Add a note that checking for flash messages defeats HTTP cacheability #21381
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carsonbot
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xabbuh
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Oct 15, 2025
xabbuh
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Oct 15, 2025
Co-authored-by: Christian Flothmann <[email protected]>
Co-authored-by: Christian Flothmann <[email protected]>
xabbuh
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Oct 15, 2025
94noni
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| Accessing flash messages means that the session must be started, which | ||
| in turn will cause Symfony to mark the responses as ``private``. In general, | ||
| since flashes shall displayed only once, pages that might display flashes | ||
| cannot reasonably be cached in HTTP caches. |
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as its a tip block you are adding, what about also write that one can load such statefull flash session message async, via for ex an ux live component completely decoupled from the main response that could be stateless
94noni
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This may be surprising when HTTP cache performance is a concern, so let's give this early heads-up notice.