HTTP Response is sent before persistence preventing Exceptions to be displayed on redirect
When a persistence Exception (e.g. "Integrity constraint violation: 1048 Column '...' cannot be null" due to missing @ORM\Column(nullable=true) annotation) is thrown after an action that does a redirect (e.g. a typical createObjectAction), the Exception isn't displayed (well it is but only for the matter of milliseconds the browser needs to do the redirect) because the redirect headers are sent before.
Therefore the Exception may go by unnoticed until the persistence is checked and Exception log inspected, which is undesired.
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