Split UnexpectedVersion exception in two

This exception was previously thrown in two cases:

1. When a store could not be opened because it had a version different
from the one neo4j was expecting (tools like ConsistencyChecker would
run into this)
2. Trying to upgrade a store with an unknown version (in many cases,
when users are unwittingly trying to downgrade a store)

This split those two separate use-cases in two, and throws distinct
exceptions in each case.

Before, this was printed

```
/home/jonas/workspace/neo4j/community/kernel/target/test-data/org.neo4j.kernel.impl.storemigration.UpgradableDatabaseTest$UnsupportedVersions/E1F262ADB34943A5536165FFEF6AEC90/graph-db/neostore' has a store version 'v0.A.8' that we cannot upgrade from
```

After, this is printed instead

```
Not possible to upgrade a store with version 'v0.A.8' to current store version `v.0.A.7` (Neo4j 3.0.7).
```

This message is thrown when the version is unknown, e.g. it is
jibberish (not sure if that would ever happen), or more likely, it's a
version that is part of a later version of Neo4j which this version has
no knowledge of. Printing the current version (as well as Neo4j version)
makes it as clear as is possible, that he has screwed up his database versions.

community/kernel/src/main/java/org/neo4j/kernel/impl/store/NeoStores.java

@@ -47,7 +47,6 @@
 import org.neo4j.kernel.impl.store.kvstore.DataInitializer;
 import org.neo4j.kernel.impl.store.record.AbstractBaseRecord;
 import org.neo4j.kernel.impl.store.record.RelationshipGroupRecord;
-import org.neo4j.kernel.impl.storemigration.StoreUpgrader;
 import org.neo4j.kernel.info.DiagnosticsManager;
 import org.neo4j.logging.Log;
 import org.neo4j.logging.LogProvider;
@@ -172,8 +171,7 @@ private void verifyRecordFormat()
             String actualStoreVersion = versionLongToString( getRecord( pageCache, neoStoreFileName, STORE_VERSION ) );
             if ( !expectedStoreVersion.equals( actualStoreVersion ) )
             {
-                throw new StoreUpgrader.UnexpectedUpgradingStoreVersionException( neoStoreFileName.getName(),
-                        actualStoreVersion );
+                throw new UnexpectedStoreVersionException( actualStoreVersion, expectedStoreVersion );
             }
         }
         catch ( NoSuchFileException e )

community/kernel/src/main/java/org/neo4j/kernel/impl/store/UnexpectedStoreVersionException.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2002-2016 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.kernel.impl.store;
+
+public class UnexpectedStoreVersionException extends StoreFailureException
+{
+    private static final String MESSAGE = "Unable to open store with version '%s', expected store version '%s'.";
+
+    public UnexpectedStoreVersionException( String actualStoreVersion, String expectedStoreVersion )
+    {
+        super( String.format( MESSAGE, actualStoreVersion, expectedStoreVersion ) );
+    }
+}

community/kernel/src/main/java/org/neo4j/kernel/impl/storemigration/StoreUpgrader.java

@@ -33,6 +33,7 @@
 import org.neo4j.kernel.impl.storemigration.monitoring.MigrationProgressMonitor;
 import org.neo4j.kernel.impl.storemigration.monitoring.MigrationProgressMonitor.Section;
 import org.neo4j.kernel.impl.util.CustomIOConfigValidator;
+import org.neo4j.kernel.internal.Version;
 import org.neo4j.logging.Log;
 import org.neo4j.logging.LogProvider;
 
@@ -318,11 +319,22 @@ public UpgradingStoreVersionNotFoundException( String filenameWithoutStoreVersio
 
     public static class UnexpectedUpgradingStoreVersionException extends UnableToUpgradeException
     {
-        protected static final String MESSAGE = "'%s' has a store version '%s' that we cannot upgrade from.";
+        protected static final String MESSAGE =
+                "Not possible to upgrade a store with version '%s' to current store version `%s` (Neo4j %s).";
+
+        public UnexpectedUpgradingStoreVersionException( String fileVersion, String currentVersion )
+        {
+            super( String.format( MESSAGE, fileVersion, currentVersion, Version.getNeo4jVersion() ) );
+        }
+    }
+
+    public static class AttemptedDowngradeException extends UnableToUpgradeException
+    {
+        protected static final String MESSAGE = "Downgrading stores are not supported.";
 
-        public UnexpectedUpgradingStoreVersionException( String filename, String actualVersion )
+        public AttemptedDowngradeException()
         {
-            super( String.format( MESSAGE, filename, actualVersion ) );
+            super( MESSAGE );
         }
     }
 

community/kernel/src/main/java/org/neo4j/kernel/impl/storemigration/StoreVersionCheck.java

