com.google.gerrit.server.git.MergeUtil Maven / Gradle / Ivy
// Copyright (C) 2012 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.server.git;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.collect.ImmutableSet.toImmutableSet;
import static com.google.common.collect.ImmutableSortedSet.toImmutableSortedSet;
import static com.google.gerrit.git.ObjectIds.abbreviateName;
import static java.nio.charset.StandardCharsets.UTF_8;
import static java.util.Comparator.naturalOrder;
import static java.util.stream.Collectors.joining;
import com.google.auto.factory.AutoFactory;
import com.google.auto.factory.Provided;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Sets;
import com.google.common.flogger.FluentLogger;
import com.google.gerrit.common.FooterConstants;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.entities.Account;
import com.google.gerrit.entities.BooleanProjectConfig;
import com.google.gerrit.entities.BranchNameKey;
import com.google.gerrit.entities.Change;
import com.google.gerrit.entities.LabelId;
import com.google.gerrit.entities.LabelType;
import com.google.gerrit.entities.PatchSet;
import com.google.gerrit.entities.PatchSetApproval;
import com.google.gerrit.exceptions.InvalidMergeStrategyException;
import com.google.gerrit.exceptions.MergeWithConflictsNotSupportedException;
import com.google.gerrit.exceptions.StorageException;
import com.google.gerrit.extensions.registration.DynamicItem;
import com.google.gerrit.extensions.restapi.BadRequestException;
import com.google.gerrit.extensions.restapi.MergeConflictException;
import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
import com.google.gerrit.server.ChangeUtil;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.approval.ApprovalsUtil;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.gerrit.server.config.UrlFormatter;
import com.google.gerrit.server.git.CodeReviewCommit.CodeReviewRevWalk;
import com.google.gerrit.server.notedb.ChangeNotes;
import com.google.gerrit.server.project.ProjectState;
import com.google.gerrit.server.submit.ChangeAlreadyMergedException;
import com.google.gerrit.server.submit.CommitMergeStatus;
import com.google.gerrit.server.submit.MergeIdenticalTreeException;
import com.google.gerrit.server.submit.MergeSorter;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import org.eclipse.jgit.diff.Sequence;
import org.eclipse.jgit.dircache.DirCache;
import org.eclipse.jgit.dircache.DirCacheBuilder;
import org.eclipse.jgit.dircache.DirCacheEntry;
import org.eclipse.jgit.errors.AmbiguousObjectException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.LargeObjectException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.errors.NoMergeBaseException;
import org.eclipse.jgit.errors.NoMergeBaseException.MergeBaseFailureReason;
import org.eclipse.jgit.errors.RevisionSyntaxException;
import org.eclipse.jgit.lib.CommitBuilder;
import org.eclipse.jgit.lib.Config;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.PersonIdent;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.merge.MergeFormatter;
import org.eclipse.jgit.merge.MergeResult;
import org.eclipse.jgit.merge.MergeStrategy;
import org.eclipse.jgit.merge.Merger;
import org.eclipse.jgit.merge.ResolveMerger;
import org.eclipse.jgit.merge.ThreeWayMergeStrategy;
import org.eclipse.jgit.merge.ThreeWayMerger;
import org.eclipse.jgit.revwalk.FooterKey;
import org.eclipse.jgit.revwalk.FooterLine;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevFlag;
import org.eclipse.jgit.revwalk.RevSort;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.util.TemporaryBuffer;
/**
* Utility methods used during the merge process.
*
* Note: Unless otherwise specified, the methods in this class do
* not flush {@link ObjectInserter}s. Callers that want to read back objects before
* flushing should use {@link ObjectInserter#newReader()}. This is already the default behavior of
* {@code BatchUpdate}.
*/
@AutoFactory
public class MergeUtil {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
/**
* Length of abbreviated hex SHA-1s in merged filenames.
*
*
This is a constant so output is stable over time even if the SHA-1 prefix becomes ambiguous.
