Perforce Conflict Resolution

Overview

Conflicts occur when multiple users modify the same file. Perforce provides powerful resolve tools for merging changes. This skill covers all resolve strategies and workflows.

When to Use

• After syncing when files have conflicts
• Before submitting changes
• When integrating between branches
• Handling binary file conflicts
• Resolving content vs attribute conflicts

Core Concepts

Conflict Types

Three-Way Merge

Base (common ancestor)
    |
    +-- Theirs (depot/source)
    |
    +-- Yours (workspace)
    |
    v
Merged Result

Basic Resolve

Check for Conflicts

# Preview resolve (see what needs resolving)
p4 resolve -n

# See files that need resolving
p4 resolve -n //depot/project/...

# Check specific file
p4 resolve -n file.txt

Automatic Resolve

# Auto-resolve all (safe merge where possible)
p4 resolve -am

# Auto-resolve accepting merge result
p4 resolve -am //depot/project/...

# Auto-resolve specific file
p4 resolve -am file.txt

Resolve Strategies

# Accept automatic merge (only if no conflicts)
p4 resolve -am

# Accept theirs (depot version)
p4 resolve -at

# Accept yours (workspace version)
p4 resolve -ay

# Force accept theirs even with conflicts
p4 resolve -at //...

# Force accept yours even with conflicts
p4 resolve -ay //...

Interactive Resolve

Launch Interactive Resolve

# Interactive resolve for all files
p4 resolve

# Interactive resolve for specific file
p4 resolve file.txt

# Interactive with specific merge tool
p4 resolve -t p4merge file.txt

Interactive Menu Options

Diff results:
  1: Accept theirs (loses your changes)
  2: Accept yours (loses depot changes)
  3: Accept merge result
  4: Edit merge result
  5: Show differences (base to theirs)
  6: Show differences (base to yours)
  7: Show differences (yours to theirs)
  8: Skip this file
  9: Help

Choose option:

Interactive Workflow

# 1. Start resolve
p4 resolve file.txt

# 2. View differences
# Option 5, 6, or 7 to understand changes

# 3. Choose resolution
# Option 1 (theirs), 2 (yours), or 3 (merge)

# 4. If merge has conflicts, option 4 to edit

# 5. Accept final result
# Option 3 to accept merge

Merge Tools

Configure P4 Merge Tool

# Set P4MERGE environment variable
export P4MERGE=/usr/local/bin/p4merge

# Or use other merge tools
export P4MERGE=/usr/local/bin/code  # VS Code
export P4MERGE=/usr/local/bin/meld  # Meld
export P4MERGE=/usr/bin/vimdiff     # Vim

P4Merge Workflow

# Launch P4Merge for conflict
p4 resolve -t file.txt

# P4Merge shows four panes:
# - Base (original)
# - Theirs (depot)
# - Yours (local)
# - Result (merged)

# Edit result pane, save, close
# Accept result in terminal

Visual Studio Code Merge

# Set VS Code as merge tool
export P4MERGE="code --wait --merge"

# Resolve using VS Code
p4 resolve file.txt

Resolve Scenarios

Simple Auto-Merge

# Both changed different parts of file
p4 sync
# File needs resolve...
p4 resolve -am
# Merge successful - changes combined

Conflicting Changes

# Both changed same lines
p4 sync
p4 resolve -am
# Conflicts detected...

# Option 1: Accept theirs
p4 resolve -at file.txt

# Option 2: Accept yours
p4 resolve -ay file.txt

# Option 3: Manual merge
p4 resolve file.txt
# Choose option 4 to edit
# Fix conflicts in editor
# Save and accept

Binary File Conflicts

# Binary files can't be merged
p4 sync
p4 resolve -n
# Binary conflict on image.psd

# Accept theirs (depot version)
p4 resolve -at image.psd

# Or accept yours (your version)
p4 resolve -ay image.psd

Delete vs Edit Conflict

# File deleted in depot, edited locally
p4 sync
p4 resolve -n
# Delete vs edit conflict...

# Keep your edited version
p4 resolve -ay file.txt

# Or accept delete
p4 resolve -at file.txt

Advanced Resolve

Partial Resolve

# Resolve only content, not attributes
p4 resolve -c //...

# Resolve only attributes
p4 resolve -A //...

# Resolve specific attribute type
p4 resolve -Aa //...  # All attributes
p4 resolve -Ab //...  # Branch action
p4 resolve -At //...  # File type

