vcs: add Hash::zero

[edvbld]

Hi all,

please review this small refactoring that adds the method Hash::zero
representing an empty hash. The zero hash was already used throughout the code
base but in a less clear way.

Testing:

• make test passes on Linux x64

Thanks,
Erik

---

Progress

• Change must not contain extraneous whitespace
• Change must be properly reviewed

Reviewers

• Robin Westberg (rwestberg - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/skara pull/469/head:pull/469
$ git checkout pull/469

[bridgekeeper]

👋 Welcome back ehelin! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request.

[mlbridge]

Webrevs

• 00: Full (2c2c69c)

[rwestberg]

Looks good!

[openjdk]

@edvbld This change now passes all automated pre-integration checks. When the change also fulfills all project specific requirements, type /integrate in a new comment to proceed. After integration, the commit message will be:

vcs: add Hash::zero

Reviewed-by: rwestberg

• If you would like to add a summary, use the /summary command.
• To credit additional contributors, use the /contributor command.
• To add additional solved issues, use the /solves command.

Since the source branch of this PR was last updated there has been 1 commit pushed to the master branch. Since there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid automatic rebasing, please merge master into your branch, and then specify the current head hash when integrating, like this: /integrate 0e9e8412256251e2c2c182343d21465838f4617f.

➡️ To integrate this PR with the above commit message, type /integrate in a new comment.

[edvbld]

/integrate

[openjdk]

@edvbld The following commits have been pushed to master since your change was applied:

• 0e9e841: Make the rest request error transform optional

Your commit was automatically rebased without conflicts.

Pushed as commit b090b57.

[mlbridge]

Mailing list message from Erik Helin on skara-dev:

Changeset: b090b57
Author: Erik Helin <ehelin at openjdk.org>
Date: 2020-02-24 14:14:32 +0000
URL: https://git.openjdk.java.net/skara/commit/b090b57c

vcs: add Hash::zero

Reviewed-by: rwestberg

! forge/src/test/java/org/openjdk/skara/forge/CheckBuilderTests.java
! jcheck/src/test/java/org/openjdk/skara/jcheck/BinaryCheckTests.java
! jcheck/src/test/java/org/openjdk/skara/jcheck/ExecutableCheckTests.java
! jcheck/src/test/java/org/openjdk/skara/jcheck/HgTagCommitCheckTests.java
! jcheck/src/test/java/org/openjdk/skara/jcheck/WhitespaceCheckTests.java
! vcs/src/main/java/org/openjdk/skara/vcs/CommitMetadata.java
! vcs/src/main/java/org/openjdk/skara/vcs/Hash.java
! vcs/src/main/java/org/openjdk/skara/vcs/Patch.java
! vcs/src/main/java/org/openjdk/skara/vcs/git/GitCommitMetadata.java
! vcs/src/main/java/org/openjdk/skara/vcs/hg/HgRepository.java
! vcs/src/main/java/org/openjdk/skara/vcs/openjdk/convert/GitToHgConverter.java
! vcs/src/main/java/org/openjdk/skara/vcs/openjdk/convert/HgToGitConverter.java
! vcs/src/test/java/org/openjdk/skara/vcs/RepositoryTests.java