Add mergetool merge feature (execute external tool)

see: https://git-scm.com/docs/git-mergetool

* implement mergetool merge function (execute external tool)
* add ExecutionResult and commandExecutionError to ToolException
* handle "base not present" case (empty or null base file path)
* handle deleted (rm) and modified (add) conflicts
* handle settings
 * keepBackup
 * keepTemporaries
 * writeToTemp

Bug: 356832
Change-Id: Id323c2fcb1c24d12ceb299801df8bac51a6d463f
Signed-off-by: Andre Bossert <andre.bossert@siemens.com>

4 files changed, 305 insertions, 69 deletions

diff --git a/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties b/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
index 8e2eef7eb2..674185df2b 100644
--- a/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
+++ b/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
@@ -58,8 +58,8 @@ couldNotCreateBranch=Could not create branch {0}: {1}
 dateInfo=Date:   {0}
 deletedBranch=Deleted branch {0}
 deletedRemoteBranch=Deleted remote branch {0}
-diffToolHelpSetToFollowing='git difftool --tool=<tool>' may be set to one of the following:\n{0}\n\tuser-defined:\n{1}\nThe following tools are valid, but not currently available:\n{2}\nSome of the tools listed above only work in a windowed\nenvironment. If run in a terminal-only session, they will fail.
-diffToolLaunch=Viewing ({0}/{1}): '{2}'\nLaunch '{3}' [Y/n]?
+diffToolHelpSetToFollowing=''git difftool --tool=<tool>'' may be set to one of the following:\n{0}\n\tuser-defined:\n{1}\nThe following tools are valid, but not currently available:\n{2}\nSome of the tools listed above only work in a windowed\nenvironment. If run in a terminal-only session, they will fail.
+diffToolLaunch=Viewing ({0}/{1}): ''{2}''\nLaunch ''{3}'' [Y/n]?
 diffToolDied=external diff died, stopping at path ''{0}'' due to exception: {1}
 doesNotExist={0} does not exist
 dontOverwriteLocalChanges=error: Your local changes to the following file would be overwritten by merge:
@@ -91,6 +91,22 @@ listeningOn=Listening on {0}
 logNoSignatureVerifier="No signature verifier available"
 mergeConflict=CONFLICT(content): Merge conflict in {0}
 mergeCheckoutConflict=error: Your local changes to the following files would be overwritten by merge:
+mergeToolHelpSetToFollowing=''git mergetool --tool=<tool>'' may be set to one of the following:\n{0}\n\tuser-defined:\n{1}\nThe following tools are valid, but not currently available:\n{2}\nSome of the tools listed above only work in a windowed\nenvironment. If run in a terminal-only session, they will fail.
+mergeToolLaunch=Hit return to start merge resolution tool ({0}):
+mergeToolDied=local or remote cannot be found in cache, stopping at {0}
+mergeToolNoFiles=No files need merging
+mergeToolMerging=Merging:\n{0}
+mergeToolUnknownConflict=\nUnknown merge conflict for ''{0}'':
+mergeToolNormalConflict=\nNormal merge conflict for ''{0}'':\n  '{'local'}': modified file\n  '{'remote'}': modified file
+mergeToolMergeFailed=merge of {0} failed
+mergeToolExecutionError=excution error
+mergeToolFileUnchanged=\n{0} seems unchanged.
+mergeToolDeletedConflict=\nDeleted merge conflict for ''{0}'':
+mergeToolDeletedConflictByUs=  {local}: deleted\n  {remote}: modified file
+mergeToolDeletedConflictByThem=  {local}: modified file\n  {remote}: deleted
+mergeToolContinueUnresolvedPaths=\nContinue merging other unresolved paths [y/n]?
+mergeToolWasMergeSuccessfull=Was the merge successful [y/n]?
+mergeToolDeletedMergeDecision=Use (m)odified or (d)eleted file, or (a)bort?
 mergeFailed=Automatic merge failed; fix conflicts and then commit the result
 mergeCheckoutFailed=Please, commit your changes or stash them before you can merge.
 mergeMadeBy=Merge made by the ''{0}'' strategy.
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/DiffTool.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/DiffTool.java
index 2e90d52cba..ffba36fe20 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/DiffTool.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/DiffTool.java
@@ -113,11 +113,14 @@ class DiffTool extends TextBuiltin {
 	@Option(name = "--", metaVar = "metaVar_paths", handler = PathTreeFilterHandler.class)
 	private TreeFilter pathFilter = TreeFilter.ALL;
 
