[tor-bugs] #25939 [Core Tor/Tor]: A Tor commit seems to have broken creation of V3 onion services with stem

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#25939: A Tor commit seems to have broken creation of V3 onion services with stem
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 Reporter:  maqp                        |          Owner:  dgoulet
     Type:  defect                      |         Status:  needs_review
 Priority:  High                        |      Milestone:  Tor:
                                        |  0.3.4.x-final
Component:  Core Tor/Tor                |        Version:
 Severity:  Major                       |     Resolution:
 Keywords:  034-must regression tor-hs  |  Actual Points:
Parent ID:                              |         Points:
 Reviewer:                              |        Sponsor:
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Changes (by dgoulet):

 * status:  accepted => needs_review


Comment:

 The onion address is missing in the `HS_DESC CREATED` event for an
 ephemeral v3 service.

 This was introduced by commit `f7633c1fcaefe72bf97c001bab9062132c919996`
 (in `tor-0.3.4.1-alpha`)

 With the work on #25500 (reducing CPU client usage), the HS service main
 loop callback is enabled as soon as the HS service map changes which
 happens when registering a new service. Unfortunately, for ephemeral
 services, we are building the onion address *after* the registration
 leading to the `service->onion_address` to be empty. Even in the tor logs,
 we had an empty string.

 Fix is trivial, we simply need to build the address before registration.

 Branch: `bug25939_034_01`

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25939#comment:16>
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