feat: add duplicate protection for JSON 5 files

Author: ashleyhindle

src/Install/Mcp/FileWriter.php

@@ -101,11 +101,18 @@ protected function injectIntoExistingConfigKey(string $content, array $matches):
             return false;
         }
 
+        // Filter out servers that already exist
+        $serversToAdd = $this->filterExistingServers($content, $openBracePos, $closeBracePos);
+
+        if (empty($serversToAdd)) {
+            return true;
+        }
+
         // Detect indentation from surrounding content
         $indentLength = $this->detectIndentation($content, $closeBracePos);
 
         $serverJsonParts = [];
-        foreach ($this->serversToAdd as $key => $serverConfig) {
+        foreach ($serversToAdd as $key => $serverConfig) {
             $serverJsonParts[] = $this->generateServerJson($key, $serverConfig, $indentLength);
         }
         $serversJson = implode(','."\n", $serverJsonParts);
@@ -130,6 +137,28 @@ protected function injectIntoExistingConfigKey(string $content, array $matches):
         return $this->writeFile($newContent);
     }
 
+    protected function filterExistingServers(string $content, int $openBracePos, int $closeBracePos): array
+    {
+        $configContent = substr($content, $openBracePos + 1, $closeBracePos - $openBracePos - 1);
+        $filteredServers = [];
+
+        foreach ($this->serversToAdd as $key => $serverConfig) {
+            if (! $this->serverExistsInContent($configContent, $key)) {
+                $filteredServers[$key] = $serverConfig;
+            }
+        }
+
+        return $filteredServers;
+    }
+
+    protected function serverExistsInContent(string $content, string $serverKey): bool
+    {
+        $quotedPattern = '/["\']'.preg_quote($serverKey, '/').'["\']\\s*:/';
+        $unquotedPattern = '/(?<=^|\\s|,|{)'.preg_quote($serverKey, '/').'\\s*:/m';
+
+        return preg_match($quotedPattern, $content) || preg_match($unquotedPattern, $content);
+    }
+
     protected function injectNewConfigKey(string $content): bool
     {
         $openBracePos = strpos($content, '{');

tests/Unit/Install/Mcp/FileWriterTest.php

@@ -282,6 +282,60 @@
     expect($writtenContent)->toContain('// Ooo, pretty cool'); // Inline comments preserved
 });
 
+test('injecting twice into existing JSON 5 doesn\'t cause duplicates', function () {
+    $capturedContent = '';
+
+    File::clearResolvedInstances();
+    File::partialMock();
+
+    File::shouldReceive('ensureDirectoryExists')->once();
+    File::shouldReceive('exists')->andReturn(true);
+    File::shouldReceive('size')->andReturn(1000);
+    File::shouldReceive('get')->andReturn(fixture('mcp.json5'));
+    File::shouldReceive('put')
+        ->with(
+            Mockery::capture($capturedPath),
+            Mockery::capture($capturedContent)
+        )
+        ->andReturn(true);
+
+    $result = (new FileWriter('/path/to/mcp.json'))
+        ->configKey('servers') // mcp.json5 uses "servers" not "mcpServers"
+        ->addServer('boost', 'php', ['artisan', 'boost:mcp'])
+        ->save();
+
+    $boostCounts = substr_count($capturedContent, '"boost"');
+    expect($result)->toBeTrue();
+    expect($boostCounts)->toBe(1);
+    expect($capturedContent)->toContain('"boost"'); // New server added
+    expect($capturedContent)->toContain('mysql'); // Existing server preserved
+    expect($capturedContent)->toContain('laravel-boost'); // Existing server preserved
+    expect($capturedContent)->toContain('// Here are comments within my JSON'); // Comments preserved
+    expect($capturedContent)->toContain('// Ooo, pretty cool'); // Inline comments preserved
+
+    $newContent = $capturedContent;
+
+    File::clearResolvedInstances();
+    File::partialMock();
+
+    File::shouldReceive('ensureDirectoryExists')->once();
+    File::shouldReceive('exists')->andReturn(true);
+    File::shouldReceive('size')->andReturn(1000);
+    File::shouldReceive('get')->andReturn($newContent);
+
+    $result = (new FileWriter('/path/to/mcp.json'))
+        ->configKey('servers')
+        ->addServer('boost', 'php', ['artisan', 'boost:mcp'])
+        ->save();
+
+    // Second call should return true but not modify the file since boost already exists
+    expect($result)->toBeTrue();
+
+    // We should still have only one instance of the boost MCP server
+    $boostCounts = substr_count($capturedContent, '"boost"');
+    expect($boostCounts)->toBe(1);
+});
+
 test('injects into empty configKey object', function () {
     $writtenContent = '';
 
