Skip to content

[turbopack] Follow re-exports for side-effect free async modules - #95993

Merged
sampoder merged 4 commits into
canaryfrom
sp/turbopack/follow-reexports
Aug 8, 2026
Merged

[turbopack] Follow re-exports for side-effect free async modules#95993
sampoder merged 4 commits into
canaryfrom
sp/turbopack/follow-reexports

Conversation

@sampoder

@sampoder sampoder commented Jul 21, 2026

Copy link
Copy Markdown
Member

This adds a very basic follow re-exports support to async-imported modules that are side effect free. For example, it supports:

// a.js
export const a = 'A'

// b.js
export const b = 'B'        // unused

// barrel.js  (pure re-export barrel)
export { a } from './a.js'
export { b } from './b.js'

// index.js
const { a } = await import('./barrel.js')
console.log(a)

apply_reexport_tree_shaking was moved into turbopack-ecmascript as part of this.

@github-actions

github-actions Bot commented Jul 21, 2026 •
edited
Loading

Copy link
Copy Markdown
Contributor

Stats from current PR

Warning

No stats were collected for Webpack because its stats job did not complete (it failed, was cancelled, or timed out). The results below only cover the bundlers that finished.

✅ No significant changes detected

📊 All Metrics
📖 Metrics Glossary

Dev Server Metrics:

  • Listen = TCP port starts accepting connections
  • First Request = HTTP server returns successful response
  • Cold = Fresh build (no cache)
  • Warm = With cached build artifacts

Build Metrics:

  • Fresh = Clean build (no .next directory)
  • Cached = With existing .next directory

Change Thresholds:

  • Time: Changes < 50ms AND < 10%, OR < 2% are insignificant
  • Size: Changes < 1KB AND < 1% are insignificant
  • All other changes are flagged to catch regressions

⚡ Dev Server

Metric Canary PR Change Trend
Cold (Listen) 813ms 813ms ✓ ▂▂▂▂▂
Cold (Ready in log) 786ms 783ms ✓ ▁▁▂▂▁
Cold (First Request) 1.296s 1.299s ✓ ▁▁▂▂▁
Warm (Listen) 813ms 812ms ✓ ▂▂▂▃▂
Warm (Ready in log) 786ms 787ms ✓ ▁▁▂▃▁
Warm (First Request) 1.287s 1.290s ✓ ▁▁▂▃▁

