internal/plugin+internal/plugin6: Fix provider schema caching

Reference: #33482

The intention of this logic is to use the global provider schema cache if it is available for a given provider address based on the `GetProviderSchemaOptional` server capability. Previously the logic was errantly checking the named return early, which was not populated yet with the server response. This flips the logic to properly use the server response to determine whether the cache should be set, thereby still gating the caching based on the server capability.

In a configuration with 19 `hashicorp/aws` provider instances and an associated data source, this drops the received `GetProviderSchema` calls from 39(?) to 1. Maximum RSS dropped from 1.22 GB to 189 MB.

internal/plugin/grpc_provider.go

@@ -79,7 +79,7 @@ func (p *GRPCProvider) GetProviderSchema() (resp providers.GetProviderSchemaResp
 	defer p.mu.Unlock()
 
 	// check the global cache if we can
-	if !p.Addr.IsZero() && resp.ServerCapabilities.GetProviderSchemaOptional {
+	if !p.Addr.IsZero() {
 		if resp, ok := providers.SchemaCache.Get(p.Addr); ok {
 			return resp
 		}
@@ -141,7 +141,7 @@ func (p *GRPCProvider) GetProviderSchema() (resp providers.GetProviderSchemaResp
 	}
 
 	// set the global cache if we can
-	if !p.Addr.IsZero() {
+	if !p.Addr.IsZero() && resp.ServerCapabilities.GetProviderSchemaOptional {
 		providers.SchemaCache.Set(p.Addr, resp)
 	}
 

internal/plugin6/grpc_provider.go

@@ -79,7 +79,7 @@ func (p *GRPCProvider) GetProviderSchema() (resp providers.GetProviderSchemaResp
 	defer p.mu.Unlock()
 
 	// check the global cache if we can
-	if !p.Addr.IsZero() && resp.ServerCapabilities.GetProviderSchemaOptional {
+	if !p.Addr.IsZero() {
 		if resp, ok := providers.SchemaCache.Get(p.Addr); ok {
 			return resp
 		}
@@ -141,7 +141,7 @@ func (p *GRPCProvider) GetProviderSchema() (resp providers.GetProviderSchemaResp
 	}
 
 	// set the global cache if we can
-	if !p.Addr.IsZero() {
+	if !p.Addr.IsZero() && resp.ServerCapabilities.GetProviderSchemaOptional {
 		providers.SchemaCache.Set(p.Addr, resp)
 	}