When attempting to commit a newly added directory to a Subversion repository, you might encounter this frustrating error:

svn: Commit failed (details follow):
svn: Server sent unexpected return value (405 Method Not Allowed) 
in response to MKCOL request for '/path/to/your/directory'

The MKCOL method (Make Collection) is the WebDAV method SVN uses to create new directories. A 405 error typically indicates one of these situations:

• A directory with the same name already exists in the repository
• The parent directory has permission issues
• There's a conflict between local and repository states

Here's the step-by-step approach that consistently resolves this issue:

# First, remove the problematic local directory
$ rm -rf problematic_directory/

# Update to sync with repository state
$ svn update

# Check if conflicting directory exists in repo
$ svn ls http://svn.example.com/repo/parent_directory/

# Delete the conflicting directory if found
$ svn delete http://svn.example.com/repo/parent_directory/conflicting_dir
$ svn commit -m "Removing conflicting directory"

# Recreate and add your new directory
$ mkdir new_directory
$ svn add new_directory
$ svn commit -m "Adding new directory structure"

To avoid encountering this issue:

1. Always run svn update before adding new directories
2. Use svn ls to verify repository state
3. Consider using svn mkdir instead of filesystem operations

For teams frequently encountering this issue, here's a bash script to automate the resolution:

#!/bin/bash
DIRNAME=$1
SVNROOT="http://svn.example.com/repo"

# Step 1: Clean local copy
rm -rf $DIRNAME
svn update

# Step 2: Check and remove remote conflict
if svn ls $SVNROOT/$DIRNAME 2>/dev/null; then
    svn delete $SVNROOT/$DIRNAME -m "Removing conflicting directory"
fi

# Step 3: Recreate properly
mkdir $DIRNAME
svn add $DIRNAME
svn commit -m "Adding directory $DIRNAME"

When working with Subversion (SVN), you might encounter this specific HTTP error during directory operations:

svn: Commit failed (details follow):
svn: Server sent unexpected return value (405 Method Not Allowed) 
     in response to MKCOL request for '/path/to/directory'

This error typically occurs when:

• The target directory already exists in the repository
• There's a permission issue on the server-side
• A previous failed operation left the directory in inconsistent state
• The parent directory has conflicting modifications

Here's how I resolved this issue in my development workflow:

# 1. First, clean up the local working copy
$ svn cleanup

# 2. Remove the problematic directory (locally)
$ rm -rf problem_directory

# 3. Update to get fresh repository state
$ svn update

# 4. Check if directory exists in repository
$ svn ls https://svn.example.com/repo/path/ | grep problem_directory

# 5. If exists, remove from repository (requires permissions)
$ svn delete https://svn.example.com/repo/path/problem_directory -m "Removing conflicting directory"

# 6. Commit the deletion
$ svn commit -m "Directory cleanup"

# 7. Recreate directory locally and add to SVN
$ mkdir problem_directory
$ svn add problem_directory

# 8. Final commit
$ svn commit -m "Adding new directory structure"

To avoid similar issues in future:

• Always run svn status before major operations
• Use svn mkdir instead of filesystem mkdir for directory creation
• Implement proper SVN hooks on server side to validate operations
• Consider using svn import for complex directory structures

If the basic solution doesn't work, try these alternatives:

# Alternative 1: Complete working copy refresh
$ svn revert -R .
$ svn update --force

# Alternative 2: Check server configuration
# Verify the DAV svn module is properly configured in Apache:
<Location /svn>
  DAV svn
  SVNPath /var/svn/repository
  <LimitExcept GET PROPFIND OPTIONS REPORT>
    Require valid-user
  </LimitExcept>
</Location>