+	private BufferedReader inputReader;
+
 	@Override
 	protected void init(Repository repository, String gitDir) {
 		super.init(repository, gitDir);
 		diffFmt = new DiffFormatter(new BufferedOutputStream(outs));
 		diffTools = new DiffTools(repository);
+		inputReader = new BufferedReader(new InputStreamReader(ins, StandardCharsets.UTF_8));
 	}
 
 	@Override
@@ -208,10 +211,9 @@ class DiffTool extends TextBuiltin {
 			String fileName, String toolNamePrompt) throws IOException {
 		boolean launchCompare = true;
 		outw.println(MessageFormat.format(CLIText.get().diffToolLaunch,
-				fileIndex, fileCount, fileName, toolNamePrompt));
+				fileIndex, fileCount, fileName, toolNamePrompt) + " "); //$NON-NLS-1$
 		outw.flush();
-		BufferedReader br = new BufferedReader(
-				new InputStreamReader(ins, StandardCharsets.UTF_8));
+		BufferedReader br = inputReader;
 		String line = null;
 		if ((line = br.readLine()) != null) {
 			if (!line.equalsIgnoreCase("Y")) { //$NON-NLS-1$
@@ -224,17 +226,18 @@ class DiffTool extends TextBuiltin {
 	private void showToolHelp() throws IOException {
 		StringBuilder availableToolNames = new StringBuilder();
 		for (String name : diffTools.getAvailableTools().keySet()) {
-			availableToolNames.append(String.format("\t\t%s\n", name)); //$NON-NLS-1$
+			availableToolNames.append(MessageFormat.format("\t\t{0}\n", name)); //$NON-NLS-1$
 		}
 		StringBuilder notAvailableToolNames = new StringBuilder();
 		for (String name : diffTools.getNotAvailableTools().keySet()) {
-			notAvailableToolNames.append(String.format("\t\t%s\n", name)); //$NON-NLS-1$
+			notAvailableToolNames
+					.append(MessageFormat.format("\t\t{0}\n", name)); //$NON-NLS-1$
 		}
 		StringBuilder userToolNames = new StringBuilder();
 		Map<String, ExternalDiffTool> userTools = diffTools
 				.getUserDefinedTools();
 		for (String name : userTools.keySet()) {
-			userToolNames.append(String.format("\t\t%s.cmd %s\n", //$NON-NLS-1$
+			userToolNames.append(MessageFormat.format("\t\t{0}.cmd {1}\n", //$NON-NLS-1$
 					name, userTools.get(name).getCommand()));
 		}
 		outw.println(MessageFormat.format(
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/MergeTool.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/MergeTool.java
index 37afa54c78..dce5a7996d 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/MergeTool.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/MergeTool.java
@@ -11,26 +11,35 @@
 package org.eclipse.jgit.pgm;
 
 import java.io.BufferedReader;
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.text.MessageFormat;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.Optional;
 import java.util.TreeMap;
 
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.Status;
 import org.eclipse.jgit.api.StatusCommand;
 import org.eclipse.jgit.api.errors.GitAPIException;
-import org.eclipse.jgit.internal.diffmergetool.ExternalMergeTool;
+import org.eclipse.jgit.diff.ContentSource;
+import org.eclipse.jgit.dircache.DirCache;
+import org.eclipse.jgit.dircache.DirCacheEntry;
 import org.eclipse.jgit.errors.NoWorkTreeException;
 import org.eclipse.jgit.errors.RevisionSyntaxException;
+import org.eclipse.jgit.internal.diffmergetool.ExternalMergeTool;
+import org.eclipse.jgit.internal.diffmergetool.FileElement;
 import org.eclipse.jgit.internal.diffmergetool.MergeTools;
+import org.eclipse.jgit.internal.diffmergetool.ToolException;
 import org.eclipse.jgit.lib.IndexDiff.StageState;
-import org.eclipse.jgit.lib.internal.BooleanTriState;
+import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.lib.internal.BooleanTriState;
+import org.eclipse.jgit.pgm.internal.CLIText;
+import org.eclipse.jgit.util.FS.ExecutionResult;
 import org.kohsuke.args4j.Argument;
 import org.kohsuke.args4j.Option;
 import org.kohsuke.args4j.spi.RestOfArgumentsHandler;
@@ -43,16 +52,16 @@ class MergeTool extends TextBuiltin {
 			"-t" }, metaVar = "metaVar_tool", usage = "usage_ToolForMerge")
 	private String toolName;
 
