From 7190f991e73a7f061c78ac15efb26ea62284059d Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 22 Feb 2024 14:17:46 -0500
Subject: [PATCH] fix some stuff

---
 packages/svelte/src/internal/client/constants.js       |  1 +
 packages/svelte/src/internal/client/dom/blocks/each.js |  4 ++--
 packages/svelte/src/internal/client/dom/blocks/if.js   |  3 ++-
 .../src/internal/client/reactivity/computations.js     |  3 +++
 packages/svelte/src/internal/client/runtime.js         | 10 ++++++++--
 5 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/packages/svelte/src/internal/client/constants.js b/packages/svelte/src/internal/client/constants.js
index d53d438ce6..4344a4d51e 100644
--- a/packages/svelte/src/internal/client/constants.js
+++ b/packages/svelte/src/internal/client/constants.js
@@ -11,6 +11,7 @@ export const MAYBE_DIRTY = 1 << 10;
 export const INERT = 1 << 11;
 export const DESTROYED = 1 << 12;
 export const ROOT_EFFECT = 1 << 13;
+export const BRANCH_EFFECT = 1 << 14;
 
 export const ROOT_BLOCK = 0;
 export const IF_BLOCK = 1;
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index d822b53fac..2f52f0b889 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -33,7 +33,7 @@ import {
 import { source, mutable_source } from '../../reactivity/sources.js';
 import { trigger_transitions } from '../../transitions.js';
 import { is_array } from '../../utils.js';
-import { EACH_BLOCK, EACH_ITEM_BLOCK } from '../../constants.js';
+import { BRANCH_EFFECT, EACH_BLOCK, EACH_ITEM_BLOCK } from '../../constants.js';
 import { unstate } from '../../proxy.js';
 
 const NEW_BLOCK = -1;
@@ -462,7 +462,7 @@ export function each_indexed(anchor_node, collection, flags, render_fn, fallback
 		}
 
 		length = nl;
-	});
+	}).f |= BRANCH_EFFECT; // TODO create a primitive for this
 }
 
 /**
diff --git a/packages/svelte/src/internal/client/dom/blocks/if.js b/packages/svelte/src/internal/client/dom/blocks/if.js
index 91251f4d78..771b225da0 100644
--- a/packages/svelte/src/internal/client/dom/blocks/if.js
+++ b/packages/svelte/src/internal/client/dom/blocks/if.js
@@ -7,6 +7,7 @@ import {
 import { remove } from '../../reconciler.js';
 import { pause_effect, render_effect, resume_effect } from '../../reactivity/computations.js';
 import { current_effect } from '../../runtime.js';
+import { BRANCH_EFFECT, RENDER_EFFECT } from '../../constants.js';
 
 /**
  * @param {Comment} anchor_node
@@ -76,5 +77,5 @@ export function if_block(anchor_node, condition_fn, consequent_fn, alternate_fn)
 				});
 			}
 		}
-	});
+	}).f |= BRANCH_EFFECT; // TODO create a primitive for this
 }
diff --git a/packages/svelte/src/internal/client/reactivity/computations.js b/packages/svelte/src/internal/client/reactivity/computations.js
index 47a2d11024..66cdb66ad4 100644
--- a/packages/svelte/src/internal/client/reactivity/computations.js
+++ b/packages/svelte/src/internal/client/reactivity/computations.js
@@ -314,9 +314,12 @@ function pause_children(effect, transitions) {
 export function destroy_effect(effect) {
 	// TODO call cleanup functions (but not sure when exactly?)
 
+	// TODO detach from parent effect
+
 	// TODO distinguish between 'block effects' (?) which own their own DOM
 	// and other render effects
 	if (effect.dom) {
+		// TODO skip already-detached DOM
 		remove(effect.dom);
 	}
 
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index caac577b91..9981cee10b 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -27,7 +27,8 @@ import {
 	INERT,
 	MANAGED,
 	SOURCE,
-	STATE_SYMBOL
+	STATE_SYMBOL,
+	BRANCH_EFFECT
 } from './constants.js';
 import { flush_tasks } from './dom/task.js';
 
@@ -404,7 +405,12 @@ export function execute_effect(signal) {
 	current_effect = signal;
 
 	try {
-		destroy_references(signal);
+		if ((signal.f & BRANCH_EFFECT) === 0) {
+			// branch effects (i.e. {#if ...} blocks) need to keep their references
+			// TODO their children should detach themselves from signal.r when destroyed
+			destroy_references(signal);
+		}
+
 		if (teardown !== null) {
 			teardown();
 		}