*/
private static final int NAME_ABBREV_LEN = 6;
private static final String R_HEADS_MASTER = Constants.R_HEADS + Constants.MASTER;
public static boolean useRecursiveMerge(Config cfg) {
return cfg.getBoolean("core", null, "useRecursiveMerge", true);
}
public static ThreeWayMergeStrategy getMergeStrategy(Config cfg) {
return useRecursiveMerge(cfg) ? MergeStrategy.RECURSIVE : MergeStrategy.RESOLVE;
}
private final IdentifiedUser.GenericFactory identifiedUserFactory;
private final DynamicItem urlFormatter;
private final ApprovalsUtil approvalsUtil;
private final ProjectState project;
private final boolean useContentMerge;
private final boolean useRecursiveMerge;
private final PluggableCommitMessageGenerator commitMessageGenerator;
MergeUtil(
@Provided @GerritServerConfig Config serverConfig,
@Provided IdentifiedUser.GenericFactory identifiedUserFactory,
@Provided DynamicItem urlFormatter,
@Provided ApprovalsUtil approvalsUtil,
@Provided PluggableCommitMessageGenerator commitMessageGenerator,
ProjectState project) {
this(
serverConfig,
identifiedUserFactory,
urlFormatter,
approvalsUtil,
commitMessageGenerator,
project,
project.is(BooleanProjectConfig.USE_CONTENT_MERGE));
}
MergeUtil(
@Provided @GerritServerConfig Config serverConfig,
@Provided IdentifiedUser.GenericFactory identifiedUserFactory,
@Provided DynamicItem urlFormatter,
@Provided ApprovalsUtil approvalsUtil,
@Provided PluggableCommitMessageGenerator commitMessageGenerator,
ProjectState project,
boolean useContentMerge) {
this.identifiedUserFactory = identifiedUserFactory;
this.urlFormatter = urlFormatter;
this.approvalsUtil = approvalsUtil;
this.commitMessageGenerator = commitMessageGenerator;
this.project = project;
this.useContentMerge = useContentMerge;
this.useRecursiveMerge = useRecursiveMerge(serverConfig);
}
public CodeReviewCommit getFirstFastForward(
CodeReviewCommit mergeTip, RevWalk rw, List toMerge) {
for (Iterator i = toMerge.iterator(); i.hasNext(); ) {
try {
final CodeReviewCommit n = i.next();
if (mergeTip == null || rw.isMergedInto(mergeTip, n)) {
i.remove();
return n;
}
} catch (IOException e) {
throw new StorageException("Cannot fast-forward test during merge", e);
}
}
return mergeTip;
}
public List reduceToMinimalMerge(
MergeSorter mergeSorter, Collection toSort) {
List result = new ArrayList<>();
try {
result.addAll(mergeSorter.sort(toSort));
} catch (IOException | StorageException e) {
throw new StorageException("Branch head sorting failed", e);
}
result.sort(CodeReviewCommit.ORDER);
return result;
}
public CodeReviewCommit createCherryPickFromCommit(
ObjectInserter inserter,
Config repoConfig,
RevCommit mergeTip,
RevCommit originalCommit,
PersonIdent cherryPickCommitterIdent,
String commitMsg,
CodeReviewRevWalk rw,
int parentIndex,
boolean ignoreIdenticalTree,
boolean allowConflicts)
throws IOException, MergeIdenticalTreeException, MergeConflictException,
MethodNotAllowedException, InvalidMergeStrategyException {
ThreeWayMerger m = newThreeWayMerger(inserter, repoConfig);
m.setBase(originalCommit.getParent(parentIndex));
DirCache dc = DirCache.newInCore();
if (allowConflicts && m instanceof ResolveMerger) {
// The DirCache must be set on ResolveMerger before calling
// ResolveMerger#merge(AnyObjectId...) otherwise the entries in DirCache don't get populated.
((ResolveMerger) m).setDirCache(dc);
}
ObjectId tree;
ImmutableSet filesWithGitConflicts;
if (m.merge(mergeTip, originalCommit)) {
filesWithGitConflicts = null;
tree = m.getResultTreeId();
if (tree.equals(mergeTip.getTree()) && !ignoreIdenticalTree) {
throw new MergeIdenticalTreeException("identical tree");
}
} else {
if (!allowConflicts) {
throw new MergeConflictException(
String.format(
"merge conflict while merging commits %s and %s",
mergeTip.toObjectId(), originalCommit.toObjectId()));
}
if (!useContentMerge) {
// If content merge is disabled we don't have a ResolveMerger and hence cannot merge with
// conflict markers.
throw new MethodNotAllowedException(
"Cherry-pick with allow conflicts requires that content merge is enabled.");
}
// For merging with conflict markers we need a ResolveMerger, double-check that we have one.
