424 lines
18 KiB
JavaScript
424 lines
18 KiB
JavaScript
/**
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* Shared diff computation utilities for the edit and similar tools.
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*/
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import * as Diff from "diff";
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import { constants } from "fs";
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import { access, readFile } from "fs/promises";
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import { resolveToCwd } from "./path-utils.js";
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export function detectLineEnding(content) {
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const crlfIdx = content.indexOf("\r\n");
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const lfIdx = content.indexOf("\n");
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if (lfIdx === -1)
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return "\n";
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if (crlfIdx === -1)
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return "\n";
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return crlfIdx < lfIdx ? "\r\n" : "\n";
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}
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export function normalizeToLF(text) {
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return text.replace(/\r\n/g, "\n").replace(/\r/g, "\n");
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}
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export function restoreLineEndings(text, ending) {
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return ending === "\r\n" ? text.replace(/\n/g, "\r\n") : text;
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}
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/**
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* Normalize text for fuzzy matching. Applies progressive transformations:
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* - Strip trailing whitespace from each line
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* - Normalize smart quotes to ASCII equivalents
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* - Normalize Unicode dashes/hyphens to ASCII hyphen
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* - Normalize special Unicode spaces to regular space
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*/
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export function normalizeForFuzzyMatch(text) {
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return (text
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.normalize("NFKC")
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// Strip trailing whitespace per line
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.split("\n")
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.map((line) => line.trimEnd())
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.join("\n")
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// Smart single quotes → '
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.replace(/[\u2018\u2019\u201A\u201B]/g, "'")
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// Smart double quotes → "
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.replace(/[\u201C\u201D\u201E\u201F]/g, '"')
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// Various dashes/hyphens → -
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// U+2010 hyphen, U+2011 non-breaking hyphen, U+2012 figure dash,
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// U+2013 en-dash, U+2014 em-dash, U+2015 horizontal bar, U+2212 minus
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.replace(/[\u2010\u2011\u2012\u2013\u2014\u2015\u2212]/g, "-")
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// Special spaces → regular space
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// U+00A0 NBSP, U+2002-U+200A various spaces, U+202F narrow NBSP,
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// U+205F medium math space, U+3000 ideographic space
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.replace(/[\u00A0\u2002-\u200A\u202F\u205F\u3000]/g, " "));
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}
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function splitLinesWithEndings(content) {
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return content.match(/[^\n]*\n|[^\n]+/g) ?? [];
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}
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function getLineSpans(content) {
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let offset = 0;
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return splitLinesWithEndings(content).map((line) => {
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const span = { start: offset, end: offset + line.length };
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offset = span.end;
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return span;
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});
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}
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function getReplacementLineRange(lines, replacement) {
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const replacementStart = replacement.matchIndex;
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const replacementEnd = replacement.matchIndex + replacement.matchLength;
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let startLine = -1;
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for (let i = 0; i < lines.length; i++) {
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const line = lines[i];
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if (replacementStart >= line.start && replacementStart < line.end) {
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startLine = i;
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break;
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}
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}
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if (startLine === -1) {
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throw new Error("Replacement range is outside the base content.");
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}
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let endLine = startLine;
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while (endLine < lines.length && lines[endLine].end < replacementEnd) {
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endLine++;
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}
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if (endLine >= lines.length) {
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throw new Error("Replacement range is outside the base content.");
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}
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return { startLine, endLine: endLine + 1 };
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}
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function applyReplacements(content, replacements, offset = 0) {
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let result = content;
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for (let i = replacements.length - 1; i >= 0; i--) {
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const replacement = replacements[i];
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const matchIndex = replacement.matchIndex - offset;
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result =
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result.substring(0, matchIndex) + replacement.newText + result.substring(matchIndex + replacement.matchLength);
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}
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return result;
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}
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/**
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* Apply replacements matched against `baseContent` to `originalContent` while
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* preserving unchanged line blocks from the original.
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*
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* This is useful when `baseContent` is a normalized view of the original. Each
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* replacement is widened to the lines it actually touches, those touched lines
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* are rewritten from the normalized base, and all other lines are copied back
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* from `originalContent`. The actual replacement ranges drive preservation so
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* duplicate normalized lines cannot be aligned to the wrong occurrence.
