From 7539a62ff5f20c6e80e03eb49d1d0b2e2b425b67 Mon Sep 17 00:00:00 2001
From: Elizabeth Craig <elcraig@microsoft.com>
Date: Mon, 9 Sep 2024 22:04:05 -0700
Subject: [PATCH] start using deep readonly

---
 src/bump/setDependentVersions.ts      |  2 +-
 src/changefile/unlinkChangeFiles.ts   | 11 +++++------
 src/changelog/getPackageChangelogs.ts |  3 ++-
 src/changelog/writeChangelog.ts       |  3 ++-
 src/types/BumpInfo.ts                 |  7 ++++---
 src/types/DeepReadonly.ts             | 17 +++++++++++++++++
 6 files changed, 31 insertions(+), 12 deletions(-)
 create mode 100644 src/types/DeepReadonly.ts

diff --git a/src/bump/setDependentVersions.ts b/src/bump/setDependentVersions.ts
index 9c51f75c4..6104c41d8 100644
--- a/src/bump/setDependentVersions.ts
+++ b/src/bump/setDependentVersions.ts
@@ -10,7 +10,7 @@ import { bumpMinSemverRange } from './bumpMinSemverRange';
  */
 export function setDependentVersions(
   packageInfos: PackageInfos,
-  scopedPackages: Set<string>,
+  scopedPackages: ReadonlySet<string>,
   options: Pick<BeachballOptions, 'verbose'>
 ): BumpInfo['dependentChangedBy'] {
   const { verbose } = options;
diff --git a/src/changefile/unlinkChangeFiles.ts b/src/changefile/unlinkChangeFiles.ts
index 0d06807a6..42d22af6c 100644
--- a/src/changefile/unlinkChangeFiles.ts
+++ b/src/changefile/unlinkChangeFiles.ts
@@ -2,8 +2,9 @@ import { ChangeSet } from '../types/ChangeInfo';
 import { getChangePath } from '../paths';
 import fs from 'fs-extra';
 import path from 'path';
-import { PackageInfo } from '../types/PackageInfo';
+import { PackageInfos } from '../types/PackageInfo';
 import type { BeachballOptions } from '../types/BeachballOptions';
+import { DeepReadonly } from '../types/DeepReadonly';
 
 /**
  * Unlink only change files that are specified in the changes param
@@ -11,14 +12,12 @@ import type { BeachballOptions } from '../types/BeachballOptions';
  * @param changes existing change files to be removed
  */
 export function unlinkChangeFiles(
-  changeSet: ChangeSet,
-  packageInfos: {
-    [pkg: string]: PackageInfo;
-  },
+  changeSet: DeepReadonly<ChangeSet>,
+  packageInfos: PackageInfos,
   options: Pick<BeachballOptions, 'path' | 'changeDir'>
 ): void {
   const changePath = getChangePath(options);
-  if (!changeSet || !changeSet.length) {
+  if (!changeSet?.length) {
     return;
   }
   console.log('Removing change files:');
diff --git a/src/changelog/getPackageChangelogs.ts b/src/changelog/getPackageChangelogs.ts
index 2061c586a..920060bd9 100644
--- a/src/changelog/getPackageChangelogs.ts
+++ b/src/changelog/getPackageChangelogs.ts
@@ -7,6 +7,7 @@ import { getChangePath } from '../paths';
 import { getFileAddedHash } from 'workspace-tools';
 import { ChangeSet } from '../types/ChangeInfo';
 import type { BeachballOptions } from '../types/BeachballOptions';
+import { DeepReadonly } from '../types/DeepReadonly';
 
