Diagnostics Reference

This reference documents all 118 diagnostic codes emitted by the Oproto.FluentDynamoDb source generator. Each code links to a detailed page with the message format, description, triggering example, and fix.

Numbering Conventions

Prefix	Code Range	Domain
DISC	001–006	Discriminator configuration and pattern matching
DYNDB	001–036, 101–115, 120–127, 1001–1004	Core DynamoDB entity validation and mapping
FDDB	001–006, 0020–0021, 050–055, 060–062, 070–072, 080, 090, 100–104, 110–116, 120–126	Table/index generation and configuration
PROJ	001–006, 101–102	Projection model validation
SEC	001–002	Security and package dependency checks

Prefix Distinction: DYNDB vs FDDB

Both DYNDB and FDDB prefixes relate to the FluentDynamoDb source generator:

• DYNDB covers core entity validation — constraints on individual entity properties, key formats, type compatibility, and attribute correctness.
• FDDB covers table and index generation — multi-entity table configuration, index consolidation, projection wiring, and computed key format validation.

DYNDB Range Bands

The DYNDB prefix uses range bands to group related diagnostics by functional area:

Range	Area
001–036	Core validation (keys, types, attributes, references)
101–115	Advanced type system (TTL, JSON, blobs, spatial, deprecation)
120–127	Index attribute validation (GSI/LSI configuration)
1001–1004	Extension method wrapper generation

The varying digit widths within DYNDB (3-digit, 4-digit) reflect these logical groupings rather than an inconsistency.

FDDB Numbering Inconsistency

Codes FDDB0020 and FDDB0021 use four-digit numbering while other FDDB codes use three-digit numbering. This is a known inconsistency retained for backward compatibility — these codes were introduced before the current naming convention was established and cannot be renumbered without breaking existing suppressions.

DISC — Discriminator Configuration

Code	Severity	Title
DISC001	Warning	Both DiscriminatorValue and DiscriminatorPattern specified
DISC002	Error	DiscriminatorValue or DiscriminatorPattern without DiscriminatorProperty
DISC003	Error	Invalid discriminator pattern syntax
DISC004	Error	Ambiguous overlapping discriminator patterns
DISC005	Info	Overlapping discriminator pattern resolved
DISC006	Error	Tautological exclusion guard detected

DYNDB — Core Entity Validation

Code	Severity	Title
DYNDB001	Error	Missing partition key
DYNDB002	Error	Multiple partition keys
DYNDB003	Error	Multiple sort keys
DYNDB004	Error	Invalid key format
DYNDB005	Error	Conflicting entity types
DYNDB006	Error	Invalid GSI configuration
DYNDB007	Error	Missing DynamoDbAttribute
DYNDB008	Warning	Ambiguous related entity pattern
DYNDB009	Error	Unsupported property type
DYNDB010	Error	Entity must be partial
DYNDB011	Error	Multi-item entity missing partition key
DYNDB012	Warning	Multi-item entity missing sort key
DYNDB013	Error	Collection property cannot be key
DYNDB014	Warning	Multi-item entity partition key format
DYNDB015	Error	Invalid related entity type
DYNDB016	Warning	Related entities require sort key
DYNDB017	Warning	Conflicting related entity patterns
DYNDB018	Error	Invalid key format syntax
DYNDB019	Warning	Potential key collision
DYNDB020	Error	Circular reference detected
DYNDB021	Warning	Reserved word usage
DYNDB022	Error	Invalid DynamoDB configuration
DYNDB023	Warning	Performance warning
DYNDB024	Error	Missing required attribute
DYNDB025	Warning	Potential data loss
DYNDB026	Error	Invalid GSI projection
DYNDB027	Warning	Scalability warning
DYNDB028	Error	Unsupported type conversion
DYNDB029	Warning	Too many attributes
DYNDB030	Error	Invalid attribute name
DYNDB031	Error	Invalid computed key source
DYNDB032	Error	Invalid extracted key source
DYNDB033	Error	Circular key dependency
DYNDB034	Error	Self-referencing computed key
DYNDB035	Error	Invalid extracted key index
DYNDB036	Warning	Invalid computed key format
DYNDB101	Error	Invalid TTL property type
DYNDB102	Error	Missing JSON serializer package
DYNDB103	Error	Missing blob provider package
DYNDB104	Error	Incompatible attribute combination
DYNDB105	Error	Multiple TTL fields
DYNDB106	Error	Unsupported collection type
DYNDB107	Error	Nested map type missing [DynamoDbEntity]
DYNDB108	Error	S2Level specified without S2 index type
DYNDB109	Error	H3Resolution specified without H3 index type
DYNDB110	Error	GeoHashPrecision specified without GeoHash index type
DYNDB111	Error	Spatial index configuration on non-GeoLocation property
DYNDB112	Warning	Missing Geospatial package
DYNDB113	Warning	Deprecated [Queryable] attribute
DYNDB115	Error	BlobStorage requires BlobData<T> type
DYNDB120	Error	GSI sort key without partition key
DYNDB121	Error	Duplicate GSI partition keys
DYNDB122	Error	Duplicate GSI sort keys
DYNDB123	Error	Duplicate LSI sort keys
DYNDB124	Error	Empty GsiPartitionKey index name
DYNDB125	Error	Empty GsiSortKey index name
DYNDB126	Error	Empty LsiSortKey index name
DYNDB127	Error	GSI/LSI index name conflict
DYNDB1001	Error	Invalid GenerateWrapper usage
DYNDB1002	Error	Invalid extension method
DYNDB1003	Warning	Interface not found
DYNDB1004	Warning	Interface not implemented

