`islands_router` update & hydration issues

[antler5]

Describe the bug
Incorrect updates (since Oct) and hydration bugs (since Nov) with component-erasure + islands-router (ie. mark-branches, etc?). I've extended the test in example islands_router to mount and increment Counter, and added a second variant showing how hydration kinda works between the Oct-Nov commits if we push through the distinct nav/update bug.

Leptos Dependencies

See examples/islands_router

To Reproduce

1. Clone, pull, or save patched islands_router test
2. Checkout or apply it
3. cd examples/island_router
4. (here i rebased onto alt commits to bisect)
5. See errors / behavior

errors

Since 61571ed, Nov 19 - present, the happy & redundant paths both fail:

 1) [chromium] › tests/navigation.spec.ts:16:5 › navigates from Home to About, increments Counter ─

    Error: expect(locator).not.toBeVisible() failed

    Locator:  getByText('Enter a search to begin viewing contacts.')
    Expected: not visible
    Received: visible
    Timeout:  5000ms

    Call log:
      - Expect "not toBeVisible" with timeout 5000ms
      - waiting for getByText('Enter a search to begin viewing contacts.')
        14 × locator resolved to <p class="note">…</p>
           - unexpected value "visible"

      27 |   await expect(page.locator("input[type=search]")).not.toBeAttached();
      28 |
    > 29 |   await expect(page.getByText("Enter a search to begin viewing contacts.")).not.toBeVisible();
         |                                                                                 ^
      30 |   await expect(page.locator("button[class=counter]")).toHaveText("Click Me: 0");
      31 |   await page.click('button[class=counter]');
      32 |   await expect(page.locator("button[class=counter]")).toHaveText("Click Me: 1");
 [...]

 2) [chromium] › tests/navigation.spec.ts:37:5 › navigates from Home to About (redundantly), increments Counter

    Error: expect(locator).toHaveText(expected) failed

    Locator:  locator('button[class=counter]')
    Expected: "Click Me: 1"
    Received: "Click Me: 0"
    Timeout:  5000ms

    Call log:
      - Expect "toHaveText" with timeout 5000ms
      - waiting for locator('button[class=counter]')
        14 × locator resolved to <button class="counter">…</button>
           - unexpected value "Click Me: 0"

      59 |   await expect(page.locator("button[class=counter]")).toHaveText("Click Me: 0");
      60 |   await page.click('button[class=counter]');
    > 61 |   await expect(page.locator("button[class=counter]")).toHaveText("Click Me: 1");
         |                                                       ^
      62 |
      63 |   expect(errors).toEqual([]);
      64 | });

Since b20903a, Oct 11, the happy-path fails and the redundant path succeeds:

 1) [chromium] › tests/navigation.spec.ts:16:5 › navigates from Home to About, increments Counter

    Error: expect(locator).not.toBeVisible() failed

    Locator:  getByText('Enter a search to begin viewing contacts.')
    Expected: not visible
    Received: visible
    Timeout:  5000ms

    Call log:
      - Expect "not toBeVisible" with timeout 5000ms
      - waiting for getByText('Enter a search to begin viewing contacts.')
        14 × locator resolved to <p class="note">…</p>
           - unexpected value "visible"

      27 |   await expect(page.locator("input[type=search]")).not.toBeAttached();
      28 |
    > 29 |   await expect(page.getByText("Enter a search to begin viewing contacts.")).not.toBeVisible();
         |                                                                                 ^
      30 |   await expect(page.locator("button[class=counter]")).toHaveText("Click Me: 0");
      31 |   await page.click('button[class=counter]');
      32 |   await expect(page.locator("button[class=counter]")).toHaveText("Click Me: 1");
 [...]

  ✓  2 …vigates from Home to About (redundantly), increments Counter (1.9s)

Before then, the results I would expect:

  ✓  1 …c.ts:16:5 › navigates from Home to About, increments Counter (1.2s)
  ✘  2 …vigates from Home to About (redundantly), increments Counter (5.3s)

Next Steps

• I will make a PR
• I would like to make a PR, but need help getting started
• I want someone else to take the time to fix this
• This is a low priority for me and is just shared for your information

Additional context
i continue teasing thru related code, but this appears to predate many otherwise related leads and i have not re-oriented 😅

[gbj]

See 4855 -- should fix this.

[antler5]

LGTM (ie. can't break misc csr/ssr/{,island-}router builds*), & what a neat mechanism -- thank you!

[gbj]

Cool! Merged.