@@ -60,7 +60,7 @@ record = MetaDataStore.getRecord( pageCache, neostoreFile, STORE_VERSION );
         String storeVersion = MetaDataStore.versionLongToString( record );
         if ( !expectedVersion.equals( storeVersion ) )
         {
-            return new Result( Outcome.unexpectedUpgradingStoreVersion, storeVersion, neostoreFile.getName() );
+            return new Result( Outcome.unexpectedStoreVersion, storeVersion, neostoreFile.getName() );
         }
 
         return new Result( Outcome.ok, null, neostoreFile.getName() );
@@ -84,7 +84,8 @@ public enum Outcome
             ok( true ),
             missingStoreFile( false ),
             storeVersionNotFound( false ),
-            unexpectedUpgradingStoreVersion( false ),
+            unexpectedStoreVersion( false ),
+            attemptedStoreDowngrade( false ),
             storeNotCleanlyShutDown( false );
 
             private final boolean success;

community/kernel/src/main/java/org/neo4j/kernel/impl/storemigration/UpgradableDatabase.java

@@ -103,7 +103,7 @@ public RecordFormats checkUpgradeable( File storeDirectory )
             if ( fromFormat.generation() > format.generation() )
             {
                 // Tried to downgrade, that isn't supported
-                result = new Result( Outcome.unexpectedUpgradingStoreVersion, fromFormat.storeVersion(),
+                result = new Result( Outcome.attemptedStoreDowngrade, fromFormat.storeVersion(),
                         new File( storeDirectory, MetaDataStore.DEFAULT_NAME ).getAbsolutePath() );
             }
             else
@@ -119,7 +119,7 @@ public RecordFormats checkUpgradeable( File storeDirectory )
         }
         catch ( IllegalArgumentException e )
         {
-            result = new Result( Outcome.unexpectedUpgradingStoreVersion, result.actualVersion, result.storeFilename );
+            result = new Result( Outcome.unexpectedStoreVersion, result.actualVersion, result.storeFilename );
         }
 
         switch ( result.outcome )
@@ -129,9 +129,10 @@ public RecordFormats checkUpgradeable( File storeDirectory )
         case storeVersionNotFound:
             throw new StoreUpgrader.UpgradingStoreVersionNotFoundException(
                     getPathToStoreFile( storeDirectory, result ) );
-        case unexpectedUpgradingStoreVersion:
-            throw new StoreUpgrader.UnexpectedUpgradingStoreVersionException(
-                    getPathToStoreFile( storeDirectory, result ), result.actualVersion );
+        case attemptedStoreDowngrade:
+            throw new StoreUpgrader.AttemptedDowngradeException();
+        case unexpectedStoreVersion:
+            throw new StoreUpgrader.UnexpectedUpgradingStoreVersionException( result.actualVersion, format.storeVersion() );
         case storeNotCleanlyShutDown:
             throw new StoreUpgrader.DatabaseNotCleanlyShutDownException();
         default:
@@ -193,7 +194,8 @@ public boolean hasCurrentVersion( File storeDir )
         case missingStoreFile: // let's assume the db is empty
             return true;
         case storeVersionNotFound:
-        case unexpectedUpgradingStoreVersion:
+        case unexpectedStoreVersion:
+        case attemptedStoreDowngrade:
             return false;
         default:
             throw new IllegalArgumentException( "Unknown outcome: " + result.outcome.name() );

community/kernel/src/main/java/org/neo4j/kernel/impl/storemigration/legacystore/LegacyStoreVersionCheck.java

@@ -64,7 +64,7 @@ public Result hasVersion( File storeFile, String expectedVersion, boolean option
             String actualVersion = readVersion( fileChannel, expectedVersionBytes.length );
             if ( !expectedVersion.equals( actualVersion ) )
             {
-                return new Result( Outcome.unexpectedUpgradingStoreVersion, actualVersion, storeFilename );
+                return new Result( Outcome.unexpectedStoreVersion, actualVersion, storeFilename );
             }
         }
         catch ( IOException e )

community/kernel/src/test/java/org/neo4j/kernel/impl/storemigration/MigrationTestUtils.java

