From: Eric Wong <e@80x24.org>
To: msgthr-public@80x24.org
Subject: [PATCH] fix missing loop check
Date: Thu, 26 Apr 2018 00:01:56 +0000 [thread overview]
Message-ID: <20180426000156.10184-1-e@80x24.org> (raw)
We failed to detect cyclic dependencies, leading to lost thread
roots. In this Ruby version, I also screwed up the `seen' hash
check in a misguided effort to avoid an extra hash lookup.
The same algorithm was recently fixed in public-inbox:
https://public-inbox.org/meta/20180425085249.14974-1-e@80x24.org/
Summarizing what happened with public-inbox: this algorithm can
still be thrown off when the References: order presented to us
is wrong, so sorting messages by age before feeding to
Msgthr#add can improve the results.
Regardless of ordering, messages should not become "lost" by the
algorithm.
---
lib/msgthr.rb | 2 +-
lib/msgthr/container.rb | 5 +++--
test/test_msgthr.rb | 30 ++++++++++++++++++++++++++++++
3 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/lib/msgthr.rb b/lib/msgthr.rb
index bf4b14e..8619c62 100644
--- a/lib/msgthr.rb
+++ b/lib/msgthr.rb
@@ -183,7 +183,7 @@ class Msgthr
end
# set parent of this message to be the last element in refs
- if prev
+ if prev && !cur.has_descendent(prev)
prev.add_child(cur)
yield(prev, cur) if block_given?
end
diff --git a/lib/msgthr/container.rb b/lib/msgthr/container.rb
index fbff719..256033b 100644
--- a/lib/msgthr/container.rb
+++ b/lib/msgthr/container.rb
@@ -64,9 +64,10 @@ class Msgthr::Container
end
def has_descendent(child) # :nodoc:
- seen = Hash.new(0)
+ seen = {}
while child
- return true if self == child || (seen[child] += 1) != 0
+ return true if self == child || seen[child]
+ seen[child] = true
child = child.parent
end
false
diff --git a/test/test_msgthr.rb b/test/test_msgthr.rb
index ee04d54..3d70d35 100644
--- a/test/test_msgthr.rb
+++ b/test/test_msgthr.rb
@@ -144,4 +144,34 @@ EOF
assert_equal threads[2][0], '2'
end
+ def test_no_lost_root
+ ids = [
+ [ 8, [] ],
+ [ 7, [8] ],
+ [ 6, [8, 7] ],
+ [ 3, [6, 7, 8] ],
+ [ 2, [6, 7, 8, 3] ],
+ [ 10, [8, 7, 6] ],
+ [ 9, [6, 3] ],
+ [ 5, [6, 7, 8, 3, 2] ],
+ [ 4, [2, 3] ],
+ [ 1, [2, 3, 4] ],
+ [ 'a', ],
+ [ 'b', ['a'] ],
+ ]
+ [ [ :forward, ids, 2 ],
+ [ :backwards, ids.reverse, 3 ],
+ [ :shuffle, ids.shuffle, nil ],
+ ].each do |desc,msgs,exp|
+ thr = Msgthr.new
+ msgs.each { |id| thr.add(id[0], id[1], id[0]) }
+ seen0 = nr = 0
+ thr.walk_thread do |level, _, _|
+ seen0 += 1 if level == 0
+ nr += 1
+ end
+ assert_equal nr, msgs.size, 'no lost messages'
+ assert_equal exp, seen0, "single root #{desc}" if exp
+ end
+ end
end
--
EW
reply other threads:[~2018-04-26 0:01 UTC|newest]
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