[LUCENE-6279] 3.x -> 4.x .si upgrade should not be tricked by leftover upgrade marker file

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.10.5
• Lucene Fields: New
• Assignee: Michael McCandless
• Reporter: Michael McCandless
• Created: 21/Feb/15 23:53
• Updated: 28/Aug/22 14:26
• Resolved: 24/Feb/15 16:54

Description

Today when you do the first IW.commit to a 3.x index from Lucene 4.x, we go
through a per-segment upgrade process when writing the next segments_N
file, writing .si files for each segment if we didn't already do so.

However, this process can be fooled by a leftover _N_upgraded.si
file, in case the app above Lucene wasn't careful and reused a
directory that had leftover files... I think we can make this more
robust.