@@ -364,35 +418,35 @@ function newFileServerConfigurations(): array
 {
     return [
         'single server without args or env' => [
-            'configKey' => 'servers',
-            'servers' => [
+            'servers',
+            [
                 'im-new-here' => ['command' => './start-mcp'],
             ],
-            'expectedJson' => '{"servers":{"im-new-here":{"command":"./start-mcp"}}}',
+            '{"servers":{"im-new-here":{"command":"./start-mcp"}}}',
         ],
         'single server with args' => [
-            'configKey' => 'mcpServers',
-            'servers' => [
+            'mcpServers',
+            [
                 'boost' => [
                     'command' => 'php',
                     'args' => ['artisan', 'boost:mcp'],
                 ],
             ],
-            'expectedJson' => '{"mcpServers":{"boost":{"command":"php","args":["artisan","boost:mcp"]}}}',
+            '{"mcpServers":{"boost":{"command":"php","args":["artisan","boost:mcp"]}}}',
         ],
         'single server with env' => [
-            'configKey' => 'servers',
-            'servers' => [
+            'servers',
+            [
                 'mysql' => [
                     'command' => 'npx',
                     'env' => ['DB_HOST' => 'localhost', 'DB_PORT' => '3306'],
                 ],
             ],
-            'expectedJson' => '{"servers":{"mysql":{"command":"npx","env":{"DB_HOST":"localhost","DB_PORT":"3306"}}}}',
+            '{"servers":{"mysql":{"command":"npx","env":{"DB_HOST":"localhost","DB_PORT":"3306"}}}}',
         ],
         'multiple servers mixed' => [
-            'configKey' => 'mcpServers',
-            'servers' => [
+            'mcpServers',
+            [
                 'boost' => [
                     'command' => 'php',
                     'args' => ['artisan', 'boost:mcp'],
@@ -403,14 +457,14 @@ function newFileServerConfigurations(): array
                     'env' => ['DB_HOST' => 'localhost'],
                 ],
             ],
-            'expectedJson' => '{"mcpServers":{"boost":{"command":"php","args":["artisan","boost:mcp"]},"mysql":{"command":"npx","args":["@benborla29/mcp-server-mysql"],"env":{"DB_HOST":"localhost"}}}}',
+            '{"mcpServers":{"boost":{"command":"php","args":["artisan","boost:mcp"]},"mysql":{"command":"npx","args":["@benborla29/mcp-server-mysql"],"env":{"DB_HOST":"localhost"}}}}',
         ],
         'custom config key' => [
-            'configKey' => 'customKey',
-            'servers' => [
+            'customKey',
+            [
                 'test' => ['command' => 'test-cmd'],
             ],
-            'expectedJson' => '{"customKey":{"test":{"command":"test-cmd"}}}',
+            '{"customKey":{"test":{"command":"test-cmd"}}}',
         ],
     ];
 }
@@ -419,49 +473,49 @@ function commentDetectionCases(): array
 {
     return [
         'plain JSON no comments' => [
-            'content' => '{"servers": {"test": {"command": "npm"}}}',
-            'expected' => false,
-            'description' => 'Plain JSON should return false',
+            '{"servers": {"test": {"command": "npm"}}}',
+            false,
+            'Plain JSON should return false',
         ],
         'JSON with comments in strings' => [
-            'content' => '{"exampleCode": "// here is the example code\n<?php", "url": "https://example.com/path"}',
-            'expected' => false,
-            'description' => 'Comments inside strings should not be detected as real comments',
+            '{"exampleCode": "// here is the example code\n<?php", "url": "https://example.com/path"}',
+            false,
+            'Comments inside strings should not be detected as real comments',
         ],
         'JSON5 with real line comments' => [
-            'content' => '{"servers": {"test": "value"} // this is a real comment}',
-            'expected' => true,
-            'description' => 'Real JSON5 line comments should be detected',
+            '{"servers": {"test": "value"} // this is a real comment}',
+            true,
+            'Real JSON5 line comments should be detected',
         ],
         'JSON5 with comment at start of line' => [
-            'content' => '{\n  // This is a comment\n  "servers": {}\n}',
-            'expected' => true,
-            'description' => 'Line comments at start should be detected',
+            '{\n  // This is a comment\n  "servers": {}\n}',
+            true,
+            'Line comments at start should be detected',
         ],
         'complex string with escaped quotes' => [
-            'content' => '{"code": "console.log(\\"// not a comment\\");", "other": "value"}',
-            'expected' => false,
