Fixes #3239.

packages/versioning/src/versioning.ts

@@ -15,7 +15,6 @@ import {
  Type,
  Union,
  UnionVariant,
- compilerAssert,
  getNamespaceFullName,
 } from "@typespec/compiler";
 import {
@@ -782,6 +781,26 @@ export enum Availability {
  Removed = "Removed",
 }
 
+function getParentAddedVersion(
+ program: Program,
+ type: Type,
+ versions: Version[]
+): Version | undefined {
+ let parentMap: Map<string, Availability> | undefined = undefined;
+ if (type.kind === "ModelProperty" && type.model !== undefined) {
+ parentMap = getAvailabilityMap(program, type.model);
+ } else if (type.kind === "Operation" && type.interface !== undefined) {
+ parentMap = getAvailabilityMap(program, type.interface);
+ }
+ if (parentMap === undefined) return undefined;
+ for (const [key, value] of parentMap.entries()) {
+ if (value === Availability.Added) {
+ return versions.find((x) => x.name === key);
+ }
+ }
+ return undefined;
+}
+
 export function getAvailabilityMap(
  program: Program,
  type: Type
@@ -792,7 +811,8 @@ export function getAvailabilityMap(
  // if unversioned then everything exists
  if (allVersions === undefined) return undefined;
 
- const added = getAddedOnVersions(program, type) ?? [];
+ const parentAdded = getParentAddedVersion(program, type, allVersions);
+ let added = getAddedOnVersions(program, type) ?? [];
  const removed = getRemovedOnVersions(program, type) ?? [];
  const typeChanged = getTypeChangedFrom(program, type);
  const returnTypeChanged = getReturnTypeChangedFrom(program, type);
@@ -807,27 +827,15 @@ export function getAvailabilityMap(
  )
  return undefined;
 
- let parentMap: Map<string, Availability> | undefined = undefined;
- if (type.kind === "ModelProperty" && type.model !== undefined) {
- parentMap = getAvailabilityMap(program, type.model);
- } else if (type.kind === "Operation" && type.interface !== undefined) {
- parentMap = getAvailabilityMap(program, type.interface);
- }
-
- // implicitly, all versioned things are assumed to have been added at
- // v1 if not specified
- if (!added.length) {
- if (parentMap !== undefined) {
- parentMap.forEach((key, value) => {
- if (key === Availability.Added.valueOf()) {
- const match = allVersions.find((x) => x.name === value);
- compilerAssert(match !== undefined, "Version not found");
- added.push(match);
- }
- });
- } else {
- added.push(allVersions[0]);
- }
+ if (!added.length && !parentAdded) {
+ // no version information on the item or its parent implicitly means it has always been available
+ added.push(allVersions[0]);
+ } else if (!added.length && parentAdded) {
+ // if no version info on type but is on parent, inherit that parent's "added" version
+ added.push(parentAdded);
+ } else if (added.length && parentAdded) {
+ // if "added" info on both the type and parent, combine them
+ added = [parentAdded, ...added];
  }
 
  // something isn't available by default

packages/versioning/test/versioning.test.ts

@@ -289,14 +289,16 @@ describe("versioning: logic", () => {
  `@added(Versions.v2)
  model Test {
  a: int32;
- @removed(Versions.v3) b: int32;
+ @removed(Versions.v3)
+ @added(Versions.v4)
+ b: int32;
  }
  `
  );
 
  assertHasProperties(v2, ["a", "b"]);
  assertHasProperties(v3, ["a"]);
- assertHasProperties(v4, ["a"]);
+ assertHasProperties(v4, ["a", "b"]);
 
  assertModelProjectsTo(
  [
@@ -1402,12 +1404,15 @@ describe("versioning: logic", () => {
  `@added(Versions.v2)
  interface Test {
  allVersions(): void;
- @removed(Versions.v3) version2Only(): void;
+ @removed(Versions.v3) 
+ @added(Versions.v4)
+ foo(): void;
  }
  `
  );
- assertHasOperations(v2, ["allVersions", "version2Only"]);
+ assertHasOperations(v2, ["allVersions", "foo"]);
  assertHasOperations(v3, ["allVersions"]);
+ assertHasOperations(v4, ["allVersions", "foo"]);
  assertInterfaceProjectsTo(
  [
  [v2, "v2"],