 /**
  * Used for `ChangelogEntry.commit` if the commit hash is not available.
@@ -18,7 +19,7 @@ const commitNotAvailable = 'not available';
  * @returns Mapping from package name to package changelog.
  */
 export function getPackageChangelogs(params: {
-  changeFileChangeInfos: ChangeSet;
+  changeFileChangeInfos: DeepReadonly<ChangeSet>;
   calculatedChangeTypes: BumpInfo['calculatedChangeTypes'];
   dependentChangedBy?: BumpInfo['dependentChangedBy'];
   packageInfos: PackageInfos;
diff --git a/src/changelog/writeChangelog.ts b/src/changelog/writeChangelog.ts
index 36dfdbb23..7d24c34b9 100644
--- a/src/changelog/writeChangelog.ts
+++ b/src/changelog/writeChangelog.ts
@@ -11,6 +11,7 @@ import { isPathIncluded } from '../monorepo/isPathIncluded';
 import { PackageChangelog, ChangelogJson } from '../types/ChangeLog';
 import { mergeChangelogs } from './mergeChangelogs';
 import { ChangeSet } from '../types/ChangeInfo';
+import { DeepReadonly } from '../types/DeepReadonly';
 
 export async function writeChangelog(
   bumpInfo: Pick<BumpInfo, 'changeFileChangeInfos' | 'calculatedChangeTypes' | 'dependentChangedBy' | 'packageInfos'>,
@@ -50,7 +51,7 @@ export async function writeChangelog(
  */
 async function writeGroupedChangelog(
   options: BeachballOptions,
-  changeFileChangeInfos: ChangeSet,
+  changeFileChangeInfos: DeepReadonly<ChangeSet>,
   calculatedChangeTypes: BumpInfo['calculatedChangeTypes'],
   packageInfos: PackageInfos
 ): Promise<string[]> {
diff --git a/src/types/BumpInfo.ts b/src/types/BumpInfo.ts
index a3880088f..40fbbb114 100644
--- a/src/types/BumpInfo.ts
+++ b/src/types/BumpInfo.ts
@@ -1,9 +1,10 @@
 import { ChangeSet, ChangeType } from './ChangeInfo';
+import { DeepReadonly } from './DeepReadonly';
 import { PackageInfos, PackageGroups } from './PackageInfo';
 
 export type BumpInfo = {
   /** Changes coming from the change files */
-  changeFileChangeInfos: ChangeSet;
+  changeFileChangeInfos: DeepReadonly<ChangeSet>;
 
   /**
    * Cached version of package info (e.g. package.json, package path).
@@ -15,7 +16,7 @@ export type BumpInfo = {
   calculatedChangeTypes: { [pkgName: string]: ChangeType };
 
   /** Package grouping */
-  packageGroups: PackageGroups;
+  packageGroups: DeepReadonly<PackageGroups>;
 
   /** Set of packages that had been modified */
   modifiedPackages: Set<string>;
@@ -27,7 +28,7 @@ export type BumpInfo = {
   dependentChangedBy: { [pkgName: string]: Set<string> };
 
   /** Set of packages that are in scope for this bump */
-  scopedPackages: Set<string>;
+  scopedPackages: ReadonlySet<string>;
 };
 
 /** Dependents cache (child points to parents): if A depends on B, then `{ B: [A] }` */
diff --git a/src/types/DeepReadonly.ts b/src/types/DeepReadonly.ts
new file mode 100644
index 000000000..9beda7f6c
--- /dev/null
+++ b/src/types/DeepReadonly.ts
@@ -0,0 +1,17 @@
+export type DeepReadonly<T> = T extends (infer R)[]
+  ? DeepReadonlyArray<R>
+  : T extends Function
+  ? T
+  : T extends Set<infer V>
+  ? ReadonlySet<DeepReadonly<V>>
+  : T extends Map<infer K, infer V>
+  ? ReadonlyMap<DeepReadonly<K>, DeepReadonly<V>>
+  : T extends object
+  ? DeepReadonlyObject<T>
+  : T;
+
+interface DeepReadonlyArray<T> extends ReadonlyArray<DeepReadonly<T>> {}
+
+type DeepReadonlyObject<T> = {
+  readonly [P in keyof T]: DeepReadonly<T[P]>;
+};