checkState(m instanceof ResolveMerger, "allow conflicts is not supported");
Map> mergeResults =
((ResolveMerger) m).getMergeResults();
filesWithGitConflicts =
mergeResults.entrySet().stream()
.filter(e -> e.getValue().containsConflicts())
.map(Map.Entry::getKey)
.collect(toImmutableSet());
tree =
mergeWithConflicts(
rw, inserter, dc, "HEAD", mergeTip, "CHANGE", originalCommit, mergeResults);
}
CommitBuilder cherryPickCommit = new CommitBuilder();
cherryPickCommit.setTreeId(tree);
cherryPickCommit.setParentId(mergeTip);
cherryPickCommit.setAuthor(originalCommit.getAuthorIdent());
cherryPickCommit.setCommitter(cherryPickCommitterIdent);
cherryPickCommit.setMessage(commitMsg);
matchAuthorToCommitterDate(project, cherryPickCommit);
CodeReviewCommit commit = rw.parseCommit(inserter.insert(cherryPickCommit));
commit.setFilesWithGitConflicts(filesWithGitConflicts);
return commit;
}
@SuppressWarnings("resource") // TemporaryBuffer requires calling close before reading.
public static ObjectId mergeWithConflicts(
RevWalk rw,
ObjectInserter ins,
DirCache dc,
String oursName,
RevCommit ours,
String theirsName,
RevCommit theirs,
Map> mergeResults)
throws IOException {
rw.parseBody(ours);
rw.parseBody(theirs);
String oursMsg = ours.getShortMessage();
String theirsMsg = theirs.getShortMessage();
int nameLength = Math.max(oursName.length(), theirsName.length());
String oursNameFormatted =
String.format(
"%-" + nameLength + "s (%s %s)",
oursName,
abbreviateName(ours, NAME_ABBREV_LEN),
oursMsg.substring(0, Math.min(oursMsg.length(), 60)));
String theirsNameFormatted =
String.format(
"%-" + nameLength + "s (%s %s)",
theirsName,
abbreviateName(theirs, NAME_ABBREV_LEN),
theirsMsg.substring(0, Math.min(theirsMsg.length(), 60)));
MergeFormatter fmt = new MergeFormatter();
Map resolved = new HashMap<>();
for (Map.Entry> entry : mergeResults.entrySet()) {
MergeResult p = entry.getValue();
TemporaryBuffer buf = null;
try {
// TODO(dborowitz): Respect inCoreLimit here.
buf = new TemporaryBuffer.LocalFile(null, 10 * 1024 * 1024);
fmt.formatMerge(buf, p, "BASE", oursNameFormatted, theirsNameFormatted, UTF_8);
buf.close(); // Flush file and close for writes, but leave available for reading.
try (InputStream in = buf.openInputStream()) {
resolved.put(entry.getKey(), ins.insert(Constants.OBJ_BLOB, buf.length(), in));
}
} finally {
if (buf != null) {
buf.destroy();
}
}
}
DirCacheBuilder builder = dc.builder();
int cnt = dc.getEntryCount();
for (int i = 0; i < cnt; ) {
DirCacheEntry entry = dc.getEntry(i);
if (entry.getStage() == 0) {
builder.add(entry);
i++;
continue;
}
int next = dc.nextEntry(i);
String path = entry.getPathString();
DirCacheEntry res = new DirCacheEntry(path);
if (resolved.containsKey(path)) {
// For a file with content merge conflict that we produced a result
// above on, collapse the file down to a single stage 0 with just
// the blob content, and a randomly selected mode (the lowest stage,
// which should be the merge base, or ours).
res.setFileMode(entry.getFileMode());
res.setObjectId(resolved.get(path));
} else if (next == i + 1) {
// If there is exactly one stage present, shouldn't be a conflict...
res.setFileMode(entry.getFileMode());
res.setObjectId(entry.getObjectId());
} else if (next == i + 2) {
// Two stages suggests a delete/modify conflict. Pick the higher
// stage as the automatic result.
entry = dc.getEntry(i + 1);
res.setFileMode(entry.getFileMode());
res.setObjectId(entry.getObjectId());
} else {
// 3 stage conflict, no resolve above
// Punt on the 3-stage conflict and show the base, for now.
