From 6886d3260f7bd36db47299287bfa99e9ff317b49 Mon Sep 17 00:00:00 2001
From: Richard Harris <richard.a.harris@gmail.com>
Date: Tue, 25 Jun 2019 07:43:00 -0400
Subject: [PATCH 1/5] remove components without props from each block - fixes
 #3035

---
 .../compile/render_dom/wrappers/EachBlock.ts        |  2 +-
 .../each-block-component-no-props/Child.svelte      |  1 +
 .../each-block-component-no-props/_config.js        | 10 ++++++++++
 .../each-block-component-no-props/main.svelte       | 13 +++++++++++++
 4 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 test/runtime/samples/each-block-component-no-props/Child.svelte
 create mode 100644 test/runtime/samples/each-block-component-no-props/_config.js
 create mode 100644 test/runtime/samples/each-block-component-no-props/main.svelte

diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index 9e4f0689fa..b57ce46b29 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -465,7 +465,7 @@ export default class EachBlockWrapper extends Wrapper {
 				`);
 				remove_old_blocks = deindent`
 					@group_outros();
-					for (; #i < ${view_length}; #i += 1) ${out}(#i);
+					for (#i = ${this.vars.each_block_value}.${length}; #i < ${view_length}; #i += 1) ${out}(#i);
 					@check_outros();
 				`;
 			} else {
diff --git a/test/runtime/samples/each-block-component-no-props/Child.svelte b/test/runtime/samples/each-block-component-no-props/Child.svelte
new file mode 100644
index 0000000000..86ef4f3319
--- /dev/null
+++ b/test/runtime/samples/each-block-component-no-props/Child.svelte
@@ -0,0 +1 @@
+<p>hello</p>
\ No newline at end of file
diff --git a/test/runtime/samples/each-block-component-no-props/_config.js b/test/runtime/samples/each-block-component-no-props/_config.js
new file mode 100644
index 0000000000..6a2bc67697
--- /dev/null
+++ b/test/runtime/samples/each-block-component-no-props/_config.js
@@ -0,0 +1,10 @@
+export default {
+	html: `
+		<p>hello</p>
+	`,
+
+	async test({ assert, component, target }) {
+		await component.remove();
+		assert.htmlEqual(target.innerHTML, ``);
+	}
+};
diff --git a/test/runtime/samples/each-block-component-no-props/main.svelte b/test/runtime/samples/each-block-component-no-props/main.svelte
new file mode 100644
index 0000000000..15139fa17b
--- /dev/null
+++ b/test/runtime/samples/each-block-component-no-props/main.svelte
@@ -0,0 +1,13 @@
+<script>
+	import Child from './Child.svelte';
+
+	let items = [1];
+
+	export function remove() {
+		items = [];
+	}
+</script>
+
+{#each items as item}
+	<Child/>
+{/each}

From 525e4c885311d2a1769c7cb0cd127586eca1c7ad Mon Sep 17 00:00:00 2001
From: Richard Harris <richard.a.harris@gmail.com>
Date: Tue, 25 Jun 2019 08:05:10 -0400
Subject: [PATCH 2/5] actually this test should fail

---
 .../samples/each-block-component-no-props/_config.js        | 6 ++++++
 .../samples/each-block-component-no-props/main.svelte       | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/test/runtime/samples/each-block-component-no-props/_config.js b/test/runtime/samples/each-block-component-no-props/_config.js
index 6a2bc67697..e8344496ca 100644
--- a/test/runtime/samples/each-block-component-no-props/_config.js
+++ b/test/runtime/samples/each-block-component-no-props/_config.js
@@ -6,5 +6,11 @@ export default {
 	async test({ assert, component, target }) {
 		await component.remove();
 		assert.htmlEqual(target.innerHTML, ``);
+
+		await component.add();
+		assert.htmlEqual(target.innerHTML, `<p>hello</p>`);
+
+		await component.remove();
+		assert.htmlEqual(target.innerHTML, ``);
 	}
 };
diff --git a/test/runtime/samples/each-block-component-no-props/main.svelte b/test/runtime/samples/each-block-component-no-props/main.svelte
index 15139fa17b..01299fe314 100644
--- a/test/runtime/samples/each-block-component-no-props/main.svelte
+++ b/test/runtime/samples/each-block-component-no-props/main.svelte
@@ -3,6 +3,10 @@
 
 	let items = [1];
 
+	export function add() {
+		items = [1];
+	}
+
 	export function remove() {
 		items = [];
 	}

From 6f9230a915d8b997ed1ab7e164ecfd467f20ee9d Mon Sep 17 00:00:00 2001
From: Richard Harris <richard.a.harris@gmail.com>
Date: Tue, 25 Jun 2019 08:43:09 -0400
Subject: [PATCH 3/5] fix #3035 for real

