{
  "id": "git-branching-and-merge",
  "title": "Resolve a Real Merge Conflict",
  "category": "Git",
  "isolation_type": "shared_namespace",
  "difficulty": "Medium",
  "type": "task",
  "weight": 6,
  "description": "## Resolve a Real Merge Conflict\n\nA repository at `/srv/git-lab-branch/` already has two branches (`main` and `feature`) that both changed the SAME line of `shared.txt` differently — merging them WILL conflict.\n\n**Your task:**\n\n1. Make sure you're on the `main` branch\n2. Merge `feature` into it: `git merge feature`\n3. Git will report a conflict — open `shared.txt` and you'll see conflict markers (`<<<<<<<`, `=======`, `>>>>>>>`)\n4. Edit the file to remove the markers and decide on final content (either version, both, or something new — your choice)\n5. Stage the resolved file and commit to complete the merge",
  "hints": [
    {
      "title": "What the conflict markers mean",
      "body": "Everything between `<<<<<<< HEAD` and `=======` is YOUR current branch's version; everything between `=======` and `>>>>>>> feature` is the incoming branch's version. Delete all three marker lines and keep whichever content (or combination) you actually want.",
      "command": "cat /srv/git-lab-branch/shared.txt"
    },
    {
      "title": "Completing the merge",
      "body": "Once the file no longer has conflict markers, staging and committing tells Git the conflict is resolved.",
      "command": "cd /srv/git-lab-branch\ngit add shared.txt\ngit commit -m 'Merge feature, resolve conflict'"
    }
  ],
  "setup_commands": [
    { "command": "git config --global init.defaultBranch main" },
    { "command": "git config --global user.email student@rootnode.local" },
    { "command": "git config --global user.name 'RootNode Student'" },
    { "command": "rm -rf /srv/git-lab-branch && mkdir -p /srv/git-lab-branch" },
    { "command": "cd /srv/git-lab-branch && git init -q && echo 'original line' > shared.txt && git add shared.txt && git commit -q -m 'Initial commit'" },
    { "command": "cd /srv/git-lab-branch && git branch feature && git checkout -q feature && echo 'feature version' > shared.txt && git commit -qam 'Update from feature branch'" },
    { "command": "cd /srv/git-lab-branch && git checkout -q main && echo 'main version' > shared.txt && git commit -qam 'Update from main branch'" },
    { "command": "cd /srv/git-lab-branch && git merge feature 2>/dev/null; true" }
  ],
  "validation": {
    "commands": [
      { "description": "the feature branch still exists", "command": "git -C /srv/git-lab-branch branch --list feature | tr -d ' *'", "expected_output": "feature", "match": "exact" },
      { "description": "a real merge commit (two parents) exists", "command": "git -C /srv/git-lab-branch log --merges --oneline 2>/dev/null | wc -l | tr -d ' '", "expected_output": "^[1-9][0-9]*$", "match": "regex" },
      { "description": "the conflict markers were actually removed", "command": "grep -c '<<<<<<<' /srv/git-lab-branch/shared.txt", "expected_output": "0", "match": "exact" },
      { "description": "the working tree is clean (nothing left uncommitted)", "command": "git -C /srv/git-lab-branch status --short | wc -l | tr -d ' '", "expected_output": "0", "match": "exact" }
    ]
  },
  "default_namespace": "default",
  "teardown_commands": [
    { "command": "rm -rf /srv/git-lab-branch" }
  ]
}