Merge pull request #3554 from square/bquenaudon.2026-03-23.parsing

Read quoted string when expecting an import

Author: oldergod

wire-schema/src/commonMain/kotlin/com/squareup/wire/schema/internal/parser/ProtoParser.kt

@@ -115,10 +115,15 @@ class ProtoParser internal constructor(
       }
 
       label == "import" && context.permitsImport() -> {
-        when (val importString = reader.readString()) {
-          "weak" -> weakImports.add(reader.readString())
-          "public" -> publicImports.add(reader.readString())
-          else -> imports.add(importString)
+        val peeked = reader.peekChar()
+        if (peeked == '"' || peeked == '\'') {
+          imports.add(reader.readQuotedString())
+        } else {
+          when (reader.readString()) {
+            "weak" -> weakImports.add(reader.readQuotedString())
+            "public" -> publicImports.add(reader.readQuotedString())
+            else -> throw reader.unexpected("expected quoted string", location)
+          }
         }
         reader.require(';')
         null

wire-schema/src/commonMain/kotlin/com/squareup/wire/schema/internal/parser/SyntaxReader.kt

@@ -52,6 +52,7 @@ class SyntaxReader(
     return data[pos]
   }
 
+  /** Note that although the name suggests otherwise, this does consume the char if it finds it. */
   fun peekChar(c: Char): Boolean {
     return when (peekChar()) {
       c -> {
@@ -79,7 +80,7 @@ class SyntaxReader(
 
   fun readQuotedString(): String {
     var startQuote = readChar()
-    check(startQuote == '"' || startQuote == '\'')
+    expect(startQuote == '"' || startQuote == '\'') { "expected quoted string" }
     val result = StringBuilder()
     while (pos < data.size) {
       var c = data[pos++]

wire-schema/src/commonTest/kotlin/com/squareup/wire/schema/internal/parser/ProtoParserTest.kt

@@ -19,8 +19,8 @@ import assertk.assertThat
 import assertk.assertions.containsOnly
 import assertk.assertions.hasMessage
 import assertk.assertions.isEqualTo
+import assertk.assertions.isInstanceOf
 import assertk.assertions.isNull
-import assertk.assertions.message
 import assertk.assertions.messageContains
 import com.squareup.wire.Syntax.PROTO_2
 import com.squareup.wire.Syntax.PROTO_3
@@ -32,6 +32,7 @@ import com.squareup.wire.schema.internal.MAX_TAG_VALUE
 import com.squareup.wire.schema.internal.parser.OptionElement.Kind
 import com.squareup.wire.schema.internal.parser.OptionElement.OptionPrimitive
 import kotlin.test.Test
+import kotlin.test.assertFails
 import kotlin.test.fail
 
 class ProtoParserTest {
@@ -1500,6 +1501,26 @@ class ProtoParserTest {
     assertThat(ProtoParser.parse(location, proto)).isEqualTo(expected)
   }
 
+  @Test
+  fun unquotedImportThrows() {
+    val expected = assertFails {
+      ProtoParser.parse(location, "import src/test/resources/unittest_import.proto;\n")
+    }
+    assertThat(expected).isInstanceOf<IllegalStateException>().hasMessage(
+      "Syntax error in file.proto:1:1: expected quoted string",
+    )
+  }
+
+  @Test
+  fun unquotedWeakImportThrows() {
+    val expected = assertFails {
+      ProtoParser.parse(location, "import weak src/test/resources/unittest_import.proto;\n")
+    }
+    assertThat(expected).isInstanceOf<IllegalStateException>().hasMessage(
+      "Syntax error in file.proto:1:14: expected quoted string",
+    )
+  }
+
   @Test
   fun extend() {
     val proto = """