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*/
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export function applyReplacementsPreservingUnchangedLines(originalContent, baseContent, replacements) {
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const originalLines = splitLinesWithEndings(originalContent);
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const baseLines = getLineSpans(baseContent);
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if (originalLines.length !== baseLines.length) {
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throw new Error("Cannot preserve unchanged lines because the base content has a different line count.");
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}
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const groups = [];
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const sortedReplacements = [...replacements].sort((a, b) => a.matchIndex - b.matchIndex);
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for (const replacement of sortedReplacements) {
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const range = getReplacementLineRange(baseLines, replacement);
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const current = groups[groups.length - 1];
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if (current && range.startLine < current.endLine) {
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current.endLine = Math.max(current.endLine, range.endLine);
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current.replacements.push(replacement);
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continue;
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}
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groups.push({ ...range, replacements: [replacement] });
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}
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let originalLineIndex = 0;
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let result = "";
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for (const group of groups) {
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result += originalLines.slice(originalLineIndex, group.startLine).join("");
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const groupStartOffset = baseLines[group.startLine].start;
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const groupEndOffset = baseLines[group.endLine - 1].end;
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result += applyReplacements(baseContent.slice(groupStartOffset, groupEndOffset), group.replacements, groupStartOffset);
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originalLineIndex = group.endLine;
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}
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result += originalLines.slice(originalLineIndex).join("");
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return result;
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}
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/**
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* Find oldText in content, trying exact match first, then fuzzy match.
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* When fuzzy matching is used, the returned contentForReplacement is the
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* fuzzy-normalized version of the content (trailing whitespace stripped,
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* Unicode quotes/dashes normalized to ASCII).
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*/
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export function fuzzyFindText(content, oldText) {
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// Try exact match first
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const exactIndex = content.indexOf(oldText);
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if (exactIndex !== -1) {
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return {
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found: true,
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index: exactIndex,
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matchLength: oldText.length,
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usedFuzzyMatch: false,
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contentForReplacement: content,
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};
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}
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// Try fuzzy match - work entirely in normalized space
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const fuzzyContent = normalizeForFuzzyMatch(content);
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const fuzzyOldText = normalizeForFuzzyMatch(oldText);
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const fuzzyIndex = fuzzyContent.indexOf(fuzzyOldText);
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if (fuzzyIndex === -1) {
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return {
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found: false,
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index: -1,
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matchLength: 0,
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usedFuzzyMatch: false,
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contentForReplacement: content,
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};
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}
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// When fuzzy matching, return offsets in normalized space. Callers can use
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// the normalized content to compute replacements, then decide how much of
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// that normalized output should be written back.
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return {
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found: true,
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index: fuzzyIndex,
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matchLength: fuzzyOldText.length,
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usedFuzzyMatch: true,
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contentForReplacement: fuzzyContent,
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};
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}
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/** Strip UTF-8 BOM if present, return both the BOM (if any) and the text without it */
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export function stripBom(content) {
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return content.startsWith("\uFEFF") ? { bom: "\uFEFF", text: content.slice(1) } : { bom: "", text: content };
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}
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function countOccurrences(content, oldText) {
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const fuzzyContent = normalizeForFuzzyMatch(content);
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const fuzzyOldText = normalizeForFuzzyMatch(oldText);
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return fuzzyContent.split(fuzzyOldText).length - 1;
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}
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function getNotFoundError(path, editIndex, totalEdits) {
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if (totalEdits === 1) {
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return new Error(`Could not find the exact text in ${path}. The old text must match exactly including all whitespace and newlines.`);
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}
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return new Error(`Could not find edits[${editIndex}] in ${path}. The oldText must match exactly including all whitespace and newlines.`);
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}
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function getDuplicateError(path, editIndex, totalEdits, occurrences) {
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if (totalEdits === 1) {
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return new Error(`Found ${occurrences} occurrences of the text in ${path}. The text must be unique. Please provide more context to make it unique.`);
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}
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return new Error(`Found ${occurrences} occurrences of edits[${editIndex}] in ${path}. Each oldText must be unique. Please provide more context to make it unique.`);
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}
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function getEmptyOldTextError(path, editIndex, totalEdits) {
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if (totalEdits === 1) {
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return new Error(`oldText must not be empty in ${path}.`);
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}
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return new Error(`edits[${editIndex}].oldText must not be empty in ${path}.`);
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}
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function getNoChangeError(path, totalEdits) {
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if (totalEdits === 1) {
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return new Error(`No changes made to ${path}. The replacement produced identical content. This might indicate an issue with special characters or the text not existing as expected.`);
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}
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return new Error(`No changes made to ${path}. The replacements produced identical content.`);
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}
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/**
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* Apply one or more exact-text replacements to LF-normalized content.
