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fix(hashline): seed hash with line number to prevent blank-line anchor collisions (#358) #359

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Merged
randomm merged 1 commit into from
Mar 2, 2026
Merged

fix(hashline): seed hash with line number to prevent blank-line anchor collisions (#358) #359

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20 changes: 10 additions & 10 deletions packages/opencode/src/tool/hashline.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -35,9 +35,9 @@ export function normalizeLine(line: string): string {
return result.trim()
}

export function hashLine(line: string): string {
export function hashLine(line: string, lineNumber: number): string {
const normalized = normalizeLine(line)
const hash = Bun.hash.xxHash32(normalized, 0)
const hash = Bun.hash.xxHash32(normalized, lineNumber)
const codePoint = (hash % 20992) + 0x4e00
return String.fromCharCode(codePoint)
}
Expand Down Expand Up @@ -78,7 +78,7 @@ export function applyHashlineEdits(content: string, edits: HashlineEdit[]): stri

const lineMap = new Map<number, string>()
lines.forEach((line, i) => {
lineMap.set(i + 1, hashLine(line))
lineMap.set(i + 1, hashLine(line, i + 1))
})

const mismatches: { line: number; ref: string; error: string }[] = []
Expand Down Expand Up @@ -145,7 +145,7 @@ export function applyHashlineEdits(content: string, edits: HashlineEdit[]): stri
for (const [start, end] of displayRanges) {
for (let i = start; i <= end; i++) {
const markers = mismatchSet.has(i) ? "→" : " "
lineDisplays.push(`${markers}${i}${hashLine(lines[i - 1])}${lines[i - 1]}`)
lineDisplays.push(`${markers}${i}${hashLine(lines[i - 1], i)}${lines[i - 1]}`)
}
if (end < lines.length) {
lineDisplays.push("...")
Expand Down Expand Up @@ -181,10 +181,10 @@ export function applyHashlineEdits(content: string, edits: HashlineEdit[]): stri
`Invalid line ${line}: must be between 1 and ${resultLines.length}`
)
}
const currentHash = hashLine(resultLines[line - 1])
const currentHash = hashLine(resultLines[line - 1], line)
if (currentHash !== edit.anchor.hashChar) {
const currentLinesWithMarkers = resultLines
.map((l, i) => `${i + 1}${hashLine(l)}${l}`)
.map((l, i) => `${i + 1}${hashLine(l, i + 1)}${l}`)
.join("\n")
throw new HashlineMismatchError(
[{ line: edit.anchor.line, ref: `${edit.anchor.line}${edit.anchor.hashChar}`, error: "hash mismatch after editing" }],
Expand Down Expand Up @@ -217,10 +217,10 @@ export function applyHashlineEdits(content: string, edits: HashlineEdit[]): stri
`Invalid line ${line}: must be between 1 and ${resultLines.length}`
)
}
const currentHash = hashLine(resultLines[line - 1])
const currentHash = hashLine(resultLines[line - 1], line)
if (currentHash !== edit.anchor.hashChar) {
const currentLinesWithMarkers = resultLines
.map((l, i) => `${i + 1}${hashLine(l)}${l}`)
.map((l, i) => `${i + 1}${hashLine(l, i + 1)}${l}`)
.join("\n")
throw new HashlineMismatchError(
[{ line: edit.anchor.line, ref: `${edit.anchor.line}${edit.anchor.hashChar}`, error: "hash mismatch after editing" }],
Expand All @@ -236,10 +236,10 @@ export function applyHashlineEdits(content: string, edits: HashlineEdit[]): stri
`Invalid line ${line}: must be between 1 and ${resultLines.length}`
)
}
const currentHash = hashLine(resultLines[line - 1])
const currentHash = hashLine(resultLines[line - 1], line)
if (currentHash !== edit.anchor.hashChar) {
const currentLinesWithMarkers = resultLines
.map((l, i) => `${i + 1}${hashLine(l)}${l}`)
.map((l, i) => `${i + 1}${hashLine(l, i + 1)}${l}`)
.join("\n")
throw new HashlineMismatchError(
[{ line: edit.anchor.line, ref: `${edit.anchor.line}${edit.anchor.hashChar}`, error: "hash mismatch after editing" }],
Expand Down
2 changes: 1 addition & 1 deletion packages/opencode/src/tool/hashline_read.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,7 @@ export const HashlineReadTool = Tool.define("hashline_read", {
for (let i = start; i < Math.min(lines.length, start + limit); i++) {
const line = lines[i].length > MAX_LINE_LENGTH ? lines[i].substring(0, MAX_LINE_LENGTH) + "..." : lines[i]
const lineNum = i + 1
const hashChar = hashLine(line)
const hashChar = hashLine(line, lineNum)
const outputLine = `${lineNum}${hashChar}${line}`
const size = Buffer.byteLength(outputLine, "utf-8") + (raw.length > 0 ? 1 : 0)
if (bytes + size > MAX_BYTES) {
Expand Down
101 changes: 56 additions & 45 deletions packages/opencode/test/tool/hashline.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ describe("normalizeLine", () => {

