Check type of string in config

2 files changed, 41 insertions, 5 deletions

diff --git a/src/main/java/org/shedlang/compiler/config/toml/TomlTableWithSource.java b/src/main/java/org/shedlang/compiler/config/toml/TomlTableWithSource.java
index e11925f6..3e560d63 100644
--- a/src/main/java/org/shedlang/compiler/config/toml/TomlTableWithSource.java
+++ b/src/main/java/org/shedlang/compiler/config/toml/TomlTableWithSource.java
@@ -107,7 +107,8 @@ public record TomlTableWithSource(
     }
 
     public String getString(String key) {
-        var value = table.getString(key);
+        var value = table.get(key);
+        var valuePosition = table.inputPositionOf(key);
 
         if (value == null) {
             throw new ConfigError(
@@ -116,6 +117,15 @@ public record TomlTableWithSource(
             );
         }
 
-        return value;
+        if (value instanceof String valueString) {
+            return valueString;
+        }
+
+        throw new UnexpectedTypeConfigError(
+            path.plusKey(key),
+            "a string",
+            value.getClass(),
+            TomlSource.sourceAtTomlPosition(fullSource, valuePosition)
+        );
     }
 }
diff --git a/src/test/java/org/shedlang/compiler/config/BinConfigTests.java b/src/test/java/org/shedlang/compiler/config/BinConfigTests.java
index cbe8ee01..dc61f023 100644
--- a/src/test/java/org/shedlang/compiler/config/BinConfigTests.java
+++ b/src/test/java/org/shedlang/compiler/config/BinConfigTests.java
@@ -39,6 +39,31 @@ public class BinConfigTests {
     }
 
     @Test
+    public void whenBinConfigIsNotStringThenErrorIsThrown() {
+        var source = Sources.string("""
+            [[shed.bins]]
+            name = "one"
+            main-namespace = "One"
+            
+            [[shed.bins]]
+            name = true
+            main-namespace = "Two"
+            """);
+
+        var error = assertThrows(
+            ConfigError.class,
+            () -> ProjectConfig.fromToml(PROJECT_PATH, TomlTableWithSource.parse(source))
+        );
+
+        assertThat(error.getMessage(), equalTo("Expected shed.bins[1].name to be a string, but was Boolean"));
+        assertThat(error.source().describe(), equalTo("""
+            <string>:6:1
+            name = true
+            ^"""
+        ));
+    }
+
+    @Test
     public void whenBinConfigIsMissingMainNamespaceThenErrorIsThrown() {
         var source = Sources.string("""
             [[shed.bins]]
@@ -47,6 +72,7 @@ public class BinConfigTests {
             
             [[shed.bins]]
             name = "two"
+            main-namespace = true
             """);
 
         var error = assertThrows(
@@ -54,10 +80,10 @@ public class BinConfigTests {
             () -> ProjectConfig.fromToml(PROJECT_PATH, TomlTableWithSource.parse(source))
         );
 
-        assertThat(error.getMessage(), equalTo("shed.bins[1] is missing main-namespace"));
+        assertThat(error.getMessage(), equalTo("Expected shed.bins[1].main-namespace to be a string, but was Boolean"));
         assertThat(error.source().describe(), equalTo("""
-            <string>:5:1
-            [[shed.bins]]
+            <string>:7:1
+            main-namespace = true
             ^"""
         ));
     }