-	private Optional<Boolean> prompt = Optional.empty();
+	private BooleanTriState prompt = BooleanTriState.UNSET;
 
 	@Option(name = "--prompt", usage = "usage_prompt")
 	void setPrompt(@SuppressWarnings("unused") boolean on) {
-		prompt = Optional.of(Boolean.TRUE);
+		prompt = BooleanTriState.TRUE;
 	}
 
 	@Option(name = "--no-prompt", aliases = { "-y" }, usage = "usage_noPrompt")
 	void noPrompt(@SuppressWarnings("unused") boolean on) {
-		prompt = Optional.of(Boolean.FALSE);
+		prompt = BooleanTriState.FALSE;
 	}
 
 	@Option(name = "--tool-help", usage = "usage_toolHelp")
@@ -74,10 +83,17 @@ class MergeTool extends TextBuiltin {
 	@Option(name = "--", metaVar = "metaVar_paths", handler = RestOfArgumentsHandler.class)
 	protected List<String> filterPaths;
 
+	private BufferedReader inputReader;
+
 	@Override
 	protected void init(Repository repository, String gitDir) {
 		super.init(repository, gitDir);
 		mergeTools = new MergeTools(repository);
+		inputReader = new BufferedReader(new InputStreamReader(ins));
+	}
+
+	enum MergeResult {
+		SUCCESSFUL, FAILED, ABORTED
 	}
 
