graphify/tests/test_csharp_object_creation.py

"""C# `new Foo(...)` links the constructing method to Foo.

The C# config only listed `invocation_expression` in `call_types`, so an
`object_creation_expression` was never dispatched and a type a method merely
constructs got no edge at all. Java has taken `new Foo(...)` as a call since
#1373; C# had not caught up. The types this loses are the ones handed straight
to something else — `Send(new OrderPlaced { ... })` on a message bus, a locally
built collaborator — so publishers looked unconnected while the class sat right
there in the graph.

Only the explicit form is claimed. Target-typed `new()` parses as
`implicit_object_creation_expression` and needs the assignment target's declared
type to name anything, so it stays out.
"""
from __future__ import annotations

import os
import tempfile
from pathlib import Path

from graphify.extract import extract


def _extract(tmp_path, files: dict[str, str]):
    for name, body in files.items():
        p = tmp_path / name
        p.parent.mkdir(parents=True, exist_ok=True)
        p.write_text(body)
    old = os.getcwd()
    try:
        os.chdir(tmp_path)
        r = extract([Path(n) for n in files], cache_root=Path(tempfile.mkdtemp()))
    finally:
        os.chdir(old)
    calls = {(e["source"], e["target"]) for e in r["edges"] if e["relation"] == "calls"}
    return calls, r


def _find(r, label, id_contains):
    return next(n["id"] for n in r["nodes"]
                if n["label"] == label and id_contains in n["id"])


def test_explicitly_declared_local_links_to_constructed_type(tmp_path):
    calls, r = _extract(tmp_path, {"S.cs": (
        "public class Worker { }\n"
        "public class Caller {\n"
        "    public void Go() { Worker w = new Worker(); }\n"
        "}\n"
    )})
    assert (_find(r, ".Go()", "go"), _find(r, "Worker", "worker")) in calls


def test_var_local_links_to_constructed_type(tmp_path):
    calls, r = _extract(tmp_path, {"S.cs": (
        "public class Worker { }\n"
        "public class Caller {\n"
        "    public void Go() { var w = new Worker(); }\n"
        "}\n"
    )})
    assert (_find(r, ".Go()", "go"), _find(r, "Worker", "worker")) in calls


def test_argument_position_links_to_constructed_type(tmp_path):
    # The publish shape: the message type never appears in a declared position.
    calls, r = _extract(tmp_path, {"S.cs": (
        "public class OrderPlaced { }\n"
        "public class Publisher {\n"
        "    public void Publish() { Send(new OrderPlaced()); }\n"
        "    private void Send(object payload) { }\n"
        "}\n"
    )})
    assert (_find(r, ".Publish()", "publish"), _find(r, "OrderPlaced", "orderplaced")) in calls


def test_object_initializer_without_parens_links(tmp_path):
    calls, r = _extract(tmp_path, {"S.cs": (
        "public class OrderPlaced { public long Id { get; set; } }\n"
        "public class Publisher {\n"
        "    public void Publish(long id) { Send(new OrderPlaced { Id = id }); }\n"
        "    private void Send(object payload) { }\n"
        "}\n"
    )})
    assert (_find(r, ".Publish()", "publish"), _find(r, "OrderPlaced", "orderplaced")) in calls


def test_generic_construction_names_the_outer_type(tmp_path):
    calls, r = _extract(tmp_path, {"S.cs": (
        "public class Cache<T> { }\n"
        "public class Caller {\n"
        "    public void Go() { var c = new Cache<string>(); }\n"
        "}\n"
    )})
    assert (_find(r, ".Go()", "go"), _find(r, "Cache", "cache")) in calls


def test_qualified_construction_names_the_last_segment(tmp_path):
    calls, r = _extract(tmp_path, {
        "Store.cs": (
            "namespace Infra.Data;\n"
            "public class Cache { }\n"
        ),
        "Caller.cs": (
            "public class Caller {\n"
            "    public void Go() { var c = new Infra.Data.Cache(); }\n"
            "}\n"
        ),
    })
    assert (_find(r, ".Go()", "go"), _find(r, "Cache", "cache")) in calls


def test_target_typed_new_produces_no_edge(tmp_path):
    # `new()` carries no type node; guessing one needs the target's declared type.
    calls, r = _extract(tmp_path, {"S.cs": (
        "public class Worker { }\n"
        "public class Caller {\n"
        "    public Worker Build() { Worker w = new(); return w; }\n"
        "}\n"
    )})
    worker = _find(r, "Worker", "worker")
    assert not any(target == worker for _, target in calls)


def test_cross_file_publisher_reaches_the_message_class(tmp_path):
    calls, r = _extract(tmp_path, {
        "Events/OrderPlaced.cs": (
            "namespace Demo.Events;\n"
            "public class OrderPlaced { public long Id { get; set; } }\n"
        ),
        "Publisher.cs": (
            "using Demo.Events;\n"
            "public class Publisher {\n"
            "    public void Publish(long id) { Send(new OrderPlaced { Id = id }); }\n"
            "    private void Send(object payload) { }\n"
            "}\n"
        ),
    })
    assert (_find(r, ".Publish()", "publish"), _find(r, "OrderPlaced", "orderplaced")) in calls


