feat: support custom image loaders in turbopack

packages/next-swc/crates/next-core/src/next_config.rs

@@ -1,6 +1,6 @@
 use anyhow::{Context, Result};
 use indexmap::IndexMap;
-use serde::{Deserialize, Serialize};
+use serde::{Deserialize, Deserializer, Serialize};
 use serde_json::Value as JsonValue;
 use turbo_tasks::{trace::TraceRawVcs, Completion, Value, Vc};
 use turbo_tasks_fs::json::parse_json_with_source_context;
@@ -310,6 +310,8 @@ pub struct ImageConfig {
     pub image_sizes: Vec<u16>,
     pub path: String,
     pub loader: ImageLoader,
+    #[serde(deserialize_with = "empty_string_is_none")]
+    pub loader_file: Option<String>,
     pub domains: Vec<String>,
     pub disable_static_images: bool,
     #[serde(rename(deserialize = "minimumCacheTTL"))]
@@ -322,6 +324,14 @@ pub struct ImageConfig {
     pub unoptimized: bool,
 }
 
+fn empty_string_is_none<'de, D>(deserializer: D) -> Result<Option<String>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let o = Option::<String>::deserialize(deserializer)?;
+    Ok(o.filter(|s| !s.is_empty()))
+}
+
 impl Default for ImageConfig {
     fn default() -> Self {
         // https://github.com/vercel/next.js/blob/327634eb/packages/next/shared/lib/image-config.ts#L100-L114
@@ -330,6 +340,7 @@ impl Default for ImageConfig {
             image_sizes: vec![16, 32, 48, 64, 96, 128, 256, 384],
             path: "/_next/image".to_string(),
             loader: ImageLoader::Default,
+            loader_file: None,
             domains: vec![],
             disable_static_images: false,
             minimum_cache_ttl: 60,

packages/next-swc/crates/next-core/src/next_import_map.rs

@@ -521,6 +521,21 @@ async fn insert_next_server_special_aliases(
         external_if_node(project_path, "next/dist/compiled/@opentelemetry/api"),
     );
 
+    let image_config = next_config.image_config().await?;
+    if let Some(loader_file) = image_config.loader_file.as_deref() {
+        import_map.insert_exact_alias(
+            "next/dist/shared/lib/image-loader",
+            request_to_import_mapping(project_path, loader_file),
+        );
+
+        if runtime == NextRuntime::Edge {
+            import_map.insert_exact_alias(
+                "next/dist/esm/shared/lib/image-loader",
+                request_to_import_mapping(project_path, loader_file),
+            );
+        }
+    }
+
     match ty {
         ServerContextType::Pages { pages_dir } | ServerContextType::PagesApi { pages_dir } => {
             insert_alias_to_alternatives(