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

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#24826: LZMA- and Zstandard 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:  Tor: 0.3.3.x-final
Component:  Core Tor/Tor  |        Version:
 Severity:  Normal        |     Resolution:
 Keywords:                |  Actual Points:
Parent ID:  #22341        |         Points:
 Reviewer:                |        Sponsor:
--------------------------+------------------------------------

Comment (by nickm):

 With that patch on master, I see:
 {{{
 Jan 10 10:17:51.000 [debug] HTTP body from server '154.35.175.225:443' was
 label
 ed as LZMA compressed, and it seems to be LZMA compressed.
 Jan 10 10:17:51.000 [debug] dir_client_decompress_response_body():
 Successfully
 decompressed body using LZMA compressed
 Jan 10 10:17:51.000 [debug] consensus_diff_apply(): About to apply
 consensus dif
 f.
 Jan 10 10:17:51.000 [debug] consensus_diff_apply(): Computed digest-as-
 signed fo
 r applying consensus diff.
 Jan 10 10:17:51.000 [debug] consdiff_apply_diff(): Extracted digests for
 consens
 us diff.
 Jan 10 10:17:51.000 [debug] consdiff_apply_diff(): Digests match; applying
 diff.
 Jan 10 10:17:51.000 [debug] consdiff_apply_diff(): Diff applied.
 Jan 10 10:17:51.000 [debug] consdiff_apply_diff(): Computing digest of
 resulting
  consensus.
 Jan 10 10:17:51.000 [debug] consdiff_apply_diff(): Digests are equal; diff
 appli
 cation succeeded.
 Jan 10 10:17:51.000 [info] handle_response_fetch_consensus(): Applied
 consensus
 diff (size 101910) from server '154.35.175.225:443', resulting in a new
 consensu
 s document (size 1884843).
 }}}

 I wonder what could be going wrong here.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24826#comment:14>
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