feat(generators): expose underlying OpenFeature client on generated clients

internal/cmd/testdata/success_angular.golden

@@ -101,6 +101,14 @@ export type FlagKey = (typeof FlagKeys)[keyof typeof FlagKeys];
 export class GeneratedFeatureFlagService {
   private readonly flagService = inject(FeatureFlagService);
 
+  /**
+   * The underlying FeatureFlagService for ad-hoc flag evaluations
+   * beyond what's defined in the manifest.
+   */
+  get client(): FeatureFlagService {
+    return this.flagService;
+  }
+
 
   /**
    * Get evaluation details for the `discountPercentage` flag.

internal/cmd/testdata/success_csharp.golden

@@ -75,6 +75,11 @@ namespace TestNamespace
         {
             _client = client ?? throw new ArgumentNullException(nameof(client));
         }
+
+        /// <summary>
+        /// The underlying OpenFeature client for ad-hoc flag evaluations.
+        /// </summary>
+        public IFeatureClient Client => _client;
         /// <summary>
         /// Discount percentage applied to purchases.
         /// </summary>

internal/cmd/testdata/success_go.golden

@@ -24,7 +24,9 @@ type (
 	evaluationDetails[T any] func(context.Context, openfeature.EvaluationContext) (openfeature.GenericEvaluationDetails[T], error)
 )
 
-var client = openfeature.NewDefaultClient()
+// Client is the underlying OpenFeature client used for flag evaluations.
+// It can be used directly for ad-hoc flag evaluations beyond what is defined in the manifest.
+var Client = openfeature.NewDefaultClient()
 
 // DiscountPercentage returns the value of the "discountPercentage" feature flag.
 // Discount percentage applied to purchases.
@@ -41,10 +43,10 @@ var DiscountPercentage = struct {
 }{
 	Stringer: stringer("discountPercentage"),
 	Value: func(ctx context.Context, evalCtx openfeature.EvaluationContext) float64 {
-		return client.Float(ctx, "discountPercentage", 0.15, evalCtx)
+		return Client.Float(ctx, "discountPercentage", 0.15, evalCtx)
 	},
 	ValueWithDetails: func(ctx context.Context, evalCtx openfeature.EvaluationContext) (openfeature.GenericEvaluationDetails[float64], error) {
-		return client.FloatValueDetails(ctx, "discountPercentage", 0.15, evalCtx)
+		return Client.FloatValueDetails(ctx, "discountPercentage", 0.15, evalCtx)
 	},
 }
 
@@ -63,10 +65,10 @@ var EnableFeatureA = struct {
 }{
 	Stringer: stringer("enableFeatureA"),
 	Value: func(ctx context.Context, evalCtx openfeature.EvaluationContext) bool {
-		return client.Boolean(ctx, "enableFeatureA", false, evalCtx)
+		return Client.Boolean(ctx, "enableFeatureA", false, evalCtx)
 	},
 	ValueWithDetails: func(ctx context.Context, evalCtx openfeature.EvaluationContext) (openfeature.GenericEvaluationDetails[bool], error) {
-		return client.BooleanValueDetails(ctx, "enableFeatureA", false, evalCtx)
+		return Client.BooleanValueDetails(ctx, "enableFeatureA", false, evalCtx)
 	},
 }
 
@@ -85,10 +87,10 @@ var GreetingMessage = struct {
 }{
 	Stringer: stringer("greetingMessage"),
 	Value: func(ctx context.Context, evalCtx openfeature.EvaluationContext) string {
-		return client.String(ctx, "greetingMessage", "Hello there!", evalCtx)
+		return Client.String(ctx, "greetingMessage", "Hello there!", evalCtx)
 	},
 	ValueWithDetails: func(ctx context.Context, evalCtx openfeature.EvaluationContext) (openfeature.GenericEvaluationDetails[string], error) {
-		return client.StringValueDetails(ctx, "greetingMessage", "Hello there!", evalCtx)
+		return Client.StringValueDetails(ctx, "greetingMessage", "Hello there!", evalCtx)
 	},
 }
 
@@ -107,10 +109,10 @@ var ThemeCustomization = struct {
 }{
 	Stringer: stringer("themeCustomization"),
 	Value: func(ctx context.Context, evalCtx openfeature.EvaluationContext) any {
-		return client.Object(ctx, "themeCustomization", map[string]any{"primaryColor": "#007bff", "secondaryColor": "#6c757d"}, evalCtx)
+		return Client.Object(ctx, "themeCustomization", map[string]any{"primaryColor": "#007bff", "secondaryColor": "#6c757d"}, evalCtx)
 	},
 	ValueWithDetails: func(ctx context.Context, evalCtx openfeature.EvaluationContext) (openfeature.GenericEvaluationDetails[any], error) {
-		return client.ObjectValueDetails(ctx, "themeCustomization", map[string]any{"primaryColor": "#007bff", "secondaryColor": "#6c757d"}, evalCtx)
+		return Client.ObjectValueDetails(ctx, "themeCustomization", map[string]any{"primaryColor": "#007bff", "secondaryColor": "#6c757d"}, evalCtx)
 	},
 }
 
