diff_utils

Matches a hunk header.

Captures, in order: old start line, old line count, new start line, new line count. Either count is absent for a single-line range, where it defaults to 1.

Stand-in line marking where a diff body was clipped for display.

Written by compute_unified_diff and rendered as a truncated row. It is also the signal that any counts recomputed from the body would be short — see DiffMessage._recount, which returns None rather than a known-low number.

Match it with is_truncation_marker rather than by hand: the renderer and the recount must agree, or a body that renders "diff truncated" is also counted as if it were complete.

Return whether a diff line is the truncation marker.

One predicate for both readers, which previously disagreed: the renderer stripped, the recount compared exactly.

Exact, deliberately. compute_unified_diff writes the marker bare, while every real diff line carries a +, -, or space prefix — so an exact match cannot collide with file content, and a source line whose own text is ... arrives here as " ..." and stays a context row. Stripping would classify that line as a clipped body and suppress the change counts for a diff that is complete.

Split a unified diff back into the lines it was assembled from.

Deliberately not splitlines(). Every diff reaching this function is "\n"-joined from lines that themselves came from splitlines() or split("\n"), so no element can contain a line boundary and "\n" is the exact inverse. splitlines() also breaks on \r, \v, \f, U+2028, U+2029 and U+0085, which splits a single diff line into fragments. The tail fragment carries no +/- marker, so it would render as an unmarked note — on the approval prompt that means changed content shown as neutral metadata.

Check any new producer against that invariant rather than against a list of the current ones.

Locate paired file headers immediately preceding a hunk.

A ---/+++ pair is only a file header when it appears outside a hunk body — a diff of a file that itself contains such lines would otherwise have its content mistaken for metadata. That is why this walks the hunks' declared old/new line budgets instead of just matching on the prefix.

Count added and removed lines in unified-diff lines.

Line counts for a change, named so the pair cannot be swapped silently.

Keyword-only and frozen so that claim holds at construction as well as in transit: a positional pair is exactly the transposition this type exists to rule out, and the counts are read long after they are computed.