From 4a1cbb0ce578458169c74fb6edb10fbdb9282f5c Mon Sep 17 00:00:00 2001
From: LichuAcu <lichu.acuna@vercel.com>
Date: Thu, 22 Aug 2024 11:30:00 -0700
Subject: [PATCH] Change ID generation strategy

---
 .../src/global_module_id_strategy.rs          | 23 +++++++++++--------
 .../src/references/external_module.rs         |  2 +-
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/turbopack/crates/turbopack-ecmascript/src/global_module_id_strategy.rs b/turbopack/crates/turbopack-ecmascript/src/global_module_id_strategy.rs
index e6c1f82c827a32..2404abfda8681b 100644
--- a/turbopack/crates/turbopack-ecmascript/src/global_module_id_strategy.rs
+++ b/turbopack/crates/turbopack-ecmascript/src/global_module_id_strategy.rs
@@ -191,20 +191,25 @@ pub async fn process_module(
         return Ok(());
     }
 
-    let mut masked_hash = full_hash & 0xF;
-    let mut mask = 0xF;
-    while used_ids.contains(&masked_hash) {
-        if mask == 0xFFFFFFFFFFFFFFFF {
-            return Err(anyhow::anyhow!("This is a... 64-bit hash collision?"));
+    let mut trimmed_hash = full_hash % 10;
+    let mut power = 10;
+    while used_ids.contains(&trimmed_hash) {
+        // TODO(LichuAcu): Fix this hack with a constant.
+        if power >= std::u64::MAX / 10 {
+            if used_ids.contains(&full_hash) {
+                return Err(anyhow::anyhow!("This is a... 64-bit hash collision?"));
+            }
+            trimmed_hash = full_hash;
+            break;
         }
-        mask = (mask << 4) | 0xF;
-        masked_hash = full_hash & mask;
+        power *= 10;
+        trimmed_hash = full_hash % power;
     }
 
-    let hashed_module_id = ModuleId::String(masked_hash.to_string().into());
+    let hashed_module_id = ModuleId::String(trimmed_hash.to_string().into());
 
     id_map.insert(ident_str, hashed_module_id.cell());
-    used_ids.insert(masked_hash);
+    used_ids.insert(trimmed_hash);
 
     Ok(())
 }
diff --git a/turbopack/crates/turbopack-ecmascript/src/references/external_module.rs b/turbopack/crates/turbopack-ecmascript/src/references/external_module.rs
index 89211f9ba94cda..65e16b175fbce9 100644
--- a/turbopack/crates/turbopack-ecmascript/src/references/external_module.rs
+++ b/turbopack/crates/turbopack-ecmascript/src/references/external_module.rs
@@ -245,7 +245,7 @@ impl EcmascriptChunkItem for CachedExternalModuleChunkItem {
     }
 }
 
-/// A module that only has an ident and no content. This is used
+/// A module that only has an ident and no content nor references. It is used
 /// to include a module's ident in the module graph before the module
 /// itself is resolved, as is the case with NextServerComponentModule's
 /// "client modules" and "client modules ssr".