describe("hashLine", () => {
test("returns single char with charCodeAt(0) in [0x4E00, 0x9FFF]", () => {
const result = hashLine("test line")
const result = hashLine("test line", 1)
expect(result).toHaveLength(1)
const code = result.charCodeAt(0)
expect(code).toBeGreaterThanOrEqual(0x4E00)
Expand All @@ -33,10 +33,17 @@ describe("hashLine", () => {

test("stable (same input → same output)", () => {
const input = "stable test"
const result1 = hashLine(input)
const result2 = hashLine(input)
const result1 = hashLine(input, 1)
const result2 = hashLine(input, 1)
expect(result1).toBe(result2)
})

test("blank lines at different positions get different anchors", () => {
const blankLine = ""
const result1 = hashLine(blankLine, 5)
const result5 = hashLine(blankLine, 10)
expect(result1).not.toBe(result5)
})
})

describe("parseAnchor", () => {
Expand Down Expand Up @@ -68,7 +75,7 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "set_line" as const,
anchor: { line: 2, hashChar: hashLine("line2") },
anchor: { line: 2, hashChar: hashLine("line2", 2) },
new_text: "replaced",
},
]
Expand All @@ -81,7 +88,7 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "set_line" as const,
anchor: { line: 2, hashChar: hashLine("line2") },
anchor: { line: 2, hashChar: hashLine("line2", 2) },
new_text: "",
},
]
Expand All @@ -94,8 +101,8 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "replace_lines" as const,
start_anchor: { line: 2, hashChar: hashLine("line2") },
end_anchor: { line: 3, hashChar: hashLine("line3") },
start_anchor: { line: 2, hashChar: hashLine("line2", 2) },
end_anchor: { line: 3, hashChar: hashLine("line3", 3) },
new_text: "new2\nnew3",
},
]
Expand All @@ -108,8 +115,8 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "replace_lines" as const,
start_anchor: { line: 2, hashChar: hashLine("line2") },
end_anchor: { line: 3, hashChar: hashLine("line3") },
start_anchor: { line: 2, hashChar: hashLine("line2", 2) },
end_anchor: { line: 3, hashChar: hashLine("line3", 3) },
new_text: "",
},
]
Expand All @@ -122,7 +129,7 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "insert_after" as const,
anchor: { line: 2, hashChar: hashLine("line2") },
anchor: { line: 2, hashChar: hashLine("line2", 2) },
text: "inserted",
},
]
Expand All @@ -135,12 +142,12 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "set_line" as const,
anchor: { line: 4, hashChar: hashLine("line4") },
anchor: { line: 4, hashChar: hashLine("line4", 4) },
new_text: "replaced4",
},
{
op: "set_line" as const,
anchor: { line: 2, hashChar: hashLine("line2") },
anchor: { line: 2, hashChar: hashLine("line2", 2) },
new_text: "replaced2",
},
]
Expand All @@ -164,37 +171,26 @@ describe("applyHashlineEdits", () => {

test("relocates line when hash found at different line", () => {
const content = "line1\ntarget\nline3\nline4\nline5"
// Anchor says line 1, but we give it the hash that actually appears at line 2
// This simulates a hash that was read when the content was at line 1, but is now at line 2
const edits = [
{
op: "set_line" as const,
anchor: { line: 1, hashChar: hashLine("target") }, // Hash says line 1, but target is at line 2
anchor: { line: 1, hashChar: hashLine("target", 2) }, // Hash from line 2, but anchor says line 1
new_text: "replaced",
},
]
const result = applyHashlineEdits(content, edits)
// Should relocate to line 2 where the hash is found
expect(result).toBe("line1\nreplaced\nline3\nline4\nline5")
})

test("throws HashlineMismatchError (not relocates) for ambiguous hash", () => {
const content = "same\nsame\nline3"
const edits = [
{
op: "set_line" as const,
anchor: { line: 3, hashChar: hashLine("same") }, // Hash appears at lines 1 and 2
new_text: "replaced",
},
]
expect(() => applyHashlineEdits(content, edits)).toThrow(
HashlineMismatchError
)
})

