diff --git a/src/main/java/com/android/tools/metalava/Driver.kt b/src/main/java/com/android/tools/metalava/Driver.kt
index 2c5586f..47dac44 100644
--- a/src/main/java/com/android/tools/metalava/Driver.kt
+++ b/src/main/java/com/android/tools/metalava/Driver.kt
@@ -67,6 +67,8 @@
 const val PROGRAM_NAME = "metalava"
 const val HELP_PROLOGUE = "$PROGRAM_NAME extracts metadata from source code to generate artifacts such as the " +
     "signature files, the SDK stub files, external annotations etc."
+const val PACKAGE_HTML = "package.html"
+const val OVERVIEW_HTML = "overview.html"
 
 @Suppress("PropertyName") // Can't mark const because trimIndent() :-(
 val BANNER: String = """
@@ -904,7 +906,7 @@
     val rootDir = sourceRoots.firstOrNull() ?: sourcePath.firstOrNull() ?: File("").canonicalFile
 
     val units = Extractor.createUnitsForFiles(environment.ideaProject, sources)
-    val packageDocs = gatherHiddenPackagesFromJavaDocs(sourcePath)
+    val packageDocs = gatherPackageJavadoc(sources, sourceRoots)
 
     val codebase = PsiBasedCodebase(rootDir, description)
     codebase.initialize(environment, units, packageDocs)
@@ -1118,9 +1120,12 @@
                 addSourceFiles(list, child)
             }
         }
-    } else {
-        if (file.isFile && (file.path.endsWith(DOT_JAVA) || file.path.endsWith(DOT_KT))) {
-            list.add(file)
+    } else if (file.isFile) {
+        when {
+            file.name.endsWith(DOT_JAVA) ||
+            file.name.endsWith(DOT_KT) ||
+            file.name.equals(PACKAGE_HTML) ||
+            file.name.equals(OVERVIEW_HTML) -> list.add(file)
         }
     }
 }
@@ -1137,94 +1142,44 @@
     return sources.sortedWith(compareBy { it.name })
 }
 
-private fun addHiddenPackages(
-    packageToDoc: MutableMap<String, String>,
-    packageToOverview: MutableMap<String, String>,
-    hiddenPackages: MutableSet<String>,
-    file: File,
-    pkg: String
-) {
-    if (FileReadSandbox.isDirectory(file)) {
-        if (skippableDirectory(file)) {
-            return
-        }
-        // Ignore symbolic links during traversal
-        if (java.nio.file.Files.isSymbolicLink(file.toPath())) {
-            reporter.report(
-                Issues.IGNORING_SYMLINK, file,
-                "Ignoring symlink during package.html discovery directory traversal"
-            )
-            return
-        }
-        val files = file.listFiles()
-        if (files != null) {
-            for (child in files) {
-                var subPkg =
-                    if (FileReadSandbox.isDirectory(child))
-                        if (pkg.isEmpty())
-                            child.name
-                        else pkg + "." + child.name
-                    else pkg
-
-                if (subPkg.endsWith("src.main.java")) {
-                    // It looks like the source path was incorrectly configured; make corrections here
-                    // to ensure that we map the package.html files to the real packages.
-                    subPkg = ""
-                }
-
-                addHiddenPackages(packageToDoc, packageToOverview, hiddenPackages, child, subPkg)
-            }
-        }
-    } else if (FileReadSandbox.isFile(file)) {
+private fun gatherPackageJavadoc(sources: List<File>, sourceRoots: List<File>): PackageDocs {
+    val packageComments = HashMap<String, String>(100)
+    val overviewHtml = HashMap<String, String>(10)
+    val hiddenPackages = HashSet<String>(100)
+    val sortedSourceRoots = sourceRoots.sortedBy { -it.name.length }
+    for (file in sources) {
         var javadoc = false
         val map = when (file.name) {
-            "package.html" -> {
-                javadoc = true; packageToDoc
+            PACKAGE_HTML -> {
+                javadoc = true; packageComments
             }
-            "overview.html" -> {
-                packageToOverview
+            OVERVIEW_HTML -> {
+                overviewHtml
             }
-            else -> return
+            else -> continue
         }
         var contents = Files.asCharSource(file, UTF_8).read()
         if (javadoc) {
             contents = packageHtmlToJavadoc(contents)
         }
 
