From 7da9d2b59b798b950b0270853b84b19431384577 Mon Sep 17 00:00:00 2001
From: Linwei Shang <linwei.shang@dfinity.org>
Date: Tue, 13 Jan 2026 14:21:47 -0500
Subject: [PATCH] feat: Wasm optimization failure issues a warning instead of
 error

---
 CHANGELOG.md                       |   5 +++++
 e2e/assets/memory64/dfx.json       |   2 +-
 e2e/assets/memory64/m64.wasm       | Bin 14 -> 21 bytes
 e2e/tests-dfx/build.bash           |   3 +++
 src/dfx/src/lib/models/canister.rs |  17 ++++++++++++++---
 5 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3670036052..5ff02af0f3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,11 @@
 
 # UNRELEASED
 
+### feat: Wasm optimization failure issues a warning instead of error
+
+The optimization functionality provided by `ic_wasm::optimize" cannot handle Wasm modules that contains 64-bit table.
+Instead of blocking the build, such optimization failure will issue a warning.
+
 ### Frontend canister
 
 Sets the `ic_env` cookie for all HTML files only if the canister environment changed in the `commit_batch` method.
diff --git a/e2e/assets/memory64/dfx.json b/e2e/assets/memory64/dfx.json
index 6a658fd247..02b44e2852 100644
--- a/e2e/assets/memory64/dfx.json
+++ b/e2e/assets/memory64/dfx.json
@@ -5,7 +5,7 @@
             "type": "custom",
             "candid": "empty.did",
             "wasm": "m64.wasm",
-            "build": "echo \"generated from (module (memory i64 0 0))\"",
+            "build": "echo \"generated from (module (memory i64 0 0) (table i64 1 10 funcref))\"",
             "shrink": true,
             "optimize": "Oz",
             "gzip": true
diff --git a/e2e/assets/memory64/m64.wasm b/e2e/assets/memory64/m64.wasm
index c4a07fdf1585dca8987bb630913e2e877b0b581f..421146f1eb719ffe6bb257ccd40e707a2f521bf0 100644
GIT binary patch
literal 21
ccmZQbEY4+QU|?WjWh`K2<YHxEWMyCg03C<{+yDRo

literal 14
VcmZQbEY4+QU|?WnVPs`s000kN0a5?}

diff --git a/e2e/tests-dfx/build.bash b/e2e/tests-dfx/build.bash
index 340ab800c0..df611a5650 100644
--- a/e2e/tests-dfx/build.bash
+++ b/e2e/tests-dfx/build.bash
@@ -370,4 +370,7 @@ teardown() {
 @test "dfx build can post-process memory64 Wasm module" {
   install_asset memory64
   assert_command dfx build --check
+  # the module contains table64 which is not supported by ic_wasm::optimize
+  # optimization failure doesn't fail the build, but a warning is issued
+  assert_contains "WARN: Failed to optimize the Wasm module:"
 }
diff --git a/src/dfx/src/lib/models/canister.rs b/src/dfx/src/lib/models/canister.rs
index 717ba6c33a..87e060e341 100644
--- a/src/dfx/src/lib/models/canister.rs
+++ b/src/dfx/src/lib/models/canister.rs
@@ -153,9 +153,20 @@ impl Canister {
         // optimize or shrink
         if let Some(level) = info.get_optimize() {
             trace!(logger, "Optimizing Wasm at level {}", level);
-            ic_wasm::optimize::optimize(&mut m, &wasm_opt_level_convert(level), false, &None, true)
-                .context("Failed to optimize the Wasm module.")?;
-            modified = true;
+            match ic_wasm::optimize::optimize(
+                &mut m,
+                &wasm_opt_level_convert(level),
+                false,
+                &None,
+                true,
+            ) {
+                Ok(()) => {
+                    modified = true;
+                }
+                Err(e) => {
+                    warn!(logger, "Failed to optimize the Wasm module: {}", e);
+                }
+            }
         } else if info.get_shrink() == Some(true)
             || (info.get_shrink().is_none() && (info.is_rust() || info.is_motoko()))
         {