Agent-Skills.md

Agent Skills: Discard Whitespace-Only Diff Hunks

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UncategorizedID: akaihola/skills-akaihola/discard-whitespace-hunks

Repository

akaihola/skills-akaihola
akaihola
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Install this agent skill to your local

pnpm dlx add-skill https://github.com/akaihola/skills-akaihola/tree/HEAD/discard-whitespace-hunks

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discard-whitespace-hunks/SKILL.md

Skill Metadata

Name
discard-whitespace-hunks
Description
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Discard Whitespace-Only Diff Hunks

Remove all unstaged diff hunks whose only effect is whitespace, indentation, or line-break reformatting — keeping hunks that change actual content.

What counts as "whitespace-only"

A hunk is whitespace-only when the removed lines and added lines, after concatenation and removal of all whitespace characters (spaces, tabs, newlines), produce the same string. This catches:

  • Pure indentation changes (tabs ↔ spaces, indent level)
  • Line-break reformatting (one long line → multiple short lines or vice-versa)
  • Trailing whitespace additions/removals
  • Blank line additions/removals
  • Any combination of the above

Procedure

1. Check for unstaged changes

git diff --stat

If there's nothing, stop — nothing to do.

2. Restore files that are entirely whitespace changes

Compare regular diff against whitespace-ignoring diff at the file level:

git diff --stat          # all changes
git diff -w --stat       # non-whitespace changes only

Files that appear in the first but not the second are entirely whitespace — restore them:

git checkout -- <file>

3. Find and discard whitespace-only hunks in mixed files

For files that appear in both diffs (they have a mix of real and whitespace-only hunks), run the bundled Python script:

python3 <skill-dir>/scripts/discard_ws_hunks.py

The script:

  1. Parses git diff output into per-file, per-hunk structures.
  2. Classifies each hunk: concatenate all removed lines (without the leading -) and all added lines (without the leading +), strip every whitespace character from both, and compare. If identical → whitespace-only.
  3. Builds a patch containing only the whitespace-only hunks.
  4. Applies it in reverse (git apply --reverse) to undo just those hunks.

4. Verify

git diff --stat

Confirm the remaining diff is smaller and all hunks are substantive.

Edge cases

  • Staged changes: This procedure only touches the working tree (unstaged changes). Staged hunks are not affected.
  • New/deleted files: Files that are fully added or fully deleted have no "whitespace-only" hunks by definition — they're left alone.
  • Binary files: Skipped automatically (no text diff to parse).
  • Mixed indentation in context lines: The reverse-apply uses exact context matching, so it works correctly as long as the working tree hasn't been modified between generating and applying the patch. Don't edit files between steps 3 and 4.