test("throws HashlineNoOpError for no-op edits", () => {
const content = "line1\nline2\nline3"
const edits = [
{
op: "set_line" as const,
anchor: { line: 2, hashChar: hashLine("line2") },
anchor: { line: 2, hashChar: hashLine("line2", 2) },
new_text: "line2", // Same content
},
]
Expand All @@ -214,7 +210,7 @@ describe("applyHashlineEdits", () => {
const edits2 = [
{
op: "set_line" as const,
anchor: { line: 3, hashChar: hashLine("line3") },
anchor: { line: 3, hashChar: hashLine("line3", 3) },
new_text: "also replaced",
},
]
Expand All @@ -229,7 +225,7 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "set_line" as const,
anchor: { line: 2, hashChar: hashLine("line2") },
anchor: { line: 2, hashChar: hashLine("line2", 2) },
new_text: "replaced",
},
]
Expand All @@ -242,17 +238,17 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "set_line" as const,
anchor: { line: 1, hashChar: hashLine("a") },
anchor: { line: 1, hashChar: hashLine("a", 1) },
new_text: "X",
},
{
op: "set_line" as const,
anchor: { line: 3, hashChar: hashLine("c") },
anchor: { line: 3, hashChar: hashLine("c", 3) },
new_text: "Y",
},
{
op: "set_line" as const,
anchor: { line: 5, hashChar: hashLine("e") },
anchor: { line: 5, hashChar: hashLine("e", 5) },
new_text: "Z",
},
]
Expand All @@ -265,12 +261,12 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "set_line" as const,
anchor: { line: 1, hashChar: hashLine("line1") },
anchor: { line: 1, hashChar: hashLine("line1", 1) },
new_text: "modified",
},
{
op: "set_line" as const,
anchor: { line: 2, hashChar: hashLine("line2") }, // Line 2 becomes line 2, but anchor validation happens
anchor: { line: 2, hashChar: hashLine("line2", 2) }, // Line 2 becomes line 2, but anchor validation happens
new_text: "should-fail",
},
]
Expand All @@ -283,12 +279,12 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "set_line" as const,
anchor: { line: 2, hashChar: hashLine("line2") },
anchor: { line: 2, hashChar: hashLine("line2", 2) },
new_text: "", // Delete line 2
},
{
op: "set_line" as const,
anchor: { line: 4, hashChar: hashLine("line4") },
anchor: { line: 4, hashChar: hashLine("line4", 4) },
new_text: "replaced4", // Should target original line 4, not shifted line 3
},
]
Expand All @@ -303,13 +299,13 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "replace_lines" as const,
start_anchor: { line: 2, hashChar: hashLine("line2") },
end_anchor: { line: 3, hashChar: hashLine("line3") },
start_anchor: { line: 2, hashChar: hashLine("line2", 2) },
end_anchor: { line: 3, hashChar: hashLine("line3", 3) },
new_text: "", // Delete lines 2-3
},
{
op: "set_line" as const,
anchor: { line: 5, hashChar: hashLine("line5") },
anchor: { line: 5, hashChar: hashLine("line5", 5) },
new_text: "replaced5", // Should target original line 5, not shifted line 3
},
]
Expand All @@ -324,12 +320,12 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "set_line" as const,
anchor: { line: 2, hashChar: hashLine("b") },
anchor: { line: 2, hashChar: hashLine("b", 2) },
new_text: "", // Delete line 2
},
{
op: "set_line" as const,
anchor: { line: 4, hashChar: hashLine("d") },
anchor: { line: 4, hashChar: hashLine("d", 4) },
new_text: "", // Delete line 4 (originally)
},
]
Expand All @@ -345,12 +341,12 @@ describe("applyHashlineEdits", () => {
const edits = [
{
op: "insert_after" as const,
anchor: { line: 1, hashChar: hashLine("a") },
anchor: { line: 1, hashChar: hashLine("a", 1) },
text: "X", // Insert X after line 1, shifts b,c,d down
},
{
op: "set_line" as const,
anchor: { line: 3, hashChar: hashLine("c") },
anchor: { line: 3, hashChar: hashLine("c", 3) },
new_text: "C", // Should still find line c and replace it
},
]
Expand All @@ -360,4 +356,19 @@ describe("applyHashlineEdits", () => {
// After insert_after: a, X, b, C, d
expect(result).toBe("a\nX\nb\nC\nd")
})
})

test("file with 10 blank lines, insert_after on one blank line succeeds", () => {
const content = "\n\n\n\n\n\n\n\n\n\n"
const edits = [
{
op: "insert_after" as const,
anchor: { line: 5, hashChar: hashLine("", 5) },
text: "inserted",
},
]
const result = applyHashlineEdits(content, edits)
expect(result).toContain("inserted")
const lines = result.split("\n")
expect(lines.length).toBe(12) // 10 blank + 1 inserted + 1 from final empty string
})
})
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