From fdacf5264e8b72149dbc2e9c1fa802b4c5ed6b5f Mon Sep 17 00:00:00 2001
From: Christopher Hiller <boneskull@boneskull.com>
Date: Fri, 20 Dec 2024 15:37:06 -0800
Subject: [PATCH] fix(compartment-mapper)!: invert keys/values of renames in
 captureFromMap

BREAKING CHANGE: The `CaptureResult.compartmentRenames` record returned by `captureFromMap()` is now _new to old_; previously it was _old to new_.

This more accurately solves for the use case of `compartmentRenames`, because the main use case demands the record is inverted. We can plainly see this issue in `captureFromMap`'s test suite (which this change simplifies).

In a future change, [branded types](https://www.learningtypescript.com/articles/branded-types) could describe the distinction between key and value, which are currently both `string`.

> [!IMPORTANT]
>
> The only consumer of `captureFromMap` that I'm aware of is _me_, and _me_ doesn't need this to be SemVer major.
---
 packages/compartment-mapper/src/capture-lite.js     |  7 ++++++-
 packages/compartment-mapper/src/types/external.ts   | 11 +++++++++++
 .../compartment-mapper/test/capture-lite.test.js    | 13 +++----------
 3 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/packages/compartment-mapper/src/capture-lite.js b/packages/compartment-mapper/src/capture-lite.js
index 20da5b58b0..30a8d8c068 100644
--- a/packages/compartment-mapper/src/capture-lite.js
+++ b/packages/compartment-mapper/src/capture-lite.js
@@ -250,7 +250,12 @@ const captureCompartmentMap = (compartmentMap, sources) => {
   return {
     captureCompartmentMap,
     captureSources,
-    compartmentRenames,
+    compartmentRenames: fromEntries(
+      entries(compartmentRenames).map(([oldName, newName]) => [
+        newName,
+        oldName,
+      ]),
+    ),
   };
 };
 
diff --git a/packages/compartment-mapper/src/types/external.ts b/packages/compartment-mapper/src/types/external.ts
index c4568d11e3..61b7efd3d9 100644
--- a/packages/compartment-mapper/src/types/external.ts
+++ b/packages/compartment-mapper/src/types/external.ts
@@ -233,8 +233,19 @@ type LinkingOptions = ParserForLanguageOption &
  * The result of `captureFromMap`.
  */
 export type CaptureResult = {
+  /**
+   * Normalized `CompartmentMapDescriptor`
+   */
   captureCompartmentMap: CompartmentMapDescriptor;
+  /**
+   * Sources found in the `CompartmentMapDescriptor`
+   */
   captureSources: Sources;
+
+  /**
+   * A record of renamed {@link CompartmentDescriptor CompartmentDescriptors}
+   * from _new_ to _original_ name
+   */
   compartmentRenames: Record<string, string>;
 };
 
diff --git a/packages/compartment-mapper/test/capture-lite.test.js b/packages/compartment-mapper/test/capture-lite.test.js
index 75d4180e83..90a8543c0f 100644
--- a/packages/compartment-mapper/test/capture-lite.test.js
+++ b/packages/compartment-mapper/test/capture-lite.test.js
@@ -8,7 +8,7 @@ import { mapNodeModules } from '../src/node-modules.js';
 import { makeReadPowers } from '../src/node-powers.js';
 import { defaultParserForLanguage } from '../src/import-parsers.js';
 
-const { keys, entries, fromEntries } = Object;
+const { keys } = Object;
 
 test('captureFromMap() should resolve with a CaptureResult', async t => {
   t.plan(5);
@@ -26,10 +26,6 @@ test('captureFromMap() should resolve with a CaptureResult', async t => {
       parserForLanguage: defaultParserForLanguage,
     });
 
-  const renames = fromEntries(
-    entries(compartmentRenames).map(([filepath, id]) => [id, filepath]),
-  );
-
   t.deepEqual(
     keys(captureSources).sort(),
     ['bundle', 'bundle-dep-v0.0.0'],
@@ -37,7 +33,7 @@ test('captureFromMap() should resolve with a CaptureResult', async t => {
   );
 
   t.deepEqual(
-    keys(renames).sort(),
+    keys(compartmentRenames).sort(),
     ['bundle', 'bundle-dep-v0.0.0'],
     'compartmentRenames must contain same compartment names as in captureCompartmentMap',
   );
@@ -82,14 +78,11 @@ test('captureFromMap() should round-trip sources based on parsers', async t => {
     },
   );
 
-  const renames = fromEntries(
-    entries(compartmentRenames).map(([filepath, id]) => [id, filepath]),
-  );
   const decoder = new TextDecoder();
   // the actual source depends on the value of `parserForLanguage` above
   const actual = decoder.decode(captureSources.bundle['./icando.cjs'].bytes);
   const expected = await fs.promises.readFile(
-    path.join(url.fileURLToPath(renames.bundle), 'icando.cjs'),
+    path.join(url.fileURLToPath(compartmentRenames.bundle), 'icando.cjs'),
     'utf-8',
   );
   t.is(actual, expected, 'Source code should not be pre-compiled');