 	@Override
@@ -88,8 +104,8 @@ class MergeTool extends TextBuiltin {
 			} else {
 				// get prompt
 				boolean showPrompt = mergeTools.isInteractive();
-				if (prompt.isPresent()) {
-					showPrompt = prompt.get().booleanValue();
+				if (prompt != BooleanTriState.UNSET) {
+					showPrompt = prompt == BooleanTriState.TRUE;
 				}
 				// get passed or default tool name
 				String toolNameSelected = toolName;
@@ -101,7 +117,7 @@ class MergeTool extends TextBuiltin {
 				if (files.size() > 0) {
 					merge(files, showPrompt, toolNameSelected);
 				} else {
-					outw.println("No files need merging"); //$NON-NLS-1$
+					outw.println(CLIText.get().mergeToolNoFiles);
 				}
 			}
 			outw.flush();
@@ -113,88 +129,273 @@ class MergeTool extends TextBuiltin {
 	private void merge(Map<String, StageState> files, boolean showPrompt,
 			String toolNamePrompt) throws Exception {
 		// sort file names
-		List<String> fileNames = new ArrayList<>(files.keySet());
-		Collections.sort(fileNames);
+		List<String> mergedFilePaths = new ArrayList<>(files.keySet());
+		Collections.sort(mergedFilePaths);
 		// show the files
-		outw.println("Merging:"); //$NON-NLS-1$
-		for (String fileName : fileNames) {
-			outw.println(fileName);
+		StringBuilder mergedFiles = new StringBuilder();
+		for (String mergedFilePath : mergedFilePaths) {
+			mergedFiles.append(MessageFormat.format("{0}\n", mergedFilePath)); //$NON-NLS-1$
 		}
+		outw.println(MessageFormat.format(CLIText.get().mergeToolMerging,
+				mergedFiles));
 		outw.flush();
-		for (String fileName : fileNames) {
-			StageState fileState = files.get(fileName);
-			// only both-modified is valid for mergetool
-			if (fileState == StageState.BOTH_MODIFIED) {
-				outw.println("\nNormal merge conflict for '" + fileName + "':"); //$NON-NLS-1$ //$NON-NLS-2$
-				outw.println("  {local}: modified file"); //$NON-NLS-1$
-				outw.println("  {remote}: modified file"); //$NON-NLS-1$
-				// check if user wants to launch merge resolution tool
-				boolean launch = true;
-				if (showPrompt) {
-					launch = isLaunch(toolNamePrompt);
-				}
-				if (launch) {
-					outw.println("TODO: Launch mergetool '" + toolNamePrompt //$NON-NLS-1$
-							+ "' for path '" + fileName + "'..."); //$NON-NLS-1$ //$NON-NLS-2$
-				} else {
-					break;
+		// merge the files
+		MergeResult mergeResult = MergeResult.SUCCESSFUL;
+		for (String mergedFilePath : mergedFilePaths) {
+			// if last merge failed...
+			if (mergeResult == MergeResult.FAILED) {
+				// check if user wants to continue
+				if (showPrompt && !isContinueUnresolvedPaths()) {
+					mergeResult = MergeResult.ABORTED;
 				}
-			} else if ((fileState == StageState.DELETED_BY_US) || (fileState == StageState.DELETED_BY_THEM)) {
-				outw.println("\nDeleted merge conflict for '" + fileName + "':"); //$NON-NLS-1$ //$NON-NLS-2$
+			}
+			// aborted ?
+			if (mergeResult == MergeResult.ABORTED) {
+				break;
+			}
+			// get file stage state and merge
+			StageState fileState = files.get(mergedFilePath);
+			if (fileState == StageState.BOTH_MODIFIED) {
+				mergeResult = mergeModified(mergedFilePath, showPrompt,
+						toolNamePrompt);
+			} else if ((fileState == StageState.DELETED_BY_US)
+					|| (fileState == StageState.DELETED_BY_THEM)) {
+				mergeResult = mergeDeleted(mergedFilePath,
+						fileState == StageState.DELETED_BY_US);
 			} else {
+				outw.println(MessageFormat.format(
+						CLIText.get().mergeToolUnknownConflict,
+						mergedFilePath));
+				mergeResult = MergeResult.ABORTED;
+			}
+		}
+	}
+
+	private MergeResult mergeModified(String mergedFilePath, boolean showPrompt,
+			String toolNamePrompt) throws Exception {
+		outw.println(MessageFormat.format(CLIText.get().mergeToolNormalConflict,
+				mergedFilePath));
+		outw.flush();
+		// check if user wants to launch merge resolution tool
+		boolean launch = true;
+		if (showPrompt) {
+			launch = isLaunch(toolNamePrompt);
+		}
+		if (!launch) {
+			return MergeResult.ABORTED; // abort
+		}
+		boolean isMergeSuccessful = true;
+		ContentSource baseSource = ContentSource.create(db.newObjectReader());
+		ContentSource localSource = ContentSource.create(db.newObjectReader());
+		ContentSource remoteSource = ContentSource.create(db.newObjectReader());
+		try {
+			FileElement base = null;
+			FileElement local = null;
+			FileElement remote = null;
+			DirCache cache = db.readDirCache();
+			int firstIndex = cache.findEntry(mergedFilePath);