res.setFileMode(entry.getFileMode());
res.setObjectId(entry.getObjectId());
}
builder.add(res);
i = next;
}
builder.finish();
return dc.writeTree(ins);
}
public static CodeReviewCommit createMergeCommit(
ObjectInserter inserter,
Config repoConfig,
RevCommit mergeTip,
RevCommit originalCommit,
String mergeStrategy,
boolean allowConflicts,
PersonIdent committerIdent,
String commitMsg,
CodeReviewRevWalk rw)
throws IOException, MergeIdenticalTreeException, MergeConflictException,
InvalidMergeStrategyException {
return createMergeCommit(
inserter,
repoConfig,
mergeTip,
originalCommit,
mergeStrategy,
allowConflicts,
committerIdent,
committerIdent,
commitMsg,
rw);
}
public static CodeReviewCommit createMergeCommit(
ObjectInserter inserter,
Config repoConfig,
RevCommit mergeTip,
RevCommit originalCommit,
String mergeStrategy,
boolean allowConflicts,
PersonIdent authorIdent,
PersonIdent committerIdent,
String commitMsg,
CodeReviewRevWalk rw)
throws IOException, MergeIdenticalTreeException, MergeConflictException,
InvalidMergeStrategyException {
if (!MergeStrategy.THEIRS.getName().equals(mergeStrategy)
&& rw.isMergedInto(originalCommit, mergeTip)) {
throw new ChangeAlreadyMergedException(
"'" + originalCommit.getName() + "' has already been merged");
}
Merger m = newMerger(inserter, repoConfig, mergeStrategy);
DirCache dc = DirCache.newInCore();
if (allowConflicts && m instanceof ResolveMerger) {
// The DirCache must be set on ResolveMerger before calling
// ResolveMerger#merge(AnyObjectId...) otherwise the entries in DirCache don't get populated.
((ResolveMerger) m).setDirCache(dc);
}
ObjectId tree;
ImmutableSet filesWithGitConflicts;
if (m.merge(false, mergeTip, originalCommit)) {
filesWithGitConflicts = null;
tree = m.getResultTreeId();
} else {
List conflicts = ImmutableList.of();
if (m instanceof ResolveMerger) {
conflicts = ((ResolveMerger) m).getUnmergedPaths();
}
if (!allowConflicts) {
throw new MergeConflictException(createConflictMessage(conflicts));
}
// For merging with conflict markers we need a ResolveMerger, double-check that we have one.
if (!(m instanceof ResolveMerger)) {
throw new MergeWithConflictsNotSupportedException(MergeStrategy.get(mergeStrategy));
}
Map> mergeResults =
((ResolveMerger) m).getMergeResults();
filesWithGitConflicts =
mergeResults.entrySet().stream()
.filter(e -> e.getValue().containsConflicts())
.map(Map.Entry::getKey)
.collect(toImmutableSet());
tree =
mergeWithConflicts(
rw,
inserter,
dc,
"TARGET BRANCH",
mergeTip,
"SOURCE BRANCH",
originalCommit,
mergeResults);
}
CommitBuilder mergeCommit = new CommitBuilder();
mergeCommit.setTreeId(tree);
mergeCommit.setParentIds(mergeTip, originalCommit);
mergeCommit.setAuthor(authorIdent);
mergeCommit.setCommitter(committerIdent);
mergeCommit.setMessage(commitMsg);
CodeReviewCommit commit = rw.parseCommit(inserter.insert(mergeCommit));
commit.setFilesWithGitConflicts(filesWithGitConflicts);
return commit;
}
public static String createConflictMessage(List conflicts) {
if (conflicts.isEmpty()) {
return "";
}
StringBuilder sb = new StringBuilder("merge conflict(s):");
for (String c : conflicts) {
sb.append('\n').append(c);
}
return sb.toString();
}
/**
* Adds footers to existing commit message based on the state of the change.
*
* This adds the following footers if they are missing:
*
*
* - Reviewed-on: url
*
- Reviewed-by | Tested-by | Other-Label-Name: reviewer
*
- Change-Id
*
*
* @return new message
*/
private String createDetailedCommitMessage(RevCommit n, ChangeNotes notes, PatchSet.Id psId) {
Change c = notes.getChange();
final List footers = n.getFooterLines();
final StringBuilder msgbuf = new StringBuilder();
msgbuf.append(n.getFullMessage());
if (msgbuf.length() == 0) {
// WTF, an empty commit message?
msgbuf.append("");
}
if (msgbuf.charAt(msgbuf.length() - 1) != '\n') {
// Missing a trailing LF? Correct it (perhaps the editor was broken).
msgbuf.append('\n');
}
if (footers.isEmpty()) {
// Doesn't end in a "Signed-off-by: ..." style line? Add another line
// break to start a new paragraph for the reviewed-by tag lines.
