EdColeman commented on code in PR #2854:
URL: https://github.com/apache/accumulo/pull/2854#discussion_r940621599
##########
core/src/main/java/org/apache/accumulo/core/metadata/TabletFile.java:
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@@ -128,24 +128,42 @@ public Path getPath() {
return metaPath;
}
+ /**
+ * The ordering of this class depends on the normal String ordering of the
normalized paths first,
+ * then any original path, if one exists as a StoredTabletFile, second. To
ensure subclasses don't
+ * break things, and to preserve commutativity, subclasses should defer to
this implementation.
+ */
Review Comment:
The addition of using StoredTabletFile original path in the comparison
breaks the implied contract that
`(x.compareTo(y) == 0 ) ==> (x.equals(y))`
Collections that use hashCode and equals (HashSet / Map) will behave
differently than collections that use compareTo (TreeSet / Map) This is
similar to the way `BigDecimal` handles `compareTo` and `equals` But is is
unusual.
This seems that it could introduce issues. If somehow there were two
metadata entries that had different "original" paths but resolved to the same
normalized path and if they were put into a HashSet and a TreeSet the
collections will have different contents.
`
For example:
If you have two StoredTabletFiles:
StoredTabletFile file1 = new StoredTabletFile(
"hdfs://nn.somewhere.com:86753/accumulo/tables/" + id + "/" +
dir + "/" + filename);
StoredTabletFile file2 = new StoredTabletFile(
"hdfs://nn.somewhere.com:86753/./accumulo/tables/" + id + "/" +
dir + "/" + filename);
And stored them in a TreeSet and a HashSet you end up with different
collections (both show the "original name(s)" in the collection:
TreeSet - 2 entries
hdfs://nn.somewhere.com:86753/./accumulo/tables/2a/t-0003/C0004.rf
hdfs://nn.somewhere.com:86753/accumulo/tables/2a/t-0003/C0004.rf
HashSet - 1 entry
hdfs://nn.somewhere.com:86753/accumulo/tables/2a/t-0003/C0004.rf
`
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