WizardMerge/.github/issues/02-file-io-git-integration.md

title, labels, assignees, milestone

title	labels	assignees	milestone
Phase 1.2: File Input/Output and Git Integration	enhancement phase-1 git-integration high-priority		Phase 1 - Foundation

Overview

Implement comprehensive file I/O and Git integration features to enable WizardMerge to work directly with Git repositories and conflicted files.

Related Roadmap Section

Phase 1.2 and 1.5 from ROADMAP.md

Features to Implement

File Input/Output Module

• Parse Git conflict markers from files (<<<<<<<, =======, >>>>>>>)
• Support for Mercurial conflict markers
• Load base, ours, and theirs versions from Git
• Save resolved merge results to files
• Support for directory-level conflict resolution
• Backup mechanism for safety (create .backup files before resolution)
• Handle file encodings (UTF-8, UTF-16, etc.)
• Validate file write permissions before attempting resolution

Deliverable: backend/src/io/ module with file handlers

Git Repository Integration

• Detect when running in Git repository (check for .git directory)
• Read .git/MERGE_HEAD to identify active merge conflicts
• List all conflicted files in repository
• Get base, ours, theirs versions using Git commands:
  • git show :1:file (base)
  • git show :2:file (ours)
  • git show :3:file (theirs)
• Mark files as resolved in Git index (git add)
• Support launching from command line: wizardmerge [file]
• Support launching with no arguments to resolve all conflicts in repo

Deliverable: Enhanced backend/src/git/ module and CLI enhancements

Technical Design

File Parser Architecture

class ConflictFileParser {
  // Parse conflict markers and extract sections
  ConflictSections parse(const std::string& file_content);
  
  // Detect conflict marker style (Git, Mercurial, etc.)
  ConflictMarkerStyle detect_marker_style(const std::string& content);
  
  // Extract base/ours/theirs sections
  std::vector<ConflictBlock> extract_conflict_blocks(const std::string& content);
};

Git Integration Architecture

class GitRepository {
  // Check if we're in a Git repository
  bool is_git_repo(const std::string& path);
  
  // List conflicted files
  std::vector<std::string> list_conflicted_files();
  
  // Get file version from Git index
  std::string get_file_version(const std::string& file, GitStage stage);
  
  // Mark file as resolved
  bool mark_resolved(const std::string& file);
};

Implementation Steps

1. Create file I/O module structure

   • Set up backend/src/io/ directory
   • Add CMake configuration
   • Create header files

2. Implement conflict marker parser

   • Parse standard Git markers
   • Support custom conflict marker labels
   • Handle nested conflicts (edge case)

3. Implement Git integration

   • Repository detection
   • Conflict file listing
   • Index stage reading (:1:, :2:, :3:)

4. Add CLI enhancements

   • File path argument handling
   • Directory scanning for conflicts
   • Progress reporting for multiple files

5. Add safety features

   • Automatic backups before resolution
   • Dry-run mode for testing
   • Verification of resolved content

6. Testing

   • Unit tests for parser
   • Integration tests with real Git repos
   • Test various conflict scenarios

Acceptance Criteria

• Can parse Git conflict markers from files
• Can load base/ours/theirs from Git index
• Can save resolved files
• Creates backups before modifying files
• CLI accepts file paths and resolves conflicts
• Works with conflicted directories
• All tests pass
• Documentation updated

Dependencies

• Git CLI integration (already implemented) ✅
• Three-way merge algorithm (already implemented) ✅

Test Cases

1. Parse simple conflict with standard markers
2. Parse multiple conflicts in same file
3. Parse conflict with custom labels
4. Read file versions from Git index
5. Save resolved file without corruption
6. Create and restore from backups
7. Handle binary file conflicts gracefully
8. Handle missing base version (add/add conflict)

Documentation Updates

• Update README.md with file I/O usage
• Update CLI documentation
• Add examples to backend/README.md
• Document conflict marker formats supported

Priority

HIGH - This is essential for Phase 1 completion and enables standalone operation without external tools.

Estimated Effort

2-3 weeks

Related Issues

• #TBD (Phase 1 completion tracking)
• #TBD (CLI enhancements)