Prevent overpatching Rails #352
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delner
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palazzem
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Feb 21, 2018
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In our current implementation, although there are guards around the Rails::Patcher module, there are no such guards around the constituent modules (e.g. in
CoreExtensions) it uses to actually patch Rails code. It's possible to call these and overpatch Rails methods, causing infinite loops and other nasty behaviors. This has actually occurred when Railties reload, as they do in our test suite.This pull request adds a helper function to
Datadog::Patchercalleddo_oncewhich is a really simple singleton-like function that prevents a function being called more than once. It's equivalent to the oldreturn @patched if @patched; patcher.patch_code; @patched = true, just a little nicer looking and abstracts away the pattern.I think this one could warrant some critical opinion, since the new function brings up questions about the direction of our patching API.