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*
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* All edits are matched against the same original content. Replacements are
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* then applied in reverse order so offsets remain stable. If any edit needs
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* fuzzy matching, the operation runs in fuzzy-normalized content space and then
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* overlays those line-level changes onto the original content so unchanged line
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* blocks keep their original bytes.
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*/
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export function applyEditsToNormalizedContent(normalizedContent, edits, path) {
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const normalizedEdits = edits.map((edit) => ({
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oldText: normalizeToLF(edit.oldText),
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newText: normalizeToLF(edit.newText),
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}));
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for (let i = 0; i < normalizedEdits.length; i++) {
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if (normalizedEdits[i].oldText.length === 0) {
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throw getEmptyOldTextError(path, i, normalizedEdits.length);
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}
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}
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const initialMatches = normalizedEdits.map((edit) => fuzzyFindText(normalizedContent, edit.oldText));
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const usedFuzzyMatch = initialMatches.some((match) => match.usedFuzzyMatch);
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const replacementBaseContent = usedFuzzyMatch ? normalizeForFuzzyMatch(normalizedContent) : normalizedContent;
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const matchedEdits = [];
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for (let i = 0; i < normalizedEdits.length; i++) {
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const edit = normalizedEdits[i];
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const matchResult = fuzzyFindText(replacementBaseContent, edit.oldText);
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if (!matchResult.found) {
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throw getNotFoundError(path, i, normalizedEdits.length);
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}
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const occurrences = countOccurrences(replacementBaseContent, edit.oldText);
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if (occurrences > 1) {
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throw getDuplicateError(path, i, normalizedEdits.length, occurrences);
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}
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matchedEdits.push({
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editIndex: i,
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matchIndex: matchResult.index,
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matchLength: matchResult.matchLength,
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newText: edit.newText,
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});
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}
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matchedEdits.sort((a, b) => a.matchIndex - b.matchIndex);
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for (let i = 1; i < matchedEdits.length; i++) {
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const previous = matchedEdits[i - 1];
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const current = matchedEdits[i];
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if (previous.matchIndex + previous.matchLength > current.matchIndex) {
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throw new Error(`edits[${previous.editIndex}] and edits[${current.editIndex}] overlap in ${path}. Merge them into one edit or target disjoint regions.`);
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}
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}
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const baseContent = normalizedContent;
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const newContent = usedFuzzyMatch
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? applyReplacementsPreservingUnchangedLines(normalizedContent, replacementBaseContent, matchedEdits)
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: applyReplacements(replacementBaseContent, matchedEdits);
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if (baseContent === newContent) {
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throw getNoChangeError(path, normalizedEdits.length);
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}
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return { baseContent, newContent };
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}
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/** Generate a standard unified patch. */
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export function generateUnifiedPatch(path, oldContent, newContent, contextLines = 4) {
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return Diff.createTwoFilesPatch(path, path, oldContent, newContent, undefined, undefined, {
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context: contextLines,
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headerOptions: Diff.FILE_HEADERS_ONLY,
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});
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}
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/**
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* Generate a display-oriented diff string with line numbers and context.
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* Returns both the diff string and the first changed line number (in the new file).
