[BUGFIX] Fix {{#each}} runtime crash when array contains null/undefined items with key #20786

[johanrd]

Summary

• Fixes {{#each}} throwing Cannot call get with '...' on an undefined object when the iterated array contains null or undefined items and a key is specified (e.g. {{#each items key="id"}})
• Guards against null/undefined items in keyForPath before calling getPath, returning the item itself as the key

Fixes #20786

Reproduction

https://limber.glimdown.com/edit?c=MYewdgzgLgBAtgTwIICcUEMEwLwwNoCMANDAK5gAmApgGYCWYVFAugFCsA8UVcADgDbpuAPlYwYAbwkBiKumAALeMjSYYAayoJsAIjoUdMdBBgAfOtzimAvtbHjJEiz1v2pAejmLXHd5YFCVMJAA&format=gjs

Test plan

• Added tests for {{#each}} with undefined and null items in the array when key is specified
• Verified tests fail without the fix with the exact error from the bug report

Alternatives to this fix

1. Wire getPath to _getPath instead of get in environment.ts
2. Remove/relax the assertion in get() for null/undefined

I'd lean toward the current fix because:

• The get() assertion is intentional for the public API — calling get(undefined, 'foo') is almost always a bug in user code, and the assertion helps catch that
• _getPath/_getProp being lenient is for internal chained path traversal (e.g. get(obj, 'a.b.c') where a.b is undefined)
• Fixing in keyForPath is more targeted

Cowritten by Claude

[github-actions]

Estimated Asset Sizes

Diff

--- main/out.txt	2026-03-03 16:45:40.000000000 +0000
+++ pr/./pr-22633693745/out.txt	2026-03-03 16:58:40.000000000 +0000
@@ -1,34 +1,34 @@
 ╔═══════╤═══════════╤═══════════╗
 ║       │ Min       │ Gzip      ║
 ╟───────┼───────────┼───────────╢
-║ Total │ 351.99 KB │ 203.84 KB ║
+║ Total │ 351.99 KB │ 203.77 KB ║
 ╚═══════╧═══════════╧═══════════╝
 
 ╔══════════════════════╤═══════════╤═══════════╗
 ║ @ember/*             │ Min       │ Gzip      ║
 ╟──────────────────────┼───────────┼───────────╢
-║ Total                │ 313.39 KB │ 181.91 KB ║
+║ Total                │ 313.39 KB │ 182.01 KB ║
 ╟──────────────────────┼───────────┼───────────╢
 ║ -internals           │ 36.65 KB  │ 26.22 KB  ║
-║ application          │ 13.23 KB  │ 8.05 KB   ║
+║ application          │ 13.23 KB  │ 8.08 KB   ║
 ║ array                │ 13.01 KB  │ 7.46 KB   ║
 ║ canary-features      │ 304 B     │ 389 B     ║
-║ component            │ 2.05 KB   │ 1.64 KB   ║
+║ component            │ 2.05 KB   │ 1.61 KB   ║
 ║ controller           │ 1.96 KB   │ 1.41 KB   ║
 ║ debug                │ 11.69 KB  │ 8.12 KB   ║
 ║ deprecated-features  │ 31 B      │ 77 B      ║
 ║ destroyable          │ 561 B     │ 383 B     ║
 ║ enumerable           │ 259 B     │ 387 B     ║
-║ helper               │ 1.08 KB   │ 811 B     ║
+║ helper               │ 1.08 KB   │ 845 B     ║
 ║ instrumentation      │ 2.43 KB   │ 1.79 KB   ║
-║ modifier             │ 1.22 KB   │ 965 B     ║
+║ modifier             │ 1.22 KB   │ 960 B     ║
 ║ object               │ 35.94 KB  │ 22.16 KB  ║
 ║ owner                │ 159 B     │ 178 B     ║
-║ renderer             │ 630 B     │ 487 B     ║
-║ routing              │ 59.3 KB   │ 34.12 KB  ║
+║ renderer             │ 630 B     │ 519 B     ║
+║ routing              │ 59.3 KB   │ 34.14 KB  ║
 ║ runloop              │ 2.36 KB   │ 1.5 KB    ║
 ║ service              │ 1 KB      │ 845 B     ║
-║ template             │ 654 B     │ 541 B     ║
+║ template             │ 654 B     │ 558 B     ║
 ║ template-compilation │ 429 B     │ 366 B     ║
 ║ template-compiler    │ 123.08 KB │ 59.45 KB  ║
 ║ template-factory     │ 370 B     │ 374 B     ║
@@ -40,19 +40,19 @@
 ╔═════════════════╤══════════╤══════════╗
 ║ @glimmer/*      │ Min      │ Gzip     ║
 ╟─────────────────┼──────────┼──────────╢
-║ Total           │ 38.6 KB  │ 21.94 KB ║
+║ Total           │ 38.6 KB  │ 21.75 KB ║
 ╟─────────────────┼──────────┼──────────╢
 ║ destroyable     │ 2.77 KB  │ 1.39 KB  ║
 ║ encoder         │ 81 B     │ 171 B    ║
 ║ env             │ 38 B     │ 87 B     ║
 ║ global-context  │ 886 B    │ 545 B    ║
 ║ manager         │ 977 B    │ 608 B    ║
-║ node            │ 175 B    │ 260 B    ║
+║ node            │ 175 B    │ 243 B    ║
 ║ opcode-compiler │ 1.11 KB  │ 894 B    ║
 ║ owner           │ 159 B    │ 202 B    ║
 ║ program         │ 252 B    │ 301 B    ║
-║ reference       │ 548 B    │ 531 B    ║
-║ runtime         │ 10.32 KB │ 5.32 KB  ║
+║ reference       │ 548 B    │ 509 B    ║
+║ runtime         │ 10.32 KB │ 5.18 KB  ║
 ║ tracking        │ 1.34 KB  │ 1.16 KB  ║
 ║ util            │ 1.94 KB  │ 1.68 KB  ║
 ║ validator       │ 15.75 KB │ 6.96 KB  ║

