Re: [PATCH] compdescribe fix for unsorted groups (workers/34814) (was: Re: completion: git: --fixup: problem with _describe -2V and duplicate commit subjects)

[Daniel Shahaf <d.s@daniel.shahaf.name>]

Daniel Shahaf wrote on Wed, May 20, 2015 at 23:51:58 +0000:
> While looking into this, I've also found a 100% CPU consumption bug; to
> reproduce (in master):

So, another summary...

- 35127#1 (fix for _describe -2V with duplicate descriptions): no reason
  to hold it back any longer; I'll push it.

- 35227 (duplicate :descriptions message): cosmetic issue.  The example
  given in that email requires 35127#2, which I'm not going to push yet,
  and no other example is known, so this issue is not blocking.

- 35246#tail (infinite loop): pre-existing problem, not related to my
  changes (it also happens in 5.0.7, which precedes my changes).  No
  known instances "in the wild".  I'm not currently looking into it.

- 35246#head (_describe output garbled): likewise, a pre-existing
  problem with no known instances.  Enclosed a patch to record its
  existence.

- Empty matches, probably added by cd_get(), are definitely related to
  the third issue and may be related to the second and fourth as well.

Is there better way to track all these issues than X-Seq numbers?

---

diff --git a/Completion/Base/Utility/_describe b/Completion/Base/Utility/_describe
index ab72005..76ab1d9 100644
--- a/Completion/Base/Utility/_describe
+++ b/Completion/Base/Utility/_describe
@@ -1,5 +1,12 @@
 #autoload
 
+# ### Note: Calling this function twice during one completion operation, such
+# ### that in each call there exists a pair of items having the same description
+# ### as each other, and the two calls specify the same $_type, currently leads
+# ### to garbled output; see workers/35229 (May 2015) and its thread (which also
+# ### discusses at least two other issues, that may or may not be related to
+# ### this one).
+
 # This can be used to add options or values with descriptions as matches.
 
 local _opt _expl _tmpm _tmpd _mlen _noprefix