Add Highlight Extra Whitespace In Diff Output as a Git TIL

git/highlight-extra-whitespace-in-diff-output.md

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+# Highlight Extra Whitespace In Diff Output
+
+When running a `git diff` (or `git add --patch`) I'll sometimes come across
+lines that don't have any visible changes. This is usually because some
+whitespace characters were either added (on accident) or removed (often by a
+autoformatter).
+
+Depending on the `core.whitespace` config, you'll probably see at least some of
+the whitespace errors that git provides. By default, git only highlights
+whitespace errors on added (`new`) lines. However if some extra whitespace was
+originally committed and is now being removed, it won't be highlighted on the
+`old` line in the diff.
+
+We can have git always highlight whitespace errors by setting
+`wsErrorHighlight` to `all` in the global git config.
+
+```bash
+$ git config --global diff.wsErrorHighlight all
+```
+
+Which updates the global gitconfig file with the following line:
+
+```
+[diff]
+	wsErrorHighlight = all
+```
+
+The `all` option is a shorthand for `old,new,context`.
+
+See `man git-diff` for more details.