⚡ Production Builds

Metric Canary PR Change Trend
Fresh Build 5.760s 5.888s ✓ ▂▁▃▃▂
Cached Build 2.905s 2.943s ✓ ▁▁▄▃▂
📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric Canary PR Change Trend
node_modules Size 553 MB 553 MB ✓ █████
📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles
Canary PR Change
0_z1ozsra2_86.js gzip 157 B N/A -
00r3fx3eeevxf.js gzip 158 B N/A -
050icza-xjz0i.js gzip 5.73 kB N/A -
07jdby0ue616s.js gzip 450 B N/A -
0anzicvq0iwy6.js gzip 46.7 kB N/A -
0bjdc8muo74n5.js gzip 8.71 kB N/A -
0cz1d0mv5g_q7.js gzip 39.4 kB 39.4 kB ✓
0rci1f3or1a19.js gzip 13.3 kB N/A -
1_2x714--ii1i.js gzip 8.76 kB N/A -
1-3y752pkth5-.js gzip 10 kB N/A -
1-pbgw6jtibj4.js gzip 157 B N/A -
111w718tsk0_p.js gzip 71.5 kB N/A -
140m6hb0qpu8v.js gzip 157 B N/A -
160n3skrv1yk5.js gzip 157 B N/A -
1elt1qium-r2m.css gzip 115 B 115 B ✓
1fsqx5xpdxd-c.js gzip 153 B N/A -
1hy0e5cihni_x.js gzip 7.54 kB N/A -
1tf1phijqlx9j.js gzip 220 B 220 B ✓
1uq5fmtkqhu5v.js gzip 158 B N/A -
1uzabyd1120a1.js gzip 8.71 kB N/A -
2-ufv8lc-g7gg.js gzip 10.6 kB N/A -
21kmjy_10x14f.js gzip 8.81 kB N/A -
22alyybqz5_09.js gzip 3.57 kB N/A -
28dhc6t85q1_p.js gzip 8.78 kB N/A -
2ahs26ct36f9f.js gzip 65.6 kB N/A -
2btssrfgthink.js gzip 158 B N/A -
2f-ilvczue-tp.js gzip 9.46 kB N/A -
2f1u17u5c8iny.js gzip 8.79 kB N/A -
2ikltg_8iegxw.js gzip 10.3 kB N/A -
2vxi673cz1-t4.js gzip 8.79 kB N/A -
38-q43pzktqhs.js gzip 1.46 kB N/A -
3a-pgojsoq5_w.js gzip 158 B N/A -
3cruv3lb9957o.js gzip 169 B N/A -
3mrwxzed0ylgv.js gzip 13.1 kB N/A -
3nbojhxiy1qv_.js gzip 13.7 kB N/A -
3t5_y-uw--87g.js gzip 159 B N/A -
3wbfmg_ucf8de.js gzip 162 B N/A -
3xbq084zz-vz8.js gzip 163 B N/A -
41u5s3oe2-erp.js gzip 2.29 kB N/A -
445s_9hf8o7ao.js gzip 8.76 kB N/A -
turbopack-1l..-5yv.js gzip 3.73 kB 3.73 kB ✓
0-6bcj16ji2wf.js gzip N/A 10.6 kB -
07ryk0jced-sc.js gzip N/A 8.78 kB -
0j64ls9v56hnd.js gzip N/A 3.56 kB -
0jwho9fkrb_t3.js gzip N/A 2.29 kB -
0lzqiphzyraxb.js gzip N/A 155 B -
0qma3l_t-wns4.js gzip N/A 168 B -
0roh390ijzxa5.js gzip N/A 8.75 kB -
0s7ldmg9glcmx.js gzip N/A 46.7 kB -
0vex9w55ursqj.js gzip N/A 8.79 kB -
0ynj-axdw_was.js gzip N/A 155 B -
12uzup57ecfw9.js gzip N/A 160 B -
17oe55cu76cd7.js gzip N/A 450 B -
1822r4f_m9r_g.js gzip N/A 154 B -
1drww5xikb-c-.js gzip N/A 9.46 kB -
1g60xde_dv17t.js gzip N/A 8.79 kB -
1srvuraudh358.js gzip N/A 71.5 kB -
1uzv47btzam64.js gzip N/A 5.73 kB -
1vy7n7wxv_rh5.js gzip N/A 8.81 kB -
2-0i7pl900-ou.js gzip N/A 8.71 kB -
2-kcbngm7ik7y.js gzip N/A 8.75 kB -
252pm4-yjo-g8.js gzip N/A 157 B -
28w0eio9rc6cp.js gzip N/A 156 B -
29p5-xa4jmdhg.js gzip N/A 13.7 kB -
2lpk5_hknut8q.js gzip N/A 13.1 kB -
2ugc69z0t0ypz.js gzip N/A 1.46 kB -
32pajiszar8p9.js gzip N/A 155 B -
3301-f5avh3en.js gzip N/A 157 B -
345geq-0tw2nd.js gzip N/A 156 B -
36a4lu088knjc.js gzip N/A 151 B -
36dn8i-_3dnq5.js gzip N/A 10 kB -
3dtb8zg2hpy5x.js gzip N/A 156 B -
3fljpmwcjxqhx.js gzip N/A 10.3 kB -
3gz44skqdlsrb.js gzip N/A 8.71 kB -
3m29pi-s05gfl.js gzip N/A 65.6 kB -
3oslhuq9luvp2.js gzip N/A 7.55 kB -
3s04zj-jqprop.js gzip N/A 155 B -
3y9tus7kb5su0.js gzip N/A 13.3 kB -
Total 401 kB 401 kB ✅ -17 B

Server

Middleware
Canary PR Change
middleware-b..fest.js gzip 1.05 kB 1.06 kB ✓
Total 1.05 kB 1.06 kB ⚠️ +2 B
Build Details
Build Manifests
Canary PR Change
_buildManifest.js gzip 881 B 876 B ✓
Total 881 B 876 B ✅ -5 B
Build Cache
Canary PR Change
00000001.sst gzip 12.7 MB 12.3 MB 🟢 381 kB (-3%)
00000002.sst gzip 12.5 MB 14 MB 🔴 +1.47 MB (+12%)
00000003.sst gzip 14.9 MB 13.8 MB 🟢 1.12 MB (-8%)
00000004.sst gzip 15 MB 15.1 MB 🔴 +63.6 kB (+0%)
00000005.sst gzip 2.81 MB 2.81 MB ✓
00000006.sst gzip 10.2 MB 10.2 MB 🟢 28.2 kB (0%)
00000007.sst gzip 59 B 59 B ✓
00000008.meta gzip 89 B 89 B ✓
00000009.meta gzip 298 kB 298 kB ✓
00000010.meta gzip 298 kB 298 kB ✓
00000011.meta gzip 298 kB 298 kB ✓
00000012.sst gzip 52 kB 52.5 kB ✓
00000013.sst gzip 1.88 MB 1.85 MB 🟢 29.7 kB (-2%)
00000014.sst gzip 59 B 59 B ✓
00000015.meta gzip 116 B 116 B ✓
00000016.meta gzip 325 kB 325 kB ✓
00000017.meta gzip 405 kB 405 kB ✓
00000018.sst gzip 52.9 kB 53.2 kB ✓
00000019.sst gzip 1.41 MB 1.38 MB 🟢 31.6 kB (-2%)
00000020.sst gzip 59 B 59 B ✓
00000021.meta gzip 116 B 116 B ✓
00000022.meta gzip 325 kB 325 kB ✓
00000023.meta gzip 371 kB 371 kB ✓
00000024.sst gzip 52.9 kB 53.3 kB ✓
00000025.sst gzip 1.41 MB 1.38 MB 🟢 32.2 kB (-2%)
00000026.sst gzip 59 B 59 B ✓
00000027.meta gzip 116 B 116 B ✓
00000028.meta gzip 325 kB 325 kB ✓
00000029.meta gzip 371 kB 371 kB ✓
00000030.sst gzip 52 kB 52.6 kB 🔴 +536 B (+1%)
00000031.sst gzip 1.41 MB 1.38 MB 🟢 32.3 kB (-2%)
00000032.sst gzip 59 B 59 B ✓
00000033.meta gzip 116 B 116 B ✓
00000034.meta gzip 325 kB 325 kB ✓
00000035.meta gzip 371 kB 371 kB ✓
00000036.sst gzip 52.7 kB 53.2 kB ✓
00000037.sst gzip 1.41 MB 1.38 MB 🟢 32.2 kB (-2%)
00000038.sst gzip 59 B 59 B ✓
00000039.meta gzip 116 B 116 B ✓
00000040.meta gzip 325 kB 325 kB ✓
00000041.meta gzip 371 kB 371 kB ✓
CURRENT gzip 24 B 24 B ✓
LOG gzip 686 B 691 B ✓
Total 80.4 MB 80.2 MB ✅ -152 kB

