Allow for FileNotFound. Do not error, instead return a default instance (#2739)

* Allow for FileNotFound. Do not error, instead return a default instance

* add tests

* update proto

Author: THardy98

temporal-envconfig/src/main/java/io/temporal/envconfig/ClientConfig.java

@@ -95,8 +95,13 @@ public static ClientConfig load(LoadClientConfigOptions options) throws IOExcept
       if (file == null || file.isEmpty()) {
         file = getDefaultConfigFilePath();
       }
-      ClientConfigToml.TomlClientConfig result = reader.readValue(new File(file));
-      return new ClientConfig(ClientConfigToml.getClientProfiles(result));
+      try {
+        ClientConfigToml.TomlClientConfig result = reader.readValue(new File(file));
+        return new ClientConfig(ClientConfigToml.getClientProfiles(result));
+      } catch (FileNotFoundException e) {
+        // File not found is ok - return default empty config
+        return getDefaultInstance();
+      }
     }
   }
 

temporal-envconfig/src/test/java/io/temporal/envconfig/ClientConfigProfileTest.java

@@ -274,6 +274,34 @@ public void loadClientOptionsTLS() throws IOException {
     Assert.assertTrue(context.isClient());
   }
 
+  @Test
+  public void loadClientConfigMissingFileReturnsDefault() throws IOException {
+    // When config file doesn't exist, should return default empty config (not throw)
+    ClientConfig config =
+        ClientConfig.load(
+            LoadClientConfigOptions.newBuilder()
+                .setConfigFilePath("/nonexistent/path/to/temporal.toml")
+                .build());
+    Assert.assertNotNull(config);
+    Assert.assertTrue(config.getProfiles().isEmpty());
+  }
+
+  @Test
+  public void loadClientConfigProfileMissingFileReturnsDefault() throws IOException {
+    // When config file doesn't exist, ClientConfigProfile.load() should also work
+    // and return a profile with default values (potentially overridden by env vars)
+    ClientConfigProfile profile =
+        ClientConfigProfile.load(
+            LoadClientConfigProfileOptions.newBuilder()
+                .setConfigFilePath("/nonexistent/path/to/temporal.toml")
+                .setEnvOverrides(Collections.emptyMap())
+                .build());
+    Assert.assertNotNull(profile);
+    // Default values should be null/empty since no file and no env vars
+    Assert.assertNull(profile.getAddress());
+    Assert.assertNull(profile.getNamespace());
+  }
+
   @Test
   public void parseToml() throws IOException {
     String toml =