//
msgbuf.append('\n');
}
if (ChangeUtil.getChangeIdsFromFooter(n, urlFormatter.get()).isEmpty()) {
msgbuf.append(FooterConstants.CHANGE_ID.getName());
msgbuf.append(": ");
msgbuf.append(c.getKey().get());
msgbuf.append('\n');
}
Optional url = urlFormatter.get().getChangeViewUrl(c.getProject(), c.getId());
if (url.isPresent()) {
if (!contains(footers, FooterConstants.REVIEWED_ON, url.get())) {
msgbuf
.append(FooterConstants.REVIEWED_ON.getName())
.append(": ")
.append(url.get())
.append('\n');
}
}
PatchSetApproval submitAudit = null;
for (PatchSetApproval a : safeGetApprovals(notes, psId)) {
if (a.value() <= 0) {
// Negative votes aren't counted.
continue;
}
if (a.isLegacySubmit()) {
// Submit is treated specially, below (becomes committer)
//
if (submitAudit == null || a.granted().compareTo(submitAudit.granted()) > 0) {
submitAudit = a;
}
continue;
}
final Account acc = identifiedUserFactory.create(a.accountId()).getAccount();
final StringBuilder identbuf = new StringBuilder();
if (acc.fullName() != null && acc.fullName().length() > 0) {
if (identbuf.length() > 0) {
identbuf.append(' ');
}
identbuf.append(acc.fullName());
}
if (acc.preferredEmail() != null && acc.preferredEmail().length() > 0) {
if (isSignedOffBy(footers, acc.preferredEmail())) {
continue;
}
if (identbuf.length() > 0) {
identbuf.append(' ');
}
identbuf.append('<');
identbuf.append(acc.preferredEmail());
identbuf.append('>');
}
if (identbuf.length() == 0) {
// Nothing reasonable to describe them by? Ignore them.
continue;
}
final String tag;
if (isCodeReview(a.labelId())) {
tag = "Reviewed-by";
} else if (isVerified(a.labelId())) {
tag = "Tested-by";
} else {
final Optional lt = project.getLabelTypes().byLabel(a.labelId());
if (!lt.isPresent()) {
continue;
}
tag = lt.get().getName();
}
if (!contains(footers, new FooterKey(tag), identbuf.toString())) {
msgbuf.append(tag);
msgbuf.append(": ");
msgbuf.append(identbuf);
msgbuf.append('\n');
}
}
return msgbuf.toString();
}
public String createCommitMessageOnSubmit(CodeReviewCommit n, RevCommit mergeTip) {
return createCommitMessageOnSubmit(n, mergeTip, n.notes(), n.getPatchsetId());
}
/**
* Creates a commit message for a change, which can be customized by plugins.
*
* By default, adds footers to existing commit message based on the state of the change.
* Plugins implementing {@link ChangeMessageModifier} can modify the resulting commit message
* arbitrarily.
*
* @return new message
*/
public String createCommitMessageOnSubmit(
RevCommit n, @Nullable RevCommit mergeTip, ChangeNotes notes, PatchSet.Id id) {
return commitMessageGenerator.generate(
n, mergeTip, notes.getChange().getDest(), createDetailedCommitMessage(n, notes, id));
}
private static boolean isCodeReview(LabelId id) {
return LabelId.CODE_REVIEW.equalsIgnoreCase(id.get());
}
private static boolean isVerified(LabelId id) {
return LabelId.VERIFIED.equalsIgnoreCase(id.get());
}
private Iterable safeGetApprovals(ChangeNotes notes, PatchSet.Id psId) {
try {
return approvalsUtil.byPatchSet(notes, psId);
} catch (StorageException e) {
logger.atSevere().withCause(e).log("Can't read approval records for %s", psId);
return Collections.emptyList();
}
}
private static boolean contains(List footers, FooterKey key, String val) {
for (FooterLine line : footers) {
if (line.matches(key) && val.equals(line.getValue())) {
return true;
}
}
return false;
}
private static boolean isSignedOffBy(List footers, String email) {
for (FooterLine line : footers) {
if (line.matches(FooterKey.SIGNED_OFF_BY) && email.equals(line.getEmailAddress())) {
