Fix basePath replacing server-side and `normalizeLocalePath()` when path is empty string #30978

styfle · 2021-11-04T19:25:07Z

This fixes our basePath detection/replacing server-side as we were incorrectly considering /docss a match for a basePath of /docs which caused us to have an unexpected value in the normalizeLocalePath function.

Fixes TypeError: Cannot read property 'toLowerCase' of undefined #22429
Regression introduced in Make sure locale detecting is case-insensitive #17757
Fixes: i18n: Next node server crashes when using a basePath in the URL with a string appended to it #31423

ijjk · 2021-11-04T19:31:33Z

packages/next/shared/lib/i18n/normalize-locale-path.ts

@@ -21,7 +21,10 @@ export function normalizeLocalePath(
  const pathnameParts = pathname.split('/')

  ;(locales || []).some((locale) => {
-    if (pathnameParts[1].toLowerCase() === locale.toLowerCase()) {
+    if (
+      pathnameParts[1] &&


Are you able to reproduce this? This might cause issues elsewhere in the server if the pathname is being passed as an empty string here. Splitting / should yield [ '', '' ] which is handled properly here

It only happens if pathname = '' which might mean the root cause is earlier in the code, before we get to this function. Because you're right, generally the assumption is that pathname is never an empty string, should be /.

Looks like we got a test case in #31423 so added that in and fixed the original error it uncovered.

ijjk · 2021-11-15T17:09:17Z

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
buildDuration	25.6s	25.1s	-541ms
buildDurationCached	4.9s	4.7s	-231ms
nodeModulesSize	335 MB	335 MB	⚠️ +1.15 kB

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
/ failed reqs	0	0	✓
/ total time (seconds)	4.315	4.334	⚠️ +0.02
/ avg req/sec	579.4	576.89	⚠️ -2.51
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.247	2.354	⚠️ +0.11
/error-in-render avg req/sec	1112.46	1062.06	⚠️ -50.4

Client Bundles (main, webpack, commons) Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	28.3 kB	28.3 kB	⚠️ +6 B
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	72.2 kB	72.2 kB	⚠️ +6 B

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
_app-HASH.js gzip	1.37 kB	1.37 kB	✓
_error-HASH.js gzip	194 B	194 B	✓
amp-HASH.js gzip	312 B	312 B	✓
css-HASH.js gzip	327 B	327 B	✓
dynamic-HASH.js gzip	2.38 kB	2.38 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	635 B	635 B	✓
image-HASH.js gzip	4.44 kB	4.44 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	1.87 kB	1.87 kB	✓
routerDirect..HASH.js gzip	321 B	321 B	✓
script-HASH.js gzip	383 B	383 B	✓
withRouter-HASH.js gzip	318 B	318 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	13.3 kB	13.3 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
index.html gzip	521 B	523 B	⚠️ +2 B
link.html gzip	534 B	536 B	⚠️ +2 B
withRouter.html gzip	515 B	517 B	⚠️ +2 B
Overall change	1.57 kB	1.58 kB	⚠️ +6 B

Diffs

Diff for main-HASH.js

@@ -3703,7 +3703,10 @@
         // first item will be empty string from splitting at first char
         var pathnameParts = pathname.split("/");
         (locales || []).some(function(locale) {
-          if (pathnameParts[1].toLowerCase() === locale.toLowerCase()) {
+          if (
+            pathnameParts[1] &&
+            pathnameParts[1].toLowerCase() === locale.toLowerCase()
+          ) {
             detectedLocale = locale;
             pathnameParts.splice(1, 1);
             pathname = pathnameParts.join("/") || "/";

Diff for index.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9e7b6529420042b3.js"
+      src="/_next/static/chunks/main-7d9df3f169873f18.js"
       defer=""
     ></script>
     <script

Diff for link.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9e7b6529420042b3.js"
+      src="/_next/static/chunks/main-7d9df3f169873f18.js"
       defer=""
     ></script>
     <script

Diff for withRouter.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9e7b6529420042b3.js"
+      src="/_next/static/chunks/main-7d9df3f169873f18.js"
       defer=""
     ></script>
     <script

Default Build with SWC (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
buildDuration	27.1s	27.2s	⚠️ +118ms
buildDurationCached	4.8s	4.7s	-79ms
nodeModulesSize	335 MB	335 MB	⚠️ +1.15 kB

