Edit Tool Not Applying Whitespace-Only Changes #20876

Description

Description

The Edit tool appears to not apply changes when the modification is primarily whitespace (indentation changes from 4 spaces to 2 spaces, or alignment of colons/equals signs).

Reproduction Steps

1. Open a file with 4-space indentation
2. Use the Edit tool to change indentation to 2 spaces
3. Tool reports "Edit applied successfully"
4. Check the file - indentation is still 4 spaces

Example

Original content:

class DataModel:
    name: str = Field(...)
    value: int = Field(...)
    count: int = Field(...)

Expected after edit:

class DataModel:
  name: str = Field(...)
  value: int = Field(...)
  count: int = Field(...)

Actual result: File remains unchanged (still 4-space indentation)

Workaround

Using sed command works:

sed -i 's/^    /  /g' file.py

Or using bash heredoc with cat > file << 'EOF' also works.

Additional Observations

• Edit tool does work when there are non-whitespace changes (e.g., adding comments)
• Tool reports success even when changes aren't applied
• Write tool also appears to have the same issue

Potential Causes

1. Edit tool may be normalizing whitespace before/after comparison
2. File system or editor may be auto-formatting after write
3. Tool may require a non-whitespace diff to trigger actual file write

Impact

Blocks ability to format code consistently with project style guidelines (2-space indentation with aligned colons).

Plugins

No response

OpenCode version

1.3.13

Steps to reproduce

No response

Screenshot and/or share link

No response

Operating System

Ubuntu 22.04

Terminal

No response