return true;
}
}
return false;
}
public boolean canMerge(
MergeSorter mergeSorter,
Repository repo,
CodeReviewCommit mergeTip,
CodeReviewCommit toMerge) {
if (hasMissingDependencies(mergeSorter, toMerge)) {
return false;
}
try (ObjectInserter ins = new InMemoryInserter(repo)) {
return newThreeWayMerger(ins, repo.getConfig()).merge(mergeTip, toMerge);
} catch (LargeObjectException e) {
logger.atWarning().log("Cannot merge due to LargeObjectException: %s", toMerge.name());
return false;
} catch (NoMergeBaseException e) {
return false;
} catch (IOException e) {
throw new StorageException("Cannot merge " + toMerge.name(), e);
}
}
public boolean canFastForward(
MergeSorter mergeSorter,
CodeReviewCommit mergeTip,
CodeReviewRevWalk rw,
CodeReviewCommit toMerge) {
if (hasMissingDependencies(mergeSorter, toMerge)) {
return false;
}
try {
return mergeTip == null
|| rw.isMergedInto(mergeTip, toMerge)
|| rw.isMergedInto(toMerge, mergeTip);
} catch (IOException e) {
throw new StorageException("Cannot fast-forward test during merge", e);
}
}
public boolean canCherryPick(
MergeSorter mergeSorter,
Repository repo,
CodeReviewCommit mergeTip,
CodeReviewRevWalk rw,
CodeReviewCommit toMerge) {
if (mergeTip == null) {
// The branch is unborn. Fast-forward is possible.
//
return true;
}
if (toMerge.getParentCount() == 0) {
// Refuse to merge a root commit into an existing branch,
// we cannot obtain a delta for the cherry-pick to apply.
//
return false;
}
if (toMerge.getParentCount() == 1) {
// If there is only one parent, a cherry-pick can be done by
// taking the delta relative to that one parent and redoing
// that on the current merge tip.
//
try (ObjectInserter ins = new InMemoryInserter(repo)) {
ThreeWayMerger m = newThreeWayMerger(ins, repo.getConfig());
m.setBase(toMerge.getParent(0));
return m.merge(mergeTip, toMerge);
} catch (IOException e) {
throw new StorageException(
String.format(
"Cannot merge commit %s with mergetip %s", toMerge.name(), mergeTip.name()),
e);
}
}
// There are multiple parents, so this is a merge commit. We
// don't want to cherry-pick the merge as clients can't easily
// rebase their history with that merge present and replaced
// by an equivalent merge with a different first parent. So
// instead behave as though MERGE_IF_NECESSARY was configured.
//
return canFastForward(mergeSorter, mergeTip, rw, toMerge)
|| canMerge(mergeSorter, repo, mergeTip, toMerge);
}
public boolean hasMissingDependencies(MergeSorter mergeSorter, CodeReviewCommit toMerge) {
try {
return !mergeSorter.sort(Collections.singleton(toMerge)).contains(toMerge);
} catch (IOException | StorageException e) {
throw new StorageException("Branch head sorting failed", e);
}
}
public CodeReviewCommit mergeOneCommit(
PersonIdent author,
PersonIdent committer,
CodeReviewRevWalk rw,
ObjectInserter inserter,
Config repoConfig,
BranchNameKey destBranch,
CodeReviewCommit mergeTip,
CodeReviewCommit n)
throws InvalidMergeStrategyException {
ThreeWayMerger m = newThreeWayMerger(inserter, repoConfig);
try {
if (m.merge(mergeTip, n)) {
return writeMergeCommit(
author, committer, rw, inserter, destBranch, mergeTip, m.getResultTreeId(), n);
}
failed(rw, mergeTip, n, CommitMergeStatus.PATH_CONFLICT);
} catch (NoMergeBaseException e) {
try {
failed(rw, mergeTip, n, getCommitMergeStatus(e.getReason()));
} catch (IOException e2) {
throw new StorageException("Cannot merge " + n.name(), e2);
}
} catch (IOException e) {
throw new StorageException("Cannot merge " + n.name(), e);
}
return mergeTip;
}
