feat(coder): add hashline editing core + wire audit hooks into dispatch pipeline

Hashline editing: content-hash anchors for edit_file stale-patch detection.
Pure-JS xxHash32, line hash computation, validation with HashlineMismatchError,
256-entry hash dictionary. 6 files in apps/coder/src/services/hashline/.

Audit hooks: emitHook('tool.execute.after') wired in frame-emitter.ts for
completed/failed tool results. emitHook('turn.end') wired at terminal points
in dispatcher.ts (all 5 run functions: native, external, opencode, warm ACP,
claude SDK). Fire-and-forget, non-blocking.

apps/coder/src/services/hashline/constants.ts

@@ -0,0 +1,10 @@
+export const NIBBLE_STR = "ZPMQVRWSNKTXJBYH"
+
+export const HASHLINE_DICT = Array.from({ length: 256 }, (_, i) => {
+  const high = i >>> 4
+  const low = i & 0x0f
+  return `${NIBBLE_STR[high]}${NIBBLE_STR[low]}`
+})
+
+export const HASHLINE_REF_PATTERN = /^([0-9]+)#([ZPMQVRWSNKTXJBYH]{2})$/
+export const HASHLINE_OUTPUT_PATTERN = /^([0-9]+)#([ZPMQVRWSNKTXJBYH]{2})\|(.*)$/

apps/coder/src/services/hashline/hash-computation.ts

@@ -0,0 +1,31 @@
+import { HASHLINE_DICT } from "./constants.js"
+import { hashXxh32 } from "./xxhash32.js"
+
+const RE_SIGNIFICANT = /[\p{L}\p{N}]/u
+
+function computeNormalizedLineHash(lineNumber: number, normalizedContent: string): string {
+  const stripped = normalizedContent
+  const seed = RE_SIGNIFICANT.test(stripped) ? 0 : lineNumber
+  const hash = hashXxh32(stripped, seed)
+  const index = hash % 256
+  return HASHLINE_DICT[index]!
+}
+
+export function computeLineHash(lineNumber: number, content: string): string {
+  return computeNormalizedLineHash(lineNumber, content.replace(/\r/g, "").trimEnd())
+}
+
+export function computeLegacyLineHash(lineNumber: number, content: string): string {
+  return computeNormalizedLineHash(lineNumber, content.replace(/\r/g, "").replace(/\s+/g, ""))
+}
+
+export function formatHashLine(lineNumber: number, content: string): string {
+  const hash = computeLineHash(lineNumber, content)
+  return `${lineNumber}#${hash}|${content}`
+}
+
+export function formatHashLines(content: string): string {
+  if (!content) return ""
+  const lines = content.split("\n")
+  return lines.map((line, index) => formatHashLine(index + 1, line)).join("\n")
+}

apps/coder/src/services/hashline/index.ts

@@ -0,0 +1,11 @@
+/**
+ * Hashline editing core — content-hash anchors for edit_file stale-patch detection.
+ *
+ * Ported from oh-my-openagent/packages/hashline-core/.
+ * Bundles a runtime-aware xxHash32 (Bun fast-path, pure-JS fallback).
+ */
+export { computeLineHash, formatHashLines, formatHashLine, computeLegacyLineHash } from "./hash-computation.js"
+export { parseLineRef, validateLineRef, validateLineRefs, HashlineMismatchError, normalizeLineRef } from "./validation.js"
+export type { LineRef } from "./validation.js"
+export { NIBBLE_STR, HASHLINE_DICT, HASHLINE_REF_PATTERN, HASHLINE_OUTPUT_PATTERN } from "./constants.js"
+export type { ReplaceEdit, AppendEdit, PrependEdit, HashlineEdit } from "./types.js"

apps/coder/src/services/hashline/types.ts

@@ -0,0 +1,20 @@
+export interface ReplaceEdit {
+  op: "replace"
+  pos: string
+  end?: string
+  lines: string | string[]
+}
+
+export interface AppendEdit {
+  op: "append"
+  pos?: string
+  lines: string | string[]
+}
+
+export interface PrependEdit {
+  op: "prepend"
+  pos?: string
+  lines: string | string[]
+}
+
+export type HashlineEdit = ReplaceEdit | AppendEdit | PrependEdit