@@ -129,9 +131,9 @@ var UsernameMaxLength = struct {
 }{
 	Stringer: stringer("usernameMaxLength"),
 	Value: func(ctx context.Context, evalCtx openfeature.EvaluationContext) int64 {
-		return client.Int(ctx, "usernameMaxLength", 50, evalCtx)
+		return Client.Int(ctx, "usernameMaxLength", 50, evalCtx)
 	},
 	ValueWithDetails: func(ctx context.Context, evalCtx openfeature.EvaluationContext) (openfeature.GenericEvaluationDetails[int64], error) {
-		return client.IntValueDetails(ctx, "usernameMaxLength", 50, evalCtx)
+		return Client.IntValueDetails(ctx, "usernameMaxLength", 50, evalCtx)
 	},
 }

internal/cmd/testdata/success_java.golden

@@ -125,6 +125,12 @@ public final class OpenFeature {
          * Returns the evaluation details containing the flag value and metadata
          */
         FlagEvaluationDetails<Integer> usernameMaxLengthDetails(EvaluationContext ctx);
+
+        /**
+         * Returns the underlying OpenFeature client for ad-hoc flag evaluations.
+         * @return The OpenFeature Client instance
+         */
+        Client getOpenFeatureClient();
     }
 
     private static final class OpenFeatureGeneratedClient implements GeneratedClient {
@@ -180,6 +186,11 @@ public final class OpenFeature {
         public FlagEvaluationDetails<Integer> usernameMaxLengthDetails(EvaluationContext ctx) {
             return client.getIntegerDetails("usernameMaxLength", 50, ctx);
         }
+
+        @Override
+        public Client getOpenFeatureClient() {
+            return client;
+        }
     }
 
     public static GeneratedClient getClient() {

internal/cmd/testdata/success_nodejs.golden

@@ -6,6 +6,7 @@ import {
   JsonValue,
 } from "@openfeature/server-sdk";
 import type {
+  Client,
   EvaluationContext,
   EvaluationDetails,
   FlagEvaluationOptions,
@@ -26,6 +27,8 @@ export const FlagKeys = {
 } as const;
 
 export interface GeneratedClient {
+  /** The underlying OpenFeature client for ad-hoc flag evaluations. */
+  readonly client: Client;
   /**
   * Discount percentage applied to purchases.
   * 
@@ -206,6 +209,7 @@ export function getGeneratedClient(domainOrContext?: string | EvaluationContext,
   const client = domain ? OpenFeature.getClient(domain, context) : OpenFeature.getClient(context)
 
   return {
+    client,
     discountPercentage: (context?: EvaluationContext, options?: FlagEvaluationOptions): Promise<number> => {
       return client.getNumberValue("discountPercentage", 0.15, context, options);
     },

internal/cmd/testdata/success_react.golden

@@ -6,6 +6,7 @@ import {
   type FlagQuery,
   useFlag,
   useSuspenseFlag,
+  useOpenFeatureClient,
   JsonValue
 } from "@openfeature/react-sdk";
 
@@ -158,3 +159,9 @@ export const useUsernameMaxLength = (options?: ReactFlagEvaluationOptions): Flag
 export const useSuspenseUsernameMaxLength = (options?: ReactFlagEvaluationNoSuspenseOptions): FlagQuery<number> => {
   return useSuspenseFlag("usernameMaxLength", 50, options);
 };
+
+/**
+ * Re-exported hook for accessing the underlying OpenFeature client
+ * for ad-hoc flag evaluations beyond what's defined in the manifest.
+ */
+export { useOpenFeatureClient };

internal/generators/README.md

@@ -55,4 +55,23 @@ To add a new generator, follow these steps:
 6. Write tests for your generator to ensure it works as expected.
 7. Update the documentation to include information about your new generator.
 
-We appreciate your contributions and look forward to seeing your new generators!
+We appreciate your contributions and look forward to seeing your new generators!
+
+## Reserved Keywords
+
+Each generator reserves certain symbol names that it exports in the generated output. If a flag key transforms to a reserved name, that flag will be **excluded** from the generated output and a warning will be printed.
+
+| Generator | Reserved names | Transform applied |
+|-----------|---------------|-------------------|
+| Go        | `Client`      | `ToPascal`        |
+| Node.js   | `client`      | `ToCamel`         |
+
+For example, a flag key `"client"` in a Go manifest would transform to `Client` (via `ToPascal`), colliding with the exported `var Client` that the Go generator places in every generated file. The flag will be skipped and the following warning emitted:
+
+```
+Flag "client" transforms to "Client" which is a reserved symbol in the Go generator. This flag will be excluded from the generated output.
+```
+
+To avoid this, rename any flags whose transformed name matches a reserved symbol.
+
+When adding a new generator, document its reserved names in the table above and enforce them in the generator's `Generate()` method using the same pattern.