Details

This PR

main

╔═══════╤═══════════╤═══════════╗ ║ │ Min │ Gzip ║ ╟───────┼───────────┼───────────╢ ║ Total │ 351.99 KB │ 203.77 KB ║ ╚═══════╧═══════════╧═══════════╝ ╔══════════════════════╤═══════════╤═══════════╗ ║ @ember/* │ Min │ Gzip ║ ╟──────────────────────┼───────────┼───────────╢ ║ Total │ 313.39 KB │ 182.01 KB ║ ╟──────────────────────┼───────────┼───────────╢ ║ -internals │ 36.65 KB │ 26.22 KB ║ ║ application │ 13.23 KB │ 8.08 KB ║ ║ array │ 13.01 KB │ 7.46 KB ║ ║ canary-features │ 304 B │ 389 B ║ ║ component │ 2.05 KB │ 1.61 KB ║ ║ controller │ 1.96 KB │ 1.41 KB ║ ║ debug │ 11.69 KB │ 8.12 KB ║ ║ deprecated-features │ 31 B │ 77 B ║ ║ destroyable │ 561 B │ 383 B ║ ║ enumerable │ 259 B │ 387 B ║ ║ helper │ 1.08 KB │ 845 B ║ ║ instrumentation │ 2.43 KB │ 1.79 KB ║ ║ modifier │ 1.22 KB │ 960 B ║ ║ object │ 35.94 KB │ 22.16 KB ║ ║ owner │ 159 B │ 178 B ║ ║ renderer │ 630 B │ 519 B ║ ║ routing │ 59.3 KB │ 34.14 KB ║ ║ runloop │ 2.36 KB │ 1.5 KB ║ ║ service │ 1 KB │ 845 B ║ ║ template │ 654 B │ 558 B ║ ║ template-compilation │ 429 B │ 366 B ║ ║ template-compiler │ 123.08 KB │ 59.45 KB ║ ║ template-factory │ 370 B │ 374 B ║ ║ test │ 923 B │ 627 B ║ ║ utils │ 4.11 KB │ 3.6 KB ║ ║ version │ 55 B │ 131 B ║ ╚══════════════════════╧═══════════╧═══════════╝ ╔═════════════════╤══════════╤══════════╗ ║ @glimmer/* │ Min │ Gzip ║ ╟─────────────────┼──────────┼──────────╢ ║ Total │ 38.6 KB │ 21.75 KB ║ ╟─────────────────┼──────────┼──────────╢ ║ destroyable │ 2.77 KB │ 1.39 KB ║ ║ encoder │ 81 B │ 171 B ║ ║ env │ 38 B │ 87 B ║ ║ global-context │ 886 B │ 545 B ║ ║ manager │ 977 B │ 608 B ║ ║ node │ 175 B │ 243 B ║ ║ opcode-compiler │ 1.11 KB │ 894 B ║ ║ owner │ 159 B │ 202 B ║ ║ program │ 252 B │ 301 B ║ ║ reference │ 548 B │ 509 B ║ ║ runtime │ 10.32 KB │ 5.18 KB ║ ║ tracking │ 1.34 KB │ 1.16 KB ║ ║ util │ 1.94 KB │ 1.68 KB ║ ║ validator │ 15.75 KB │ 6.96 KB ║ ║ vm │ 495 B │ 569 B ║ ║ wire-format │ 1.84 KB │ 1.35 KB ║ ╚═════════════════╧══════════╧══════════╝

