diff --git a/scripts/functions-discover-tests/fixtures/esm/firebase.json b/scripts/functions-discover-tests/fixtures/esm/firebase.json
index 9e26dfeeb6e..93f83c8cfa7 100644
--- a/scripts/functions-discover-tests/fixtures/esm/firebase.json
+++ b/scripts/functions-discover-tests/fixtures/esm/firebase.json
@@ -1 +1,3 @@
-{}
\ No newline at end of file
+{
+  "functions": {}
+}
diff --git a/scripts/functions-discover-tests/fixtures/pnpm/firebase.json b/scripts/functions-discover-tests/fixtures/pnpm/firebase.json
index 9e26dfeeb6e..93f83c8cfa7 100644
--- a/scripts/functions-discover-tests/fixtures/pnpm/firebase.json
+++ b/scripts/functions-discover-tests/fixtures/pnpm/firebase.json
@@ -1 +1,3 @@
-{}
\ No newline at end of file
+{
+  "functions": {}
+}
diff --git a/scripts/functions-discover-tests/fixtures/simple/firebase.json b/scripts/functions-discover-tests/fixtures/simple/firebase.json
index 9e26dfeeb6e..93f83c8cfa7 100644
--- a/scripts/functions-discover-tests/fixtures/simple/firebase.json
+++ b/scripts/functions-discover-tests/fixtures/simple/firebase.json
@@ -1 +1,3 @@
-{}
\ No newline at end of file
+{
+  "functions": {}
+}
diff --git a/src/config.ts b/src/config.ts
index 9da92c32d28..3e514f61b23 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -76,15 +76,17 @@ export class Config {
       }
     });
 
-    // Inject default functions config and source if missing.
-    if (this.projectDir && fsutils.dirExistsSync(this.path(Config.DEFAULT_FUNCTIONS_SOURCE))) {
-      if (Array.isArray(this.get("functions"))) {
-        if (!this.get("functions.[0].source")) {
-          this.set("functions.[0].source", Config.DEFAULT_FUNCTIONS_SOURCE);
-        }
-      } else {
-        if (!this.get("functions.source")) {
-          this.set("functions.source", Config.DEFAULT_FUNCTIONS_SOURCE);
+    // Inject default functions source if missing.
+    if (this.get("functions")) {
+      if (this.projectDir && fsutils.dirExistsSync(this.path(Config.DEFAULT_FUNCTIONS_SOURCE))) {
+        if (Array.isArray(this.get("functions"))) {
+          if (!this.get("functions.[0].source")) {
+            this.set("functions.[0].source", Config.DEFAULT_FUNCTIONS_SOURCE);
+          }
+        } else {
+          if (!this.get("functions.source")) {
+            this.set("functions.source", Config.DEFAULT_FUNCTIONS_SOURCE);
+          }
         }
       }
     }