@@ -222,7 +222,7 @@ public static boolean allStoreFilesHaveNoTrailer( FileSystemAbstraction fs, File
             File file = new File( dir, storeFile.storeFileName() );
             StoreVersionCheck.Result result =
                     legacyStoreVersionCheck.hasVersion( file, StandardV3_0.STORE_VERSION, storeFile.isOptional() );
-            success &= result.outcome == Outcome.unexpectedUpgradingStoreVersion ||
+            success &= result.outcome == Outcome.unexpectedStoreVersion ||
                        result.outcome == Outcome.storeVersionNotFound;
         }
         return success;

community/kernel/src/test/java/org/neo4j/kernel/impl/storemigration/StoreVersionCheckTest.java

@@ -96,7 +96,7 @@ public void shouldReportFileWithIncorrectVersion() throws IOException
 
         // then
         assertFalse( result.outcome.isSuccessful() );
-        assertEquals( StoreVersionCheck.Result.Outcome.unexpectedUpgradingStoreVersion, result.outcome );
+        assertEquals( StoreVersionCheck.Result.Outcome.unexpectedStoreVersion, result.outcome );
         assertEquals( "V1", result.actualVersion );
     }
 

community/kernel/src/test/java/org/neo4j/kernel/impl/storemigration/UpgradableDatabaseTest.java

@@ -44,6 +44,7 @@
 import org.neo4j.kernel.impl.store.format.standard.StandardV2_3;
 import org.neo4j.kernel.impl.store.format.standard.StandardV3_0;
 import org.neo4j.kernel.impl.storemigration.legacystore.LegacyStoreVersionCheck;
+import org.neo4j.kernel.internal.Version;
 import org.neo4j.string.UTF8;
 import org.neo4j.test.PageCacheRule;
 import org.neo4j.test.TargetDirectory;
@@ -261,8 +262,8 @@ public void shouldCommunicateWhatCausesInabilityToUpgrade()
             {
                 // then
                 assertFalse( StoreVersion.isEnterpriseStoreVersion( version ) );
-                File expectedFile = new File( workingDirectory, neostoreFilename ).getAbsoluteFile();
-                assertEquals( String.format( MESSAGE, expectedFile, version ), e.getMessage() );
+                assertEquals( String.format( MESSAGE, version, upgradableDatabase.currentVersion(),
+                        Version.getNeo4jVersion() ), e.getMessage() );
             }
             catch ( StoreUpgrader.UnexpectedUpgradingStoreFormatException e )
             {

community/neo4j/src/test/java/db/DatabaseStartupTest.java

@@ -37,9 +37,7 @@
 import org.neo4j.test.TargetDirectory;
 import org.neo4j.test.TestGraphDatabaseFactory;
 
-import static org.hamcrest.Matchers.containsString;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -120,8 +118,6 @@ public void startTheDatabaseWithWrongVersionShouldFailAlsoWhenUpgradeIsAllowed()
             // then
             assertTrue( ex.getCause() instanceof LifecycleException );
             assertTrue( ex.getCause().getCause() instanceof StoreUpgrader.UnexpectedUpgradingStoreVersionException );
-            assertThat( ex.getCause().getCause().getMessage(),
-                    containsString( "has a store version '" + badStoreVersion + "' that we cannot upgrade from." ) );
         }
     }
 }

community/shell/src/main/java/org/neo4j/shell/impl/BashVariableInterpreter.java

@@ -26,6 +26,7 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import org.neo4j.kernel.internal.Version;
 import org.neo4j.shell.Session;
 import org.neo4j.shell.ShellException;
 import org.neo4j.shell.ShellServer;

integrationtests/src/test/java/org/neo4j/storeupgrade/StoreUpgradeIntegrationTest.java

@@ -61,7 +61,6 @@
 import org.neo4j.kernel.impl.core.ThreadToStatementContextBridge;
 import org.neo4j.kernel.impl.ha.ClusterManager;
 import org.neo4j.kernel.impl.storageengine.impl.recordstorage.RecordStorageEngine;
-import org.neo4j.kernel.impl.store.MetaDataStore;
 import org.neo4j.kernel.impl.store.format.highlimit.HighLimit;
 import org.neo4j.kernel.impl.store.format.standard.StandardV3_0;
 import org.neo4j.kernel.impl.storemigration.StoreUpgrader;
@@ -332,7 +331,7 @@ public void migrationShouldFail() throws Throwable
             {
                 assertTrue( ex.getCause() instanceof LifecycleException );
                 Throwable realException = ex.getCause().getCause();
-                assertTrue( Exceptions.contains( realException, MetaDataStore.DEFAULT_NAME,
+                assertTrue( "Unexpected exception", Exceptions.contains( realException,
                         StoreUpgrader.UnexpectedUpgradingStoreVersionException.class ) );
             }
         }