From 0f96270840f3b3ab20f566b18a421acdc0eb8d35 Mon Sep 17 00:00:00 2001
From: Michel Weststrate <mweststrate@fb.com>
Date: Tue, 11 Jan 2022 11:54:19 +0000
Subject: [PATCH] fix: No patches being generated for root primitive
 replacements. Fixes #888

---
 __tests__/patch.js     | 49 ++++++++++++++++++++++++++++++++++++++++++
 src/core/finalize.ts   |  2 +-
 src/core/immerClass.ts |  8 ++++++-
 src/plugins/patches.ts |  4 ++--
 src/utils/plugins.ts   |  2 +-
 5 files changed, 60 insertions(+), 5 deletions(-)

diff --git a/__tests__/patch.js b/__tests__/patch.js
index 345d75d0..1aa9a533 100644
--- a/__tests__/patch.js
+++ b/__tests__/patch.js
@@ -1340,3 +1340,52 @@ test("#876 Ensure empty patch set for atomic set+delete on Map", () => {
 		expect(patches).toEqual([])
 	}
 })
+
+test("#888 patch to a primitive produces the primitive", () => {
+	{
+		const [res, patches] = produceWithPatches({abc: 123}, draft => nothing)
+		expect(res).toEqual(undefined)
+		expect(patches).toEqual([{op: "replace", path: [], value: undefined}])
+	}
+	{
+		debugger
+		const [res, patches] = produceWithPatches(null, draft => nothing)
+		expect(res).toEqual(undefined)
+		expect(patches).toEqual([{op: "replace", path: [], value: undefined}])
+	}
+	{
+		const [res, patches] = produceWithPatches(0, draft => nothing)
+		expect(res).toEqual(undefined)
+		expect(patches).toEqual([{op: "replace", path: [], value: undefined}])
+	}
+	{
+		const [res, patches] = produceWithPatches("foobar", draft => nothing)
+		expect(res).toEqual(undefined)
+		expect(patches).toEqual([{op: "replace", path: [], value: undefined}])
+	}
+	{
+		const [res, patches] = produceWithPatches([], draft => nothing)
+		expect(res).toEqual(undefined)
+		expect(patches).toEqual([{op: "replace", path: [], value: undefined}])
+	}
+	{
+		const [res, patches] = produceWithPatches(false, draft => nothing)
+		expect(res).toEqual(undefined)
+		expect(patches).toEqual([{op: "replace", path: [], value: undefined}])
+	}
+	{
+		const [res, patches] = produceWithPatches(
+			"foobar",
+			draft => "something else"
+		)
+		expect(res).toEqual("something else")
+		expect(patches).toEqual([
+			{op: "replace", path: [], value: "something else"}
+		])
+	}
+	{
+		const [res, patches] = produceWithPatches(false, draft => true)
+		expect(res).toEqual(true)
+		expect(patches).toEqual([{op: "replace", path: [], value: true}])
+	}
+})
diff --git a/src/core/finalize.ts b/src/core/finalize.ts
index 7c3c404a..ad95b124 100644
--- a/src/core/finalize.ts
+++ b/src/core/finalize.ts
@@ -37,7 +37,7 @@ export function processResult(result: any, scope: ImmerScope) {
 		}
 		if (scope.patches_) {
 			getPlugin("Patches").generateReplacementPatches_(
-				baseDraft[DRAFT_STATE],
+				baseDraft[DRAFT_STATE].base_,
 				result,
 				scope.patches_,
 				scope.inversePatches_!
diff --git a/src/core/immerClass.ts b/src/core/immerClass.ts
index c8da4023..2a6da927 100644
--- a/src/core/immerClass.ts
+++ b/src/core/immerClass.ts
@@ -114,9 +114,15 @@ export class Immer implements ProducersFns {
 			return processResult(result, scope)
 		} else if (!base || typeof base !== "object") {
 			result = recipe(base)
-			if (result === NOTHING) return undefined
 			if (result === undefined) result = base
+			if (result === NOTHING) result = undefined
 			if (this.autoFreeze_) freeze(result, true)
+			if (patchListener) {
+				const p: Patch[] = []
+				const ip: Patch[] = []
+				getPlugin("Patches").generateReplacementPatches_(base, result, p, ip)
+				patchListener(p, ip)
+			}
 			return result
 		} else die(21, base)
 	}
diff --git a/src/plugins/patches.ts b/src/plugins/patches.ts
index bd3e3d92..08fe9141 100644
--- a/src/plugins/patches.ts
+++ b/src/plugins/patches.ts
@@ -183,7 +183,7 @@ export function enablePatches() {
 	}
 
 	function generateReplacementPatches_(
-		rootState: ImmerState,
+		baseValue: any,
 		replacement: any,
 		patches: Patch[],
 		inversePatches: Patch[]
@@ -196,7 +196,7 @@ export function enablePatches() {
 		inversePatches.push({
 			op: REPLACE,
 			path: [],
-			value: rootState.base_
+			value: baseValue
 		})
 	}
 
diff --git a/src/utils/plugins.ts b/src/utils/plugins.ts
index 6c959acc..089cf015 100644
--- a/src/utils/plugins.ts
+++ b/src/utils/plugins.ts
@@ -21,7 +21,7 @@ const plugins: {
 			inversePatches: Patch[]
 		): void
 		generateReplacementPatches_(
-			rootState: ImmerState,
+			base: any,
 			replacement: any,
 			patches: Patch[],
 			inversePatches: Patch[]