-            'description' => 'Comments in strings with escaped quotes should not be detected',
+            '{"code": "console.log(\\"// not a comment\\");", "other": "value"}',
+            false,
+            'Comments in strings with escaped quotes should not be detected',
         ],
         'multiple comments in strings' => [
-            'content' => '{"example1": "// comment 1", "example2": "some // comment 2 here"}',
-            'expected' => false,
-            'description' => 'Multiple comments in different strings should not be detected',
+            '{"example1": "// comment 1", "example2": "some // comment 2 here"}',
+            false,
+            'Multiple comments in different strings should not be detected',
         ],
         'mixed real and string comments' => [
-            'content' => '{"example": "// fake comment"} // real comment',
-            'expected' => true,
-            'description' => 'Should detect real comment even when fake ones exist in strings',
+            '{"example": "// fake comment"} // real comment',
+            true,
+            'Should detect real comment even when fake ones exist in strings',
         ],
         'empty string' => [
-            'content' => '',
-            'expected' => false,
-            'description' => 'Empty string should return false',
+            '',
+            false,
+            'Empty string should return false',
         ],
         'single slash not comment' => [
-            'content' => '{"path": "/usr/bin/test"}',
-            'expected' => false,
-            'description' => 'Single slash should not be detected as comment',
+            '{"path": "/usr/bin/test"}',
+            false,
+            'Single slash should not be detected as comment',
         ],
     ];
 }
@@ -470,39 +524,39 @@ function trailingCommaCases(): array
 {
     return [
         'valid JSON no trailing comma' => [
-            'content' => '{"servers": {"test": "value"}}',
-            'expected' => true,
-            'description' => 'Valid JSON should return true (is plain JSON)',
+            '{"servers": {"test": "value"}}',
+            true,
+            'Valid JSON should return true (is plain JSON)',
         ],
         'trailing comma in object same line' => [
-            'content' => '{"servers": {"test": "value",}}',
-            'expected' => false,
-            'description' => 'Trailing comma in object should return false (is JSON5)',
+            '{"servers": {"test": "value",}}',
+            false,
+            'Trailing comma in object should return false (is JSON5)',
         ],
         'trailing comma in array same line' => [
-            'content' => '{"items": ["a", "b", "c",]}',
-            'expected' => false,
-            'description' => 'Trailing comma in array should return false (is JSON5)',
+            '{"items": ["a", "b", "c",]}',
+            false,
+            'Trailing comma in array should return false (is JSON5)',
         ],
         'trailing comma across newlines in object' => [
-            'content' => "{\n  \"servers\": {\n    \"test\": \"value\",\n  }\n}",
-            'expected' => false,
-            'description' => 'Trailing comma across newlines in object should be detected',
+            "{\n  \"servers\": {\n    \"test\": \"value\",\n  }\n}",
+            false,
+            'Trailing comma across newlines in object should be detected',
         ],
         'trailing comma across newlines in array' => [
-            'content' => "{\n  \"items\": [\n    \"a\",\n    \"b\",\n  ]\n}",
-            'expected' => false,
-            'description' => 'Trailing comma across newlines in array should be detected',
+            "{\n  \"items\": [\n    \"a\",\n    \"b\",\n  ]\n}",
+            false,
+            'Trailing comma across newlines in array should be detected',
         ],
         'trailing comma with tabs and spaces' => [
-            'content' => "{\n  \"test\": \"value\",\t \n}",
-            'expected' => false,
-            'description' => 'Trailing comma with mixed whitespace should be detected',
+            "{\n  \"test\": \"value\",\t \n}",
+            false,
+            'Trailing comma with mixed whitespace should be detected',
         ],
         'comma in string not trailing' => [
-            'content' => '{"example": "value,", "other": "test"}',
-            'expected' => true,
-            'description' => 'Comma inside string should not be detected as trailing',
+            '{"example": "value,", "other": "test"}',
+            true,
+            'Comma inside string should not be detected as trailing',
         ],
     ];
 }
@@ -511,52 +565,52 @@ function indentationDetectionCases(): array
