If I have multiple filters that match the same email do they all get processed? If so, in what order are they processed? What if the first filter matched modifies the email to make it match (or no longer match) a different filter?
I have two filters, A and B, and two labels, A and B. If filter A is applicable to an email then I wanted label A to be applied to the email and for that email to skip the inbox and be archived.
I also want to do the same thing with filter B, but I don't want label B to be applied if label A has been applied.
It turns out this can be done.
In filter B adjust the filter so it reads
-label:[FilterA] AND [ rest of filter B ]. This will cause filter B to by bypassed if label A has been applied.
Make sure filter B is listed AFTER filter A in the list. If this is not the case just open filter B and re-save it.
Note that Gmail may throw up a message about using "label" as a filter is not recommended because it cause the filter to not be applied to any incoming messages. I just ignored it, this seemed to work.
Any and all GMail filter rules that match will run and do their thing.
I'm not sure it's possible to create rules that potentially conflict. The filter criteria available are:
- Containing words
- Doesn't contain words
- Has attachment
You can't affect any of these with the filter actions that are available, so I don't see how one rule could run and then affect the message in a way that would stop it matching another filter that it would have previously matched.
The only exception to bbodiens comment (I was just about to post almost exactly the same answer!!) is that one would expect a 'marked as read' and 'archived' message to essentially skip further filtering, but this is not the case.
To test this i set up two test filters, one that labels incoming mail with the subject 'testing' as test1 and archives it, and a second filter on 'testing' that labels test2.
The mail was archived AND labeled twice, so it appears that filters are concurrent.
From Gmail help:
Fun fact: these actions will take place in the order they're listed -- for example, you could choose to Forward matching messages to a specific email address, then Delete the messages.
I ran into a funky bug where the order of filters made a difference:
Filter #1: Apply label "Foo" to mail from "foo-sender"
Filter #2: Apply label "Bar" to all mail EXCEPT for mail from "foo-sender".
If I fully specify the email address in the filter definition, including the domain ("email@example.com"), then the order doesn't matter. But if I just give the username without the domain in the filter definition (just plain "foo-sender"), then both labels are incorrectly applied to mail from "foo-sender". It only works if I reverse the order of the filters.
I think this is just a bug, not a feature.