-        var realPkg = pkg
-        // Sanity check the package; it's computed from the directory name
-        // relative to the source path, but if the real source path isn't
-        // passed in (and is instead some directory containing the source path)
-        // then we compute the wrong package here. Instead, look for an adjacent
-        // java class and pick the package from it
-        for (sibling in file.parentFile?.listFiles() ?: emptyArray()) {
-            if (sibling.path.endsWith(DOT_JAVA)) {
-                val javaPkg = ClassName(sibling.readText()).packageName
-                if (javaPkg != null) {
-                    realPkg = javaPkg
-                    break
-                }
-            }
+        // Figure out the package: if there is a java file in the same directory, get the package
+        // name from the java file. Otherwise, guess from the directory path + source roots.
+        // NOTE: This causes metalava to read files other than the ones explicitly passed to it.
+        var pkg = file.parentFile?.listFiles()
+            ?.filter { it.name.endsWith(DOT_JAVA) }
+            ?.asSequence()?.mapNotNull { findPackage(it) }
+            ?.firstOrNull()
+        if (pkg == null) {
+            // Strip the longest prefix source root.
+            val prefix = sortedSourceRoots.firstOrNull { file.startsWith(it) }?.path ?: ""
+            pkg = file.parentFile.path.substring(prefix.length).trim('/').replace("/", ".")
         }
-
-        map[realPkg] = contents
+        map[pkg] = contents
         if (contents.contains("@hide")) {
-            hiddenPackages.add(realPkg)
+            hiddenPackages.add(pkg)
         }
     }
-}
-
-private fun gatherHiddenPackagesFromJavaDocs(sourcePath: List<File>): PackageDocs {
-    val packageComments = HashMap<String, String>(100)
-    val overviewHtml = HashMap<String, String>(10)
-    val hiddenPackages = HashSet<String>(100)
-    for (file in sourcePath) {
-        if (file.path.isBlank()) {
-            // Ignoring empty paths, which means "no source path search". Use "." for current directory.
-            continue
-        }
-        addHiddenPackages(packageComments, overviewHtml, hiddenPackages, file, "")
-    }
 
     return PackageDocs(packageComments, overviewHtml, hiddenPackages)
 }
diff --git a/src/test/java/com/android/tools/metalava/DriverTest.kt b/src/test/java/com/android/tools/metalava/DriverTest.kt
index 7542c0f..9f45870 100644
--- a/src/test/java/com/android/tools/metalava/DriverTest.kt
+++ b/src/test/java/com/android/tools/metalava/DriverTest.kt
@@ -1380,8 +1380,9 @@
                     val actualContents = readFile(actual, stripBlankLines, trim)
                     assertEquals(expected.contents, actualContents)
                 } else {
+                    val existing = stubsDir.walkTopDown().filter { it.isFile }.map { it.path }.joinToString("\n  ")
                     throw FileNotFoundException(
-                        "Could not find a generated stub for ${expected.targetRelativePath}"
+                        "Could not find a generated stub for ${expected.targetRelativePath}. Found these files: \n  $existing"
                     )
                 }
             }
diff --git a/src/test/java/com/android/tools/metalava/SymlinkTest.kt b/src/test/java/com/android/tools/metalava/SymlinkTest.kt
index c2a222b..16187ff 100644
--- a/src/test/java/com/android/tools/metalava/SymlinkTest.kt
+++ b/src/test/java/com/android/tools/metalava/SymlinkTest.kt
@@ -16,7 +16,6 @@
 
 package com.android.tools.metalava
 
-import com.android.tools.lint.checks.infrastructure.TestFiles.source
 import org.junit.Test
 import java.io.File
 
@@ -38,9 +37,20 @@
         val before = System.getProperty("user.dir")
         try {
             check(
-                expectedIssues = "TESTROOT/src/test/pkg/sub1/sub2/sub3: info: Ignoring symlink during package.html discovery directory traversal [IgnoringSymlink]",
-                sourceFiles = arrayOf(
-                    java(
+                expectedIssues = "TESTROOT/src/test/pkg/sub1/sub2/sub3: info: Ignoring symlink during source file discovery directory traversal [IgnoringSymlink]",
+                projectSetup = { dir ->
+                    // Add a symlink from deep in the source tree back out to the
+                    // root, which makes a cycle
+                    val file = File(dir, "src/test/pkg/sub1/sub2")
+                    file.mkdirs()
+                    val symlink = File(file, "sub3").toPath()
+                    java.nio.file.Files.createSymbolicLink(symlink, dir.toPath())
+
+                    val git = File(file, ".git").toPath()
+                    java.nio.file.Files.createSymbolicLink(git, dir.toPath())
+
+                    // Write implicit source files to be discovered by our crawl.
+                    File(dir, "src/test/pkg/Foo.java").writeText(
                         """
                         package test.pkg;
                         import android.annotation.Nullable;
@@ -52,10 +62,8 @@
                             @Nullable public Double method2(@NonNull Double factor1, @NonNull Double factor2) { }
                             @Nullable public Double method3(@NonNull Double factor1, @NonNull Double factor2) { }
                         }
-                        """
-                    ),
-                    source(
-                        "src/test/pkg/sub1/package.html",
+                        """)
+                    File(dir, "src/test/pkg/sub1/package.html").writeText(
                         """
                         <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
                         <!-- not a body tag: <body> -->
@@ -67,21 +75,7 @@
                         Another line.<br>
                         </BODY>
                         </html>
-                        """
-                    ).indented(),
-                    nonNullSource,
-                    nullableSource
-                ),
-                projectSetup = { dir ->
-                    // Add a symlink from deep in the source tree back out to the
-                    // root, which makes a cycle
-                    val file = File(dir, "src/test/pkg/sub1/sub2")
-                    file.mkdirs()
-                    val symlink = File(file, "sub3").toPath()
-                    java.nio.file.Files.createSymbolicLink(symlink, dir.toPath())
-
-                    val git = File(file, ".git").toPath()
-                    java.nio.file.Files.createSymbolicLink(git, dir.toPath())
+                        """)
                 },
                 // Empty source path: don't pick up random directory stuff
                 extraArguments = arrayOf(
@@ -113,4 +107,4 @@
             System.setProperty("user.dir", before)
         }
     }
-}
\ No newline at end of file
+}