ErrorProne: Enable and fix UnusedException check

Enable UnusedException at ERROR level which causes the build to fail
in many places with:

  [UnusedException] This catch block catches an symbol and re-throws
  another, but swallows the caught symbol rather than setting it as a
  cause. This can make debugging harder.

Fix it by setting the caught exception as cause on the subsequently
thrown exception.

Note: The grammatically incorrect error message is copy-pasted as-is
from the version of ErrorProne currently used in Bazel; it has been
fixed by [1] in the latest version.

[1] https://github.com/google/error-prone/commit/d57a39c

Change-Id: I11ed38243091fc12f64f1b2db404ba3f1d2e98b5
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

4 files changed, 15 insertions, 10 deletions

diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPointer.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPointer.java
index c4a51c7b93..55d2cfa6ec 100644
--- a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPointer.java
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPointer.java
@@ -18,7 +18,6 @@ import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.PrintStream;
 import java.io.UnsupportedEncodingException;
-import java.nio.charset.UnsupportedCharsetException;
 import java.util.Locale;
 
 import org.eclipse.jgit.annotations.Nullable;
@@ -110,7 +109,6 @@ public class LfsPointer implements Comparable<LfsPointer> {
 			ps.print(size + "\n"); //$NON-NLS-1$
 		} catch (UnsupportedEncodingException e) {
 			// should not happen, we are using a standard charset
-			throw new UnsupportedCharsetException(UTF_8.name());
 		}
 	}
 
diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/AbbreviatedLongObjectId.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/AbbreviatedLongObjectId.java
index a2bcc35eeb..9016e53940 100644
--- a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/AbbreviatedLongObjectId.java
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/AbbreviatedLongObjectId.java
@@ -121,8 +121,11 @@ public final class AbbreviatedLongObjectId implements Serializable {
 			final long c = hexUInt64(bs, ptr + 32, end);
 			final long d = hexUInt64(bs, ptr + 48, end);
 			return new AbbreviatedLongObjectId(end - ptr, a, b, c, d);
-		} catch (ArrayIndexOutOfBoundsException e1) {
-			throw new InvalidLongObjectIdException(bs, ptr, end - ptr);
+		} catch (ArrayIndexOutOfBoundsException e) {
+			InvalidLongObjectIdException e1 = new InvalidLongObjectIdException(
+					bs, ptr, end - ptr);
+			e1.initCause(e);
+			throw e1;
 		}
 	}
 
diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/LongObjectId.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/LongObjectId.java
index 000e9b206d..15b3ca4c62 100644
--- a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/LongObjectId.java
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/LongObjectId.java
@@ -223,9 +223,11 @@ public class LongObjectId extends AnyLongObjectId implements Serializable {
 			final long c = RawParseUtils.parseHexInt64(bs, p + 32);
 			final long d = RawParseUtils.parseHexInt64(bs, p + 48);
 			return new LongObjectId(a, b, c, d);
-		} catch (ArrayIndexOutOfBoundsException e1) {
-			throw new InvalidLongObjectIdException(bs, p,
-					Constants.LONG_OBJECT_ID_STRING_LENGTH);
+		} catch (ArrayIndexOutOfBoundsException e) {
+			InvalidLongObjectIdException e1 = new InvalidLongObjectIdException(
+					bs, p, Constants.LONG_OBJECT_ID_STRING_LENGTH);
+			e1.initCause(e);
+			throw e1;
 		}
 	}
 
diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/MutableLongObjectId.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/MutableLongObjectId.java
index 368f6af7ed..012e4ae915 100644
--- a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/MutableLongObjectId.java
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/MutableLongObjectId.java
@@ -213,9 +213,11 @@ public class MutableLongObjectId extends AnyLongObjectId {
 			w2 = RawParseUtils.parseHexInt64(bs, p + 16);
 			w3 = RawParseUtils.parseHexInt64(bs, p + 32);
 			w4 = RawParseUtils.parseHexInt64(bs, p + 48);
-		} catch (ArrayIndexOutOfBoundsException e1) {
-			throw new InvalidLongObjectIdException(bs, p,
-					Constants.LONG_OBJECT_ID_STRING_LENGTH);
+		} catch (ArrayIndexOutOfBoundsException e) {
+			InvalidLongObjectIdException e1 = new InvalidLongObjectIdException(
+					bs, p, Constants.LONG_OBJECT_ID_STRING_LENGTH);
+			e1.initCause(e);
+			throw e1;
 		}
 	}