---
 .../compile/render_dom/wrappers/EachBlock.ts   | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index b57ce46b29..6f592d3869 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -445,13 +445,18 @@ export default class EachBlockWrapper extends Wrapper {
 					}
 				`
 				: deindent`
-					${iterations}[#i] = ${create_each_block}(child_ctx);
-					${iterations}[#i].c();
-					${has_transitions && `@transition_in(${this.vars.iterations}[#i], 1);`}
-					${iterations}[#i].m(${update_mount_node}, ${anchor});
+					if (${iterations}[#i]) {
+						${has_transitions && `@transition_in(${this.vars.iterations}[#i], 1);`}
+					} else {
+						${iterations}[#i] = ${create_each_block}(child_ctx);
+						${iterations}[#i].c();
+						${has_transitions && `@transition_in(${this.vars.iterations}[#i], 1);`}
+						${iterations}[#i].m(${update_mount_node}, ${anchor});
+					}
+
 				`;
 
-			const start = this.block.has_update_method ? '0' : `${view_length}`;
+			const start = this.block.has_update_method ? '0' : `old_length`;
 
 			let remove_old_blocks;
 
@@ -470,7 +475,7 @@ export default class EachBlockWrapper extends Wrapper {
 				`;
 			} else {
 				remove_old_blocks = deindent`
-					for (${this.block.has_update_method ? `` : `#i = ${this.vars.each_block_value}.${length}`}; #i < ${view_length}; #i += 1) {
+					for (${this.block.has_update_method ? `` : `#i = ${this.vars.each_block_value}.${length}`}; #i < ${this.block.has_update_method ? view_length : 'old_length'}; #i += 1) {
 						${iterations}[#i].d(1);
 					}
 					${!fixed_length && `${view_length} = ${this.vars.each_block_value}.${length};`}
@@ -478,6 +483,7 @@ export default class EachBlockWrapper extends Wrapper {
 			}
 
 			const update = deindent`
+				${!this.block.has_update_method && `const old_length = ${this.vars.each_block_value}.length;`}
 				${this.vars.each_block_value} = ${snippet};
 
 				for (var #i = ${start}; #i < ${this.vars.each_block_value}.${length}; #i += 1) {

From 5a732658cecb4a021c4cfaa6a32f58e20cf6f85d Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Tue, 25 Jun 2019 10:41:42 -0400
Subject: [PATCH 4/5] prevent empty if block

---
 .../compile/render_dom/wrappers/EachBlock.ts  | 29 ++++++++++++-------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index 6f592d3869..c2f6c50249 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -444,17 +444,24 @@ export default class EachBlockWrapper extends Wrapper {
 						${iterations}[#i].m(${update_mount_node}, ${anchor});
 					}
 				`
-				: deindent`
-					if (${iterations}[#i]) {
-						${has_transitions && `@transition_in(${this.vars.iterations}[#i], 1);`}
-					} else {
-						${iterations}[#i] = ${create_each_block}(child_ctx);
-						${iterations}[#i].c();
-						${has_transitions && `@transition_in(${this.vars.iterations}[#i], 1);`}
-						${iterations}[#i].m(${update_mount_node}, ${anchor});
-					}
-
-				`;
+				: has_transitions
+					? deindent`
+						if (${iterations}[#i]) {
+							@transition_in(${this.vars.iterations}[#i], 1);
+						} else {
+							${iterations}[#i] = ${create_each_block}(child_ctx);
+							${iterations}[#i].c();
+							@transition_in(${this.vars.iterations}[#i], 1);
+							${iterations}[#i].m(${update_mount_node}, ${anchor});
+						}
+					`
+					: deindent`
+						if (!${iterations}[#i]) {
+							${iterations}[#i] = ${create_each_block}(child_ctx);
+							${iterations}[#i].c();
+							${iterations}[#i].m(${update_mount_node}, ${anchor});
+						}
+					`;
 
 			const start = this.block.has_update_method ? '0' : `old_length`;
 

From a93f089765bcc89aba482c1e4fba07e1d77b896c Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Tue, 25 Jun 2019 10:49:03 -0400
Subject: [PATCH 5/5] doh

---
 src/compiler/compile/render_dom/wrappers/EachBlock.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index c2f6c50249..06d8d5593f 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -463,7 +463,7 @@ export default class EachBlockWrapper extends Wrapper {
 						}
 					`;
 
-			const start = this.block.has_update_method ? '0' : `old_length`;
+			const start = this.block.has_update_method ? '0' : `#old_length`;
 
 			let remove_old_blocks;
 
@@ -482,7 +482,7 @@ export default class EachBlockWrapper extends Wrapper {
 				`;
 			} else {
 				remove_old_blocks = deindent`
-					for (${this.block.has_update_method ? `` : `#i = ${this.vars.each_block_value}.${length}`}; #i < ${this.block.has_update_method ? view_length : 'old_length'}; #i += 1) {
+					for (${this.block.has_update_method ? `` : `#i = ${this.vars.each_block_value}.${length}`}; #i < ${this.block.has_update_method ? view_length : '#old_length'}; #i += 1) {
 						${iterations}[#i].d(1);
 					}
 					${!fixed_length && `${view_length} = ${this.vars.each_block_value}.${length};`}
@@ -490,7 +490,7 @@ export default class EachBlockWrapper extends Wrapper {
 			}
 
 			const update = deindent`
-				${!this.block.has_update_method && `const old_length = ${this.vars.each_block_value}.length;`}
+				${!this.block.has_update_method && `const #old_length = ${this.vars.each_block_value}.length;`}
 				${this.vars.each_block_value} = ${snippet};
 
 				for (var #i = ${start}; #i < ${this.vars.each_block_value}.${length}; #i += 1) {