🔄 Shared (bundler-independent)

Runtimes
Canary PR Change
app-page-exp...dev.js gzip 375 kB 375 kB ✓
app-page-exp..prod.js gzip 207 kB 207 kB ✓
app-page-tur...dev.js gzip 374 kB 374 kB ✓
app-page-tur..prod.js gzip 207 kB 207 kB ✓
app-page-tur...dev.js gzip 371 kB 371 kB ✓
app-page-tur..prod.js gzip 205 kB 205 kB ✓
app-page.run...dev.js gzip 371 kB 371 kB ✓
app-page.run..prod.js gzip 205 kB 205 kB ✓
app-route-ex...dev.js gzip 83.3 kB 83.3 kB ✓
app-route-ex..prod.js gzip 56.4 kB 56.4 kB ✓
app-route-tu...dev.js gzip 83.3 kB 83.3 kB ✓
app-route-tu..prod.js gzip 56.4 kB 56.4 kB ✓
app-route-tu...dev.js gzip 82.9 kB 82.9 kB ✓
app-route-tu..prod.js gzip 56.2 kB 56.2 kB ✓
app-route.ru...dev.js gzip 82.8 kB 82.8 kB ✓
app-route.ru..prod.js gzip 56.2 kB 56.2 kB ✓
dev-validati...dev.js gzip 133 kB 133 kB ✓
dev-validati...dev.js gzip 133 kB 133 kB ✓
dev-validati...dev.js gzip 131 kB 131 kB ✓
dev-validati...dev.js gzip 131 kB 131 kB ✓
dist_client_...dev.js gzip 324 B 324 B ✓
dist_client_...dev.js gzip 326 B 326 B ✓
dist_client_...dev.js gzip 318 B 318 B ✓
dist_client_...dev.js gzip 317 B 317 B ✓
pages-api-tu...dev.js gzip 46 kB 46 kB ✓
pages-api-tu..prod.js gzip 34.3 kB 34.3 kB ✓
pages-api.ru...dev.js gzip 46 kB 46 kB ✓
pages-api.ru..prod.js gzip 34.3 kB 34.3 kB ✓
pages-turbo....dev.js gzip 54.8 kB 54.8 kB ✓
pages-turbo...prod.js gzip 39.9 kB 39.9 kB ✓
pages.runtim...dev.js gzip 54.8 kB 54.8 kB ✓
pages.runtim..prod.js gzip 39.9 kB 39.9 kB ✓
server.runti..prod.js gzip 67 kB 67 kB ✓
use-cache-pr...dev.js gzip 72.3 kB 72.3 kB ✓
use-cache-pr...dev.js gzip 72.4 kB 72.4 kB ✓
use-cache-pr...dev.js gzip 70.6 kB 70.6 kB ✓
use-cache-pr...dev.js gzip 70.6 kB 70.6 kB ✓
Total 4.1 MB 4.1 MB ✓
📎 Tarball URL 
https://vercel-packages.vercel.app/next/commits/bfbb8ca02f3c0bac2e9dfb60070f1f79b34a38c7/next

Commit: bfbb8ca

@github-actions

github-actions Bot commented Jul 21, 2026 •
edited
Loading

Copy link
Copy Markdown
Contributor

Tests Passed

Commit: bfbb8ca

@sampoder
sampoder requested a review from lukesandberg July 21, 2026 01:43
@sampoder
sampoder force-pushed the sp/turbopack/follow-reexports branch from b8694bf to a3d8bc1 Compare July 21, 2026 03:51
bgw
bgw approved these changes Aug 7, 2026
View reviewed changes
Comment thread turbopack/crates/turbopack-ecmascript/src/references/esm/dynamic.rs
@sampoder
sampoder merged commit a677cf6 into canary Aug 8, 2026
112 of 113 checks passed
@sampoder
sampoder deleted the sp/turbopack/follow-reexports branch August 8, 2026 01:28
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@bgw bgw bgw approved these changes
@lukesandberg lukesandberg Awaiting requested review from lukesandberg

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

2 participants

@sampoder @bgw