Performing 'svn merge URL_TO_TRUNK BRANCH_WC' and handling conflicts with SVNKit
This example is similar to Merging from trunk to a branch except for that the merge to the branch working copy produces a conflict since we make some changes to the same files in the branch working copy. In this example we demonstrate how you can handle conflicts programmatically using ISVNConflictHandler.
1 /*
2 * ====================================================================
3 * Copyright (c) 2004-2008 TMate Software Ltd. All rights reserved.
4 *
5 * This software is licensed as described in the file COPYING, which
6 * you should have received as part of this distribution. The terms
7 * are also available at http://svnkit.com/license.html.
8 * If newer versions of this license are posted there, you may use a
9 * newer version instead, at your option.
10 * ====================================================================
11 */
12 package org.tmatesoft.svn.examples.wc;
13
14 import java.io.File;
15 import java.io.IOException;
16 import java.util.Collections;
17
18 import org.tmatesoft.svn.core.SVNCommitInfo;
19 import org.tmatesoft.svn.core.SVNDepth;
20 import org.tmatesoft.svn.core.SVNException;
21 import org.tmatesoft.svn.core.SVNPropertyValue;
22 import org.tmatesoft.svn.core.SVNURL;
23 import org.tmatesoft.svn.core.internal.wc.DefaultSVNOptions;
24 import org.tmatesoft.svn.core.wc.ISVNConflictHandler;
25 import org.tmatesoft.svn.core.wc.SVNClientManager;
26 import org.tmatesoft.svn.core.wc.SVNCommitClient;
27 import org.tmatesoft.svn.core.wc.SVNConflictChoice;
28 import org.tmatesoft.svn.core.wc.SVNConflictDescription;
29 import org.tmatesoft.svn.core.wc.SVNConflictReason;
30 import org.tmatesoft.svn.core.wc.SVNConflictResult;
31 import org.tmatesoft.svn.core.wc.SVNCopyClient;
32 import org.tmatesoft.svn.core.wc.SVNCopySource;
33 import org.tmatesoft.svn.core.wc.SVNDiffClient;
34 import org.tmatesoft.svn.core.wc.SVNMergeFileSet;
35 import org.tmatesoft.svn.core.wc.SVNRevision;
36 import org.tmatesoft.svn.core.wc.SVNRevisionRange;
37 import org.tmatesoft.svn.core.wc.SVNWCClient;
38
39
40 /**
41 * @version 1.2.0
42 * @author TMate Software Ltd.
43 */
44 public class ConflictedMerge {
45 /**
46 * Pass the absolute path of the base directory where all example data will be created in
47 * arg[0]. The sample will create:
48 *
49 * - arg[0]/exampleRepository - repository with some test data
50 * - arg[0]/exampleWC - working copy checked out from exampleRepository
51 */
52 public static void main (String[] args) {
53 //initialize SVNKit to work through file:/// protocol
54 SamplesUtility.initializeFSFSprotocol();
55
56 File baseDirectory = new File(args[0]);
57 File reposRoot = new File(baseDirectory, "exampleRepository");
58 File wcRoot = new File(baseDirectory, "exampleWC");
59
60 try {
61 //first create a repository and fill it with data
62 SamplesUtility.createRepository(reposRoot);
63 SVNCommitInfo info = SamplesUtility.createRepositoryTree(reposRoot);
64 //print out new revision info
65 System.out.println(info);
66
67 SVNClientManager clientManager = SVNClientManager.newInstance();
68
69 SVNURL reposURL = SVNURL.fromFile(reposRoot);
70
71 //copy A to A_copy in repository (url-to-url copy)
72 SVNCopyClient copyClient = clientManager.getCopyClient();
73 SVNURL A_URL = reposURL.appendPath("A", true);
74 SVNURL copyTargetURL = reposURL.appendPath("A_copy", true);
75 SVNCopySource copySource = new SVNCopySource(SVNRevision.UNDEFINED, SVNRevision.HEAD, A_URL);
76 info = copyClient.doCopy(new SVNCopySource[] { copySource }, copyTargetURL, false, false, true,
77 "copy A to A_copy", null);
78 //print out new revision info
79 System.out.println(info);
80
81 //checkout the entire repository tree
82 SamplesUtility.checkOutWorkingCopy(reposURL, wcRoot);
83
84
85 //now make some changes to the A tree
86 SamplesUtility.writeToFile(new File(wcRoot, "A/B/lambda"), "New text appended to 'lambda'", true);
87 SamplesUtility.writeToFile(new File(wcRoot, "A/mu"), "New text in 'mu'", false);
88
89 SVNWCClient wcClient = SVNClientManager.newInstance().getWCClient();
90 wcClient.doSetProperty(new File(wcRoot, "A/B"), "spam", SVNPropertyValue.create("egg"), false,
91 SVNDepth.EMPTY, null, null);
92
93 //commit local changes
94 SVNCommitClient commitClient = clientManager.getCommitClient();
95 commitClient.doCommit(new File[] { wcRoot }, false, "committing changes", null, null, false, false, SVNDepth.INFINITY);
96
97 //now make some local changes to the A_copy tree
98 //change file contents of A_copy/B/lambda and A_copy/mu
99 SamplesUtility.writeToFile(new File(wcRoot, "A_copy/B/lambda"), "New text in copied 'lambda'", true);
100 SamplesUtility.writeToFile(new File(wcRoot, "A_copy/mu"), "New text in copied 'mu'", false);
101
102 //now diff the base revision of the working copy against the repository
103 SVNDiffClient diffClient = clientManager.getDiffClient();
104
105 /*
106 * Since we provided no custom ISVNOptions implementation to SVNClientManager, our
107 * manager uses DefaultSVNOptions, which is set to all SVN*Client classes which the
108 * manager produces. So, we can cast ISVNOptions to DefaultSVNOptions.
