IDEA-157915: Fix symbolic-ref in HEAD

[illabefat]

No description provided.

[klikh]

Have you submitted a contributor license agreement? If not, please check your mail box: I've just sent a sign request there via DocuSign.

[illabefat]

Yes, I've just signed it.

[klikh]

Received, thanks.

I see that you've at first closed this pull request right after creation, and then reopened it a week later. But Github doesn't show any new/rewritten commits here. You just wanted to test it more, or you closed it by accident?

[illabefat]

Yes, I just wanted PR to be first reviewed by my colleagues, but accidentally created it in JetBrains repo instead of my fork

[klikh]

Looks like this should be changed to

  @NotNull
  File getBranchFile(@NotNull String fullBranchName) {
    return file(myMainDir.getPath() + slash(fullBranchName));
  }

(see other get*File methods and isBranchFile())

[klikh]

Merged the patch with a few mentioned corrections. Thanks a lot!

[klikh]

Ah. Together we missed the fact that the linked reference can reside in .git/packed-refs. Currently it leads to RepoStateException: Couldn't load file /Users/loki/temp/t/.git/refs/heads/master.
Seems that this fix can't be easily adjusted. Temporary reverted.

[illabefat]

And how can this happen? symbolic-ref in origin?

[klikh]

git pack-refs --all makes everything packed, including refs/heads/master thus the code can't find .git/refs/heads/master written in .git/HEAD.

It seems that to solve the issue we'll have first to read all references to a map, both from .git/refs and .git/packed-refs, and then resolve them by following links inside the map.

[illabefat]

Thank you, I'll try to do something with this.

[klikh]

Cool, thanks. I've written a test which reveals the issue.

package git4idea.repo

import com.intellij.openapi.util.io.FileUtil
import com.intellij.openapi.vfs.LocalFileSystem
import git4idea.branch.GitBranchUtil.stripRefsPrefix
import git4idea.test.GitExecutor.cd
import git4idea.test.GitExecutor.git
import git4idea.test.GitPlatformTest
import git4idea.test.GitTestUtil.makeCommit
import java.io.File

class GitRepositoryReaderNew2Test : GitPlatformTest() {

  fun `test packed symbolic ref`() {
    cd(myProjectPath)
    git("init")
    makeCommit("file.txt")
    git("pack-refs --all")

    // verify master is packed
    val gitDir = LocalFileSystem.getInstance().refreshAndFindFileByIoFile(File(myProjectPath, ".git"))!!
    val repoFiles = GitRepositoryFiles.getInstance(gitDir)

    assertFalse("setup failed: master is not packed", File(repoFiles.refsHeadsFile, "master").exists())
    assertTrue("setup failed: master is not packed",
               FileUtil.loadFile(repoFiles.packedRefsPath).lines().any { it.endsWith("refs/heads/master") })

    val repo = GitRepositoryImpl.getInstance(myProjectRoot, myProject, false)
    assertEquals("HEAD should be on master", "master", stripRefsPrefix(repo.currentBranchName!!))
    assertEquals("HEAD revision is incorrect", git("rev-parse HEAD"), repo.currentRevision)
    assertEquals("master revision is incorrect",
                 git("rev-parse master"),
                 repo.branches.getHash(repo.branches.findLocalBranch("master")!!)!!.asString())
  }
}