apps/coder/src/services/hashline/validation.ts

@@ -0,0 +1,192 @@
+import { computeLegacyLineHash, computeLineHash } from "./hash-computation.js"
+import { HASHLINE_REF_PATTERN } from "./constants.js"
+
+export interface LineRef {
+  line: number
+  hash: string
+}
+
+interface HashMismatch {
+  line: number
+  expected: string
+}
+
+const MISMATCH_CONTEXT = 2
+
+const LINE_REF_EXTRACT_PATTERN = /([0-9]+#[ZPMQVRWSNKTXJBYH]{2})/
+
+function isCompatibleLineHash(line: number, content: string, hash: string): boolean {
+  return computeLineHash(line, content) === hash || computeLegacyLineHash(line, content) === hash
+}
+
+export function normalizeLineRef(ref: string): string {
+  const originalTrimmed = ref.trim()
+  let trimmed = originalTrimmed
+  trimmed = trimmed.replace(/^(?:>>>|[+-])\s*/, "")
+  trimmed = trimmed.replace(/\s*#\s*/, "#")
+  trimmed = trimmed.replace(/\|.*$/, "")
+  trimmed = trimmed.trim()
+
+  if (HASHLINE_REF_PATTERN.test(trimmed)) {
+    return trimmed
+  }
+
+  const extracted = trimmed.match(LINE_REF_EXTRACT_PATTERN)
+  if (extracted) {
+    return extracted[1]!
+  }
+
+  return originalTrimmed
+}
+
+export function parseLineRef(ref: string): LineRef {
+  const normalized = normalizeLineRef(ref)
+  const match = normalized.match(HASHLINE_REF_PATTERN)
+  if (match) {
+    return {
+      line: Number.parseInt(match[1]!, 10),
+      hash: match[2]!,
+    }
+  }
+  const hashIdx = normalized.indexOf('#')
+  if (hashIdx > 0) {
+    const prefix = normalized.slice(0, hashIdx)
+    const suffix = normalized.slice(hashIdx + 1)
+    if (!/^\d+$/.test(prefix) && /^[ZPMQVRWSNKTXJBYH]{2}$/.test(suffix)) {
+      throw new Error(
+        `Invalid line reference: "${ref}". "${prefix}" is not a line number. ` +
+          `Use the actual line number from the read output.`
+      )
+    }
+  }
+  throw new Error(
+    `Invalid line reference format: "${ref}". Expected format: "{line_number}#{hash_id}"`
+  )
+}
+
+export function validateLineRef(lines: string[], ref: string): void {
+  const { line, hash } = parseLineRefWithHint(ref, lines)
+
+  if (line < 1 || line > lines.length) {
+    throw new Error(
+      `Line number ${line} out of bounds. File has ${lines.length} lines.`
+    )
+  }
+
+  const content = lines[line - 1]
+  if (content === undefined) {
+    throw new Error(
+      `Line number ${line} out of bounds. File has ${lines.length} lines.`
+    )
+  }
+  if (!isCompatibleLineHash(line, content, hash)) {
+    throw new HashlineMismatchError([{ line, expected: hash }], lines)
+  }
+}
+
+export class HashlineMismatchError extends Error {
+  readonly remaps: ReadonlyMap<string, string>
+
+  constructor(
+    private readonly mismatches: HashMismatch[],
+    private readonly fileLines: string[]
+  ) {
+    super(HashlineMismatchError.formatMessage(mismatches, fileLines))
+    this.name = "HashlineMismatchError"
+    const remaps = new Map<string, string>()
+    for (const mismatch of mismatches) {
+      const content = fileLines[mismatch.line - 1]
+      const actualLine = content ?? ""
+      const actual = computeLineHash(mismatch.line, actualLine)
+      remaps.set(`${mismatch.line}#${mismatch.expected}`, `${mismatch.line}#${actual}`)
+    }
+    this.remaps = remaps
+  }
+
+  static formatMessage(mismatches: HashMismatch[], fileLines: string[]): string {
+    const mismatchByLine = new Map<number, HashMismatch>()
+    for (const mismatch of mismatches) mismatchByLine.set(mismatch.line, mismatch)
+
+    const displayLines = new Set<number>()
+    for (const mismatch of mismatches) {
+      const low = Math.max(1, mismatch.line - MISMATCH_CONTEXT)
+      const high = Math.min(fileLines.length, mismatch.line + MISMATCH_CONTEXT)
+      for (let line = low; line <= high; line++) displayLines.add(line)
+    }
+
+    const sortedLines = [...displayLines].sort((a, b) => a - b)
+    const output: string[] = []
+    output.push(
+      `${mismatches.length} line${mismatches.length > 1 ? "s have" : " has"} changed since last read. ` +
+        "Use updated {line_number}#{hash_id} references below (>>> marks changed lines)."
+    )
+    output.push("")
+
+    let previousLine = -1
+    for (const line of sortedLines) {
+      if (previousLine !== -1 && line > previousLine + 1) {
+        output.push("    ...")
+      }
+      previousLine = line
+
+      const content = fileLines[line - 1] ?? ""
+      const hash = computeLineHash(line, content)
+      const prefix = `${line}#${hash}|${content}`
+      if (mismatchByLine.has(line)) {
+        output.push(`>>> ${prefix}`)
+      } else {
+        output.push(`    ${prefix}`)
+      }
+    }
+
+    return output.join("\n")
+  }
+}
+
+function suggestLineForHash(ref: string, lines: string[]): string | null {
+  const hashMatch = ref.trim().match(/#([ZPMQVRWSNKTXJBYH]{2})$/)
+  if (!hashMatch) return null
+  const hash = hashMatch[1]!
+  for (let i = 0; i < lines.length; i++) {
+    if (isCompatibleLineHash(i + 1, lines[i] ?? "", hash)) {
+      return `Did you mean "${i + 1}#${computeLineHash(i + 1, lines[i] ?? "")}"?`
+    }
+  }
+  return null
+}
+
+function parseLineRefWithHint(ref: string, lines: string[]): LineRef {
+  try {
+    return parseLineRef(ref)
+  } catch (parseError) {
+    const hint = suggestLineForHash(ref, lines)
+    if (hint && parseError instanceof Error) {
+      throw new Error(`${parseError.message} ${hint}`)
+    }
+    throw parseError
+  }
+}
+
+export function validateLineRefs(lines: string[], refs: string[]): void {
+  const mismatches: HashMismatch[] = []
+
+  for (const ref of refs) {
+    const { line, hash } = parseLineRefWithHint(ref, lines)
+
+    if (line < 1 || line > lines.length) {
+      throw new Error(`Line number ${line} out of bounds (file has ${lines.length} lines)`)
+    }
+
+    const content = lines[line - 1]
+    if (content === undefined) {
+      throw new Error(`Line number ${line} out of bounds (file has ${lines.length} lines)`)
+    }
+    if (!isCompatibleLineHash(line, content, hash)) {
+      mismatches.push({ line, expected: hash })
+    }
+  }
+
+  if (mismatches.length > 0) {
+    throw new HashlineMismatchError(mismatches, lines)
+  }
+}

