Prototype what it would be like to remove the classic / pre-octane things from @ember/component

[NullVoxPopuli]

Spiking out an idea I had:

• https://github.com/NullVoxPopuli/legacy-ember-component
  • Generally, I want to figure out if all the legacy stuff can be extracted to a library and used independently -- combined with a babel plugin to re-write old imports to the library, this would give folks a path to migrating forward -- at least until the underlying private APIs are removed (a lot of glimmer runtime/reference stuff)

Additional motivation is that I want to simplify what all goes in to the renderer.

In order to land this:

• need RFC to deprecate Component, Helper, helper, Input, Textarea
  earliest this could target deprecation is probably v8
  • might depend on @wagenet's deprecations
    See: [DO NOT MERGE] the delta between main and what we're experimenting with that needs a bunch of RFCs first #20923
  • needs deprecation guide
• our internal tests need to migrate away from @ember/component except when specifically testing @ember/component

[github-actions]

Estimated Asset Sizes

Diff

--- main/out.txt	2025-09-04 03:19:38.000000000 +0000
+++ pr/./pr-17531355995/out.txt	2025-09-07 16:59:10.000000000 +0000
@@ -1,41 +1,41 @@
 ╔═══════╤═══════════╤═══════════╗
 ║       │ Min       │ Gzip      ║
 ╟───────┼───────────┼───────────╢
-║ Total │ 418.65 KB │ 232.22 KB ║
+║ Total │ 418.16 KB │ 231.83 KB ║
 ╚═══════╧═══════════╧═══════════╝
 
-╔══════════════════════╤══════════╤═══════════╗
-║ @ember/*             │ Min      │ Gzip      ║
-╟──────────────────────┼──────────┼───────────╢
-║ Total                │ 239.4 KB │ 147.23 KB ║
-╟──────────────────────┼──────────┼───────────╢
-║ -internals           │ 35.46 KB │ 25.49 KB  ║
-║ application          │ 12.83 KB │ 7.7 KB    ║
-║ array                │ 12.66 KB │ 7.32 KB   ║
-║ canary-features      │ 304 B    │ 419 B     ║
-║ component            │ 1.07 KB  │ 1005 B    ║
-║ controller           │ 1.8 KB   │ 1.36 KB   ║
-║ debug                │ 11.4 KB  │ 7.92 KB   ║
-║ deprecated-features  │ 31 B     │ 77 B      ║
-║ destroyable          │ 561 B    │ 383 B     ║
-║ enumerable           │ 259 B    │ 387 B     ║
-║ helper               │ 823 B    │ 605 B     ║
-║ instrumentation      │ 2.43 KB  │ 1.78 KB   ║
-║ modifier             │ 669 B    │ 581 B     ║
-║ object               │ 33.78 KB │ 20.79 KB  ║
-║ owner                │ 159 B    │ 178 B     ║
-║ renderer             │ 406 B    │ 350 B     ║
-║ routing              │ 58.08 KB │ 33.43 KB  ║
-║ runloop              │ 2.2 KB   │ 1.33 KB   ║
-║ service              │ 859 B    │ 741 B     ║
-║ template             │ 430 B    │ 364 B     ║
-║ template-compilation │ 429 B    │ 366 B     ║
-║ template-compiler    │ 57.91 KB │ 30.4 KB   ║
-║ template-factory     │ 94 B     │ 160 B     ║
-║ test                 │ 923 B    │ 627 B     ║
-║ utils                │ 3.93 KB  │ 3.5 KB    ║
-║ version              │ 55 B     │ 131 B     ║
-╚══════════════════════╧══════════╧═══════════╝
+╔══════════════════════╤═══════════╤═══════════╗
+║ @ember/*             │ Min       │ Gzip      ║
+╟──────────────────────┼───────────┼───────────╢
+║ Total                │ 238.91 KB │ 146.84 KB ║
+╟──────────────────────┼───────────┼───────────╢
+║ -internals           │ 35.39 KB  │ 25.46 KB  ║
+║ application          │ 12.83 KB  │ 7.69 KB   ║
+║ array                │ 12.66 KB  │ 7.32 KB   ║
+║ canary-features      │ 304 B     │ 419 B     ║
+║ component            │ 665 B     │ 620 B     ║
+║ controller           │ 1.8 KB    │ 1.36 KB   ║
+║ debug                │ 11.4 KB   │ 7.92 KB   ║
+║ deprecated-features  │ 31 B      │ 77 B      ║
+║ destroyable          │ 561 B     │ 383 B     ║
+║ enumerable           │ 259 B     │ 387 B     ║
+║ helper               │ 823 B     │ 604 B     ║
+║ instrumentation      │ 2.43 KB   │ 1.78 KB   ║
+║ modifier             │ 669 B     │ 588 B     ║
+║ object               │ 33.78 KB  │ 20.79 KB  ║
+║ owner                │ 159 B     │ 178 B     ║
+║ renderer             │ 406 B     │ 344 B     ║
+║ routing              │ 58.08 KB  │ 33.44 KB  ║
+║ runloop              │ 2.2 KB    │ 1.33 KB   ║
+║ service              │ 859 B     │ 741 B     ║
+║ template             │ 430 B     │ 382 B     ║
+║ template-compilation │ 429 B     │ 366 B     ║
+║ template-compiler    │ 57.91 KB  │ 30.4 KB   ║
+║ template-factory     │ 94 B      │ 160 B     ║
+║ test                 │ 923 B     │ 627 B     ║
+║ utils                │ 3.93 KB   │ 3.5 KB    ║
+║ version              │ 55 B      │ 131 B     ║
+╚══════════════════════╧═══════════╧═══════════╝
 
