earendil-works/pi · error

Cannot preserve unchanged lines because the base content has

Error message

Cannot preserve unchanged lines because the base content has a different line count.

What it means

Error "Cannot preserve unchanged lines because the base content has a different line count." thrown in earendil-works/pi.

Source

Thrown at packages/coding-agent/src/core/tools/edit-diff.ts:140

/**
 * Apply replacements matched against `baseContent` to `originalContent` while
 * preserving unchanged line blocks from the original.
 *
 * This is useful when `baseContent` is a normalized view of the original. Each
 * replacement is widened to the lines it actually touches, those touched lines
 * are rewritten from the normalized base, and all other lines are copied back
 * from `originalContent`. The actual replacement ranges drive preservation so
 * duplicate normalized lines cannot be aligned to the wrong occurrence.
 */
export function applyReplacementsPreservingUnchangedLines(
	originalContent: string,
	baseContent: string,
	replacements: TextReplacement[],
): string {
	const originalLines = splitLinesWithEndings(originalContent);
	const baseLines = getLineSpans(baseContent);
	if (originalLines.length !== baseLines.length) {
		throw new Error("Cannot preserve unchanged lines because the base content has a different line count.");
	}

	const groups: Array<{ startLine: number; endLine: number; replacements: TextReplacement[] }> = [];
	const sortedReplacements = [...replacements].sort((a, b) => a.matchIndex - b.matchIndex);
	for (const replacement of sortedReplacements) {
		const range = getReplacementLineRange(baseLines, replacement);
		const current = groups[groups.length - 1];
		if (current && range.startLine < current.endLine) {
			current.endLine = Math.max(current.endLine, range.endLine);
			current.replacements.push(replacement);
			continue;
		}
		groups.push({ ...range, replacements: [replacement] });
	}

	let originalLineIndex = 0;
	let result = "";
	for (const group of groups) {

View on GitHub (pinned to 4af9d21d3b)

When it happens

Trigger: Thrown at packages/coding-agent/src/core/tools/edit-diff.ts:140 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of earendil-works/pi@4af9d21d3b (2026-08-24). Data as JSON: /api/errors/c20f49e46e8040b8. Report an issue: GitHub.