+			if (firstIndex >= 0) {
+				int nextIndex = cache.nextEntry(firstIndex);
+				for (; firstIndex < nextIndex; firstIndex++) {
+					DirCacheEntry entry = cache.getEntry(firstIndex);
+					ObjectId id = entry.getObjectId();
+					switch (entry.getStage()) {
+					case DirCacheEntry.STAGE_1:
+						base = new FileElement(mergedFilePath, id.name(),
+								baseSource.open(mergedFilePath, id)
+										.openStream());
+						break;
+					case DirCacheEntry.STAGE_2:
+						local = new FileElement(mergedFilePath, id.name(),
+								localSource.open(mergedFilePath, id)
+										.openStream());
+						break;
+					case DirCacheEntry.STAGE_3:
+						remote = new FileElement(mergedFilePath, id.name(),
+								remoteSource.open(mergedFilePath, id)
+										.openStream());
+						break;
+					}
+				}
+			}
+			if ((local == null) || (remote == null)) {
+				throw die(MessageFormat.format(CLIText.get().mergeToolDied,
+						mergedFilePath));
+			}
+			File merged = new File(mergedFilePath);
+			long modifiedBefore = merged.lastModified();
+			try {
+				// TODO: check how to return the exit-code of the
+				// tool to jgit / java runtime ?
+				// int rc =...
+				ExecutionResult executionResult = mergeTools.merge(db, local,
+						remote, base, mergedFilePath, toolName, prompt, gui);
 				outw.println(
-						"\nUnknown merge conflict for '" + fileName + "':"); //$NON-NLS-1$ //$NON-NLS-2$
+						new String(executionResult.getStdout().toByteArray()));
+				outw.flush();
+				errw.println(
+						new String(executionResult.getStderr().toByteArray()));
+				errw.flush();
+			} catch (ToolException e) {
+				isMergeSuccessful = false;
+				outw.println(e.getResultStdout());
+				outw.flush();
+				errw.println(MessageFormat.format(
+						CLIText.get().mergeToolMergeFailed, mergedFilePath));
+				errw.flush();
+				if (e.isCommandExecutionError()) {
+					errw.println(e.getMessage());
+					throw die(CLIText.get().mergeToolExecutionError, e);
+				}
+			}
+			// if merge was successful check file modified
+			if (isMergeSuccessful) {
+				long modifiedAfter = merged.lastModified();
+				if (modifiedBefore == modifiedAfter) {
+					outw.println(MessageFormat.format(
+							CLIText.get().mergeToolFileUnchanged,
+							mergedFilePath));
+					isMergeSuccessful = !showPrompt || isMergeSuccessful();
+				}
+			}
+			// if automatically or manually successful
+			// -> add the file to the index
+			if (isMergeSuccessful) {
+				addFile(mergedFilePath);
+			}
+		} finally {
+			baseSource.close();
+			localSource.close();
+			remoteSource.close();
+		}
+		return isMergeSuccessful ? MergeResult.SUCCESSFUL : MergeResult.FAILED;
+	}
+
+	private MergeResult mergeDeleted(String mergedFilePath, boolean deletedByUs)
+			throws Exception {
+		outw.println(MessageFormat.format(CLIText.get().mergeToolFileUnchanged,
+				mergedFilePath));
+		if (deletedByUs) {
+			outw.println(CLIText.get().mergeToolDeletedConflictByUs);
+		} else {
+			outw.println(CLIText.get().mergeToolDeletedConflictByThem);
+		}
+		int mergeDecision = getDeletedMergeDecision();
+		if (mergeDecision == 1) {
+			// add modified file
+			addFile(mergedFilePath);
+		} else if (mergeDecision == -1) {
+			// remove deleted file
+			rmFile(mergedFilePath);
+		} else {
+			return MergeResult.ABORTED;
+		}
+		return MergeResult.SUCCESSFUL;
+	}
+
+	private void addFile(String fileName) throws Exception {
+		try (Git git = new Git(db)) {
+			git.add().addFilepattern(fileName).call();
+		}
+	}
+
+	private void rmFile(String fileName) throws Exception {
+		try (Git git = new Git(db)) {
+			git.rm().addFilepattern(fileName).call();
+		}
+	}
+
+	private boolean hasUserAccepted(String message) throws IOException {
+		boolean yes = true;
+		outw.print(message + " "); //$NON-NLS-1$
+		outw.flush();
+		BufferedReader br = inputReader;
+		String line = null;
+		while ((line = br.readLine()) != null) {
+			if (line.equalsIgnoreCase("y")) { //$NON-NLS-1$
+				yes = true;
+				break;
+			} else if (line.equalsIgnoreCase("n")) { //$NON-NLS-1$
+				yes = false;
 				break;
 			}
+			outw.print(message);
+			outw.flush();
 		}
+		return yes;
+	}
+
+	private boolean isContinueUnresolvedPaths() throws IOException {
+		return hasUserAccepted(CLIText.get().mergeToolContinueUnresolvedPaths);
+	}
+
+	private boolean isMergeSuccessful() throws IOException {
+		return hasUserAccepted(CLIText.get().mergeToolWasMergeSuccessfull);
 	}
 
