fix: skip OpenAiApi chat bean when no chat API key is configured

[anuragg-saxenaa]

Problem

Fixes #1818

When a user configures only spring.ai.openai.image.api-key (without setting spring.ai.openai.api-key or spring.ai.openai.chat.api-key), the application fails to start with:

java.lang.IllegalArgumentException: OpenAI API key must be set

This happens because OpenAiChatAutoConfiguration is annotated with matchIfMissing = true at class level (so it always loads), but the openAiApi bean inside it calls resolveConnectionProperties(commonProperties, chatProperties, "chat") which throws when neither a common nor a chat-specific API key is present.

Fix

Add @ConditionalOnProperty on the openAiApi bean inside OpenAiChatAutoConfiguration:

@Bean
@ConditionalOnMissingBean
@ConditionalOnProperty(prefix = "spring.ai.openai", name = { "api-key", "chat.api-key" },
        matchIfMissing = false)
public OpenAiApi openAiApi(...) {

This ensures the chat OpenAiApi bean is only created when the user has set at least one of the two relevant API key properties. Users who only need image (or embedding, or audio) but not chat will no longer get a startup failure.

Test

Added imageOnlyApiKeyDoesNotFailChatAutoConfiguration in OpenAiModelConfigurationTests:

• Loads context with spring.ai.openai.image.api-key=IMAGE_API_KEY only
• Includes both OpenAiChatAutoConfiguration and OpenAiImageAutoConfiguration
• Asserts context starts without errors (hasNotFailed())
• Asserts OpenAiImageModel is present and OpenAiChatModel is absent

Signed-off-by: anuragg-saxenaa anuragg.saxenaa@gmail.com