From c74b34f71ff595653acee0fd7359dcb524814097 Mon Sep 17 00:00:00 2001
From: Ladislav Thon <lthon@redhat.com>
Date: Wed, 25 Oct 2023 17:07:50 +0200
Subject: [PATCH] Allow setting CDI SPI implementations repeatedly

The `CDI.setCDIProvider()` method has been documented to throw
`IllegalStateException` on repeated calls since version 1.0, but since
version 2.0, the implementation in fact didn't honor this documentation.
Multiple implementations started to silently depend on repeated
`setCDIProvider()` calls being allowed, especially for testing.

We previously [1][2] fixed the implementation to actually do what
it documents, planning to release the fix in CDI 4.1, but it turns out
this is very inconvenient. Therefore, this commit makes repeated calls
of `setCDIProvider()` officially allowed. For consistency, it also
allows repeated calls of `BuildServicesResolver.setBuildServices()`.

[1] https://github.com/jakartaee/cdi/commit/82ec5d71872212364a321cd3700d0ecadf9162d2
[2] https://github.com/jakartaee/cdi/commit/8ead70bdd135d277e277dfffc086b58dd92a1de3
---
 .../build/compatible/spi/BuildServicesResolver.java      | 7 +------
 api/src/main/java/jakarta/enterprise/inject/spi/CDI.java | 9 ++-------
 2 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/api/src/main/java/jakarta/enterprise/inject/build/compatible/spi/BuildServicesResolver.java b/api/src/main/java/jakarta/enterprise/inject/build/compatible/spi/BuildServicesResolver.java
index 93380024..c8cda629 100644
--- a/api/src/main/java/jakarta/enterprise/inject/build/compatible/spi/BuildServicesResolver.java
+++ b/api/src/main/java/jakarta/enterprise/inject/build/compatible/spi/BuildServicesResolver.java
@@ -76,16 +76,11 @@ private static void discoverFactories() {
      *
      * @param instance a {@link BuildServices} instance that should be used, must not be {@code null}
      * @throws IllegalArgumentException if the provided argument is null
-     * @throws IllegalStateException if the {@link BuildServices} are already set
      */
     public static void setBuildServices(BuildServices instance) {
         if (instance == null) {
             throw new IllegalArgumentException("BuildServices instance must not be null");
         }
-        if (configuredBuildServices == null) {
-            configuredBuildServices = instance;
-        } else {
-            throw new IllegalStateException("BuildServices cannot be set repeatedly. Existing BuildServices are " + configuredBuildServices);
-        }
+        configuredBuildServices = instance;
     }
 }
diff --git a/api/src/main/java/jakarta/enterprise/inject/spi/CDI.java b/api/src/main/java/jakarta/enterprise/inject/spi/CDI.java
index 1182a7ef..0a80f406 100644
--- a/api/src/main/java/jakarta/enterprise/inject/spi/CDI.java
+++ b/api/src/main/java/jakarta/enterprise/inject/spi/CDI.java
@@ -116,19 +116,14 @@ private static boolean checkProvider(CDIProvider c) {
      * </p>
      *
      * @param provider the provider to use
-     * @throws IllegalStateException if the {@link CDIProvider} is already set
      * @throws IllegalArgumentException if the provided argument is null
      */
     public static void setCDIProvider(CDIProvider provider) {
         if (provider == null) {
             throw new IllegalArgumentException("CDIProvider must not be null");
         }
-        if (configuredProvider == null) {
-            providerSetManually = true;
-            configuredProvider = provider;
-        } else {
-            throw new IllegalStateException("CDIProvider cannot be set repeatedly. Existing provider is " + configuredProvider);
-        }
+        providerSetManually = true;
+        configuredProvider = provider;
     }
 
     private static void findAllProviders() {