-	private boolean isLaunch(String toolNamePrompt)
-			throws IOException {
+	private boolean isLaunch(String toolNamePrompt) throws IOException {
 		boolean launch = true;
-		outw.println("Hit return to start merge resolution tool (" //$NON-NLS-1$
-				+ toolNamePrompt + "): "); //$NON-NLS-1$
+		outw.print(MessageFormat.format(CLIText.get().mergeToolLaunch,
+				toolNamePrompt) + " "); //$NON-NLS-1$
 		outw.flush();
-		BufferedReader br = new BufferedReader(new InputStreamReader(ins));
+		BufferedReader br = inputReader;
 		String line = null;
 		if ((line = br.readLine()) != null) {
-			if (!line.equalsIgnoreCase("Y") && !line.equalsIgnoreCase("")) { //$NON-NLS-1$ //$NON-NLS-2$
+			if (!line.equalsIgnoreCase("y") && !line.equalsIgnoreCase("")) { //$NON-NLS-1$ //$NON-NLS-2$
 				launch = false;
 			}
 		}
 		return launch;
 	}
 
+	private int getDeletedMergeDecision() throws IOException {
+		int ret = 0; // abort
+		final String message = CLIText.get().mergeToolDeletedMergeDecision
+				+ " "; //$NON-NLS-1$
+		outw.print(message);
+		outw.flush();
+		BufferedReader br = inputReader;
+		String line = null;
+		while ((line = br.readLine()) != null) {
+			if (line.equalsIgnoreCase("m")) { //$NON-NLS-1$
+				ret = 1; // modified
+				break;
+			} else if (line.equalsIgnoreCase("d")) { //$NON-NLS-1$
+				ret = -1; // deleted
+				break;
+			} else if (line.equalsIgnoreCase("a")) { //$NON-NLS-1$
+				break;
+			}
+			outw.print(message);
+			outw.flush();
+		}
+		return ret;
+	}
+
 	private void showToolHelp() throws IOException {
-		outw.println(
-				"'git mergetool --tool=<tool>' may be set to one of the following:"); //$NON-NLS-1$
+		StringBuilder availableToolNames = new StringBuilder();
 		for (String name : mergeTools.getAvailableTools().keySet()) {
-			outw.println("\t\t" + name); //$NON-NLS-1$
+			availableToolNames.append(MessageFormat.format("\t\t{0}\n", name)); //$NON-NLS-1$
 		}
-		outw.println(""); //$NON-NLS-1$
-		outw.println("\tuser-defined:"); //$NON-NLS-1$
+		StringBuilder notAvailableToolNames = new StringBuilder();
+		for (String name : mergeTools.getNotAvailableTools().keySet()) {
+			notAvailableToolNames
+					.append(MessageFormat.format("\t\t{0}\n", name)); //$NON-NLS-1$
+		}
+		StringBuilder userToolNames = new StringBuilder();
 		Map<String, ExternalMergeTool> userTools = mergeTools
 				.getUserDefinedTools();
 		for (String name : userTools.keySet()) {
-			outw.println("\t\t" + name + ".cmd " //$NON-NLS-1$ //$NON-NLS-2$
-					+ userTools.get(name).getCommand());
-		}
-		outw.println(""); //$NON-NLS-1$
-		outw.println(
-				"The following tools are valid, but not currently available:"); //$NON-NLS-1$
-		for (String name : mergeTools.getNotAvailableTools().keySet()) {
-			outw.println("\t\t" + name); //$NON-NLS-1$
+			userToolNames.append(MessageFormat.format("\t\t{0}.cmd {1}\n", //$NON-NLS-1$
+					name, userTools.get(name).getCommand()));
 		}
-		outw.println(""); //$NON-NLS-1$
-		outw.println("Some of the tools listed above only work in a windowed"); //$NON-NLS-1$
-		outw.println(
-				"environment. If run in a terminal-only session, they will fail."); //$NON-NLS-1$
-		return;
+		outw.println(MessageFormat.format(
+				CLIText.get().mergeToolHelpSetToFollowing, availableToolNames,
+				userToolNames, notAvailableToolNames));
 	}
 
-	private Map<String, StageState> getFiles()
-			throws RevisionSyntaxException, NoWorkTreeException,
-			GitAPIException {
+	private Map<String, StageState> getFiles() throws RevisionSyntaxException,
+			NoWorkTreeException, GitAPIException {
 		Map<String, StageState> files = new TreeMap<>();
 		try (Git git = new Git(db)) {
 			StatusCommand statusCommand = git.status();
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/internal/CLIText.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/internal/CLIText.java
index 7fe5b0fa45..989e649b72 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/internal/CLIText.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/internal/CLIText.java
@@ -169,6 +169,22 @@ public class CLIText extends TranslationBundle {
 	/***/ public String logNoSignatureVerifier;
 	/***/ public String mergeCheckoutConflict;
 	/***/ public String mergeConflict;
+	/***/ public String mergeToolHelpSetToFollowing;
+	/***/ public String mergeToolLaunch;
+	/***/ public String mergeToolDied;
+	/***/ public String mergeToolNoFiles;
+	/***/ public String mergeToolMerging;
+	/***/ public String mergeToolUnknownConflict;
+	/***/ public String mergeToolNormalConflict;
+	/***/ public String mergeToolMergeFailed;
+	/***/ public String mergeToolExecutionError;
+	/***/ public String mergeToolFileUnchanged;
+	/***/ public String mergeToolDeletedConflict;
+	/***/ public String mergeToolDeletedConflictByUs;
+	/***/ public String mergeToolDeletedConflictByThem;
+	/***/ public String mergeToolContinueUnresolvedPaths;
+	/***/ public String mergeToolWasMergeSuccessfull;
+	/***/ public String mergeToolDeletedMergeDecision;
 	/***/ public String mergeFailed;
 	/***/ public String mergeCheckoutFailed;
 	/***/ public String mergeMadeBy;