Use branch.<x>.mergeoptions and merge.ff as defaults for merging

Read options that control squashing, whether or not to commit the merge
and regarding fast forwarding from the configuration and use them if no
explicit values for these options have been provided to MergeCommand.

Change-Id: Ifdaed4b5e4adc142657c03c8e78b709a99eeddbd
Signed-off-by: Konrad Kügler <swamblumat-eclipsebugs@yahoo.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

3 files changed, 259 insertions, 6 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java
index 630bd7dc0d..d30c1911de 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java
@@ -66,6 +66,7 @@ import java.util.Set;
 import org.eclipse.jgit.api.MergeCommand.FastForwardMode;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.junit.MockSystemReader;
+import org.eclipse.jgit.merge.MergeConfig;
 import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.SystemReader;
 import org.junit.After;
@@ -334,19 +335,27 @@ public class ConfigTest {
 		assertSame(FastForwardMode.FF, c.getEnum(
 				ConfigConstants.CONFIG_BRANCH_SECTION, "side",
 				ConfigConstants.CONFIG_KEY_MERGEOPTIONS, FastForwardMode.FF));
+		MergeConfig mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF, mergeConfig.getFastForwardMode());
 		c = parse("[branch \"side\"]\n\tmergeoptions = --ff-only\n");
 		assertSame(FastForwardMode.FF_ONLY, c.getEnum(
 				ConfigConstants.CONFIG_BRANCH_SECTION, "side",
 				ConfigConstants.CONFIG_KEY_MERGEOPTIONS,
 				FastForwardMode.FF_ONLY));
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF_ONLY, mergeConfig.getFastForwardMode());
 		c = parse("[branch \"side\"]\n\tmergeoptions = --ff\n");
 		assertSame(FastForwardMode.FF, c.getEnum(
 				ConfigConstants.CONFIG_BRANCH_SECTION, "side",
 				ConfigConstants.CONFIG_KEY_MERGEOPTIONS, FastForwardMode.FF));
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF, mergeConfig.getFastForwardMode());
 		c = parse("[branch \"side\"]\n\tmergeoptions = --no-ff\n");
 		assertSame(FastForwardMode.NO_FF, c.getEnum(
 				ConfigConstants.CONFIG_BRANCH_SECTION, "side",
 				ConfigConstants.CONFIG_KEY_MERGEOPTIONS, FastForwardMode.NO_FF));
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.NO_FF, mergeConfig.getFastForwardMode());
 	}
 
 	@Test
@@ -368,18 +377,56 @@ public class ConfigTest {
 		assertSame(FastForwardMode.Merge.TRUE, c.getEnum(
 				ConfigConstants.CONFIG_KEY_MERGE, null,
 				ConfigConstants.CONFIG_KEY_FF, FastForwardMode.Merge.TRUE));
+		MergeConfig mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF, mergeConfig.getFastForwardMode());
 		c = parse("[merge]\n\tff = only\n");
 		assertSame(FastForwardMode.Merge.ONLY, c.getEnum(
 				ConfigConstants.CONFIG_KEY_MERGE, null,
 				ConfigConstants.CONFIG_KEY_FF, FastForwardMode.Merge.ONLY));
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF_ONLY, mergeConfig.getFastForwardMode());
 		c = parse("[merge]\n\tff = true\n");
 		assertSame(FastForwardMode.Merge.TRUE, c.getEnum(
 				ConfigConstants.CONFIG_KEY_MERGE, null,
 				ConfigConstants.CONFIG_KEY_FF, FastForwardMode.Merge.TRUE));
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF, mergeConfig.getFastForwardMode());
 		c = parse("[merge]\n\tff = false\n");
 		assertSame(FastForwardMode.Merge.FALSE, c.getEnum(
 				ConfigConstants.CONFIG_KEY_MERGE, null,
 				ConfigConstants.CONFIG_KEY_FF, FastForwardMode.Merge.FALSE));
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.NO_FF, mergeConfig.getFastForwardMode());
+	}
+
+	@Test
+	public void testCombinedMergeOptions() throws ConfigInvalidException {
+		Config c = new Config(null); // not set
+		MergeConfig mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF, mergeConfig.getFastForwardMode());
+		assertTrue(mergeConfig.isCommit());
+		assertFalse(mergeConfig.isSquash());
+		// branch..mergeoptions should win over merge.ff
+		c = parse("[merge]\n\tff = false\n"
+				+ "[branch \"side\"]\n\tmergeoptions = --ff-only\n");
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF_ONLY, mergeConfig.getFastForwardMode());
+		assertTrue(mergeConfig.isCommit());
+		assertFalse(mergeConfig.isSquash());
+		// merge.ff used for ff setting if not set via mergeoptions
+		c = parse("[merge]\n\tff = only\n"
+				+ "[branch \"side\"]\n\tmergeoptions = --squash\n");
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF_ONLY, mergeConfig.getFastForwardMode());
+		assertTrue(mergeConfig.isCommit());
+		assertTrue(mergeConfig.isSquash());
+		// mergeoptions wins if it has ff options amongst other options
+		c = parse("[merge]\n\tff = false\n"
+				+ "[branch \"side\"]\n\tmergeoptions = --ff-only --no-commit\n");
+		mergeConfig = c.get(MergeConfig.getParser("side"));
+		assertSame(FastForwardMode.FF_ONLY, mergeConfig.getFastForwardMode());
+		assertFalse(mergeConfig.isCommit());
+		assertFalse(mergeConfig.isSquash());
 	}
 
