fix(audit): ScadaBridge C3 review — safe enum-parse (fallback) in SqliteAuditWriter.MapRow + AuditEventDtoMapper.FromDto (Task 2.5)

src/ZB.MOM.WW.ScadaBridge.AuditLog/Site/SqliteAuditWriter.cs

@@ -800,9 +800,9 @@ public class SqliteAuditWriter : IAuditWriter, ISiteAuditQueue, IAsyncDisposable
                 System.Globalization.CultureInfo.InvariantCulture,
                 System.Globalization.DateTimeStyles.RoundtripKind),
             IngestedAtUtc: null,
-            Channel: Enum.Parse<AuditChannel>(reader.GetString(2)),
+            Channel: AuditRowProjection.ParseEnum<AuditChannel>(reader.GetString(2), AuditChannel.ApiInbound),
-            Kind: Enum.Parse<AuditKind>(reader.GetString(3)),
+            Kind: AuditRowProjection.ParseEnum<AuditKind>(reader.GetString(3), AuditKind.InboundRequest),
-            Status: Enum.Parse<AuditStatus>(reader.GetString(11)),
+            Status: AuditRowProjection.ParseEnum<AuditStatus>(reader.GetString(11), AuditStatus.Submitted),
             CorrelationId: reader.IsDBNull(4) ? null : Guid.Parse(reader.GetString(4)),
             ExecutionId: reader.IsDBNull(21) ? null : Guid.Parse(reader.GetString(21)),
             ParentExecutionId: reader.IsDBNull(22) ? null : Guid.Parse(reader.GetString(22)),

src/ZB.MOM.WW.ScadaBridge.Commons/Types/Audit/AuditRowProjection.cs

@@ -173,7 +173,13 @@ public static class AuditRowProjection
         return evt with { DetailsJson = AuditDetailsCodec.Serialize(d) };
     }
 
-    private static TEnum ParseEnum<TEnum>(string? value, TEnum fallback) where TEnum : struct, Enum
+    /// <summary>
+    /// Case-sensitive <see cref="Enum.TryParse{TEnum}"/> with a caller-supplied fallback.
+    /// Returns <paramref name="fallback"/> when <paramref name="value"/> is null, empty,
+    /// or does not match any declared member name — so callers never throw on an
+    /// unknown/renamed enum string (legacy or corrupt rows degrade gracefully).
+    /// </summary>
+    public static TEnum ParseEnum<TEnum>(string? value, TEnum fallback) where TEnum : struct, Enum
         => !string.IsNullOrEmpty(value) && Enum.TryParse<TEnum>(value, ignoreCase: false, out var parsed)
             ? parsed
             : fallback;

src/ZB.MOM.WW.ScadaBridge.Communication/Grpc/AuditEventDtoMapper.cs

@@ -105,9 +105,9 @@ public static class AuditEventDtoMapper
             EventId: Guid.Parse(dto.EventId),
             OccurredAtUtc: DateTime.SpecifyKind(dto.OccurredAtUtc.ToDateTime(), DateTimeKind.Utc),
             IngestedAtUtc: null,
-            Channel: Enum.Parse<AuditChannel>(dto.Channel),
+            Channel: AuditRowProjection.ParseEnum<AuditChannel>(dto.Channel, AuditChannel.ApiInbound),
-            Kind: Enum.Parse<AuditKind>(dto.Kind),
+            Kind: AuditRowProjection.ParseEnum<AuditKind>(dto.Kind, AuditKind.InboundRequest),
-            Status: Enum.Parse<AuditStatus>(dto.Status),
+            Status: AuditRowProjection.ParseEnum<AuditStatus>(dto.Status, AuditStatus.Submitted),
             CorrelationId: NullIfEmpty(dto.CorrelationId) is { } cid ? Guid.Parse(cid) : null,
             ExecutionId: NullIfEmpty(dto.ExecutionId) is { } eid ? Guid.Parse(eid) : null,
             ParentExecutionId: NullIfEmpty(dto.ParentExecutionId) is { } pid ? Guid.Parse(pid) : null,

