feat: add experimental hashline edit mode

packages/opencode/test/tool/hashline.test.ts

@@ -0,0 +1,184 @@
+import { describe, expect, test } from "bun:test"
+import { applyHashlineEdits, hashlineID, hashlineLine, hashlineRef, parseHashlineRef } from "../../src/tool/hashline"
+
+function swapID(ref: string) {
+  const [line, id] = ref.split("#")
+  const next = id[0] === "Z" ? `P${id[1]}` : `Z${id[1]}`
+  return `${line}#${next}`
+}
+
+describe("tool.hashline", () => {
+  test("hash computation is stable and 2-char alphabet encoded", () => {
+    const a = hashlineID(1, "  const x = 1")
+    const b = hashlineID(1, "constx=1")
+    const c = hashlineID(99, "constx=1")
+    expect(a).toBe(b)
+    expect(a).toBe(c)
+    expect(a).toMatch(/^[ZPMQVRWSNKTXJBYH]{2}$/)
+  })
+
+  test("autocorrect strips copied hashline prefixes when enabled", () => {
+    const old = Bun.env.OPENCODE_HL_AUTOCORRECT
+    Bun.env.OPENCODE_HL_AUTOCORRECT = "1"
+    try {
+      const result = applyHashlineEdits({
+        lines: ["a"],
+        trailing: false,
+        edits: [
+          {
+            type: "set_line",
+            line: hashlineRef(1, "a"),
+            text: hashlineLine(1, "a"),
+          },
+        ],
+      })
+      expect(result.lines).toEqual(["a"])
+    } finally {
+      if (old === undefined) delete Bun.env.OPENCODE_HL_AUTOCORRECT
+      else Bun.env.OPENCODE_HL_AUTOCORRECT = old
+    }
+  })
+
+  test("parses strict LINE#ID references with tolerant extraction", () => {
+    const ref = parseHashlineRef(">>> 12#ZP:const value = 1", "line")
+    expect(ref.line).toBe(12)
+    expect(ref.id).toBe("ZP")
+    expect(ref.raw).toBe("12#ZP")
+
+    expect(() => parseHashlineRef("12#ab", "line")).toThrow("LINE#ID")
+  })
+
+  test("aggregates mismatch errors with >>> context and retry refs", () => {
+    const lines = ["alpha", "beta", "gamma"]
+    const wrong = swapID(hashlineRef(2, lines[1]))
+
+    expect(() =>
+      applyHashlineEdits({
+        lines,
+        trailing: false,
+        edits: [
+          {
+            type: "set_line",
+            line: wrong,
+            text: "BETA",
+          },
+        ],
+      }),
+    ).toThrow("changed since last read")
+
+    expect(() =>
+      applyHashlineEdits({
+        lines,
+        trailing: false,
+        edits: [
+          {
+            type: "set_line",
+            line: wrong,
+            text: "BETA",
+          },
+        ],
+      }),
+    ).toThrow(">>> retry with")
+  })
+
+  test("applies batched line edits bottom-up for stable results", () => {
+    const lines = ["a", "b", "c", "d"]
+    const one = hashlineRef(1, lines[0])
+    const two = hashlineRef(2, lines[1])
+    const three = hashlineRef(3, lines[2])
+    const four = hashlineRef(4, lines[3])
+
+    const result = applyHashlineEdits({
+      lines,
+      trailing: false,
+      edits: [
+        {
+          type: "replace_lines",
+          start_line: two,
+          end_line: three,
+          text: ["B", "C"],
+        },
+        {
+          type: "insert_after",
+          line: one,
+          text: "A1",
+        },
+        {
+          type: "set_line",
+          line: four,
+          text: "D",
+        },
+      ],
+    })
+
+    expect(result.lines).toEqual(["a", "A1", "B", "C", "D"])
+  })
+
+  test("orders append and prepend deterministically on empty files", () => {
+    const result = applyHashlineEdits({
+      lines: [],
+      trailing: false,
+      edits: [
+        {
+          type: "append",
+          text: "end",
+        },
+        {
+          type: "prepend",
+          text: "start",
+        },
+      ],
+    })
+
+    expect(result.lines).toEqual(["start", "end"])
+  })
+
+  test("validates ranges, between constraints, and non-empty insert text", () => {
+    const lines = ["a", "b", "c"]
+    const one = hashlineRef(1, lines[0])
+    const two = hashlineRef(2, lines[1])
+
+    expect(() =>
+      applyHashlineEdits({
+        lines,
+        trailing: false,
+        edits: [
+          {
+            type: "replace_lines",
+            start_line: two,
+            end_line: one,
+            text: "x",
+          },
+        ],
+      }),
+    ).toThrow("start_line")
+
+    expect(() =>
+      applyHashlineEdits({
+        lines,
+        trailing: false,
+        edits: [
+          {
+            type: "insert_between",
+            after_line: two,
+            before_line: one,
+            text: "x",
+          },
+        ],
+      }),
+    ).toThrow("insert_between.after_line")
+
+    expect(() =>
+      applyHashlineEdits({
+        lines,
+        trailing: false,
+        edits: [
+          {
+            type: "append",
+            text: "",
+          },
+        ],
+      }),
+    ).toThrow("append.text")
+  })
+})