fix: keep validating after a line without '=' (Resolves #562)

src/main/resources/net/sjrx/intellij/plugins/systemdunitfiles/grammar/SystemdUnitFile.bnf

@@ -19,14 +19,22 @@
 
 unitFile ::= section_items* section_groups*
 
-section_groups ::= section_ section_items* { name="section header" pin=1 }
+section_groups ::= section_ section_items* { name="section header" pin=1 recoverWhile=section_recover }
 
 private section_items ::= property | comment_
 
-property ::= key_ separator_ value? { pin=1 }
+property ::= key_ separator_ value? { pin=1 recoverWhile=property_recover }
 
 value ::= (CONTINUING_VALUE| comment_ )* COMPLETED_VALUE
 
+// Error recovery (#562). A line that is not a section, comment or key=value (e.g. "some free text") lexes as a KEY
+// followed by BAD_CHARACTERs. Without recovery the parser gave up there and the rest of the file became one error
+// element, so nothing after it was validated. systemd itself logs "Missing '='" and carries on with the next line.
+// After a (possibly broken) property, skip to the next token that can start a line item; if junk appears where an
+// item should start, skip to the next section header.
+private property_recover ::= !(KEY | SECTION | COMMENT)
+private section_recover ::= !SECTION
+
 // Single rules for tokens so that I can alias them for better error handling shown above.
 private comment_ ::= COMMENT {name="comment" }
 private section_ ::= SECTION

src/test/kotlin/net/sjrx/intellij/plugins/systemdunitfiles/inspections/InvalidValueAfterLineWithoutSeparatorTest.kt

@@ -0,0 +1,70 @@
+package net.sjrx.intellij.plugins.systemdunitfiles.inspections
+
+import net.sjrx.intellij.plugins.systemdunitfiles.AbstractUnitFileTest
+
+/**
+ * A line that is not a section, comment or key=value must not stop validation of the lines after it (#562).
+ * systemd logs "Missing '=', ignoring line." and keeps going; the plugin used to stop validating the rest of the file.
+ */
+class InvalidValueAfterLineWithoutSeparatorTest : AbstractUnitFileTest() {
+
+  private fun invalidValueHighlightTexts(fileName: String, file: String): List<String> {
+    setupFileInEditor(fileName, file)
+    enableInspection(InvalidValueInspection::class.java)
+    return myFixture.doHighlighting().filter { it.inspectionToolId == "InvalidValue" }.map { it.text }
+  }
+
+  fun testValuesAfterAFreeTextLineInTheSameSectionAreStillValidated() {
+    // language="unit file (systemd)"
+    val file = """
+      [Service]
+      Nice=abc
+      this line has no equals
+      Nice=def
+      """.trimIndent()
+
+    assertEquals(listOf("abc", "def"), invalidValueHighlightTexts("file.service", file))
+  }
+
+  fun testLaterSectionsAfterAFreeTextLineAreStillValidated() {
+    // The shape that hid ~300 invalid values in the kf6-syntax-highlighting test unit: free text inside an
+    // extension section, followed by more sections.
+    // language="unit file (systemd)"
+    val file = """
+      [X-Unit]
+      name = value
+      Some text in an extension section.
+      The extension section ends with the next section header.
+
+      [Service]
+      Nice=abc
+      [Unit]
+      StartLimitIntervalSec=invalid
+      """.trimIndent()
+
+    assertEquals(listOf("abc", "invalid"), invalidValueHighlightTexts("file.service", file))
+  }
+
+  fun testFreeTextBeforeTheFirstSectionDoesNotStopValidation() {
+    // language="unit file (systemd)"
+    val file = """
+      some free text here
+      [Service]
+      Nice=abc
+      """.trimIndent()
+
+    assertEquals(listOf("abc"), invalidValueHighlightTexts("file.service", file))
+  }
+
+  fun testValidFileIsUnaffected() {
+    // language="unit file (systemd)"
+    val file = """
+      [Service]
+      Nice=5
+      [Unit]
+      StartLimitIntervalSec=10
+      """.trimIndent()
+
+    assertEquals(emptyList<String>(), invalidValueHighlightTexts("file.service", file))
+  }
+}

src/test/kotlin/net/sjrx/intellij/plugins/systemdunitfiles/parser/UnitFileParserTest.kt

@@ -2,6 +2,9 @@ package net.sjrx.intellij.plugins.systemdunitfiles.parser
 
 import com.intellij.testFramework.ParsingTestCase
 import junit.framework.TestCase
+import com.intellij.psi.PsiErrorElement
+import com.intellij.psi.util.PsiTreeUtil
+import net.sjrx.intellij.plugins.systemdunitfiles.psi.UnitFileProperty
 import net.sjrx.intellij.plugins.systemdunitfiles.psi.UnitFileSectionGroups
 import net.sjrx.intellij.plugins.systemdunitfiles.psi.UnitFileValueType
 
@@ -769,6 +772,37 @@ KeyThree=value 2\
      */assertSameLines(expectedPsiTree, parseTree)
   }
 
+  fun testLineWithoutSeparatorDoesNotSwallowTheRestOfTheFile() {
+    // A free-text line (several words, no '=') used to make the parser give up, turning everything after it into
+    // one error element (#562). It must stay a local error and the following properties and sections must parse.
+    val sourceCode = "[Service]\nNice=abc\nthis line has no equals\nNice=def\n[Unit]\nDescription=x\n"
+
+    val file = createPsiFile("a", sourceCode)
+    ensureParsed(file)
+    TestCase.assertEquals(sourceCode, file.text)
+
+    val sections = PsiTreeUtil.getChildrenOfTypeAsList(file, UnitFileSectionGroups::class.java)
+    TestCase.assertEquals(listOf("[Service]", "[Unit]"), sections.map { it.sectionName.let { n -> "[$n]" } })
+
+    val properties = PsiTreeUtil.findChildrenOfType(file, UnitFileProperty::class.java).map { it.key to it.valueText }
+    TestCase.assertEquals(listOf("Nice" to "abc", "this" to null, "Nice" to "def", "Description" to "x"), properties)
+
+    val errors = PsiTreeUtil.findChildrenOfType(file, PsiErrorElement::class.java)
+    TestCase.assertEquals(1, errors.size)
+    TestCase.assertTrue(errors.first().errorDescription.contains("key-value separator"))
+  }
+
+  fun testLineWithoutSeparatorBeforeFirstSectionDoesNotSwallowTheRestOfTheFile() {
+    val sourceCode = "some free text here\n[Service]\nNice=abc\n"
+
+    val file = createPsiFile("a", sourceCode)
+    ensureParsed(file)
+
+    val properties = PsiTreeUtil.findChildrenOfType(file, UnitFileProperty::class.java).map { it.key to it.valueText }
+    TestCase.assertEquals(listOf("some" to null, "Nice" to "abc"), properties)
+    TestCase.assertEquals(1, PsiTreeUtil.getChildrenOfTypeAsList(file, UnitFileSectionGroups::class.java).size)
+  }
+
   /**
    * Converts the source code supplied as an argument to a parse tree.
    *