tests/ZB.MOM.WW.ScadaBridge.AuditLog.Tests/Site/SqliteAuditWriterWriteTests.cs

@@ -457,4 +457,47 @@ public class SqliteAuditWriterWriteTests
         var row = Assert.Single(rows);
         Assert.Null(row.SourceNode);
     }
+
+    // ----- C3 hardening: safe enum-parse in MapRow ----- //
+
+    /// <summary>
+    /// C3 hardening (Task 2.5): a row whose Channel/Kind/Status columns hold
+    /// an unknown/renamed enum string must NOT fault the read path; it degrades
+    /// gracefully to the same fallbacks used by <c>AuditRowProjection.Decompose</c>
+    /// (ApiInbound / InboundRequest / Submitted).  The read is exercised via the
+    /// public <see cref="SqliteAuditWriter.ReadPendingAsync"/> surface which calls
+    /// the private <c>MapRow</c>.
+    /// </summary>
+    [Fact]
+    public async Task ReadPendingAsync_UnknownEnumStrings_DoNotThrow_YieldFallbackValues()
+    {
+        var (writer, dataSource) = CreateWriter(
+            nameof(ReadPendingAsync_UnknownEnumStrings_DoNotThrow_YieldFallbackValues));
+        await using var _ = writer;
+
+        var evt = NewEvent();
+        await writer.WriteAsync(evt);
+
+        // Tamper: overwrite the three enum columns with unknown strings that are
+        // not declared AuditChannel/AuditKind/AuditStatus member names.
+        using (var conn = OpenVerifierConnection(dataSource))
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText =
+                "UPDATE AuditLog SET Channel = 'ObsoleteChannelV0', " +
+                "Kind = 'LegacyKindName', Status = 'RenamedStatus99' " +
+                "WHERE EventId = $id;";
+            cmd.Parameters.AddWithValue("$id", evt.EventId.ToString());
+            cmd.ExecuteNonQuery();
+        }
+
+        // Must not throw (previously would throw ArgumentException from Enum.Parse).
+        var rows = await writer.ReadPendingAsync(limit: 10);
+
+        var row = Assert.Single(rows);
+        var typedRow = row.AsRow();
+        Assert.Equal(AuditChannel.ApiInbound,     typedRow.Channel);
+        Assert.Equal(AuditKind.InboundRequest,    typedRow.Kind);
+        Assert.Equal(AuditStatus.Submitted,       typedRow.Status);
+    }
 }

tests/ZB.MOM.WW.ScadaBridge.Communication.Tests/AuditEventDtoMapperTests.cs

@@ -268,4 +268,30 @@ public class AuditEventDtoMapperTests
         // …and FromDto rehydrates empty → null.
         Assert.Null(roundTripped.SourceNode);
     }
+
+    /// <summary>
+    /// C3 hardening (Task 2.5): a DTO that carries an unknown/renamed enum string
+    /// for Channel, Kind, or Status must NOT throw on <see cref="AuditEventDtoMapper.FromDto"/>;
+    /// it degrades gracefully to the same fallbacks used by <c>AuditRowProjection.Decompose</c>
+    /// (ApiInbound / InboundRequest / Submitted).
+    /// </summary>
+    [Fact]
+    public void FromDto_UnknownEnumStrings_DoNotThrow_YieldFallbackValues()
+    {
+        var dto = new AuditEventDto
+        {
+            EventId = Guid.NewGuid().ToString(),
+            OccurredAtUtc = Timestamp.FromDateTime(DateTime.UtcNow),
+            Channel = "ObsoleteChannelV0",   // unknown — not a declared AuditChannel member
+            Kind    = "LegacyKindName",       // unknown — not a declared AuditKind member
+            Status  = "RenamedStatus99",      // unknown — not a declared AuditStatus member
+        };
+
+        // Must not throw (previously would throw ArgumentException from Enum.Parse).
+        var row = AuditEventDtoMapper.FromDto(dto).AsRow();
+
+        Assert.Equal(AuditChannel.ApiInbound,     row.Channel);
+        Assert.Equal(AuditKind.InboundRequest,    row.Kind);
+        Assert.Equal(AuditStatus.Submitted,       row.Status);
+    }
 }