New 'auto_command_starting' signal when 'nikola auto' is starting.

[matthew16550]

Pull Request Checklist

• I’ve read the guidelines for contributing.
• I updated AUTHORS.txt and CHANGES.txt (if the change is non-trivial) and documentation (if applicable).
• I tested my changes.

Description

When adding support for the PlantUML PicoWeb server (getnikola/plugins#378) I would like nikola auto to start one PicoWeb server and share it with all child build processes. So the plantuml plugin needs to know when nikola auto is happening.

The simplest solution I've thought of is a new auto_command_starting signal but perhaps something like these more generic solutions would be preferred?

• A new command_starting signal including command name as a param
• BasePlugin.get_command_name()

(Haven't looked closely if either of those is actually possible)

[matthew16550]

The build is failing on an unrelated test and I haven't been able to reproduce it locally as yet. 😢

    def test_compiling_markdown(
        compiler, input_path, output_path, input_str, expected_output
    ):
        output = markdown_compile(compiler, input_path, output_path, input_str)
>       assert output.strip() == expected_output.strip()
E       assert '<table class...</tr></table>' == '<table class...</tr></table>'
E         Skipping 73 identical leading characters in diff, use -v to show
E         - div"><pre>1</pre></div></td><td class="code"><pre class="code literal-block"><span></span><code><span class="kn">from</span> <span class="nn">this</span>
E         + div"><pre><span class="normal">1</span></pre></div></td><td class="code"><pre class="code literal-block"><span></span><code><span class="kn">from</span> <span class="nn">this</span>
E         ?           +++++++++++++++++++++ +++++++
E           </code></pre>
E           </td></tr></table>

[matthew16550]

Made #3514 for why the build is failiing.

[Kwpolska]

A new command_starting signal including command name as a param

What commands, other than auto (and perhaps build) could make use of that?

(Although build could end up allowing people to do fairly ugly things; it does make sense to use this in auto to launch PlantUML, or perhaps some JS/CSS live compiler.)

[Kwpolska]

I merged the auto_command_starting version, if there are any other commands which could use a signal (I don’t really think we need more), you can open further PRs. A signal for any command seems unnecessary to me (it also becomes harder to catch).

[matthew16550]

What commands, other than auto (and perhaps build) could make use of that?

Hadn't thought of any other use cases, just thinking out loud.

Thanks for finishing this one.