Advanced Filtering

def name_callback(name):
  YOUR_CODE_HERE
  return modified_name

git filter-repo --name-callback '
  return name.replace(b"Wiliam", b"William")
'

git filter-repo --email-callback '
  # Fix common typos
  email = email.replace(b".cm", b".com")
  email = email.replace(b"gmial.com", b"gmail.com")
  return email
'

git filter-repo --refname-callback '
  # Add prefix to all branches (refs/heads/main -> refs/heads/v2-main)
  if refname.startswith(b"refs/heads/"):
    branch = refname[11:]  # Remove "refs/heads/"
    return b"refs/heads/v2-" + branch
  return refname
'

git filter-repo --filename-callback '
  # Remove all files in src/ subdirectories (except toplevel src/)
  if b"/src/" in filename:
    return None  # Delete file
  
  # Rename tools/ -> scripts/misc/
  if filename.startswith(b"tools/"):
    return b"scripts/misc/" + filename[6:]
  
  # Keep all other files unchanged
  return filename
'

git filter-repo --message-callback '
  # Add Signed-off-by if missing
  if b"Signed-off-by:" not in message:
    message += b"\nSigned-off-by: Me Myself <[email protected]>"
  
  # Fix typos
  message = re.sub(b"[Ee]-?[Mm][Aa][Ii][Ll]", b"email", message)
  
  return message
'

git filter-repo --blob-callback '
  # Skip blobs over 25 bytes
  if len(blob.data) > 25:
    blob.skip()
  else:
    blob.data = blob.data.replace(b"Hello", b"Goodbye")
'

git filter-repo --commit-callback '
  # Remove executable files with "666" in their name
  commit.file_changes = [
    change for change in commit.file_changes
    if not (change.mode == b"100755" and b"666" in change.filename)
  ]
  
  # Prevent deletion of specific file
  commit.file_changes = [
    change for change in commit.file_changes
    if not (change.type == b"D" and change.filename == b"important.txt")
  ]
  
  # Make all .sh files executable
  for change in commit.file_changes:
    if change.filename.endswith(b".sh"):
      change.mode = b"100755"
'

git filter-repo --tag-callback '
  # Skip tags by specific author
  if tag.tagger_name == b"Jim Williams":
    tag.skip()
  else:
    # Add extra info to tag message
    tag.message += b"\n\nTag of %s by %s on %s" % (
      tag.ref, tag.tagger_email, tag.tagger_date
    )
'

git filter-repo --reset-callback '
  # Rename master branch to main
  reset.ref = reset.ref.replace(b"master", b"main")
'

git filter-repo --filename-callback '
  # Define a mapping
  renames = {
    b"README": b"README.md",
    b"COPYING": b"LICENSE",
    b"AUTHORS": b"CONTRIBUTORS.md",
  }
  
  # Apply renames
  if filename in renames:
    return renames[filename]
  
  # Remove backup files
  if filename.endswith(b".bak") or filename.endswith(b"~"):
    return None
  
  return filename
'

git filter-repo --message-callback '
  # Convert issue references: #123 -> JIRA-123
  message = re.sub(b"#(\\d+)", b"JIRA-\\1", message)
  
  # Remove trailing whitespace from each line
  lines = message.split(b"\\n")
  lines = [re.sub(b"\\s+$", b"", line) for line in lines]
  message = b"\\n".join(lines)
  
  return message
'

git filter-repo --commit-callback '
  # aux_info contains:
  # - orig_parents: original parent commit IDs
  # - had_file_changes: whether commit had file changes
  
  # Example: Mark commits that lost all files
  if not commit.file_changes and aux_info["had_file_changes"]:
    commit.message += b"\n\n[Note: All file changes filtered out]"
'

git filter-repo --blob-callback '
  # Only process small text files
  if len(blob.data) > 1024 * 1024:  # > 1MB
    return
  
  if b"\\0" in blob.data[0:8192]:  # Binary file
    return
  
  # Safe to process as text
  blob.data = blob.data.upper()
'

git filter-repo \
  --name-callback 'return name.title()' \
  --email-callback 'return email.lower()' \
  --filename-callback '
    if filename.endswith(b".tmp"):
      return None
    return filename
  ' \
  --message-callback '
    return message.replace(b"TODO", b"DONE")
  '

git filter-repo --filename-callback '
  # Convert to lowercase
  parts = filename.split(b"/")
  parts[-1] = parts[-1].lower()
  filename = b"/".join(parts)
  
  # Replace spaces with hyphens
  filename = filename.replace(b" ", b"-")
  
  # Remove special characters
  filename = re.sub(b"[^a-z0-9/_.-]", b"", filename)
  
  return filename
'

git filter-repo --blob-callback '
  # Skip binary files
  if b"\\0" in blob.data[0:8192]:
    return
  
  # Add copyright header to source files
  header = b"""# Copyright (C) 2024 Example Corp
# Licensed under MIT License

"""
  
  if not blob.data.startswith(b"# Copyright"):
    blob.data = header + blob.data
'

git filter-repo --commit-callback '
  # Skip commits with tiny messages
  if len(commit.message) < 10:
    commit.skip(commit.first_parent())
'

git filter-repo --commit-callback '
  # Make all commits appear to be from 2024
  import time
  from datetime import datetime
  
  # Parse existing date
  timestamp, timezone = commit.author_date.split()
  dt = datetime.fromtimestamp(int(timestamp))
  
  # Update year
  new_dt = dt.replace(year=2024)
  new_timestamp = int(new_dt.timestamp())
  
  # Update both author and committer dates
  commit.author_date = b"%d %s" % (new_timestamp, timezone)
  commit.committer_date = commit.author_date
'

git filter-repo --commit-callback '
  # Skip merge commits (commits with multiple parents)
  if len(commit.parents) > 1:
    commit.skip(commit.first_parent())
'

git filter-repo --commit-callback "$(cat my_callback.py)"

import json

# Load configuration
with open('filter-config.json', 'rb') as f:
  config = json.load(f)

# Complex filtering logic
if commit.branch in config['protected_branches']:
  return

# ... more logic ...