fix(stackable-versioned): Handle fields added in later versions (#1031)

* fix(stackable-versioned): Handle fields added in later versions

* test(stackable-versioned): Update snapshot test

* test(stackable-versioned): Add compile pass test

* chore: Rename default function

* chore: Apply suggestion

Co-authored-by: Sebastian Bernauer <[email protected]>

* chore: Add changelog entry

---------

Co-authored-by: Sebastian Bernauer <[email protected]>

Author: Techassi

crates/stackable-versioned-macros/fixtures/inputs/default/basic_struct.rs

@@ -7,6 +7,9 @@
 )]
 // ---
 pub(crate) struct Foo {
+    #[versioned(added(since = "v1"))]
+    foo: String,
+
     #[versioned(
         changed(since = "v1beta1", from_name = "jjj", from_type = "u8"),
         changed(since = "v1", from_type = "u16"),

crates/stackable-versioned-macros/fixtures/snapshots/stackable_versioned_macros__test__default_snapshots@basic_struct.rs.snap

@@ -172,6 +172,10 @@ impl ChangesetExt for BTreeMap<Version, ItemStatus> {
                             ty,
                             ..
                         } => (ident, ty, *previously_deprecated),
+                        ItemStatus::NotPresent => {
+                            self.insert(version.inner, ItemStatus::NotPresent);
+                            continue;
+                        }
                         // TODO (@NickLarsenNZ): Explain why it is unreachable, as it can be reached during testing.
                         // To reproduce, use an invalid version, eg: #[versioned(deprecated(since = "v99"))]
                         _ => unreachable!(),

crates/stackable-versioned-macros/src/codegen/changes.rs

@@ -143,6 +143,7 @@ impl VersionedField {
         }
     }
 
+    // TODO (@Techassi): This should probably return an optional token stream.
     pub(crate) fn generate_for_from_impl(
         &self,
         version: &VersionDefinition,
@@ -155,6 +156,12 @@ impl VersionedField {
                 let change = changes.get_expect(&version.inner);
 
                 match (change, next_change) {
+                    // If both this status and the next one is NotPresent, which means
+                    // a field was introduced after a bunch of versions, we don't
+                    // need to generate any code for the From impl.
+                    (ItemStatus::NotPresent, ItemStatus::NotPresent) => {
+                        quote! {}
+                    }
                     (
                         _,
                         ItemStatus::Addition {

crates/stackable-versioned-macros/src/codegen/item/field.rs

@@ -0,0 +1,23 @@
+use stackable_versioned_macros::versioned;
+
+fn main() {
+    #[versioned(
+        version(name = "v1alpha1"),
+        version(name = "v1alpha2"),
+        version(name = "v1beta1"),
+        version(name = "v1")
+    )]
+    struct Foo {
+        username: String,
+
+        #[versioned(added(since = "v1alpha2", default = default_first_name))]
+        first_name: String,
+
+        #[versioned(added(since = "v1beta1"))]
+        last_name: String,
+    }
+}
+
+fn default_first_name() -> String {
+    "foo".into()
+}

crates/stackable-versioned-macros/tests/default/pass/added.rs

@@ -27,6 +27,7 @@ mod default {
 fn default_macros() {
     let t = trybuild::TestCases::new();
     t.compile_fail("tests/default/fail/*.rs");
+    t.pass("tests/default/pass/*.rs");
 }
 
 #[cfg(feature = "k8s")]

crates/stackable-versioned-macros/tests/trybuild.rs

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+### Fixed
+
+- Correctly handle fields added in later versions ([#1031]).
+
+[#1031]: https://github.com/stackabletech/operator-rs/pull/1031
+
 ## [0.7.1] - 2025-04-02
 
 ### Fixed