Formatter surrounds single-quoted attributes with double-quotes

[fbricon]

Formatting this

<?xml version='1.0' encoding='UTF-8'?>
<?compositeMetadataRepository version='1.0.0'?>
<repository name='m2e-apt updates' type='org.eclipse.equinox.internal.p2.metadata.repository.CompositeMetadataRepository' version='1.0.0'>
<properties size='2'>
<property name='p2.compressed' value='true'/>
<property name='p2.timestamp' value='1328709112213'/>
</properties>
<children size='9'>
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.5.1-2018-11-16_19-54-26-H16/' />
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.5.0-2018-08-14_20-24-39-H12/' />
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.4.0-2018-01-12_16-25-02-H6/' />
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.3.0-2016-10-26_18-05-00-B50/' />
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.2.0-2016-01-25_16-03-44-H45/' />
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.1.1-2014-11-26_15-11-10-H37/' />
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.1.0-2014-05-21_05-04-36-H34/' />
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.0.1-2012-09-20_03-20-41-H23/'/>
<child location='http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.0.0-2012-06-05_16-15-59-H16/'/>
</children>
</repository>

yields:

<?xml version="1.0" encoding="UTF-8"?>
<?compositeMetadataRepository version='1.0.0' ?>
<repository name="'m2e-apt updates'" type="'org.eclipse.equinox.internal.p2.metadata.repository.CompositeMetadataRepository'" version="'1.0.0'">
    <properties size="'2'">
        <property name="'p2.compressed'" value="'true'" />
        <property name="'p2.timestamp'" value="'1328709112213'" />
    </properties>
    <children size="'9'">
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.5.1-2018-11-16_19-54-26-H16/'" />
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.5.0-2018-08-14_20-24-39-H12/'" />
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.4.0-2018-01-12_16-25-02-H6/'" />
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.3.0-2016-10-26_18-05-00-B50/'" />
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.2.0-2016-01-25_16-03-44-H45/'" />
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.1.1-2014-11-26_15-11-10-H37/'" />
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.1.0-2014-05-21_05-04-36-H34/'" />
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.0.1-2012-09-20_03-20-41-H23/'" />
        <child location="'http://download.jboss.org/jbosstools/updates/m2e-extensions/m2e-apt/1.0.0-2012-06-05_16-15-59-H16/'" />
    </children>
</repository>

single quotes should be either ignored/reused or replaced

[NikolasKomonen]

@fbricon
How should formatting behave with a mix of single and double quotes,
should we preserve the type of quotation for each value?

And maybe this calls for a preference to determine which type of quotation.

[angelozerr]

@NikolasKomonen I think we should store the field boolean useDoubleQuote in DOMAttr class (set by scanner). After the formatter could use it and we will able to manage mix of single and double quotes.