I'm trying to write and test a ResourceXmlDetector to check for cases where textAppearance styles contain style items which will be ignored using AGP 3.1.0-beta4 and Lint 26.1.0-beta4.

I expected the following test to fail:

@Test
fun failLint() {
lint()
.files(
xml(
"res/values/styles.xml",
"""
|<?xml version="1.0" encoding="utf-8"?>
|<resources>
| <style name="TextAppearance">
| <item name="android:lineSpacingMultiplier">1.33</item>
| </style>
|</resources>
|/>
""".trimMargin()
),
xml(
"res/layout/layout.xml",
"""
|<?xml version="1.0" encoding="utf-8"?>
|<TextView
| android:textAppearance="@style/TextAppearance"
|/>
""".trimMargin()
)
)
.issues(ISSUE_STYLE_ITEM)
.run()
.expectClean()
}

but it instead succeeded.

Attaching a debugger and digging into org.apache.xerces.internal.parsers.XML11Configuration#parse(boolean), I entered a catch block and introspected the exception to find: "::::4:3:-1:The prefix "android" for attribute "android:textAppearance" associated with an element type "TextView" is not bound." -- a helpful debugging message.

Unfortunately, this exception is swallowed and ignored in LintCliXmlParser.parseXml(CharSequence, File) returning null. Its caller LintDriver#checkResourceFolder uses this null XmlContext as a sign to stop processing the current xml file and continue on to the next XmlFile in the iterated set (line 1679).

Instead, I would have expected the XML processing to fail, bubbling up to my test and resulting in a failure.