 ╔═════════════════╤═══════════╤══════════╗
 ║ @glimmer/*      │ Min       │ Gzip     ║

Details

This PR

main

╔═══════╤═══════════╤═══════════╗ ║ │ Min │ Gzip ║ ╟───────┼───────────┼───────────╢ ║ Total │ 418.16 KB │ 231.83 KB ║ ╚═══════╧═══════════╧═══════════╝ ╔══════════════════════╤═══════════╤═══════════╗ ║ @ember/* │ Min │ Gzip ║ ╟──────────────────────┼───────────┼───────────╢ ║ Total │ 238.91 KB │ 146.84 KB ║ ╟──────────────────────┼───────────┼───────────╢ ║ -internals │ 35.39 KB │ 25.46 KB ║ ║ application │ 12.83 KB │ 7.69 KB ║ ║ array │ 12.66 KB │ 7.32 KB ║ ║ canary-features │ 304 B │ 419 B ║ ║ component │ 665 B │ 620 B ║ ║ controller │ 1.8 KB │ 1.36 KB ║ ║ debug │ 11.4 KB │ 7.92 KB ║ ║ deprecated-features │ 31 B │ 77 B ║ ║ destroyable │ 561 B │ 383 B ║ ║ enumerable │ 259 B │ 387 B ║ ║ helper │ 823 B │ 604 B ║ ║ instrumentation │ 2.43 KB │ 1.78 KB ║ ║ modifier │ 669 B │ 588 B ║ ║ object │ 33.78 KB │ 20.79 KB ║ ║ owner │ 159 B │ 178 B ║ ║ renderer │ 406 B │ 344 B ║ ║ routing │ 58.08 KB │ 33.44 KB ║ ║ runloop │ 2.2 KB │ 1.33 KB ║ ║ service │ 859 B │ 741 B ║ ║ template │ 430 B │ 382 B ║ ║ template-compilation │ 429 B │ 366 B ║ ║ template-compiler │ 57.91 KB │ 30.4 KB ║ ║ template-factory │ 94 B │ 160 B ║ ║ test │ 923 B │ 627 B ║ ║ utils │ 3.93 KB │ 3.5 KB ║ ║ version │ 55 B │ 131 B ║ ╚══════════════════════╧═══════════╧═══════════╝ ╔═════════════════╤═══════════╤══════════╗ ║ @glimmer/* │ Min │ Gzip ║ ╟─────────────────┼───────────┼──────────╢ ║ Total │ 179.25 KB │ 84.99 KB ║ ╟─────────────────┼───────────┼──────────╢ ║ destroyable │ 2.7 KB │ 1.35 KB ║ ║ encoder │ 596 B │ 653 B ║ ║ env │ 38 B │ 87 B ║ ║ global-context │ 886 B │ 545 B ║ ║ manager │ 12.19 KB │ 5.44 KB ║ ║ node │ 2.71 KB │ 1.81 KB ║ ║ opcode-compiler │ 29.89 KB │ 13.23 KB ║ ║ owner │ 159 B │ 202 B ║ ║ program │ 7.1 KB │ 3.63 KB ║ ║ reference │ 5.51 KB │ 3.18 KB ║ ║ runtime │ 95.26 KB │ 42.69 KB ║ ║ tracking │ 989 B │ 961 B ║ ║ util │ 3.03 KB │ 2.29 KB ║ ║ validator │ 15.64 KB │ 6.86 KB ║ ║ vm │ 784 B │ 798 B ║ ║ wire-format │ 1.84 KB │ 1.35 KB ║ ╚═════════════════╧═══════════╧══════════╝