FDDB — Table/Index Generation

Code	Severity	Title
FDDB001	Error	No default entity specified
FDDB002	Error	Multiple default entities
FDDB003	Error	Conflicting accessor configuration
FDDB004	Error	Empty entity property name
FDDB005	Warning	Inconsistent discriminator properties
FDDB006	Error	Conflicting table namespaces
FDDB0020	Error	EnableDynamicFields requires partial class
FDDB0021	Warning	DynamicFields property already exists
FDDB050	Error	Conflicting index Name values
FDDB051	Error	Non-partial table type
FDDB052	Warning	Redundant index Name specification
FDDB053	Error	Conflicting index partition key attribute
FDDB054	Error	Conflicting index sort key attribute
FDDB055	Error	Conflicting index type
FDDB060	Error	Projection source entity not found
FDDB061	Error	Projection metadata inheritance failure
FDDB062	Error	Projection interface violation
FDDB070	Warning	Include projection without properties
FDDB072	Warning	KeysOnly with UseProjection
FDDB080	Error	Unresolvable source property in computed key
FDDB090	Error	Format placeholder count mismatch
FDDB100	Error	Key prefix conflicts with explicit computed format
FDDB101	Error	Explicit discriminator pattern conflicts with key format
FDDB102	Warning	Overlapping auto-derived discriminator patterns
FDDB103	Info	Redundant explicit discriminator pattern
FDDB104	Info	Compound discrimination resolved overlap
FDDB110	Warning	Missing schema version attribute
FDDB111	Error	Declared version below minimum supported
FDDB112	Error	Declared version above current
FDDB113	Info	Older-but-supported version, upgrade available
FDDB114	Error	Major version less than 1
FDDB115	Error	Minor version less than 0
FDDB116	Error	Multiple schema version attributes detected
FDDB120	Error	Constant key conflicts with computed attribute
FDDB121	Error	Prefix not applicable to constant key
FDDB122	Error	Cannot extract from constant key
FDDB123	Error	Empty constant key value
FDDB124	Error	Extracted property conflicts with DynamoDbAttribute
FDDB125	Error	Computed key property has redundant Prefix
FDDB126	Error	Key property references non-compile-time-constant value

PROJ — Projection Model Validation

Code	Severity	Title
PROJ001	Error	Projection property not found
PROJ002	Error	Projection property type mismatch
PROJ003	Error	Invalid projection source entity
PROJ004	Error	Projection must be partial
PROJ005	Error	UseProjection references invalid type
PROJ006	Error	Conflicting UseProjection attributes
PROJ101	Warning	Projection includes all properties
PROJ102	Warning	Projection has many properties

SEC — Security and Package Dependencies

Code	Severity	Title
SEC001	Warning	Missing Encryption.Kms package
SEC002	Error	Missing Amazon.Lambda.DynamoDBEvents package