com.google.gerrit.server.git.strategy.RebaseIfNecessary.java Source code

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// 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.strategy;

import com.google.common.collect.Lists;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.reviewdb.client.PatchSet;
import com.google.gerrit.reviewdb.client.PatchSetApproval;
import com.google.gerrit.server.change.PatchSetInserter.ValidatePolicy;
import com.google.gerrit.server.change.RebaseChange;
import com.google.gerrit.server.git.CodeReviewCommit;
import com.google.gerrit.server.git.CommitMergeStatus;
import com.google.gerrit.server.git.MergeConflictException;
import com.google.gerrit.server.git.MergeException;
import com.google.gerrit.server.git.MergeTip;
import com.google.gerrit.server.git.RebaseSorter;
import com.google.gerrit.server.patch.PatchSetInfoFactory;
import com.google.gerrit.server.project.InvalidChangeOperationException;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gwtorm.server.OrmException;

import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.PersonIdent;

import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class RebaseIfNecessary extends SubmitStrategy {
    private final PatchSetInfoFactory patchSetInfoFactory;
    private final RebaseChange rebaseChange;
    private final Map<Change.Id, CodeReviewCommit> newCommits;

    RebaseIfNecessary(SubmitStrategy.Arguments args, PatchSetInfoFactory patchSetInfoFactory,
            RebaseChange rebaseChange) {
        super(args);
        this.patchSetInfoFactory = patchSetInfoFactory;
        this.rebaseChange = rebaseChange;
        this.newCommits = new HashMap<>();
    }

    @Override
    protected MergeTip _run(final CodeReviewCommit branchTip, final Collection<CodeReviewCommit> toMerge)
            throws MergeException {
        MergeTip mergeTip = new MergeTip(branchTip, toMerge);
        List<CodeReviewCommit> sorted = sort(toMerge);
        while (!sorted.isEmpty()) {
            CodeReviewCommit n = sorted.remove(0);

            if (mergeTip.getCurrentTip() == null) {
                // The branch is unborn. Take a fast-forward resolution to
                // create the branch.
                //
                n.setStatusCode(CommitMergeStatus.CLEAN_MERGE);
                mergeTip.moveTipTo(n, n);

            } else if (n.getParentCount() == 0) {
                // Refuse to merge a root commit into an existing branch,
                // we cannot obtain a delta for the rebase to apply.
                //
                n.setStatusCode(CommitMergeStatus.CANNOT_REBASE_ROOT);

            } else if (n.getParentCount() == 1) {
                if (args.mergeUtil.canFastForward(args.mergeSorter, mergeTip.getCurrentTip(), args.rw, n)) {
                    n.setStatusCode(CommitMergeStatus.CLEAN_MERGE);
                    mergeTip.moveTipTo(n, n);

                } else {
                    try {
                        PatchSet newPatchSet = rebaseChange.rebase(args.repo, args.rw, args.inserter, n.change(),
                                n.getPatchsetId(), args.caller, mergeTip.getCurrentTip(), args.mergeUtil,
                                args.serverIdent.get(), false, ValidatePolicy.NONE);
                        List<PatchSetApproval> approvals = Lists.newArrayList();
                        for (PatchSetApproval a : args.approvalsUtil.byPatchSet(args.db, n.getControl(),
                                n.getPatchsetId())) {
                            approvals.add(new PatchSetApproval(newPatchSet.getId(), a));
                        }
                        // rebaseChange.rebase() may already have copied some approvals,
                        // use upsert, not insert, to avoid constraint violation on database
                        args.db.patchSetApprovals().upsert(approvals);
                        CodeReviewCommit newTip = args.rw
                                .parseCommit(ObjectId.fromString(newPatchSet.getRevision().get()));
                        mergeTip.moveTipTo(newTip, newTip);
                        n.change().setCurrentPatchSet(
                                patchSetInfoFactory.get(mergeTip.getCurrentTip(), newPatchSet.getId()));
                        mergeTip.getCurrentTip().copyFrom(n);
                        mergeTip.getCurrentTip()
                                .setControl(args.changeControlFactory.controlFor(n.change(), args.caller));
                        mergeTip.getCurrentTip().setPatchsetId(newPatchSet.getId());
                        mergeTip.getCurrentTip().setStatusCode(CommitMergeStatus.CLEAN_REBASE);
                        newCommits.put(newPatchSet.getId().getParentKey(), mergeTip.getCurrentTip());
                        setRefLogIdent();
                    } catch (MergeConflictException e) {
                        n.setStatusCode(CommitMergeStatus.REBASE_MERGE_CONFLICT);
                    } catch (NoSuchChangeException | OrmException | IOException
                            | InvalidChangeOperationException e) {
                        throw new MergeException("Cannot rebase " + n.name(), e);
                    }
                }

            } else if (n.getParentCount() > 1) {
                // There are multiple parents, so this is a merge commit. We
                // don't want to rebase 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.
                //
                try {
                    if (args.rw.isMergedInto(mergeTip.getCurrentTip(), n)) {
                        mergeTip.moveTipTo(n, n);
                    } else {
                        PersonIdent myIdent = args.serverIdent.get();
                        mergeTip.moveTipTo(args.mergeUtil.mergeOneCommit(myIdent, myIdent, args.repo, args.rw,
                                args.inserter, args.canMergeFlag, args.destBranch, mergeTip.getCurrentTip(), n), n);
                    }
                    args.mergeUtil.markCleanMerges(args.rw, args.canMergeFlag, mergeTip.getCurrentTip(),
                            args.alreadyAccepted);
                    setRefLogIdent();
                } catch (IOException e) {
                    throw new MergeException("Cannot merge " + n.name(), e);
                }
            }

            args.alreadyAccepted.add(mergeTip.getCurrentTip());
        }

        return mergeTip;
    }

    private List<CodeReviewCommit> sort(Collection<CodeReviewCommit> toSort) throws MergeException {
        try {
            List<CodeReviewCommit> result = new RebaseSorter(args.rw, args.alreadyAccepted, args.canMergeFlag)
                    .sort(toSort);
            Collections.sort(result, CodeReviewCommit.ORDER);
            return result;
        } catch (IOException e) {
            throw new MergeException("Commit sorting failed", e);
        }
    }

    @Override
    public Map<Change.Id, CodeReviewCommit> getNewCommits() {
        return newCommits;
    }

    @Override
    public boolean dryRun(CodeReviewCommit mergeTip, CodeReviewCommit toMerge) throws MergeException {
        return !args.mergeUtil.hasMissingDependencies(args.mergeSorter, toMerge)
                && args.mergeUtil.canCherryPick(args.mergeSorter, args.repo, mergeTip, args.rw, toMerge);
    }
}