internal/generators/angular/angular.tmpl

@@ -79,6 +79,14 @@ export type FlagKey = (typeof FlagKeys)[keyof typeof FlagKeys];
 export class GeneratedFeatureFlagService {
   private readonly flagService = inject(FeatureFlagService);
 
+  /**
+   * The underlying FeatureFlagService for ad-hoc flag evaluations
+   * beyond what's defined in the manifest.
+   */
+  get client(): FeatureFlagService {
+    return this.flagService;
+  }
+
 {{ range .Flagset.Flags }}
   /**
    * Get evaluation details for the `{{ .Key }}` flag.

internal/generators/csharp/csharp.tmpl

@@ -70,6 +70,11 @@ namespace {{ if .Params.Custom.Namespace }}{{ .Params.Custom.Namespace }}{{ else
             _client = client ?? throw new ArgumentNullException(nameof(client));
         }
 
+        /// <summary>
+        /// The underlying OpenFeature client for ad-hoc flag evaluations.
+        /// </summary>
+        public IFeatureClient Client => _client;
+
         {{- range .Flagset.Flags }}
         /// <summary>
         /// {{ if .Description }}{{ .Description }}{{ else }}Feature flag{{ end }}

internal/generators/golang/golang.go

@@ -10,8 +10,10 @@ import (
 	"strings"
 	"text/template"
 
+	"github.com/iancoleman/strcase"
 	"github.com/open-feature/cli/internal/flagset"
 	"github.com/open-feature/cli/internal/generators"
+	"github.com/open-feature/cli/internal/logger"
 	"golang.org/x/tools/imports"
 )
 
@@ -128,7 +130,28 @@ func formatNestedValue(value any) string {
 	}
 }
 
+// reservedNames are symbols exported by the Go generator itself. Flag keys
+// that transform (via ToPascal) to one of these names will be excluded from
+// the generated output and a warning will be emitted.
+var reservedNames = map[string]bool{
+	"Client": true,
+}
+
 func (g *GolangGenerator) Generate(params *generators.Params[Params]) error {
+	filtered := &flagset.Flagset{}
+	for _, flag := range g.Flagset.Flags {
+		transformed := strcase.ToCamel(flag.Key)
+		if reservedNames[transformed] {
+			logger.Default.Warning(fmt.Sprintf(
+				"Flag %q transforms to %q which is a reserved symbol in the Go generator. This flag will be excluded from the generated output.",
+				flag.Key, transformed,
+			))
+			continue
+		}
+		filtered.Flags = append(filtered.Flags, flag)
+	}
+	g.Flagset = filtered
+
 	funcs := template.FuncMap{
 		"SupportImports":  supportImports,
 		"OpenFeatureType": openFeatureType,

internal/generators/golang/golang.tmpl

@@ -23,7 +23,9 @@ type (
 	evaluationDetails[T any] func(context.Context, openfeature.EvaluationContext) (openfeature.GenericEvaluationDetails[T], error)
 )
 
-var client = openfeature.NewDefaultClient()
+// Client is the underlying OpenFeature client used for flag evaluations.
+// It can be used directly for ad-hoc flag evaluations beyond what is defined in the manifest.
+var Client = openfeature.NewDefaultClient()
 
 {{- range .Flagset.Flags }}
 // {{ .Key | ToPascal }} returns the value of the "{{ .Key }}" feature flag.
@@ -41,10 +43,10 @@ var {{ .Key | ToPascal }} = struct {
 }{
 		Stringer: stringer({{ .Key | Quote }}),
 	 Value: func(ctx context.Context, evalCtx openfeature.EvaluationContext) {{- if eq (.Type | OpenFeatureType)  "Object"}}any{{- else}}{{ .Type | TypeString }}{{- end}} {
-	     return client.{{ .Type | OpenFeatureType }}(ctx, {{ .Key | Quote }}, {{ if eq (.Type | OpenFeatureType)  "Object" }}{{.DefaultValue | ToMapLiteral }}{{- else }}{{ .DefaultValue | QuoteString }}{{- end}}, evalCtx)
+	     return Client.{{ .Type | OpenFeatureType }}(ctx, {{ .Key | Quote }}, {{ if eq (.Type | OpenFeatureType)  "Object" }}{{.DefaultValue | ToMapLiteral }}{{- else }}{{ .DefaultValue | QuoteString }}{{- end}}, evalCtx)
 	 },
 	 ValueWithDetails: func(ctx context.Context, evalCtx openfeature.EvaluationContext) (openfeature.GenericEvaluationDetails[{{- if eq (.Type | OpenFeatureType)  "Object"}}any{{- else}}{{ .Type | TypeString }}{{- end}}], error){
-	     return client.{{ .Type | OpenFeatureType }}ValueDetails(ctx, {{ .Key | Quote }}, {{ if eq (.Type | OpenFeatureType)  "Object" }}{{.DefaultValue | ToMapLiteral }}{{- else }}{{ .DefaultValue | QuoteString }}{{- end}}, evalCtx)
+	     return Client.{{ .Type | OpenFeatureType }}ValueDetails(ctx, {{ .Key | Quote }}, {{ if eq (.Type | OpenFeatureType)  "Object" }}{{.DefaultValue | ToMapLiteral }}{{- else }}{{ .DefaultValue | QuoteString }}{{- end}}, evalCtx)
 	 },
 }
 {{- end}}

