Documentation
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Overview ¶
Package requireddepsgen generates validateRequired() methods for Service structs by reading gocell:"required" struct field tags.
Usage:
out, err := requireddepsgen.Generate("/path/to/slice")
// out contains the formatted Go source for service_required_gen.go
Primary Tag ¶
Mark a Service struct field as required:
type Service struct {
repo domain.Repository `gocell:"required"`
}
The generator emits a validateRequired() method that checks each tagged field and returns an errcode.Error on the first nil dependency found.
Sub-Tags (all optional) ¶
Sub-tags customize the generated error for a specific field. They have no effect on fields without gocell:"required".
gocellKind errcode.Kind constant name (default: KindInternal)
e.g. gocellKind:"KindInvalid"
gocellCode errcode error code constant (default: ErrCellInvalidConfig)
e.g. gocellCode:"ErrValidationFailed"
gocellErr error message string literal
(default: "{pkg}.NewService: {field} required")
e.g. gocellErr:"slicepkg: TxRunner required; use WithTxManager"
Typical case (default KindInternal/ErrCellInvalidConfig with custom message):
txRunner persistence.CellTxManager `gocell:"required" gocellErr:"mypkg: TxRunner required; use WithTxManager"`
Overriding all three sub-tags (rare — different HTTP status intentional):
codec *query.CursorCodec `gocell:"required" gocellCode:"ErrCellMissingCodec" gocellErr:"mypkg: cursor codec required"`
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // ErrNoServiceStruct is returned when service.go contains no // "type Service struct" declaration. ErrNoServiceStruct = errcode.New(errcode.KindInvalid, errcode.ErrValidationFailed, "requireddepsgen: no Service struct in service.go") // ErrUnknownTagValue is returned when a struct field has a gocell tag // whose value is not "" or "required", or when gocellKind/gocellCode tags // contain values that do not match the errcode identifier whitelist. ErrUnknownTagValue = errcode.New(errcode.KindInvalid, errcode.ErrValidationFailed, "requireddepsgen: unknown gocell tag value (allowed: \"\", \"required\")") // ErrBadTagSyntax is returned when a struct field carries a malformed // struct tag (one reflect.StructTag.Lookup would silently drop). Surfacing // it fail-closed prevents a typo'd tag from silently skipping a required // dependency guard. ErrBadTagSyntax = errcode.New(errcode.KindInvalid, errcode.ErrValidationFailed, "requireddepsgen: malformed struct tag") )
Sentinel errors returned by Generate. Declared via errcode.New (not errors.New) so exported package-scope sentinels participate in the project error taxonomy — EXPORTED-ERROR-NEW-01 bans exported errors.New sentinels module-wide, tools/ included. They keep stable pointer identity (single package-var construction), so errors.Is against them is unaffected.
Functions ¶
func FindSlicePaths ¶
FindSlicePaths discovers all slice directories containing a service.go under modRoot. Exported so the REQUIRED-DEP-NIL-GUARD-01 A1 archtest regen-diffs the exact same set of gen files the generator emits — generator and verifier share one discovery, so no gen file can escape the byte-granularity Hard check.
func Generate ¶
Generate reads slicePath/service.go, scans the Service struct for gocell:"required" field tags, and returns the formatted Go source for service_required_gen.go.
Returns byte-identical output for identical inputs (no map iteration order dependency). Field guards appear in struct declaration order.
func GenerateAll ¶
GenerateAll walks modRoot for all cells/*/slices/*/service.go files and returns a map from slice directory path to generated file contents.
Slices whose service.go does not declare a "Service" struct are silently skipped (ErrNoServiceStruct). All other errors are fatal.
func GenerateWithOpts ¶
GenerateWithOpts is the option-aware variant of Generate. See Opts.
func TagSyntaxValid ¶
TagSyntaxValid reports whether raw (the unquoted struct-tag body, e.g. `json:"x" gocell:"required"`) is a well-formed sequence of conventional key:"value" pairs. It mirrors the scan loop of reflect.StructTag.Lookup but, unlike Lookup — which silently stops at the first malformed pair and reports the key as absent — returns false on any malformation so callers can fail closed. Exported so the REQUIRED-DEP-NIL-GUARD-01 A4 archtest shares this single malformed-tag definition rather than re-deriving it. ref: Go src reflect/type.go StructTag.Lookup.
Source Files