Extra-space between fenced code block start and attributes

[kdeldycke]

Here is a collection of fenced code blocks in Markdown:

$ cat ./fenced-code-block-attributes.md

```shell-session
cp --help
```

``` shell-session
cp --help
```

```{.shell-session}
cp --help
```

``` {.shell-session}
cp --help
```

To normalize the style of their attributes, I ran pandoc:

$ pandoc ./fenced-code-block-attributes.md --to=markdown

``` shell-session
cp --help
```

``` shell-session
cp --help
```

``` shell-session
cp --help
```

``` shell-session
cp --help
```

Notice how each code block header gets normalized to ``` shell-session, i.e. a triple-quote followed by a space then by the language attribute.

I think this is a bug, and I expect the extra space to not be there.

For reference I use the latest pandoc on macOS Big Sur:

$ pandoc --version
pandoc 2.14.2
Compiled with pandoc-types 1.22, texmath 0.12.3.1, skylighting 0.11,
citeproc 0.5, ipynb 0.1.0.1

[jgm]

Why is it a bug? The space is allowed and (I think) looks nicer.

[kdeldycke]

Sorry @jgm for this nitpicking! 🙇

I was just under the impression that the non-space version ```shell-session was the canonical form of fenced blocks. I was misled by unforgiving implementation of some markdown librairies. But it seems that, indeed, spaces are allowed between triple-quotes and attributes. I now have to track down that bug on third-party libraries. 😣

Again sorry for the noise and feel free to close that issue. 😅

[jgm]

No problem.