Add a test that verifies @model is stable between route transitions

[Windvis]

This adds a failing test for the issue mentioned in #18987 based on the StackBlitz reproduction and supersedes #19257.

I needed to do some changes to the Vite and CI setup to make the @glimmer/component imports working in the test files. Not sure if what I did is the best solution but it works for the reproduction at least.

[github-actions]

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╔═══════╤═══════════╤═══════════╗ ║ │ Min │ Gzip ║ ╟───────┼───────────┼───────────╢ ║ Total │ 408.84 KB │ 228.88 KB ║ ╚═══════╧═══════════╧═══════════╝ ╔══════════════════════╤═══════════╤══════════╗ ║ @ember/* │ Min │ Gzip ║ ╟──────────────────────┼───────────┼──────────╢ ║ Total │ 239.23 KB │ 147.2 KB ║ ╟──────────────────────┼───────────┼──────────╢ ║ -internals │ 35.44 KB │ 25.49 KB ║ ║ application │ 12.83 KB │ 7.62 KB ║ ║ array │ 12.66 KB │ 7.32 KB ║ ║ canary-features │ 304 B │ 419 B ║ ║ component │ 1.07 KB │ 1004 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 │ 570 B ║ ║ instrumentation │ 2.43 KB │ 1.78 KB ║ ║ modifier │ 669 B │ 614 B ║ ║ object │ 33.78 KB │ 20.79 KB ║ ║ owner │ 159 B │ 178 B ║ ║ renderer │ 385 B │ 327 B ║ ║ routing │ 58.05 KB │ 33.43 KB ║ ║ runloop │ 2.2 KB │ 1.33 KB ║ ║ service │ 859 B │ 741 B ║ ║ template │ 430 B │ 390 B ║ ║ template-compilation │ 429 B │ 366 B ║ ║ template-compiler │ 57.81 KB │ 30.44 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 │ 169.61 KB │ 81.68 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 │ 42.51 KB ║ ║ tracking │ 989 B │ 961 B ║ ║ util │ 3.03 KB │ 2.29 KB ║ ║ validator │ 6 KB │ 3.72 KB ║ ║ vm │ 784 B │ 798 B ║ ║ wire-format │ 1.84 KB │ 1.35 KB ║ ╚═════════════════╧═══════════╧══════════╝

╔═══════╤═══════════╤═══════════╗ ║ │ Min │ Gzip ║ ╟───────┼───────────┼───────────╢ ║ Total │ 408.84 KB │ 228.88 KB ║ ╚═══════╧═══════════╧═══════════╝ ╔══════════════════════╤═══════════╤══════════╗ ║ @ember/* │ Min │ Gzip ║ ╟──────────────────────┼───────────┼──────────╢ ║ Total │ 239.23 KB │ 147.2 KB ║ ╟──────────────────────┼───────────┼──────────╢ ║ -internals │ 35.44 KB │ 25.49 KB ║ ║ application │ 12.83 KB │ 7.62 KB ║ ║ array │ 12.66 KB │ 7.32 KB ║ ║ canary-features │ 304 B │ 419 B ║ ║ component │ 1.07 KB │ 1004 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 │ 570 B ║ ║ instrumentation │ 2.43 KB │ 1.78 KB ║ ║ modifier │ 669 B │ 614 B ║ ║ object │ 33.78 KB │ 20.79 KB ║ ║ owner │ 159 B │ 178 B ║ ║ renderer │ 385 B │ 327 B ║ ║ routing │ 58.05 KB │ 33.43 KB ║ ║ runloop │ 2.2 KB │ 1.33 KB ║ ║ service │ 859 B │ 741 B ║ ║ template │ 430 B │ 390 B ║ ║ template-compilation │ 429 B │ 366 B ║ ║ template-compiler │ 57.81 KB │ 30.44 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 │ 169.61 KB │ 81.68 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 │ 42.51 KB ║ ║ tracking │ 989 B │ 961 B ║ ║ util │ 3.03 KB │ 2.29 KB ║ ║ validator │ 6 KB │ 3.72 KB ║ ║ vm │ 784 B │ 798 B ║ ║ wire-format │ 1.84 KB │ 1.35 KB ║ ╚═════════════════╧═══════════╧══════════╝

[NullVoxPopuli]

do you happen to know if this ever worked?

[Windvis]

do you happen to know if this ever worked?

I don't think so, no. As far as I know it has been an issue since @model was introduced, which is why the template-lint rule exists.

It's just a tricky to reproduce issue so it seemed that it was "solved" at some point in time.