fix: fail to load config if configured profile doesn't exist (#2309)

.changelog/bde54e56c1d44544baef8c6afdfd68d0.json

@@ -0,0 +1,8 @@
+{
+    "id": "bde54e56-c1d4-4544-baef-8c6afdfd68d0",
+    "type": "bugfix",
+    "description": "Fail to load config if an explicitly provided profile doesn't exist.",
+    "modules": [
+        "config"
+    ]
+}

config/config.go

@@ -2,18 +2,11 @@ package config
 
 import (
 	"context"
+	"os"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
 )
 
-// defaultLoaders are a slice of functions that will read external configuration
-// sources for configuration values. These values are read by the AWSConfigResolvers
-// using interfaces to extract specific information from the external configuration.
-var defaultLoaders = []loader{
-	loadEnvConfig,
-	loadSharedConfigIgnoreNotExist,
-}
-
 // defaultAWSConfigResolvers are a slice of functions that will resolve external
 // configuration values into AWS configuration values.
 //
@@ -190,7 +183,7 @@ func LoadDefaultConfig(ctx context.Context, optFns ...func(*LoadOptions) error)
 	// assign Load Options to configs
 	var cfgCpy = configs{options}
 
-	cfgCpy, err = cfgCpy.AppendFromLoaders(ctx, defaultLoaders)
+	cfgCpy, err = cfgCpy.AppendFromLoaders(ctx, resolveConfigLoaders(&options))
 	if err != nil {
 		return aws.Config{}, err
 	}
@@ -202,3 +195,17 @@ func LoadDefaultConfig(ctx context.Context, optFns ...func(*LoadOptions) error)
 
 	return cfg, nil
 }
+
+func resolveConfigLoaders(options *LoadOptions) []loader {
+	loaders := make([]loader, 2)
+	loaders[0] = loadEnvConfig
+
+	// specification of a profile should cause a load failure if it doesn't exist
+	if os.Getenv(awsProfileEnvVar) != "" || options.SharedConfigProfile != "" {
+		loaders[1] = loadSharedConfig
+	} else {
+		loaders[1] = loadSharedConfigIgnoreNotExist
+	}
+
+	return loaders
+}

config/resolve_credentials_test.go

@@ -577,8 +577,6 @@ func TestResolveCredentialsIMDSClient(t *testing.T) {
 			opts := []func(*LoadOptions) error{
 				WithRetryer(func() aws.Retryer { return aws.NopRetryer{} }),
 				WithHTTPClient(httpClient),
-				// separate from the local config, should it exist - the default loader will ignore nonexistent profiles
-				WithSharedConfigProfile(" "),
 				WithSharedConfigFiles([]string{}),
 			}