internal/generators/java/java.tmpl

@@ -44,6 +44,12 @@ public final class OpenFeature {
         FlagEvaluationDetails<{{ .Type | OpenFeatureType }}> {{ .Key | ToCamel }}Details(EvaluationContext ctx);
 
 {{- end }}
+
+        /**
+         * Returns the underlying OpenFeature client for ad-hoc flag evaluations.
+         * @return The OpenFeature Client instance
+         */
+        Client getOpenFeatureClient();
     }
 
     private static final class OpenFeatureGeneratedClient implements GeneratedClient {
@@ -65,6 +71,11 @@ public final class OpenFeature {
         }
 
 {{- end }}
+
+        @Override
+        public Client getOpenFeatureClient() {
+            return client;
+        }
     }
 
     public static GeneratedClient getClient() {

internal/generators/nodejs/nodejs.go

@@ -3,10 +3,13 @@ package nodejs
 import (
 	_ "embed"
 	"encoding/json"
+	"fmt"
 	"text/template"
 
+	"github.com/iancoleman/strcase"
 	"github.com/open-feature/cli/internal/flagset"
 	"github.com/open-feature/cli/internal/generators"
+	"github.com/open-feature/cli/internal/logger"
 )
 
 type NodejsGenerator struct {
@@ -43,7 +46,28 @@ func toJSONString(value any) string {
 	return string(bytes)
 }
 
+// reservedNames are symbols exported by the Node.js generator itself. Flag
+// keys that transform (via ToCamel) to one of these names will be excluded
+// from the generated output and a warning will be emitted.
+var reservedNames = map[string]bool{
+	"client": true,
+}
+
 func (g *NodejsGenerator) Generate(params *generators.Params[Params]) error {
+	filtered := &flagset.Flagset{}
+	for _, flag := range g.Flagset.Flags {
+		transformed := strcase.ToLowerCamel(flag.Key)
+		if reservedNames[transformed] {
+			logger.Default.Warning(fmt.Sprintf(
+				"Flag %q transforms to %q which is a reserved symbol in the Node.js generator. This flag will be excluded from the generated output.",
+				flag.Key, transformed,
+			))
+			continue
+		}
+		filtered.Flags = append(filtered.Flags, flag)
+	}
+	g.Flagset = filtered
+
 	funcs := template.FuncMap{
 		"OpenFeatureType": openFeatureType,
 		"ToJSONString":    toJSONString,

internal/generators/nodejs/nodejs.tmpl

@@ -6,6 +6,7 @@ import {
   JsonValue,
 } from "@openfeature/server-sdk";
 import type {
+  Client,
   EvaluationContext,
   EvaluationDetails,
   FlagEvaluationOptions,
@@ -20,6 +21,8 @@ export const FlagKeys = {
 } as const;
 
 export interface GeneratedClient {
+  /** The underlying OpenFeature client for ad-hoc flag evaluations. */
+  readonly client: Client;
 {{- range .Flagset.Flags }}
   /**
   * {{ if .Description }}{{ .Description }}{{ else }}Feature flag{{ end }}
@@ -82,6 +85,7 @@ export function getGeneratedClient(domainOrContext?: string | EvaluationContext,
   const client = domain ? OpenFeature.getClient(domain, context) : OpenFeature.getClient(context)
 
   return {
+    client,
 {{- range .Flagset.Flags }}
     {{ .Key | ToCamel }}: (context?: EvaluationContext, options?: FlagEvaluationOptions): Promise<{{ if eq (.Type | OpenFeatureType) "object" }}JsonValue{{ else }}{{ .Type | OpenFeatureType }}{{ end }}> => {
       return client.get{{ .Type | OpenFeatureType | ToPascal }}Value({{ .Key | Quote }}, {{ if eq (.Type | OpenFeatureType) "object"}}{{ .DefaultValue | ToJSONString }}{{ else }}{{ .DefaultValue | QuoteString }}{{ end }}, context, options);