker
       - id: check-executables-have-shebangs

pkg/systemd/parser/unitfile.go

@@ -378,12 +378,23 @@ func nextLine(data string, afterPos int) (string, string) {
 	return data, ""
 }
 
+func trimSpacesFromLines(data string) string {
+	lines := strings.Split(data, "\n")
+	for i, line := range lines {
+		lines[i] = strings.TrimSpace(line)
+	}
+	return strings.Join(lines, "\n")
+}
+
 // Parse an already loaded unit file (in the form of a string)
 func (f *UnitFile) Parse(data string) error {
 	p := &UnitFileParser{
 		file:   f,
 		lineNr: 1,
 	}
+
+	data = trimSpacesFromLines(data)
+
 	for len(data) > 0 {
 		origdata := data
 		nLines := 1

test/e2e/quadlet/line-continuation-whitespace.container

@@ -0,0 +1,9 @@
+## assert-podman-final-args localhost/imagename "/some/binary file" "--arg1" "arg 2"
+## assert-podman-args "--publish" "80:80"
+
+[Container]
+Image=localhost/imagename
+# Keep whitespace at the end of the following line
+Exec="/some/binary file" --arg1 \ 
+  "arg 2"
+PublishPort=80:80

test/e2e/quadlet_test.go

@@ -776,6 +776,7 @@ BOGUS=foo
 		Entry("install.container", "install.container", 0, ""),
 		Entry("ip.container", "ip.container", 0, ""),
 		Entry("label.container", "label.container", 0, ""),
+		Entry("line-continuation-whitespace.container", "line-continuation-whitespace.container", 0, ""),
 		Entry("logdriver.container", "logdriver.container", 0, ""),
 		Entry("mask.container", "mask.container", 0, ""),
 		Entry("mount.container", "mount.container", 0, ""),