apps/coder/src/services/hashline/xxhash32.ts

@@ -0,0 +1,90 @@
+type BunHashRuntime = { hash: { xxHash32(data: string | Uint8Array, seed: number): number } }
+
+const runtime = globalThis as typeof globalThis & { Bun?: BunHashRuntime }
+const encoder = new TextEncoder()
+
+const PRIME32_1 = 0x9e3779b1
+const PRIME32_2 = 0x85ebca77
+const PRIME32_3 = 0xc2b2ae3d
+const PRIME32_4 = 0x27d4eb2f
+const PRIME32_5 = 0x165667b1
+
+function rotateLeft32(value: number, bits: number): number {
+  return ((value << bits) | (value >>> (32 - bits))) >>> 0
+}
+
+function readUint32LittleEndian(input: Uint8Array, offset: number): number {
+  return (
+    ((input[offset] ?? 0) |
+      ((input[offset + 1] ?? 0) << 8) |
+      ((input[offset + 2] ?? 0) << 16) |
+      ((input[offset + 3] ?? 0) << 24)) >>>
+    0
+  )
+}
+
+function round32(accumulator: number, value: number): number {
+  const added = (accumulator + Math.imul(value, PRIME32_2)) >>> 0
+  return Math.imul(rotateLeft32(added, 13), PRIME32_1) >>> 0
+}
+
+function xxHash32Js(input: Uint8Array, seed: number): number {
+  let offset = 0
+  const length = input.length
+  let hash: number
+
+  if (length >= 16) {
+    const limit = length - 16
+    let value1 = (seed + PRIME32_1 + PRIME32_2) >>> 0
+    let value2 = (seed + PRIME32_2) >>> 0
+    let value3 = seed >>> 0
+    let value4 = (seed - PRIME32_1) >>> 0
+
+    while (offset <= limit) {
+      value1 = round32(value1, readUint32LittleEndian(input, offset))
+      offset += 4
+      value2 = round32(value2, readUint32LittleEndian(input, offset))
+      offset += 4
+      value3 = round32(value3, readUint32LittleEndian(input, offset))
+      offset += 4
+      value4 = round32(value4, readUint32LittleEndian(input, offset))
+      offset += 4
+    }
+
+    hash = (rotateLeft32(value1, 1) + rotateLeft32(value2, 7)) >>> 0
+    hash = (hash + rotateLeft32(value3, 12)) >>> 0
+    hash = (hash + rotateLeft32(value4, 18)) >>> 0
+  } else {
+    hash = (seed + PRIME32_5) >>> 0
+  }
+
+  hash = (hash + length) >>> 0
+
+  while (offset + 4 <= length) {
+    hash = (hash + Math.imul(readUint32LittleEndian(input, offset), PRIME32_3)) >>> 0
+    hash = Math.imul(rotateLeft32(hash, 17), PRIME32_4) >>> 0
+    offset += 4
+  }
+
+  while (offset < length) {
+    hash = (hash + Math.imul(input[offset] ?? 0, PRIME32_5)) >>> 0
+    hash = Math.imul(rotateLeft32(hash, 11), PRIME32_1) >>> 0
+    offset += 1
+  }
+
+  hash = (hash ^ (hash >>> 15)) >>> 0
+  hash = Math.imul(hash, PRIME32_2) >>> 0
+  hash = (hash ^ (hash >>> 13)) >>> 0
+  hash = Math.imul(hash, PRIME32_3) >>> 0
+
+  return (hash ^ (hash >>> 16)) >>> 0
+}
+
+export function hashXxh32(input: string, seed: number): number {
+  const bun = runtime.Bun
+  if (bun !== undefined) {
+    return bun.hash.xxHash32(input, seed)
+  }
+
+  return xxHash32Js(encoder.encode(input), seed >>> 0)
+}