static diff()

in resources/perf.webkit.org/public/v3/models/commit-set.js [209:262]
45 lines of code
18 McCabe index (conditional complexity)

    static diff(firstCommitSet, secondCommitSet)
    {
        console.assert(!firstCommitSet.equals(secondCommitSet));
        const allRepositories = new Set([...firstCommitSet.repositories(), ...secondCommitSet.repositories()]);
        const sortedRepositories = Repository.sortByNamePreferringOnesWithURL([...allRepositories]);
        const nameParts = [];
        const missingCommit = {label: () => 'none'};
        const missingPatch = {filename: () => 'none'};
        const makeNameGenerator = () => {
            const existingNameSet = new Set;
            return (name) => {
                const newName = CommitSet.createNameWithoutCollision(name, existingNameSet);
                existingNameSet.add(newName);
                return newName;
            }
        };

        for (const repository of sortedRepositories) {
            const firstCommit = firstCommitSet.commitForRepository(repository) || missingCommit;
            const secondCommit = secondCommitSet.commitForRepository(repository) || missingCommit;
            const firstPatch = firstCommitSet.patchForRepository(repository) || missingPatch;
            const secondPatch = secondCommitSet.patchForRepository(repository) || missingPatch;
            const nameGenerator = makeNameGenerator();

            if (firstCommit == secondCommit && firstPatch == secondPatch)
                continue;

            if (firstCommit != secondCommit && firstPatch == secondPatch)
                nameParts.push(`${repository.name()}: ${secondCommit.diff(firstCommit).label}`);

            // FIXME: It would be nice if we can abbreviate the name when it's too long.
            const nameForFirstPatch = nameGenerator(firstPatch.filename());
            const nameForSecondPath = nameGenerator(secondPatch.filename());

            if (firstCommit == secondCommit && firstPatch != secondPatch)
                nameParts.push(`${repository.name()}: ${nameForFirstPatch} - ${nameForSecondPath}`);

            if (firstCommit != secondCommit && firstPatch != secondPatch)
                nameParts.push(`${repository.name()}: ${firstCommit.label()} with ${nameForFirstPatch} - ${secondCommit.label()} with ${nameForSecondPath}`);
        }

        if (firstCommitSet.allRootFiles().length || secondCommitSet.allRootFiles().length) {
            const firstRootFileSet = new Set(firstCommitSet.allRootFiles());
            const secondRootFileSet = new Set(secondCommitSet.allRootFiles());
            const uniqueInFirstCommitSet = firstCommitSet.allRootFiles().filter((rootFile) => !secondRootFileSet.has(rootFile));
            const uniqueInSecondCommitSet = secondCommitSet.allRootFiles().filter((rootFile) => !firstRootFileSet.has(rootFile));
            const nameGenerator = makeNameGenerator();
            const firstDescription = uniqueInFirstCommitSet.map((rootFile) => nameGenerator(rootFile.filename())).join(', ');
            const secondDescription = uniqueInSecondCommitSet.map((rootFile) => nameGenerator(rootFile.filename())).join(', ');
            nameParts.push(`Roots: ${firstDescription || 'none'} - ${secondDescription || 'none'}`);
        }

        return nameParts.join(' ');
    }