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*/
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export function generateDiffString(oldContent, newContent, contextLines = 4) {
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const parts = Diff.diffLines(oldContent, newContent);
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const output = [];
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const oldLines = oldContent.split("\n");
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const newLines = newContent.split("\n");
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const maxLineNum = Math.max(oldLines.length, newLines.length);
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const lineNumWidth = String(maxLineNum).length;
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let oldLineNum = 1;
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let newLineNum = 1;
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let lastWasChange = false;
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let firstChangedLine;
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for (let i = 0; i < parts.length; i++) {
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const part = parts[i];
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const raw = part.value.split("\n");
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if (raw[raw.length - 1] === "") {
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raw.pop();
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}
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if (part.added || part.removed) {
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// Capture the first changed line (in the new file)
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if (firstChangedLine === undefined) {
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firstChangedLine = newLineNum;
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}
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// Show the change
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for (const line of raw) {
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if (part.added) {
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const lineNum = String(newLineNum).padStart(lineNumWidth, " ");
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output.push(`+${lineNum} ${line}`);
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newLineNum++;
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}
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else {
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// removed
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const lineNum = String(oldLineNum).padStart(lineNumWidth, " ");
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output.push(`-${lineNum} ${line}`);
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oldLineNum++;
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}
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}
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lastWasChange = true;
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}
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else {
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// Context lines - only show a few before/after changes
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const nextPartIsChange = i < parts.length - 1 && (parts[i + 1].added || parts[i + 1].removed);
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const hasLeadingChange = lastWasChange;
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const hasTrailingChange = nextPartIsChange;
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if (hasLeadingChange && hasTrailingChange) {
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if (raw.length <= contextLines * 2) {
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for (const line of raw) {
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const lineNum = String(oldLineNum).padStart(lineNumWidth, " ");
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output.push(` ${lineNum} ${line}`);
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oldLineNum++;
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newLineNum++;
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}
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}
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else {
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const leadingLines = raw.slice(0, contextLines);
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const trailingLines = raw.slice(raw.length - contextLines);
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const skippedLines = raw.length - leadingLines.length - trailingLines.length;
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for (const line of leadingLines) {
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const lineNum = String(oldLineNum).padStart(lineNumWidth, " ");
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output.push(` ${lineNum} ${line}`);
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oldLineNum++;
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newLineNum++;
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}
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output.push(` ${"".padStart(lineNumWidth, " ")} ...`);
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oldLineNum += skippedLines;
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newLineNum += skippedLines;
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for (const line of trailingLines) {
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const lineNum = String(oldLineNum).padStart(lineNumWidth, " ");
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output.push(` ${lineNum} ${line}`);
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oldLineNum++;
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newLineNum++;
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}
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}
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}
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else if (hasLeadingChange) {
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const shownLines = raw.slice(0, contextLines);
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const skippedLines = raw.length - shownLines.length;
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for (const line of shownLines) {
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const lineNum = String(oldLineNum).padStart(lineNumWidth, " ");
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output.push(` ${lineNum} ${line}`);
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oldLineNum++;
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newLineNum++;
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}
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if (skippedLines > 0) {
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output.push(` ${"".padStart(lineNumWidth, " ")} ...`);
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oldLineNum += skippedLines;
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newLineNum += skippedLines;
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}
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}
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else if (hasTrailingChange) {
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const skippedLines = Math.max(0, raw.length - contextLines);
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if (skippedLines > 0) {
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output.push(` ${"".padStart(lineNumWidth, " ")} ...`);
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oldLineNum += skippedLines;
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newLineNum += skippedLines;
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}
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for (const line of raw.slice(skippedLines)) {
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const lineNum = String(oldLineNum).padStart(lineNumWidth, " ");
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output.push(` ${lineNum} ${line}`);
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oldLineNum++;
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newLineNum++;
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}
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}
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else {
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// Skip these context lines entirely
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oldLineNum += raw.length;
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newLineNum += raw.length;
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}
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lastWasChange = false;
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}
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}
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return { diff: output.join("\n"), firstChangedLine };
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}
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/**
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* Compute the diff for one or more edit operations without applying them.
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* Used for preview rendering in the TUI before the tool executes.
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*/
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export async function computeEditsDiff(path, edits, cwd) {
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const absolutePath = resolveToCwd(path, cwd);
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try {
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// Check if file exists and is readable
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try {
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await access(absolutePath, constants.R_OK);
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}
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catch (error) {
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const errorMessage = error instanceof Error && "code" in error ? `Error code: ${error.code}` : String(error);
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return { error: `Could not edit file: ${path}. ${errorMessage}.` };
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}
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// Read the file
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const rawContent = await readFile(absolutePath, "utf-8");
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// Strip BOM before matching (LLM won't include invisible BOM in oldText)
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const { text: content } = stripBom(rawContent);
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const normalizedContent = normalizeToLF(content);
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const { baseContent, newContent } = applyEditsToNormalizedContent(normalizedContent, edits, path);
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// Generate the diff
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return generateDiffString(baseContent, newContent);
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}
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catch (err) {
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return { error: err instanceof Error ? err.message : String(err) };
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}
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}
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/**
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* Compute the diff for a single edit operation without applying it.
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* Kept as a convenience wrapper for single-edit callers.
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*/
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export async function computeEditDiff(path, oldText, newText, cwd) {
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return computeEditsDiff(path, [{ oldText, newText }], cwd);
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}
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//# sourceMappingURL=edit-diff.js.map
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