[FW][FIX] website: prevent creation of 308 to existing controller

[fw-bot]

Creating a 308 which redirects to an existing controller will have unpredictable (and unwanted) behaviors.

Indeed, 308 are there to redirect an existing URL (like /shop) to a non-existing URL (like /my-super-shop) and to make it so that non existing URL will respond with the content of the existing URL.

The way it's done is that it simply replace the routing map rule for the given URL by two new rules:

• One for the non-existing URL (chosen url_to) which will serve the existing url endpoint
• One for the existing URL, which will be turned into a redirect endpoint

This works fine except if you actually select an existing controller as url_to in the 308 rewrite.

In this case, there will be 2 werkzeug Rules for the same URL, which is bad. Worst than that, depending of the selected controller the order of those 2 Rules will change, leading to different behavior.

Step to reproduce:

• Create a 308 from /blog to / (note that "/" is a controller)
• Go to /blog, it will redirect and show the homepage
• Go to /, it will show the homepage
• Now edit the 308 and redirect /shop to /
• Go to /shop, it redirects to / but won't show the homepage, it will show the shop page
• Go to /, it will show the shop page

Technically, here is the routing map for both cases:

1. 308 shop case

<FasterRule '/' -> functools.partial(<bound method WebsiteSale.shop of <odoo.http.CustomerPortal (extended by PortalAccount, PaymentPortal, CustomerPortalExternalTax, SaleStockPortal, CustomerPortal, PaymentPortal, PaymentPortal, WebsiteSaleDelivery, WebsiteSaleExternalTaxCalculation, WebsiteSale, WebsiteSaleStockRenting, WebsiteSaleStockRenting, WebsiteSale, WebsiteSaleRenting, PaymentPortal, CustomerPortalExternalTax, CustomerPortal, WebsiteAccount) object at 0x7f4d9468a6b0>>)>,
<FasterRule '/' -> functools.partial(<bound method Website.index of <odoo.http.Home (extended by Home, Home, Routing, AuthSignupHome, Website) object at 0x7f4d94583460>>)>,

2. 308 blog case

<FasterRule '/' -> functools.partial(<bound method Website.index of <odoo.http.Home (extended by Home, Home, Routing, AuthSignupHome, Website) object at 0x7f7fc9ebd7e0>>)>,
<FasterRule '/' -> functools.partial(<bound method WebsiteBlog.blog of <odoo.http.WebsiteBlog object at 0x7f7fc9d69090>>)>,

You see that the Rule order is inverted from one case to another.

We could have decided to do another fix and adapt the _generate_routing_rules() method to keep only one Route but that seems worst as:

1. 308 are not designed for that in the first place, not even sure what we would want
2. it will technically be far from ideal, having the check routing map to check if exists already and ensure the same behavior all the time

Note that testing a few main controllers, only the /shop seems to lead
to this different behavior.

Note that it's a bit of a non-stable change, so 17.0 seems like a good
compromise. Especially since the /shop example is not buggy before 17.0
as somehow the Website.index Rule is before the WebsiteSale.shop.

<FasterRule '/' -> functools.partial(<bound method Website.index of <odoo.http.Home (extended by Home, Home, Routing, AuthSignupHome, Website, WebsiteTest) object at 0x7fad28571660>>)>,
<FasterRule '/' -> functools.partial(<bound method WebsiteSale.shop of <odoo.http.WebsiteSale (extended by WebsiteSaleDelivery, WebsiteSale) object at 0x7fad28435e40>>)>,

opw-3901713

Forward-Port-Of: #165083

[robodoo]

.

[fw-bot]

@rdeodoo @qsm-odoo cherrypicking of pull request #165083 failed.

stdout:

Auto-merging addons/website/i18n/website.pot
CONFLICT (content): Merge conflict in addons/website/i18n/website.pot

stderr:

22:02:24.925770 git.c:463               trace: built-in: git cherry-pick adaa80a2216f4667af6213cc43a28bc8768bfd5b
error: could not apply adaa80a2216f... [FIX] website: prevent creation of 308 to existing controller
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".
----------
status:

Either perform the forward-port manually (and push to this branch, proceeding as usual) or close this PR (maybe?).

In the former case, you may want to edit this PR message as well.

⚠️ after resolving this conflict, you will need to merge it via @robodoo.

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[rdeodoo]

@robodoo r+