Resolve constant parent templates once instead of on every lookup - #4924
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| ->raw(')') | ||
| ; | ||
| // a constant parent never depends on the context, so resolve it once | ||
| $compiler->raw('$this->parent ??= '); |
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This property should be defined in the template class?
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This PR was merged into the 3.x branch. Discussion ---------- Resolve block chains against the render context While working on the Symfony PR for #4917, I realize that the performance was worse with the Twig's way. #4924 fixes part of the performance "regression". This one closes the gap. `BlockChain` currently freezes each template's lineage by cloning it, so the block map and `parent()` both resolve `{% extends %}` against the constructor context. This PR changes that to resolve the chain against the render context instead. `hasBlock()` and `getBlockNames()` take a context, like `TemplateWrapper` already does, and the third constructor argument becomes a default the render context can override. A lineage whose templates all have a fixed parent (none, or constant) is resolved once and cached, so the common case costs nothing; a dynamic `{% extends %}` re-resolves per call (not use by Symfony anyway). This fixes also an inconsistency: a chained template with a dynamic parent now behaves exactly as it does when rendered directly. It also removes all changes in the "core" logic of Template. ``` construct render 1 chain + 40 renders Symfony's engine today 13.44us 0.78us 50.3us #4917 ~70us 0.96us ~117us this PR 0.61us 0.84us 53.0us ``` Commits ------- 897717d Resolve block chains against the render context instead of freezing lineages
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Currently,
Template::$parentis only memoized by the compileddoDisplay(). Anything that reaches a template throughgetParent()without rendering it (TemplateWrapper::hasBlock(),getBlockNames(),renderBlock(),yieldParentBlock(),MacroNamespace::getParent()) re-evaluatesdoGetParent()and re-runs the sandbox check on every call, even when the parent is a string literal.doGetParent()now does$this->parent ??= $this->load("name", $line)for a constant parent, which is whatdoDisplay()already does one line later. Dynamic parents are untouched and still resolve per context.This also fixes a bug:
getParent()loaded a constant parent with line-1, so a missing parent reported throughhasBlock()/getBlockNames()lost its line number, whilerender()reported the{% extends %}line. All three now agree.