 	@Test
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
index 78b260df71..d8e73e3911 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
@@ -72,6 +72,7 @@ import org.eclipse.jgit.lib.Ref.Storage;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.RefUpdate.Result;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.merge.MergeConfig;
 import org.eclipse.jgit.merge.MergeMessageFormatter;
 import org.eclipse.jgit.merge.MergeStrategy;
 import org.eclipse.jgit.merge.Merger;
@@ -99,9 +100,9 @@ public class MergeCommand extends GitCommand<MergeResult> {
 
 	private List<Ref> commits = new LinkedList<Ref>();
 
-	private boolean squash;
+	private Boolean squash;
 
-	private FastForwardMode fastForwardMode = FastForwardMode.FF;
+	private FastForwardMode fastForwardMode;
 
 	/**
 	 * The modes available for fast forward merges corresponding to the
@@ -195,7 +196,7 @@ public class MergeCommand extends GitCommand<MergeResult> {
 		}
 	}
 
-	private boolean commit = true;
+	private Boolean commit;
 
 	/**
 	 * @param repo
@@ -212,10 +213,12 @@ public class MergeCommand extends GitCommand<MergeResult> {
 	 *
 	 * @return the result of the merge
 	 */
+	@SuppressWarnings("boxing")
 	public MergeResult call() throws GitAPIException, NoHeadException,
 			ConcurrentRefUpdateException, CheckoutConflictException,
 			InvalidMergeHeadsException, WrongRepositoryStateException, NoMessageException {
 		checkCallable();
+		fallBackToConfiguration();
 		checkParameters();
 
 		RevWalk revWalk = null;
@@ -413,7 +416,7 @@ public class MergeCommand extends GitCommand<MergeResult> {
 	}
 
 	private void checkParameters() throws InvalidMergeHeadsException {
-		if (squash && fastForwardMode == FastForwardMode.NO_FF) {
+		if (squash.booleanValue() && fastForwardMode == FastForwardMode.NO_FF) {
 			throw new JGitInternalException(
 					JGitText.get().cannotCombineSquashWithNoff);
 		}
@@ -427,6 +430,20 @@ public class MergeCommand extends GitCommand<MergeResult> {
 									Integer.valueOf(commits.size())));
 	}
 
+	/**
+	 * Use values from the configuation if they have not been explicitly defined
+	 * via the setters
+	 */
+	private void fallBackToConfiguration() {
+		MergeConfig config = MergeConfig.getConfigForCurrentBranch(repo);
+		if (squash == null)
+			squash = Boolean.valueOf(config.isSquash());
+		if (commit == null)
+			commit = Boolean.valueOf(config.isCommit());
+		if (fastForwardMode == null)
+			fastForwardMode = config.getFastForwardMode();
+	}
+
 	private void updateHead(StringBuilder refLogMessage, ObjectId newHeadId,
 			ObjectId oldHeadID) throws IOException,
 			ConcurrentRefUpdateException {
@@ -511,7 +528,7 @@ public class MergeCommand extends GitCommand<MergeResult> {
 	 */
 	public MergeCommand setSquash(boolean squash) {
 		checkCallable();
-		this.squash = squash;
+		this.squash = Boolean.valueOf(squash);
 		return this;
 	}
 