private static CommitMergeStatus getCommitMergeStatus(MergeBaseFailureReason reason) {
switch (reason) {
case MULTIPLE_MERGE_BASES_NOT_SUPPORTED:
case TOO_MANY_MERGE_BASES:
default:
return CommitMergeStatus.MANUAL_RECURSIVE_MERGE;
case CONFLICTS_DURING_MERGE_BASE_CALCULATION:
return CommitMergeStatus.PATH_CONFLICT;
}
}
private static CodeReviewCommit failed(
CodeReviewRevWalk rw,
CodeReviewCommit mergeTip,
CodeReviewCommit n,
CommitMergeStatus failure)
throws MissingObjectException, IncorrectObjectTypeException, IOException {
rw.reset();
rw.markStart(n);
rw.markUninteresting(mergeTip);
CodeReviewCommit failed;
while ((failed = rw.next()) != null) {
failed.setStatusCode(failure);
}
return failed;
}
public CodeReviewCommit writeMergeCommit(
PersonIdent author,
PersonIdent committer,
CodeReviewRevWalk rw,
ObjectInserter inserter,
BranchNameKey destBranch,
CodeReviewCommit mergeTip,
ObjectId treeId,
CodeReviewCommit n)
throws IOException, MissingObjectException, IncorrectObjectTypeException {
final List merged = new ArrayList<>();
rw.reset();
rw.markStart(n);
rw.markUninteresting(mergeTip);
CodeReviewCommit crc;
while ((crc = rw.next()) != null) {
if (crc.getPatchsetId() != null) {
merged.add(crc);
}
}
StringBuilder msgbuf = new StringBuilder().append(summarize(rw, merged));
if (!R_HEADS_MASTER.equals(destBranch.branch())) {
msgbuf.append(" into ");
msgbuf.append(destBranch.shortName());
}
if (merged.size() > 1) {
msgbuf.append("\n\n* changes:\n");
for (CodeReviewCommit c : merged) {
rw.parseBody(c);
msgbuf.append(" ");
msgbuf.append(c.getShortMessage());
msgbuf.append("\n");
}
}
final CommitBuilder mergeCommit = new CommitBuilder();
mergeCommit.setTreeId(treeId);
mergeCommit.setParentIds(mergeTip, n);
mergeCommit.setAuthor(author);
mergeCommit.setCommitter(committer);
mergeCommit.setMessage(msgbuf.toString());
CodeReviewCommit mergeResult = rw.parseCommit(inserter.insert(mergeCommit));
mergeResult.setNotes(n.getNotes());
return mergeResult;
}
private String summarize(RevWalk rw, List merged) throws IOException {
if (merged.size() == 1) {
CodeReviewCommit c = merged.get(0);
rw.parseBody(c);
return String.format("Merge \"%s\"", c.getShortMessage());
}
ImmutableSortedSet topics =
merged.stream()
.map(c -> c.change().getTopic())
.filter(t -> !Strings.isNullOrEmpty(t))
.map(t -> "\"" + t + "\"")
.collect(toImmutableSortedSet(naturalOrder()));
if (!topics.isEmpty()) {
return String.format(
"Merge changes from topic%s %s",
topics.size() > 1 ? "s" : "", topics.stream().collect(joining(", ")));
}
return merged.stream()
.limit(5)
.map(c -> c.change().getKey().abbreviate())
.collect(joining(",", "Merge changes ", merged.size() > 5 ? ", ..." : ""));
}
public ThreeWayMerger newThreeWayMerger(ObjectInserter inserter, Config repoConfig)
throws InvalidMergeStrategyException {
return newThreeWayMerger(inserter, repoConfig, mergeStrategyName());
}
public String mergeStrategyName() {
return mergeStrategyName(useContentMerge, useRecursiveMerge);
}
public static String mergeStrategyName(boolean useContentMerge, boolean useRecursiveMerge) {
String mergeStrategy;
if (useContentMerge) {
// Settings for this project allow us to try and automatically resolve
// conflicts within files if needed. Use either the old resolve merger or
// new recursive merger, and instruct to operate in core.
if (useRecursiveMerge) {
mergeStrategy = MergeStrategy.RECURSIVE.getName();
} else {
mergeStrategy = MergeStrategy.RESOLVE.getName();
}
} else {
// No auto conflict resolving allowed. If any of the
// affected files was modified, merge will fail.