╔═══════╤═══════════╤═══════════╗ ║ │ Min │ Gzip ║ ╟───────┼───────────┼───────────╢ ║ Total │ 418.65 KB │ 232.22 KB ║ ╚═══════╧═══════════╧═══════════╝ ╔══════════════════════╤══════════╤═══════════╗ ║ @ember/* │ Min │ Gzip ║ ╟──────────────────────┼──────────┼───────────╢ ║ Total │ 239.4 KB │ 147.23 KB ║ ╟──────────────────────┼──────────┼───────────╢ ║ -internals │ 35.46 KB │ 25.49 KB ║ ║ application │ 12.83 KB │ 7.7 KB ║ ║ array │ 12.66 KB │ 7.32 KB ║ ║ canary-features │ 304 B │ 419 B ║ ║ component │ 1.07 KB │ 1005 B ║ ║ controller │ 1.8 KB │ 1.36 KB ║ ║ debug │ 11.4 KB │ 7.92 KB ║ ║ deprecated-features │ 31 B │ 77 B ║ ║ destroyable │ 561 B │ 383 B ║ ║ enumerable │ 259 B │ 387 B ║ ║ helper │ 823 B │ 605 B ║ ║ instrumentation │ 2.43 KB │ 1.78 KB ║ ║ modifier │ 669 B │ 581 B ║ ║ object │ 33.78 KB │ 20.79 KB ║ ║ owner │ 159 B │ 178 B ║ ║ renderer │ 406 B │ 350 B ║ ║ routing │ 58.08 KB │ 33.43 KB ║ ║ runloop │ 2.2 KB │ 1.33 KB ║ ║ service │ 859 B │ 741 B ║ ║ template │ 430 B │ 364 B ║ ║ template-compilation │ 429 B │ 366 B ║ ║ template-compiler │ 57.91 KB │ 30.4 KB ║ ║ template-factory │ 94 B │ 160 B ║ ║ test │ 923 B │ 627 B ║ ║ utils │ 3.93 KB │ 3.5 KB ║ ║ version │ 55 B │ 131 B ║ ╚══════════════════════╧══════════╧═══════════╝ ╔═════════════════╤═══════════╤══════════╗ ║ @glimmer/* │ Min │ Gzip ║ ╟─────────────────┼───────────┼──────────╢ ║ Total │ 179.25 KB │ 84.99 KB ║ ╟─────────────────┼───────────┼──────────╢ ║ destroyable │ 2.7 KB │ 1.35 KB ║ ║ encoder │ 596 B │ 653 B ║ ║ env │ 38 B │ 87 B ║ ║ global-context │ 886 B │ 545 B ║ ║ manager │ 12.19 KB │ 5.44 KB ║ ║ node │ 2.71 KB │ 1.81 KB ║ ║ opcode-compiler │ 29.89 KB │ 13.23 KB ║ ║ owner │ 159 B │ 202 B ║ ║ program │ 7.1 KB │ 3.63 KB ║ ║ reference │ 5.51 KB │ 3.18 KB ║ ║ runtime │ 95.26 KB │ 42.69 KB ║ ║ tracking │ 989 B │ 961 B ║ ║ util │ 3.03 KB │ 2.29 KB ║ ║ validator │ 15.64 KB │ 6.86 KB ║ ║ vm │ 784 B │ 798 B ║ ║ wire-format │ 1.84 KB │ 1.35 KB ║ ╚═════════════════╧═══════════╧══════════╝