LUCENE-7592: if segments file is truncated, throw CorruptIndexException

lucene/CHANGES.txt

@@ -138,6 +138,10 @@ Improvements
   necessarily refer to that field (AKA requireFieldMatch==false). Disabled by default.
   See UH get/setFieldMatcher. (Jim Ferenczi via David Smiley)
 
+* LUCENE-7592: If the segments file is truncated, we now throw
+  CorruptIndexException instead of the more confusing EOFException
+  (Mike Drob via Mike McCandless)
+
 Optimizations
 
 * LUCENE-7568: Optimize merging when index sorting is used but the

lucene/core/src/java/org/apache/lucene/index/SegmentInfos.java

@@ -17,6 +17,7 @@
 package org.apache.lucene.index;
 
 
+import java.io.EOFException;
 import java.io.IOException;
 import java.io.PrintStream;
 import java.util.ArrayList;
@@ -277,7 +278,11 @@ public final class SegmentInfos implements Cloneable, Iterable<SegmentCommitInfo
     long generation = generationFromSegmentsFileName(segmentFileName);
     //System.out.println(Thread.currentThread() + ": SegmentInfos.readCommit " + segmentFileName);
     try (ChecksumIndexInput input = directory.openChecksumInput(segmentFileName, IOContext.READ)) {
-      return readCommit(directory, input, generation);
+      try {
+        return readCommit(directory, input, generation);
+      } catch (EOFException e) {
+        throw new CorruptIndexException("Unexpected end of file while reading index.", input, e);
+      }
     }
   }