 {
     return [
         'mcp.json5 servers indentation' => [
-            'content' => "{\n    // Here are comments within my JSON\n    \"servers\": {\n        \"mysql\": {\n            \"command\": \"npx\"\n        },\n        \"laravel-boost\": {\n            \"command\": \"php\"\n        }\n    },\n    \"inputs\": []\n}",
-            'position' => 200, // Position near end of servers block
-            'expected' => 8,
-            'description' => 'Should detect 8 spaces for server definitions in mcp.json5',
+            "{\n    // Here are comments within my JSON\n    \"servers\": {\n        \"mysql\": {\n            \"command\": \"npx\"\n        },\n        \"laravel-boost\": {\n            \"command\": \"php\"\n        }\n    },\n    \"inputs\": []\n}",
+            200, // Position near end of servers block
+            8,
+            'Should detect 8 spaces for server definitions in mcp.json5',
         ],
         'nested object with 4-space base indent' => [
-            'content' => "{\n    \"config\": {\n        \"server1\": {\n            \"command\": \"test\"\n        }\n    }\n}",
-            'position' => 80,
-            'expected' => 8,
-            'description' => 'Should detect 8 spaces for nested server definitions',
+            "{\n    \"config\": {\n        \"server1\": {\n            \"command\": \"test\"\n        }\n    }\n}",
+            80,
+            8,
+            'Should detect 8 spaces for nested server definitions',
         ],
         'no previous server definitions' => [
-            'content' => "{\n    \"inputs\": []\n}",
-            'position' => 20,
-            'expected' => 8,
-            'description' => 'Should fallback to 8 spaces when no server definitions found',
+            "{\n    \"inputs\": []\n}",
+            20,
+            8,
+            'Should fallback to 8 spaces when no server definitions found',
         ],
         'deeper nesting with 2-space indent' => [
-            'content' => "{\n  \"config\": {\n    \"servers\": {\n      \"mysql\": {\n        \"command\": \"test\"\n      }\n    }\n  }\n}",
-            'position' => 80,
-            'expected' => 6,
-            'description' => 'Should detect correct indentation in deeply nested structures',
+            "{\n  \"config\": {\n    \"servers\": {\n      \"mysql\": {\n        \"command\": \"test\"\n      }\n    }\n  }\n}",
+            80,
+            6,
+            'Should detect correct indentation in deeply nested structures',
         ],
         'single server definition at root level' => [
-            'content' => "{\n\"mysql\": {\n  \"command\": \"npx\"\n}\n}",
-            'position' => 30,
-            'expected' => 0,
-            'description' => 'Should detect no indentation for root-level server definitions',
+            "{\n\"mysql\": {\n  \"command\": \"npx\"\n}\n}",
+            30,
+            0,
+            'Should detect no indentation for root-level server definitions',
         ],
         'multiple server definitions with consistent indentation' => [
-            'content' => "{\n    \"servers\": {\n        \"mysql\": {\n            \"command\": \"npx\"\n        },\n        \"postgres\": {\n            \"command\": \"pg\"\n        }\n    }\n}",
-            'position' => 150,
-            'expected' => 8,
-            'description' => 'Should consistently detect indentation across multiple servers',
+            "{\n    \"servers\": {\n        \"mysql\": {\n            \"command\": \"npx\"\n        },\n        \"postgres\": {\n            \"command\": \"pg\"\n        }\n    }\n}",
+            150,
+            8,
+            'Should consistently detect indentation across multiple servers',
         ],
         'server definition with comments' => [
-            'content' => "{\n    // Comment here\n    \"servers\": {\n        \"mysql\": { // inline comment\n            \"command\": \"npx\"\n        }\n    }\n}",
-            'position' => 120,
-            'expected' => 8,
-            'description' => 'Should detect indentation correctly when comments are present',
+            "{\n    // Comment here\n    \"servers\": {\n        \"mysql\": { // inline comment\n            \"command\": \"npx\"\n        }\n    }\n}",
+            120,
+            8,
+            'Should detect indentation correctly when comments are present',
         ],
         'empty content' => [
-            'content' => '',
-            'position' => 0,
-            'expected' => 8,
-            'description' => 'Should fallback to 8 spaces for empty content',
+            '',
+            0,
+            8,
+            'Should fallback to 8 spaces for empty content',
         ],
     ];
 }