╔═══════╤═══════════╤═══════════╗ ║ │ Min │ Gzip ║ ╟───────┼───────────┼───────────╢ ║ Total │ 351.99 KB │ 203.84 KB ║ ╚═══════╧═══════════╧═══════════╝ ╔══════════════════════╤═══════════╤═══════════╗ ║ @ember/* │ Min │ Gzip ║ ╟──────────────────────┼───────────┼───────────╢ ║ Total │ 313.39 KB │ 181.91 KB ║ ╟──────────────────────┼───────────┼───────────╢ ║ -internals │ 36.65 KB │ 26.22 KB ║ ║ application │ 13.23 KB │ 8.05 KB ║ ║ array │ 13.01 KB │ 7.46 KB ║ ║ canary-features │ 304 B │ 389 B ║ ║ component │ 2.05 KB │ 1.64 KB ║ ║ controller │ 1.96 KB │ 1.41 KB ║ ║ debug │ 11.69 KB │ 8.12 KB ║ ║ deprecated-features │ 31 B │ 77 B ║ ║ destroyable │ 561 B │ 383 B ║ ║ enumerable │ 259 B │ 387 B ║ ║ helper │ 1.08 KB │ 811 B ║ ║ instrumentation │ 2.43 KB │ 1.79 KB ║ ║ modifier │ 1.22 KB │ 965 B ║ ║ object │ 35.94 KB │ 22.16 KB ║ ║ owner │ 159 B │ 178 B ║ ║ renderer │ 630 B │ 487 B ║ ║ routing │ 59.3 KB │ 34.12 KB ║ ║ runloop │ 2.36 KB │ 1.5 KB ║ ║ service │ 1 KB │ 845 B ║ ║ template │ 654 B │ 541 B ║ ║ template-compilation │ 429 B │ 366 B ║ ║ template-compiler │ 123.08 KB │ 59.45 KB ║ ║ template-factory │ 370 B │ 374 B ║ ║ test │ 923 B │ 627 B ║ ║ utils │ 4.11 KB │ 3.6 KB ║ ║ version │ 55 B │ 131 B ║ ╚══════════════════════╧═══════════╧═══════════╝ ╔═════════════════╤══════════╤══════════╗ ║ @glimmer/* │ Min │ Gzip ║ ╟─────────────────┼──────────┼──────────╢ ║ Total │ 38.6 KB │ 21.94 KB ║ ╟─────────────────┼──────────┼──────────╢ ║ destroyable │ 2.77 KB │ 1.39 KB ║ ║ encoder │ 81 B │ 171 B ║ ║ env │ 38 B │ 87 B ║ ║ global-context │ 886 B │ 545 B ║ ║ manager │ 977 B │ 608 B ║ ║ node │ 175 B │ 260 B ║ ║ opcode-compiler │ 1.11 KB │ 894 B ║ ║ owner │ 159 B │ 202 B ║ ║ program │ 252 B │ 301 B ║ ║ reference │ 548 B │ 531 B ║ ║ runtime │ 10.32 KB │ 5.32 KB ║ ║ tracking │ 1.34 KB │ 1.16 KB ║ ║ util │ 1.94 KB │ 1.68 KB ║ ║ validator │ 15.75 KB │ 6.96 KB ║ ║ vm │ 495 B │ 569 B ║ ║ wire-format │ 1.84 KB │ 1.35 KB ║ ╚═════════════════╧══════════╧══════════╝