109 */
110 DefaultSVNOptions options = (DefaultSVNOptions) diffClient.getOptions();
111 //This way we set a conflict handler which will automatically resolve conflicts for those
112 //cases that we would like
113 options.setConflictHandler(new ConflictResolverHandler());
114
115 /* do the same merge call, merge-tracking feature will merge only those revisions
116 * which were not still merged.
117 */
118 SVNRevisionRange rangeToMerge = new SVNRevisionRange(SVNRevision.create(1), SVNRevision.HEAD);
119 diffClient.doMerge(A_URL, SVNRevision.HEAD, Collections.singleton(rangeToMerge),
120 new File(wcRoot, "A_copy"), SVNDepth.UNKNOWN, true, false, false, false);
121
122 } catch (SVNException svne) {
123 System.out.println(svne.getErrorMessage());
124 System.exit(1);
125 } catch (IOException ioe) {
126 ioe.printStackTrace();
127 System.exit(1);
128 }
129 }
130
131 /**
132 * Conflict resolver which always selects the local version of a file.
133 *
134 * @version 1.2.0
135 * @author TMate Software Ltd.
136 */
137 private static class ConflictResolverHandler implements ISVNConflictHandler {
138
139 public SVNConflictResult handleConflict(SVNConflictDescription conflictDescription) throws SVNException {
140 SVNConflictReason reason = conflictDescription.getConflictReason();
141 SVNMergeFileSet mergeFiles = conflictDescription.getMergeFiles();
142
143 SVNConflictChoice choice = SVNConflictChoice.THEIRS_FULL;
144 if (reason == SVNConflictReason.EDITED) {
145 //If the reason why conflict occurred is local edits, chose local version of the file
146 //Otherwise the repository version of the file will be chosen.
147 choice = SVNConflictChoice.MINE_FULL;
148 }
149 System.out.println("Automatically resolving conflict for " + mergeFiles.getWCFile() +
150 ", choosing " + (choice == SVNConflictChoice.MINE_FULL ? "local file" : "repository file"));
151 return new SVNConflictResult(choice, mergeFiles.getResultFile());
152 }
153
154 }
155 }
Remarks on the example
When no custom run-time options object (ISVNOptions) is set to the SVNDiffClient (in our case by SVNClientManager), DefaultSVNOptions will be used. This default implementation of run-time options provides a default implementation of ISVNMerger - DefaultSVNMerger - merge driver which is used to merge files and properties. This DefaultSVNMerger can use the caller's implementation of ISVNConflictHandler for automatic conflict resolution. A conflict handler is provided through DefaultSVNOptions, so we set our custom conflict handler - ConflictResolverHandler - to the DefaultSVNOptions used by our SVNDiffClient. Our handler instructs the merge driver to choose a local working copy file in case of a conflict given that the conflict itself is caused by our local edits to the file. In all other cases we just say:"Just take what the repository is giving us".
When you run the program you will see an output similar to this one:
r1 by 'alex' at Thu Sep 04 18:05:00 CEST 2008 r2 by 'alex' at Thu Sep 04 18:05:00 CEST 2008 Automatically resolving conflict for /home/alex/workspace/tmp/exampleWC/A_copy/B/lambda, choosing local file Automatically resolving conflict for /home/alex/workspace/tmp/exampleWC/A_copy/mu, choosing local file