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A post function runs under with the permissions of the user that initiated the transition. The post functions only do actions that the user is permitted to do. The post function runs after the transition completes and so errors that occur during the post function only report errors via the server log. Specifically, this means that errors are effectively ignored from the user's perspective. The workflow designer needs to construct post functions with this in mind. For instance, this could include putting conditions on that transition to prevent the transition from happening if the user does not have enough permission to do all the things necessary in the post function.
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