Handle nested tables in TOML encoder

src/Encoder/ArrayToDocumentConverter.php

@@ -26,8 +26,11 @@ public function convert(array $data): Document
         $nodes = [];
         $position = new Position(1, 1, 0);
 
-        // Categorize data into root entries, tables, and table arrays
-        [$rootEntries, $tables, $tableArrays] = $this->categorizeData($data);
+        // Flatten the data structure to handle nested tables
+        $flatData = $this->flattenData($data);
+
+        // Categorize flattened data into root entries, tables, and table arrays
+        [$rootEntries, $tables, $tableArrays] = $this->categorizeData($flatData);
 
         // Root key-value pairs first
         foreach ($rootEntries as $key => $value) {
@@ -49,6 +52,65 @@ public function convert(array $data): Document
         return new Document($nodes, $position);
     }
 
+    /**
+     * Flattens nested array structure into dotted keys.
+     *
+     * Example:
+     * ['github' => ['token' => ['key' => 'val']]]
+     * becomes:
+     * ['github.token' => ['key' => 'val']]
+     *
+     * @param array<string, mixed> $data
+     * @param string $prefix
+     * @return array<string, mixed>
+     */
+    private function flattenData(array $data, string $prefix = ''): array
+    {
+        $result = [];
+
+        foreach ($data as $key => $value) {
+            if (!\is_string($key)) {
+                throw new \InvalidArgumentException('TOML keys must be strings, got: ' . \get_debug_type($key));
+            }
+
+            $fullKey = $prefix === '' ? $key : $prefix . '.' . $key;
+
+            if (!\is_array($value)) {
+                // Scalar value
+                $result[$fullKey] = $value;
+            } elseif ($this->isTableArray($value)) {
+                // Table array - keep as is
+                $result[$fullKey] = $value;
+            } elseif ($this->isAssociativeArray($value)) {
+                // Check if this table has only scalar/array values (leaf table)
+                // or if it has nested tables
+                $hasNestedTables = false;
+                foreach ($value as $subValue) {
+                    if (\is_array($subValue) && $this->isAssociativeArray($subValue) && !$this->isTableArray($subValue)) {
+                        $hasNestedTables = true;
+                        break;
+                    }
+                }
+
+                if ($hasNestedTables) {
+                    // Recursively flatten nested tables
+                    $flattened = $this->flattenData($value, $fullKey);
+                    foreach ($flattened as $flatKey => $flatValue) {
+                        $result[$flatKey] = $flatValue;
+                    }
+                } else {
+                    // Leaf table - keep as is
+                    $result[$fullKey] = $value;
+                }
+            } else {
+                // Simple array (list of scalars)
+                $result[$fullKey] = $value;
+            }
+        }
+
+        return $result;
+    }
+
     /**
      * Categorizes data into root entries, tables, and table arrays.
      *
@@ -102,18 +164,14 @@ private function createTable(string $name, array $data): Table
         $entries = [];
         $position = new Position(0, 0, 0);
 
-        // Categorize table data
-        [$rootEntries, $nestedTables, $nestedTableArrays] = $this->categorizeData($data);
-
-        // Add root entries
-        foreach ($rootEntries as $key => $value) {
+        // Add all entries (data is already flattened, so no nested tables here)
+        foreach ($data as $key => $value) {
+            if (!\is_string($key)) {
+                throw new \InvalidArgumentException('TOML keys must be strings, got: ' . \get_debug_type($key));
+            }
             $entries[] = $this->createEntry($key, $value);
         }
 
-        // Nested tables and table arrays will be handled at document level
-        // For now, we only handle simple table entries
-        // TODO: Handle nested structures properly
-
         return new Table($keyNode, $entries, null, $position);
     }
 

tests/Unit/TomlEncodeTest.php

@@ -40,6 +40,11 @@ public static function provideRoundTripData(): \Generator
             ['str' => 'text', 'int' => 42, 'float' => 3.14, 'bool' => true],
         ];
     }
+
+    public static function provideFixtureFiles(): \Generator
+    {
+        yield 'roadrunner config' => ['rr.toml'];
+    }
     // ============================================
     // Basic Encoding Tests
     // ============================================
@@ -345,4 +350,35 @@ public function testEncodeStringWithNewlinesProducesMultilineString(): void
         $lines = \explode("\n", $toml);
         self::assertGreaterThan(3, \count($lines), 'Should have multiple lines');
     }
+
+    // ============================================
+    // Fixture-based Round-Trip Tests
+    // ============================================
+
+    #[DataProvider('provideFixtureFiles')]
+    public function testEncodeFixtureFileRoundTrip(string $filename): void
+    {
+        // Arrange
+        $fixturePath = __DIR__ . '/fixtures/' . $filename;
+        $tomlContent = \file_get_contents($fixturePath);
+        self::assertNotFalse($tomlContent, "Failed to read fixture file: {$filename}");
+
+        // Parse original TOML to array
+        $originalArray = Toml::parseToArray($tomlContent);
+
+        // Act
+        // Encode array back to TOML string
+        $encodedToml = (string) Toml::encode($originalArray);
+
+        // Parse the encoded TOML back to array
+        $reEncodedArray = Toml::parseToArray($encodedToml);
+
+        // Assert
+        // The re-encoded array should match the original parsed array
+        self::assertEquals(
+            $originalArray,
+            $reEncodedArray,
+            "Round-trip encoding/decoding changed the data structure for {$filename}"
+        );
+    }
 }

tests/Unit/fixtures/rr.toml

@@ -0,0 +1,34 @@
+[roadrunner]
+ref = "v2025.1.1"
+
+[log]
+level = "info"
+mode = "production"
+
+[github.token]
+token = "123adryen7y123"
+
+[github.plugins.temporal]
+ref = "v5.7.0"
+owner = "temporalio"
+repository = "roadrunner-temporal"
+
+[github.plugins.kv]
+ref = "v5.2.8"
+owner = "roadrunner-server"
+repository = "kv"
+
+[github.plugins.logger]
+ref = "v5.1.8"
+owner = "roadrunner-server"
+repository = "logger"
+
+[github.plugins.server]
+ref = "v5.2.9"
+owner = "roadrunner-server"
+repository = "server"
+
+[github.plugins.rpc]
+ref = "v5.1.8"
+owner = "roadrunner-server"
+repository = "rpc"