Nested transitions: dynamic components in EachBlock prevent parent from being removed

[jacwright]

When nested transitions is turned on and you have dynamic components in an EachBlock the parent block is never removed. See: https://svelte.technology/repl?version=2.7.0&gist=41168eab5f3ed4c781ab1453eb6900f4

[stalkerg]

Sorry, I was wrong, I have totally same case.

[stalkerg]

I found why it happens - if outro has already passed:

o: function outro(outrocallback) {
    if (outroing) return;
    outroing = true;
    introing = false;
    if (!div_transition) div_transition = wrapTransition(component, div, fade, {}, false);
    div_transition.run(0, () => {
        outrocallback();
        div_transition = null;
    });
},

and upper:

o: function outro(outrocallback) {
    if (outroing) return;
    outroing = true;

    if (if_block_7) if_block_7.o(outrocallback);
    else outrocallback();
},

in my case, outroing have already true, because Modal window hide by itself and after emit the event to they have already hide and parent component can remove it. Looks like if "outroing" have already true we can just remove this block.

[stalkerg]

Ohhh I found extra problems even I have no any "transition" inside.

[stalkerg]

Fast hack way obviously didn't help me:

diff --git a/src/compile/dom/Block.ts b/src/compile/dom/Block.ts
index 6b753ed1..1313b896 100644
--- a/src/compile/dom/Block.ts
+++ b/src/compile/dom/Block.ts
@@ -302,13 +302,14 @@ export default class Block {
                        if (hasOutros) {
                                properties.addBlock(deindent`
                                        ${dev ? 'o: function outro' : 'o'}(#outrocallback) {
-                                               if (${outroing}) return;
+                                               if (${outroing}) return false;
                                                ${outroing} = true;
                                                ${hasIntros && `${introing} = false;`}

                                                ${this.outros > 1 && `#outrocallback = @callAfter(#outrocallback, ${this.outros});`}

                                                ${this.builders.outro}
+                                               return true;
                                        },
                                `);
                        } else {
diff --git a/src/compile/nodes/IfBlock.ts b/src/compile/nodes/IfBlock.ts
index ee5cb41a..b00a7cc6 100644
--- a/src/compile/nodes/IfBlock.ts
+++ b/src/compile/nodes/IfBlock.ts
@@ -148,8 +148,7 @@ export default class IfBlock extends Node {

                        if (hasOutros && this.compiler.options.nestedTransitions) {
                                block.builders.outro.addBlock(deindent`
-                                       if (${name}) ${name}.o(#outrocallback);
-                                       else #outrocallback();
+                                       if (!(${name} && ${name}.o(#outrocallback))) #outrocallback();
                                `);
                        }
                }

[Rich-Harris]

Came here while looking into #1660. It seems that this specific issue was fixed a while back, so I'll close this. Thanks