fix(typescript): honor HeaderAuthScheme prefix in HeaderAuthProvider (#15814)

* fix(ts): honor HeaderAuthScheme prefix in HeaderAuthProvider

Co-Authored-By: will.kendall@buildwithfern.com <wpk235@gmail.com>

* test(typescript): update header-auth-with-prefix snapshot for new HEADER_PREFIX behavior

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: will.kendall@buildwithfern.com <wpk235@gmail.com>

Author: 3 people

generators/typescript/sdk/changes/unreleased/fix-header-auth-prefix.yml

@@ -0,0 +1,9 @@
+# yaml-language-server: $schema=../../../../../fern-changes-yml.schema.json
+
+- summary: |
+    Honor the auth scheme `prefix` for `HeaderAuthScheme` when generating `HeaderAuthProvider`.
+    Previously, the generator emitted the raw header value into the configured header (e.g.
+    `Authorization`) and dropped any prefix declared in the API definition (e.g. `Bearer`).
+    The provider now emits a `HEADER_PREFIX` constant and prepends it to the header value,
+    matching the behavior of the Java, Python, Go, C#, PHP, Rust, and Ruby v2 generators.
+  type: fix

generators/typescript/sdk/client-class-generator/src/__test__/AuthProviders.test.ts

@@ -721,7 +721,7 @@ describe("HeaderAuthProviderGenerator", () => {
                 createHeaderAuthScheme({
                     name: "authorization",
                     wireValue: "Authorization",
-                    prefix: "Bearer "
+                    prefix: "Bearer"
                 })
             );
             const ir = createMinimalIR({ authSchemes: [authScheme] });

generators/typescript/sdk/client-class-generator/src/__test__/__snapshots__/AuthProviders.test.ts.snap

@@ -640,6 +640,7 @@ exports[`HeaderAuthProviderGenerator > getAuthOptionsProperties() > returns requ
 exports[`HeaderAuthProviderGenerator > writeToFile() > generates header auth provider with custom header name and prefix 1`] = `
 "const PARAM_KEY = "authorization" as const;
 const HEADER_NAME = "Authorization" as const;
+const HEADER_PREFIX = "Bearer " as const;
 
 export class HeaderAuthProvider implements core.AuthProvider {
     private readonly options: HeaderAuthProvider.Options;
@@ -664,7 +665,7 @@ export class HeaderAuthProvider implements core.AuthProvider {
                 }
 
                 return {
-                    headers: { [HEADER_NAME]: headerValue },
+                    headers: { [HEADER_NAME]: \`\${HEADER_PREFIX}\${headerValue}\` },
                 };
                 
     }

generators/typescript/sdk/client-class-generator/src/auth-provider/HeaderAuthProviderGenerator.ts

@@ -137,6 +137,7 @@ export class HeaderAuthProviderGenerator implements AuthProviderGenerator {
         const headerEnvVar = this.authScheme.headerEnvVar;
         const headerName = getWireValue(this.authScheme.name);
         const wrapperPropertyName = this.getWrapperPropertyName();
+        const prefix = this.authScheme.prefix;
 
         const constants: string[] = [];
 
@@ -147,6 +148,9 @@ export class HeaderAuthProviderGenerator implements AuthProviderGenerator {
             constants.push(`const ENV_HEADER_KEY = "${headerEnvVar}" as const;`);
         }
         constants.push(`const HEADER_NAME = "${headerName}" as const;`);
+        if (prefix != null) {
+            constants.push(`const HEADER_PREFIX = "${prefix} " as const;`);
+        }
 
         for (const constant of constants.filter((c) => c !== "")) {
             context.sourceFile.addStatements(constant);
@@ -272,6 +276,8 @@ export class HeaderAuthProviderGenerator implements AuthProviderGenerator {
                 ? `\n            (${supplierGetCode}) ??\n            process.env?.[ENV_HEADER_KEY]`
                 : supplierGetCode;
 
+        const headerValueExpr = this.authScheme.prefix != null ? `\`\${HEADER_PREFIX}\${${headerVar}}\`` : headerVar;
+
         if (this.neverThrowErrors) {
             // When neverThrowErrors is true, return empty headers if header value is missing
             return `
@@ -281,7 +287,7 @@ export class HeaderAuthProviderGenerator implements AuthProviderGenerator {
         }
 
         return {
-            headers: { [HEADER_NAME]: ${headerVar} },
+            headers: { [HEADER_NAME]: ${headerValueExpr} },
         };
         `;
         } else {
@@ -299,7 +305,7 @@ export class HeaderAuthProviderGenerator implements AuthProviderGenerator {
         }
 
         return {
-            headers: { [HEADER_NAME]: ${headerVar} },
+            headers: { [HEADER_NAME]: ${headerValueExpr} },
         };
         `;
         }