when does a 302 become a 301?

[lucy24]

Someone asked me about temporary redirects and I could only say
(a) I have no idea
and
(b) I don't even know whether the answer is known (to anyone, anywhere)

Assume for the sake of discussion that you're using 301 and 302 the way God intended:
301 = "I've moved, here is my new address"
302 = "We've got painters in, so here's our address for the next few weeks"

Now suppose an individual site uses both 301 and 302, and google has satisfied itself by observation that they mean different things:
-- have I already derailed myself by assuming a numerical code can ever make a difference?
-- if the two are, in fact, interpreted differently, does there come a point when google decides that although your lips say 302, your eyes mean 301?
-- is there any way of knowing how long it takes to reach this point (a month? a year? does it depend on whether the "temporary vs. permanent" decision originated with the site or with google?)

Attempting to look it up locally led me to, among other things, this thread from 2012 [webmasterworld.com] which ended with Tedster stepping in to break up a fistfight between me and TMS so I'm not sure the question was ever answered. If there's a better and/or newer thread, I couldn't find it. And in the internet, two-plus years can be quite a long time.

[rainborick]

I know Google strays from strict interpretations of HTTP response codes because they have to deal with "the web as it is" rather than "the web as it should be", with lots of valuable information that would otherwise be lost to users. But it seems to me that you're always best off doing your best to adhere to the real standards. In any case, I don't see any reason to be concerned about changing the status code on a long-standing redirect as long as the destination URL is unchanged. No matter how often Google has seen the original response, ultimately, you're just correcting an error.

[lammert]

Assume for the sake of discussion that you're using 301 and 302 the way God intended:
301 = "I've moved, here is my new address"
302 = "We've got painters in, so here's our address for the next few weeks"

Yes, that is more or less the definition.

301 redirection has never been a problem, but about ten years ago a flaw in the way Google handled 302 redirects allowed malicious sites to hijack your rankings in the SERPs [webmasterworld.com]. Although Google has fixed this problem long ago, I still have a better feeling to use a 301 than a 302, whenever a URL needs to be redirected permanently.

[RedBar]

FWIW I stopped using 302s years ago since G simply did not seem to understand insofar as my stuff was concerned.

I could write a lot more but what would be the point? Nothing's going to change.

[lucy24]

about ten years ago

Well, thanks, that was edifying. (Was Buckworks really a he in 2005? Who knew!) In fact the original 3-page thread goes on for 16 more pages (467 posts) here [webmasterworld.com] but 2005 really was a very, very long time ago in Internet terms so I won't apologize for not reading the whole thing. I tried, but it made my brain tired.

Continuing to chew on the central question: The essence of a 302 is that you're temporarily relocated. In real life it wouldn't make much sense to create a brand-new URL and immediately 302 it to somewhere else. (Here "real life" = "for ordinary, non-spamming, non-hijacking purposes".) It would be like opening a new brick-and-mortar store at a temporary location while expecting people to associate your business with some other location that you've never used.

So when google sees a 302, do they check whether
-- the original URL was already indexed before the googlebot started meeting the 302 response
and if so
-- was the content of this pre-302 URL roughly similar to the content of the new "target" URL?

[phranque]

just to make things more confusing, why does google treat 301s like 302s?

301 from old site showing as #1 in Google now:
http://www.webmasterworld.com/google/4721592.htm [webmasterworld.com]

John Mueller: Google May Not Show the Redirect Target URL in SERPs:
http://www.webmasterworld.com/google/4646897.htm [webmasterworld.com]

perhaps the answer is "whenever the google thinks it knows better than the webmaster it may decide to ignore protocol".