Align XML attributes when formatting

[xorye]

It would be nice if there was an option to align the beginning of attribute names if the attributes exist in different lines when formatting.

Currently by default, when formatting this XML:

<a attr="value"
   attr="value">
    <b></b>
</a>

The resulting XML is:

<a attr="value" attr="value">
    <b></b>
</a>

Ideally, after formatting, the initial XML should stay as is.

[xorye]

In this case:

<a attr="value"
           attr="value">
    <b></b>
</a>

Since the attributes are in separate lines, it should be aligned after formatting:

<a attr="value"
   attr="value">
    <b></b>
</a>

[BinToss]

This is EditorConfig Rule xml_pi_attributes_indent as specified by ReSharper.
Possible values are single_indent, double_indent, and align_by_first_attribute.

See https://www.jetbrains.com/help/resharper/EditorConfig_XML_XmlCodeStylePageSchema.html#resharper_xml_pi_attributes_indent

[angelozerr]

@JessicaJHee I think we can close this issue since the provided new formatter, right?

[angelozerr]

@BinToss please read https://github.com/redhat-developer/vscode-xml/blob/main/docs/Formatting.md#xmlformatsplitattributes

[BinToss]

@angelozerr The documentation's example indicates the spaces/indentation of the inner element(s) are formatted, but does not state it also affects tags' attributes.

If this format rule does affect attributes, then the documentation could be clarified.

Edit: also, there's no way to specify that the rule should only apply to attributes i.e. inner elements' spaces should be formatted, but not the attributes.

[JessicaJHee]

The xml.format.splitAttributes setting applies to attributes and not inner elements.
Currently, when this setting is set to true. the following is formatted from

<project a="1" b="2" c="3"></project>

to:

<project
    a="1"
    b="2"
    c="3"></project>

To address the use case in this comment, we can update this settings with a new option: preserve (currently xml.format.splitAttributes = true), split-new-line (currently xml.format.splitAttributes = false), and align-with-first-attr.

The new setting would format to:

<project a="1"
         b="2"
         c="3"></project>

What do you think about this solution @BinToss?

[BinToss]

That looks perfect!
That solution may also resolve #631...of which this issue is probably a duplicate.

On the subject of editorconfig files and rules, it seems there's been community interest in this extension supporting them, but that's a different issue with a different solution. A quick search in Lemminx's Issues returned no results.

• Request: Support EditorConfig #296
• xml.format.maxLineWidth should respect the .editorconfig setting, if there is one #850
• [EditorConfig] Respect what's from it before applying local user rules #904

[angelozerr]

@BinToss for your information, @JessicaJHee has implemented the format settings of this issue (thanks so much @JessicaJHee !).

See doc at https://github.com/redhat-developer/vscode-xml/blob/main/docs/Formatting.md#xmlformatsplitattributes

It would be nice if tomorrow you could install prrelease https://github.com/redhat-developer/vscode-xml#contributing and give us feedback. Thanks!

[angelozerr]

@BinToss the prerelease is avaiable, please play with it and give us feedback. Thanks!

[BinToss]

Roger that. I should have time to try it out this weekend.

[BinToss]

Excellent work!

The only thing people may complain about is when the formatter can't handle a file with "mixed" formatting—that is, they desire both preserve and alignWithFirstAttr in the same file. Or they may want preserve without affecting alignment.
However, I'd say this request is resolved.

[angelozerr]

Thanks @BinToss for your feedback.

Thanks so much again @JessicaJHee for your great work!