An answer with spoiler formatting is displaying weirdly

Question

I am viewing the answer by User 3.1415926535897932384626433832 to Why didn't Madara start his own plan when he was still young?. The entire answer is currently (revision number 2) within a spoiler block, but it is being displayed rather weirdly — perhaps due to the presence of a blockquote within the spoiler block?

1. Even without clicking on "Reveal spoiler", the last line of the answer is visible, despite the fact that the last line is placed inside the spoiler block (check the source formatting of the second revision to confirm).

2. After clicking on "Reveal spoiler", the line before the blockquote is revealed, whereas the blockquote is still not revealed, and a new "Reveal spoiler" button appears over the blockquoted part. At the same time, some portion of the blockquote is revealed, namely " --- Quoted from " and the full stop at the end of the sentence, a little distance away. The part between "from" and the full stop is a link, and it is hidden at this point.

3. After clicking on "Reveal spoiler" a second time, the entire answer is revealed properly.

4. Oddly enough, the spoiler formatting seems to work properly in the revision history of the answer, under the "Inline" as well as "Side-by-side" views.

5. For more weirdness, go to the link to the second revision. Here, the last line starts out unhidden, just as on the main answer under the question. However, clicking on "Reveal spoiler" just once opens the rest of the answer, unlike what happens on the main answer.

Considering the age of the question, it's probably fine in this case to fix the answer simply by editing out the spoilers completely; but, I thought it might be worth noting the bug with the spoiler formatting just in case it can be fixed.

Answer 1

This is possibly an artifact of the older markdown engine before the CommonMark migration.

This is easy to check since the post wasn't migrated automatically by the Community bot due to the different rendering results:

• Before CommonMark: 2 spoiler blocks nested inside
• After CommonMark: 1 spoiler block

We avoid breaking existing posts by erring on the side of safety. If a post looks different using the new renderer (and if it’s just one whitespace off) we won’t automatically re-render the post and put it up for investigation first. This way we can be sure that all changes are safe.

[...]

Things might get funky when you're editing a post that renders differently with the new CommonMark renderer. Again, if we detected that a post would look differently when rendered with the new CommonMark renderer during the migration, we wouldn't save a new version of this post as part of the migration. This way, all posts continue to look the same when being viewed. However, once someone comes in and edits it, it will be rendered using the new CommonMark renderer and this might cause the post to look slightly different than what we had before. This will only be a small fraction of all of our posts, and of that small fraction a smaller fraction will actually be edited moving forward. However, it's important to keep in mind that editing old posts has a slight chance that you run into differences between our old and our new markdown renderers.

As such, re-editing the post to use CommonMark and fixing the markdown is recommended.

---

For more details:

1. Even without clicking on "Reveal spoiler", the last line of the answer is visible, despite the fact that the last line is placed inside the spoiler block (check the source formatting of the second revision to confirm).

Status by-design.

2. After clicking on "Reveal spoiler", the line before the blockquote is revealed, whereas the blockquote is still not revealed, and a new "Reveal spoiler" button appears over the blockquoted part. At the same time, some portion of the blockquote is revealed, namely " --- Quoted from " and the full stop at the end of the sentence, a little distance away. The part between "from" and the full stop is a link, and it is hidden at this point.

3. After clicking on "Reveal spoiler" a second time, the entire answer is revealed properly.

Fixed in CommonMark; only 1 spoiler block remains.

4. Oddly enough, the spoiler formatting seems to work properly in the revision history of the answer, under the "Inline" as well as "Side-by-side" views.

(not sure; spoiler block is not a standard markdown. Its interaction with other markdowns are often buggy)

5. For more weirdness, go to the link to the second revision. Here, the last line starts out unhidden, just as on the main answer under the question. However, clicking on "Reveal spoiler" just once opens the rest of the answer, unlike what happens on the main answer.

Presumably rendered with the current CommonMark, as observed with 2) and 3).