def test_ambiguous_type_name_produces_no_edge(tmp_path):
    # Two classes share a name, so the construction site cannot be pinned to one
    # of them. No edge beats a coin flip here — #437 is about exactly the kind of
    # false edge a name-only guess creates.
    calls, r = _extract(tmp_path, {
        "Left.cs": "namespace Left;\npublic class Cache { }\n",
        "Right.cs": "namespace Right;\npublic class Cache { }\n",
        "Caller.cs": (
            "using Right;\n"
            "public class Caller {\n"
            "    public void Go() { var c = new Cache(); }\n"
            "}\n"
        ),
    })
    caches = {n["id"] for n in r["nodes"] if n["label"] == "Cache"}
    assert len(caches) == 2
    assert not any(target in caches for _, target in calls)


_COLLIDING_CACHES = {
    "Left.cs": "namespace Infra.Data;\npublic class Cache { }\n",
    "Right.cs": "namespace Other;\npublic class Cache { }\n",
}


def test_qualified_construction_picks_the_named_namespace(tmp_path):
    # The bare name is ambiguous, but the source says which Cache it means.
    calls, r = _extract(tmp_path, {**_COLLIDING_CACHES, "Caller.cs": (
        "public class Caller {\n"
        "    public void Go() { var c = new Infra.Data.Cache(); }\n"
        "}\n"
    )})
    wanted = _find(r, "Cache", "left")
    other = _find(r, "Cache", "right")
    go = _find(r, ".Go()", "go")
    assert (go, wanted) in calls
    assert (go, other) not in calls


def test_partially_qualified_construction_stays_unresolved(tmp_path):
    # `new Data.Cache()` under `using Infra;` would need the using directives in
    # scope to become a namespace. Resolving it by suffix would be a guess.
    calls, r = _extract(tmp_path, {**_COLLIDING_CACHES, "Caller.cs": (
        "using Infra;\n"
        "public class Caller {\n"
        "    public void Go() { var c = new Data.Cache(); }\n"
        "}\n"
    )})
    caches = {n["id"] for n in r["nodes"] if n["label"] == "Cache"}
    assert not any(target in caches for _, target in calls)


def test_qualified_construction_with_two_candidates_in_one_namespace(tmp_path):
    # Same namespace declared in two files, both holding a Cache: the qualifier
    # cannot separate them either, so the guard still applies.
    calls, r = _extract(tmp_path, {
        "One.cs": "namespace Infra.Data;\npublic class Cache { }\n",
        "Two.cs": "namespace Infra.Data;\npublic class Cache { }\n",
        "Caller.cs": (
            "public class Caller {\n"
            "    public void Go() { var c = new Infra.Data.Cache(); }\n"
            "}\n"
        ),
    })
    caches = {n["id"] for n in r["nodes"] if n["label"] == "Cache"}
    assert not any(target in caches for _, target in calls)


def test_receiver_typed_member_call_still_resolves(tmp_path):
    # Guard for #1609: adding a node type to call_types must not disturb the
    # invocation path that binds a call to its receiver's declared type.
    calls, r = _extract(tmp_path, {"S.cs": (
        "public class Server { public bool Save() => true; }\n"
        "public class Cache  { public bool Save() => false; }\n"
        "public class Repo {\n"
        "    private Server _server = new Server();\n"
        "    public bool Commit() { return _server.Save(); }\n"
        "}\n"
    )})
    commit = _find(r, ".Commit()", "commit")
    assert (commit, _find(r, ".Save()", "server")) in calls
    assert (commit, _find(r, ".Save()", "cache")) not in calls

def test_qualified_construction_resolves_when_the_method_also_declares_the_type(tmp_path):
    # The method takes the type as a parameter and constructs it. The declared
    # position mints a bare-name stub in this file, and binding the construction
    # to that stub would keep it away from the namespace resolver, so the call
    # would land on a sourceless node instead of the class.
    calls, r = _extract(tmp_path, {**_COLLIDING_CACHES, "Caller.cs": (
        "public class Caller {\n"
        "    public void Go(Infra.Data.Cache existing) { var c = new Infra.Data.Cache(); }\n"
        "}\n"
    )})
    go = _find(r, ".Go()", "go")
    assert (go, _find(r, "Cache", "left")) in calls
    sourceless = {n["id"] for n in r["nodes"]
                  if n["label"] == "Cache" and not n.get("source_file")}
    assert not any(target in sourceless for _, target in calls)


def test_qualified_construction_of_a_foreign_type_makes_no_stub_edge(tmp_path):
    # `new System.Text.StringBuilder()` has no declaration in the corpus. No edge
    # beats an edge into a sourceless placeholder that stands for nothing.
    calls, r = _extract(tmp_path, {"Caller.cs": (
        "public class Caller {\n"
        "    public void Go() { var b = new System.Text.StringBuilder(); }\n"
        "}\n"
    )})
    builders = {n["id"] for n in r["nodes"] if n["label"] == "StringBuilder"}
    assert not any(target in builders for _, target in calls)