[ci] Match symbols with changed signatures in memory impact analysis (#14600)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

tests/unit_tests/analyze_memory/test_ci_memory_impact_comment.py

@@ -0,0 +1,99 @@
+"""Tests for script/ci_memory_impact_comment.py symbol matching."""
+
+from pathlib import Path
+import sys
+
+# Add script directory to path so we can import the module
+sys.path.insert(0, str(Path(__file__).parent.parent.parent.parent / "script"))
+
+from ci_memory_impact_comment import prepare_symbol_changes_data  # noqa: E402
+
+
+def test_prepare_symbol_changes_signature_match() -> None:
+    """Symbols with same base name but different args are matched as changed."""
+    target = {
+        "Foo::bar(std::vector<unsigned char>&, int)": 300,
+        "unchanged()": 50,
+    }
+    pr = {
+        "Foo::bar(ProtoByteBuffer&, int)": 320,
+        "unchanged()": 50,
+    }
+    result = prepare_symbol_changes_data(target, pr)
+    assert result is not None
+    assert len(result["changed_symbols"]) == 1
+    assert len(result["new_symbols"]) == 0
+    assert len(result["removed_symbols"]) == 0
+    sym, t_size, p_size, delta = result["changed_symbols"][0]
+    assert sym == "Foo::bar(ProtoByteBuffer&, int)"
+    assert t_size == 300
+    assert p_size == 320
+    assert delta == 20
+
+
+def test_prepare_symbol_changes_ambiguous_overloads_not_matched() -> None:
+    """Multiple overloads with same base name stay as new/removed."""
+    target = {
+        "Foo::bar(int)": 100,
+        "Foo::bar(float)": 200,
+    }
+    pr = {
+        "Foo::bar(double)": 150,
+        "Foo::bar(long)": 250,
+    }
+    result = prepare_symbol_changes_data(target, pr)
+    assert result is not None
+    assert len(result["changed_symbols"]) == 0
+    assert len(result["new_symbols"]) == 2
+    assert len(result["removed_symbols"]) == 2
+
+
+def test_prepare_symbol_changes_no_parens_not_matched() -> None:
+    """Symbols without parens (variables) are not fuzzy-matched."""
+    target = {"my_global_var": 100}
+    pr = {"my_global_var_v2": 120}
+    result = prepare_symbol_changes_data(target, pr)
+    assert result is not None
+    assert len(result["changed_symbols"]) == 0
+    assert len(result["new_symbols"]) == 1
+    assert len(result["removed_symbols"]) == 1
+
+
+def test_prepare_symbol_changes_nested_symbols_matched_separately() -> None:
+    """Nested symbols like ::__pstr__ don't collide with parent function."""
+    target = {
+        "Foo::bar(std::vector<unsigned char>&, int)": 300,
+        "Foo::bar(std::vector<unsigned char>&, int)::__pstr__": 19,
+    }
+    pr = {
+        "Foo::bar(ProtoByteBuffer&, int)": 320,
+        "Foo::bar(ProtoByteBuffer&, int)::__pstr__": 19,
+    }
+    result = prepare_symbol_changes_data(target, pr)
+    assert result is not None
+    # Both the function and its nested __pstr__ should be matched (not new/removed)
+    assert len(result["new_symbols"]) == 0
+    assert len(result["removed_symbols"]) == 0
+    # __pstr__ has delta=0 so it's silently dropped, only the function shows
+    assert len(result["changed_symbols"]) == 1
+    sym, t_size, p_size, delta = result["changed_symbols"][0]
+    assert sym == "Foo::bar(ProtoByteBuffer&, int)"
+    assert delta == 20
+
+
+def test_prepare_symbol_changes_exact_match_preferred() -> None:
+    """Exact name matches are found before fuzzy matching runs."""
+    target = {
+        "Foo::bar(int)": 100,
+    }
+    pr = {
+        "Foo::bar(int)": 120,
+    }
+    result = prepare_symbol_changes_data(target, pr)
+    assert result is not None
+    assert len(result["changed_symbols"]) == 1
+    assert len(result["new_symbols"]) == 0
+    assert len(result["removed_symbols"]) == 0
+    sym, t_size, p_size, delta = result["changed_symbols"][0]
+    assert sym == "Foo::bar(int)"
+    assert delta == 20