mergeStrategy = MergeStrategy.SIMPLE_TWO_WAY_IN_CORE.getName();
}
logger.atFine().log(
"mergeStrategy = %s (useContentMerge = %s, useRecursiveMerge = %s)",
mergeStrategy, useContentMerge, useRecursiveMerge);
return mergeStrategy;
}
public static ThreeWayMerger newThreeWayMerger(
ObjectInserter inserter, Config repoConfig, String strategyName)
throws InvalidMergeStrategyException {
Merger m = newMerger(inserter, repoConfig, strategyName);
checkArgument(
m instanceof ThreeWayMerger,
"merge strategy %s does not support three-way merging",
strategyName);
return (ThreeWayMerger) m;
}
public static Merger newMerger(ObjectInserter inserter, Config repoConfig, String strategyName)
throws InvalidMergeStrategyException {
MergeStrategy strategy = MergeStrategy.get(strategyName);
if (strategy == null) {
throw new InvalidMergeStrategyException(strategyName);
}
return strategy.newMerger(
new ObjectInserter.Filter() {
@Override
protected ObjectInserter delegate() {
return inserter;
}
@Override
public void flush() {}
@Override
public void close() {}
},
repoConfig);
}
public void markCleanMerges(
RevWalk rw, RevFlag canMergeFlag, CodeReviewCommit mergeTip, Set alreadyAccepted) {
if (mergeTip == null) {
// If mergeTip is null here, branchTip was null, indicating a new branch
// at the start of the merge process. We also elected to merge nothing,
// probably due to missing dependencies. Nothing was cleanly merged.
//
return;
}
try {
rw.resetRetain(canMergeFlag);
rw.sort(RevSort.TOPO);
rw.sort(RevSort.REVERSE, true);
rw.markStart(mergeTip);
for (RevCommit c : alreadyAccepted) {
// If branch was not created by this submit.
if (!Objects.equals(c, mergeTip)) {
rw.markUninteresting(c);
}
}
CodeReviewCommit c;
while ((c = (CodeReviewCommit) rw.next()) != null) {
if (c.getPatchsetId() != null && c.getStatusCode() == null) {
c.setStatusCode(CommitMergeStatus.CLEAN_MERGE);
}
}
} catch (IOException e) {
throw new StorageException("Cannot mark clean merges", e);
}
}
public Set findUnmergedChanges(
Set expected,
CodeReviewRevWalk rw,
RevFlag canMergeFlag,
CodeReviewCommit oldTip,
CodeReviewCommit mergeTip,
Iterable alreadyMerged) {
if (mergeTip == null) {
return expected;
}
try {
Set found = Sets.newHashSetWithExpectedSize(expected.size());
Iterables.addAll(found, alreadyMerged);
rw.resetRetain(canMergeFlag);
rw.sort(RevSort.TOPO);
rw.markStart(mergeTip);
if (oldTip != null) {
rw.markUninteresting(oldTip);
}
CodeReviewCommit c;
while ((c = rw.next()) != null) {
if (c.getPatchsetId() == null) {
continue;
}
Change.Id id = c.getPatchsetId().changeId();
if (!expected.contains(id)) {
continue;
}
found.add(id);
if (found.size() == expected.size()) {
return Collections.emptySet();
}
}
return Sets.difference(expected, found);
} catch (IOException e) {
throw new StorageException("Cannot check if changes were merged", e);
}
}
public static CodeReviewCommit findAnyMergedInto(
CodeReviewRevWalk rw, Iterable commits, CodeReviewCommit tip)
throws IOException {
for (CodeReviewCommit c : commits) {
// TODO(dborowitz): Seems like this could get expensive for many patch
// sets. Is there a more efficient implementation?
if (rw.isMergedInto(c, tip)) {
return c;
}
}
return null;
}
public static RevCommit resolveCommit(Repository repo, RevWalk rw, String str)
throws BadRequestException, ResourceNotFoundException, IOException {
try {
ObjectId commitId = repo.resolve(str);
if (commitId == null) {
throw new BadRequestException("Cannot resolve '" + str + "' to a commit");
}
return rw.parseCommit(commitId);
} catch (AmbiguousObjectException | IncorrectObjectTypeException | RevisionSyntaxException e) {
throw new BadRequestException(e.getMessage());
} catch (MissingObjectException e) {
throw new ResourceNotFoundException(e.getMessage());
}
}
private static void matchAuthorToCommitterDate(ProjectState project, CommitBuilder commit) {
if (project.is(BooleanProjectConfig.MATCH_AUTHOR_TO_COMMITTER_DATE)) {
commit.setAuthor(
new PersonIdent(
commit.getAuthor(),
commit.getCommitter().getWhen(),
commit.getCommitter().getTimeZone()));
}
}
}