Re-Resolve

# Re-resolve already resolved file
p4 resolve -f file.txt

# Re-resolve with different strategy
p4 resolve -f -at file.txt

Resolve During Integration

# Integrate between branches
p4 integrate //depot/dev/... //depot/main/...

# Resolve integration conflicts
p4 resolve -am //depot/main/...

# If conflicts remain
p4 resolve //depot/main/...

Safe Resolve Workflow

# 1. Preview what needs resolving
p4 resolve -n

# 2. Try automatic merge first
p4 resolve -am

# 3. Check what remains
p4 resolve -n

# 4. Handle remaining manually
p4 resolve remaining_file.txt

# 5. Verify resolve complete
p4 resolve -n  # Should show nothing

Conflict Markers

Understanding Markers

When editing merge result manually:

<<<<<<< THEIRS (depot version)
code from depot
=======
code from your workspace
>>>>>>> YOURS (workspace version)

Resolving Markers

# Edit file to remove markers
vim file.txt

# Original with markers:
<<<<<<< THEIRS
function getValue() {
    return this.value;
}
=======
function getValue() {
    return this.cachedValue || this.value;
}
>>>>>>> YOURS

# Resolved (choose best version or combine):
function getValue() {
    return this.cachedValue || this.value;
}

# Save and mark resolved
p4 resolve -am file.txt

Resolve Workflows

Pre-Submit Workflow

#!/bin/bash
# pre-submit-resolve.sh

# Sync latest
p4 sync

# Check for conflicts
CONFLICTS=$(p4 resolve -n 2>&1 | grep -c "resolve")

if [ "$CONFLICTS" -gt 0 ]; then
    echo "Found $CONFLICTS files needing resolve"
    
    # Try auto-merge
    p4 resolve -am
    
    # Check remaining
    REMAINING=$(p4 resolve -n 2>&1 | grep -c "resolve")
    
    if [ "$REMAINING" -gt 0 ]; then
        echo "Manual resolve needed for $REMAINING files"
        p4 resolve -n
        exit 1
    fi
fi

echo "Ready to submit"

Integration Workflow

# 1. Integrate from source to target
p4 integrate //depot/feature/... //depot/main/...

# 2. Preview conflicts
p4 resolve -n //depot/main/...

# 3. Auto-resolve safe merges
p4 resolve -am //depot/main/...

# 4. Handle remaining conflicts
p4 resolve //depot/main/...

# 5. Test merged code

# 6. Submit integration
p4 submit -d "Integrate feature to main"

Batch Resolve Pattern

# Accept all theirs (when their changes are correct)
p4 resolve -at //depot/project/...

# Accept all yours (when your changes are correct)
p4 resolve -ay //depot/project/...

# Mixed resolution
p4 resolve -at //depot/project/Assets/...  # Accept art assets
p4 resolve -am //depot/project/Scripts/... # Merge code

Undoing Resolve

Revert and Re-Sync

# If resolve went wrong, revert and start over
p4 revert file.txt
p4 sync file.txt
p4 edit file.txt
# Re-apply your changes manually

Back Out Bad Merge

# After bad submit, can sync to previous and re-submit
p4 sync //depot/project/file.txt#head-1
p4 edit file.txt
p4 sync -f //depot/project/file.txt#head-1
p4 resolve -ay file.txt
p4 submit -d "Revert bad merge"

Best Practices

1. Sync frequently - Smaller merges are easier
2. Resolve before submit - Never submit unresolved
3. Preview first with p4 resolve -n
4. Try auto-merge before manual
5. Use visual merge tool for complex conflicts
6. Test after resolve - Merged code may have bugs
7. Keep changelists small - Easier to resolve
8. Communicate with team about conflicting areas
9. Use exclusive locks for binary files
10. Document conflict resolution in submit description

Troubleshooting