@@ -545,7 +562,7 @@ public class MergeCommand extends GitCommand<MergeResult> {
 	 * @since 3.0
 	 */
 	public MergeCommand setCommit(boolean commit) {
-		this.commit = commit;
+		this.commit = Boolean.valueOf(commit);
 		return this;
 	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/merge/MergeConfig.java b/org.eclipse.jgit/src/org/eclipse/jgit/merge/MergeConfig.java
new file mode 100644
index 0000000000..9125ddfd68
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/merge/MergeConfig.java
@@ -0,0 +1,189 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Konrad Kügler
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *******************************************************************************/
+package org.eclipse.jgit.merge;
+
+import java.io.IOException;
+
+import org.eclipse.jgit.api.MergeCommand.FastForwardMode;
+import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.ConfigConstants;
+import org.eclipse.jgit.lib.Config.SectionParser;
+import org.eclipse.jgit.lib.Repository;
+
+/**
+ * Holds configuration for merging into a given branch
+ *
+ * @since 3.3
+ */
+public class MergeConfig {
+
+	/**
+	 * @param repo
+	 * @return merge configuration for the current branch of the repository
+	 */
+	public static MergeConfig getConfigForCurrentBranch(Repository repo) {
+		try {
+			String branch = repo.getBranch();
+			if (branch != null)
+				return repo.getConfig().get(getParser(branch));
+		} catch (IOException e) {
+			// ignore
+		}
+		// use defaults if branch can't be determined
+		return new MergeConfig();
+	}
+
+	/**
+	 * @param branch
+	 *            short branch name to get the configuration for, as returned
+	 *            e.g. by {@link Repository#getBranch()}
+	 * @return a parser for use with {@link Config#get(SectionParser)}
+	 */
+	public static final SectionParser<MergeConfig> getParser(
+			final String branch) {
+		return new MergeConfigSectionParser(branch);
+	}
+
+	private final FastForwardMode fastForwardMode;
+
+	private final boolean squash;
+
+	private final boolean commit;
+
+	private MergeConfig(String branch, Config config) {
+		String[] mergeOptions = getMergeOptions(branch, config);
+		fastForwardMode = getFastForwardMode(config, mergeOptions);
+		squash = isMergeConfigOptionSet("--squash", mergeOptions); //$NON-NLS-1$
+		commit = !isMergeConfigOptionSet("--no-commit", mergeOptions); //$NON-NLS-1$
+	}
+
+	private MergeConfig() {
+		fastForwardMode = FastForwardMode.FF;
+		squash = false;
+		commit = true;
+	}
+
+	/**
+	 * @return the fast forward mode configured for this branch
+	 */
+	public FastForwardMode getFastForwardMode() {
+		return fastForwardMode;
+	}
+
+	/**
+	 * @return true if merges into this branch are configured to be squash
+	 *         merges, false otherwise
+	 */
+	public boolean isSquash() {
+		return squash;
+	}
+
+	/**
+	 * @return false if --no-commit is configured for this branch, true
+	 *         otherwise (event if --squash is configured)
+	 */
+	public boolean isCommit() {
+		return commit;
+	}
+
+	private static FastForwardMode getFastForwardMode(Config config,
+			String[] mergeOptions) {
+		for (String option : mergeOptions) {
+			for (FastForwardMode mode : FastForwardMode.values())
+				if (mode.matchConfigValue(option))
+					return mode;
+		}
+		FastForwardMode ffmode = FastForwardMode.valueOf(config.getEnum(
+				ConfigConstants.CONFIG_KEY_MERGE, null,
+				ConfigConstants.CONFIG_KEY_FF, FastForwardMode.Merge.TRUE));
+		return ffmode;
+	}
+
+	private static boolean isMergeConfigOptionSet(String optionToLookFor,
+			String[] mergeOptions) {
+		for (String option : mergeOptions) {
+			if (optionToLookFor.equals(option))
+				return true;
+		}
+		return false;
+	}
+
+	private static String[] getMergeOptions(String branch, Config config) {
+		String mergeOptions = config.getString(
+				ConfigConstants.CONFIG_BRANCH_SECTION, branch,
+				ConfigConstants.CONFIG_KEY_MERGEOPTIONS);
+		if (mergeOptions != null)
+			return mergeOptions.split("\\s"); //$NON-NLS-1$
+		else
+			return new String[0];
+	}
+
+	private static class MergeConfigSectionParser implements
+			SectionParser<MergeConfig> {
+
+		private final String branch;
+
+		public MergeConfigSectionParser(String branch) {
+			this.branch = branch;
+		}
+
+		public MergeConfig parse(Config cfg) {
+			return new MergeConfig(branch, cfg);
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (obj instanceof MergeConfigSectionParser)
+				return branch.equals(((MergeConfigSectionParser) obj).branch);
+			else
+				return false;
+		}
+
+		@Override
+		public int hashCode() {
+			return branch.hashCode();
+		}
+
+	}
+
+}