Method combine_with

atomic-core/src/record/workflow/graph_op/pending.rs:219–264

(&self, other: &Self)

    /// Panics if `other` comes before `self`.
    #[must_use]
    pub fn combine_with(&self, other: &Self) -> Self {
        assert!(
            other.old_start >= self.old_start,
            "Cannot combine with a change that comes before"
        );

        // Calculate combined old range
        let other_old_end = other.old_start + other.old_len;
        let new_old_len = other_old_end.saturating_sub(self.old_start);

        // Calculate combined new range.
        //
        // This must span from the first change's new_start through the
        // later change's new end, not merely sum the two changed ranges.
        // When two changes are adjacent in the old file but separated in
        // the new file by preserved or inserted lines, summing the lengths
        // drops that middle section from the replacement hunk.  The graph
        // then records a patch that deletes a broad old range but only
        // inserts the changed fragments, causing materialization to skip or
        // rotate content after sequential inserts.
        let self_new_end = self.new_start + self.new_len;
        let other_new_end = other.new_start + other.new_len;
        let combined_new_len = self_new_end
            .max(other_new_end)
            .saturating_sub(self.new_start);

        // Determine the combined kind
        let kind = if new_old_len == 0 && combined_new_len > 0 {
            PendingChangeKind::Insert
        } else if combined_new_len == 0 && new_old_len > 0 {
            PendingChangeKind::Delete
        } else if new_old_len > 0 && combined_new_len > 0 {
            PendingChangeKind::Replace
        } else {
            // Both are zero - shouldn't happen but default to delete
            PendingChangeKind::Delete
        };

        Self {
            kind,
            old_start: self.old_start,
            old_len: new_old_len,
            new_start: self.new_start,
            new_len: combined_new_len,
        }
    }
}

impl fmt::Display for PendingChange {