FA-75548 / Text diff and three-way merge / Member archive

Whitespace comparison modes: -b collapses only spaces, not tabs · case 03

Replacing a tab with a space is reported as a change under -b.

Member previewVariant 3 · 3 implementations · 10 checks per implementation

Case contract

Normalize each line: with strip_cr remove one trailing "\r"; mode "w" deletes all whitespace (str.split semantics); mode "b" collapses runs of spaces and tabs to one space and strips trailing spaces and tabs; mode "none" leaves the line. With ignore_blank, drop lines whose normalized key is empty. Return both key lists and whether they are equal.

Why this case matters

Diff options like -w, -b, --strip-trailing-cr and --ignore-blank-lines decide which changes are shown at all.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
amount of whitespace ignored	`{"a": ["a b", "c\t\td"], "b": ["a b", "c d"], "equal": false}`	`{"a": ["a b", "c d"], "b": ["a b", "c d"], "equal": true}`	Failed

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