[tor-bugs] #24826 [Core Tor/Tor]: LZMA-compressed consensus diffs stall Tor Browser launch for at least 20s or break it entirely

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#24826: LZMA-compressed consensus diffs stall Tor Browser launch for at least 20s
or break it entirely
------------------------------+--------------------
     Reporter:  gk            |      Owner:  (none)
         Type:  defect        |     Status:  new
     Priority:  Medium        |  Milestone:
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:
Actual Points:                |  Parent ID:
       Points:                |   Reviewer:
      Sponsor:                |
------------------------------+--------------------
 In #22341 we are thinking about picking up LZMA- and zstd-support for
 consensus diffs.

 For LZMA-compressed diffs I often encounter boostrap delays of at least
 20s like this:
 {{{
 Dec 26 21:01:18.000 [debug] HTTP body from server 'XX.XX.XX.XX:9001' was
 labeled as LZMA compressed, and it seems to be LZMA compressed.
 Dec 26 21:01:38.000 [info] handle_response_fetch_consensus(): Applied
 consensus diff (size 482897) from server 'XX.XX.XX.XX:9001', resulting in
 a new consensus document (size 1903167).
 }}}

 But, worse, it might even break Tor Browser bootstrap entirely when
 blocking a Tor Launcher `GETCONF` call (throwing an exception as Tor
 Launcher thinks tor is not working) like so:
 {{{
 Dec 30 23:54:54.000 [debug] HTTP body from server 'XX.XX.XX.XX:9001' was
 labeled as LZMA compressed, and it seems to be LZMA compressed.
 Illegal AddressMatcher: [xpconnect wrapped nsIPrefBranch] -- TypeError:
 s.split is not a function
 Illegal AddressMatcher: [xpconnect wrapped nsIPrefBranch] -- TypeError:
 s.split is not a function
 [12-30 22:54:55] TorLauncher DBUG: readTorSettings
 ----------------------------------------------
 [12-30 22:54:55] TorLauncher DBUG: Sending Tor command: GETCONF UseBridges
 [12-30 22:55:10] TorLauncher NOTE: Exception on control port [Exception...
 "Component returned failure code: 0x804b000e (NS_ERROR_NET_TIMEOUT)
 [nsIBinaryInputStream.readBytes]"  nsresult: "0x804b000e
 (NS_ERROR_NET_TIMEOUT)"  location: "JS frame ::
 jar:file:///home/thomas/Arbeit/TBB/tor-browser_en-
 US/Browser/TorBrowser/Data/Browser/profile.default/extensions/tor-
 launcher at torproject.org.xpi!/components/tl-protocol.js ::
 TorProtocolService.prototype._torReadLine :: line 920"  data: no]
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24826>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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