chore: import upstream snapshot with attribution

tests/test_tools/test_source_diff_candidates.py

@@ -0,0 +1,154 @@
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+
+from opensquilla.tools.source_diff_candidates import (
+    MAX_PATCH_CHARS,
+    capture_source_diff_candidate,
+    latest_recoverable_source_candidate,
+    mark_source_diff_candidates_lost,
+)
+from opensquilla.tools.types import ToolContext
+
+
+def _run_git(workspace: Path, *args: str) -> None:
+    subprocess.run(
+        ["git", *args],
+        cwd=workspace,
+        check=True,
+        capture_output=True,
+    )
+
+
+def _init_git_workspace(workspace: Path) -> Path:
+    (workspace / "src").mkdir()
+    target = workspace / "src" / "a.py"
+    target.write_text("old\n", encoding="utf-8")
+    _run_git(workspace, "init")
+    _run_git(workspace, "config", "user.email", "test@example.com")
+    _run_git(workspace, "config", "user.name", "Test User")
+    _run_git(workspace, "add", ".")
+    _run_git(workspace, "commit", "-m", "init")
+    return target
+
+
+def test_capture_source_candidate_records_patch(tmp_path: Path) -> None:
+    target = _init_git_workspace(tmp_path)
+    target.write_text("new\n", encoding="utf-8")
+    events: list[dict[str, object]] = []
+
+    ctx = ToolContext(workspace_dir=str(tmp_path), on_runtime_event=events.append)
+    candidate = capture_source_diff_candidate(
+        ctx=ctx,
+        relative_path="src/a.py",
+        workspace_epoch=1,
+        receipt_id="receipt-1",
+        tool_name="edit_source",
+    )
+
+    assert candidate is not None
+    assert candidate["candidate_id"].startswith("srcdiff-")
+    assert candidate["paths"] == ["src/a.py"]
+    assert "-old" in candidate["patch"]
+    assert "+new" in candidate["patch"]
+    assert latest_recoverable_source_candidate(ctx) == candidate
+    assert events[-1]["name"] == "source_diff_candidate.captured"
+
+
+def test_capture_source_candidate_skips_when_mode_off(tmp_path: Path) -> None:
+    target = _init_git_workspace(tmp_path)
+    target.write_text("new\n", encoding="utf-8")
+    events: list[dict[str, object]] = []
+
+    ctx = ToolContext(
+        workspace_dir=str(tmp_path),
+        source_diff_candidate_mode="off",
+        on_runtime_event=events.append,
+    )
+    candidate = capture_source_diff_candidate(
+        ctx=ctx,
+        relative_path="src/a.py",
+        workspace_epoch=1,
+        receipt_id="receipt-1",
+        tool_name="edit_source",
+    )
+
+    assert candidate is None
+    assert ctx.source_diff_candidates == []
+    assert events == []
+
+
+def test_capture_source_candidate_skips_non_git_workspace(tmp_path: Path) -> None:
+    target = tmp_path / "src" / "a.py"
+    target.parent.mkdir()
+    target.write_text("new\n", encoding="utf-8")
+    events: list[dict[str, object]] = []
+
+    ctx = ToolContext(workspace_dir=str(tmp_path), on_runtime_event=events.append)
+    candidate = capture_source_diff_candidate(
+        ctx=ctx,
+        relative_path="src/a.py",
+        workspace_epoch=1,
+        receipt_id="receipt-1",
+        tool_name="edit_source",
+    )
+
+    assert candidate is None
+    assert events[-1]["name"] == "source_diff_candidate.capture_skipped"
+    assert events[-1]["reason"] == "git_diff_failed"
+
+
+def test_capture_source_candidate_skips_oversized_patch(tmp_path: Path) -> None:
+    target = _init_git_workspace(tmp_path)
+    target.write_text("x" * (MAX_PATCH_CHARS + 1), encoding="utf-8")
+    events: list[dict[str, object]] = []
+
+    ctx = ToolContext(workspace_dir=str(tmp_path), on_runtime_event=events.append)
+    candidate = capture_source_diff_candidate(
+        ctx=ctx,
+        relative_path="src/a.py",
+        workspace_epoch=1,
+        receipt_id="receipt-1",
+        tool_name="edit_source",
+    )
+
+    assert candidate is None
+    assert ctx.source_diff_candidates == []
+    assert events[-1]["reason"] == "patch_too_large"
+
+
+def test_mark_source_diff_candidates_lost_updates_matching_candidates() -> None:
+    events: list[dict[str, object]] = []
+    ctx = ToolContext(on_runtime_event=events.append)
+    ctx.source_diff_candidates.extend(
+        [
+            {
+                "candidate_id": "srcdiff-1",
+                "paths": ["src/a.py"],
+                "patch": "diff --git a/src/a.py b/src/a.py\n",
+                "lost": False,
+                "restored": False,
+            },
+            {
+                "candidate_id": "srcdiff-2",
+                "paths": ["src/b.py"],
+                "patch": "diff --git a/src/b.py b/src/b.py\n",
+                "lost": False,
+                "restored": False,
+            },
+        ]
+    )
+
+    marked = mark_source_diff_candidates_lost(
+        ctx=ctx,
+        paths=["src/a.py"],
+        reason="source_diff_revert_observed",
+        command="git checkout -- src/a.py",
+    )
+
+    assert [item["candidate_id"] for item in marked] == ["srcdiff-1"]
+    assert ctx.source_diff_candidates[0]["lost"] is True
+    assert ctx.source_diff_candidates[0]["lost_reason"] == "source_diff_revert_observed"
+    assert ctx.source_diff_candidates[1]["lost"] is False
+    assert events[-1]["name"] == "source_diff_candidate.marked_lost"