Page Load Tests Overall increase ✓

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
/ failed reqs	0	0	✓
/ total time (seconds)	4.191	4.381	⚠️ +0.19
/ avg req/sec	596.46	570.69	⚠️ -25.77
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.307	2.242	-0.06
/error-in-render avg req/sec	1083.78	1114.94	+31.16

Client Bundles (main, webpack, commons) Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	28.5 kB	28.6 kB	⚠️ +4 B
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	72.5 kB	72.5 kB	⚠️ +4 B

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	180 B	180 B	✓
amp-HASH.js gzip	305 B	305 B	✓
css-HASH.js gzip	321 B	321 B	✓
dynamic-HASH.js gzip	2.38 kB	2.38 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	622 B	622 B	✓
image-HASH.js gzip	4.46 kB	4.46 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	1.91 kB	1.91 kB	✓
routerDirect..HASH.js gzip	314 B	314 B	✓
script-HASH.js gzip	375 B	375 B	✓
withRouter-HASH.js gzip	309 B	309 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	13.2 kB	13.2 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js fix-pathnameparts-undefined	Change
index.html gzip	523 B	523 B	✓
link.html gzip	535 B	535 B	✓
withRouter.html gzip	516 B	516 B	✓
Overall change	1.57 kB	1.57 kB	✓

Diffs

Diff for main-HASH.js

@@ -3703,7 +3703,10 @@
         // first item will be empty string from splitting at first char
         var pathnameParts = pathname.split("/");
         (locales || []).some(function(locale) {
-          if (pathnameParts[1].toLowerCase() === locale.toLowerCase()) {
+          if (
+            pathnameParts[1] &&
+            pathnameParts[1].toLowerCase() === locale.toLowerCase()
+          ) {
             detectedLocale = locale;
             pathnameParts.splice(1, 1);
             pathname = pathnameParts.join("/") || "/";

Diff for index.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9e7b6529420042b3.js"
+      src="/_next/static/chunks/main-7d9df3f169873f18.js"
       defer=""
     ></script>
     <script

Diff for link.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9e7b6529420042b3.js"
+      src="/_next/static/chunks/main-7d9df3f169873f18.js"
       defer=""
     ></script>
     <script

Diff for withRouter.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9e7b6529420042b3.js"
+      src="/_next/static/chunks/main-7d9df3f169873f18.js"
       defer=""
     ></script>
     <script

Commit: ed9de3e

test/integration/i18n-support/test/shared.js

Fix normalizeLocalePath() when path is /

99824ad

styfle requested review from huozhi, ijjk, shuding and timneutkens as code owners November 4, 2021 19:25

ijjk added created-by: Next.js team PRs by the Next.js team type: next labels Nov 4, 2021

ijjk reviewed Nov 4, 2021

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styfle changed the title ~~Fix normalizeLocalePath() when path is /~~ Fix normalizeLocalePath() when path is empty string Nov 4, 2021

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ijjk added 2 commits November 15, 2021 09:39

Merge branch 'canary' into fix-pathnameparts-undefined

4776490

Ensure basePath is checked/replaced correctly and add tests

ee8e778

ijjk changed the title ~~Fix normalizeLocalePath() when path is empty string~~ Fix basePath replacing server-side and normalizeLocalePath() when path is empty string Nov 15, 2021

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ijjk approved these changes Nov 15, 2021

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Merge branch 'canary' into fix-pathnameparts-undefined

ed9de3e

kodiakhq bot merged commit eb0bd63 into canary Nov 15, 2021

kodiakhq bot deleted the fix-pathnameparts-undefined branch November 15, 2021 17:33

styfle commented Nov 15, 2021

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Fix basePath replacing server-side and `normalizeLocalePath()` when path is empty string #30978

Fix basePath replacing server-side and `normalizeLocalePath()` when path is empty string #30978

styfle commented Nov 4, 2021 •

edited by ijjk

ijjk Nov 4, 2021

styfle Nov 4, 2021 •

edited

ijjk Nov 15, 2021

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ijjk commented Nov 15, 2021

Diffs

Diffs

Fix basePath replacing server-side and normalizeLocalePath() when path is empty string #30978

Fix basePath replacing server-side and normalizeLocalePath() when path is empty string #30978

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styfle commented Nov 4, 2021 • edited by ijjk

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ijjk commented Nov 15, 2021

Stats from current PR

Diffs

Diffs

Fix basePath replacing server-side and `normalizeLocalePath()` when path is empty string #30978

Fix basePath replacing server-side and `normalizeLocalePath()` when path is empty string #30978

styfle commented Nov 4, 2021 •

edited by ijjk

styfle Nov 4, 2021 •

edited