Add distinct error types

ballerina/Dependencies.toml

@@ -10,7 +10,7 @@ distribution-version = "2201.12.0"
 [[package]]
 org = "ballerina"
 name = "crypto"
-version = "2.10.0"
+version = "2.10.1"
 dependencies = [
 	{org = "ballerina", name = "jballerina.java"},
 	{org = "ballerina", name = "time"}
@@ -46,7 +46,7 @@ modules = [
 [[package]]
 org = "ballerina"
 name = "data.xmldata"
-version = "1.5.2"
+version = "1.5.3"
 dependencies = [
 	{org = "ballerina", name = "jballerina.java"},
 	{org = "ballerina", name = "lang.object"}
@@ -215,7 +215,7 @@ modules = [
 [[package]]
 org = "ballerina"
 name = "observe"
-version = "1.5.0"
+version = "1.5.1"
 dependencies = [
 	{org = "ballerina", name = "jballerina.java"}
 ]
@@ -233,7 +233,7 @@ dependencies = [
 [[package]]
 org = "ballerina"
 name = "task"
-version = "2.11.0"
+version = "2.11.1"
 dependencies = [
 	{org = "ballerina", name = "jballerina.java"},
 	{org = "ballerina", name = "time"},

ballerina/error.bal

@@ -16,3 +16,23 @@
 
 # Defines the common error type for the module.
 public type Error distinct error;
+
+# Represents an error that occurs when connecting to the FTP/SFTP server.
+# This includes network failures, host unreachable, connection refused, etc.
+public type ConnectionError distinct Error;
+
+# Represents an error that occurs when a requested file or directory is not found.
+public type FileNotFoundError distinct Error;
+
+# Represents an error that occurs when attempting to create a file or directory that already exists.
+public type FileAlreadyExistsError distinct Error;
+
+# Represents an error that occurs when FTP/SFTP configuration is invalid.
+# This includes invalid port numbers, invalid regex patterns, invalid timeout values, etc.
+public type InvalidConfigError distinct Error;
+
+# Represents an error that occurs when the FTP/SFTP service is temporarily unavailable.
+# This is a transient error indicating the operation may succeed on retry.
+# Common causes include: server overload (421), connection issues (425, 426),
+# temporary file locks (450), or server-side processing errors (451).
+public type ServiceUnavailableError distinct Error;

ballerina/tests/advanced_file_selection_test.bal

@@ -65,7 +65,7 @@ function testFileAgeFilterRespectsMaxAge() returns error? {
             }
         },
         path: "/home/in/advanced/age",
-        pollingInterval: 5,
+        pollingInterval: 2,
         fileAgeFilter: {
             maxAge: 60
         },

ballerina/tests/client_endpoint_negative_test.bal

@@ -28,11 +28,11 @@ public function testConnectionWithNonExistingServer() returns error? {
         auth: {credentials: {username: "wso2", password: "wso2123"}}
     };
     Client|Error nonExistingServerClientEp = new (nonExistingServerConfig);
-    if nonExistingServerClientEp is Error {
+    test:assertTrue(nonExistingServerClientEp is ConnectionError,
+        msg = "Expected ConnectionError when connecting to non-existing server");
+    if nonExistingServerClientEp is ConnectionError {
         test:assertTrue(nonExistingServerClientEp.message().startsWith("Error while connecting to the FTP server with URL: "),
             msg = "Unexpected error when tried to connect to a non existing server. " + nonExistingServerClientEp.message());
-    } else {
-        test:assertFail(msg = "Found a non-error response when tried to connect to a non existing server.");
     }
 }
 
@@ -60,11 +60,11 @@ public function testConnectionWithInvalidConfiguration() returns error? {
 }
 public function testReadNonExistingFile() returns error? {
     stream<byte[] & readonly, io:Error?>|Error str = (<Client>clientEp)->get("/home/in/nonexisting.txt");
-    if str is Error {
+    test:assertTrue(str is FileNotFoundError,
+        msg = "Expected FileNotFoundError when reading non-existing file");
+    if str is FileNotFoundError {
         test:assertEquals(str.message(), "Failed to read file: ftp://wso2:***@127.0.0.1:21212/home/in/nonexisting.txt not found",
             msg = "Unexpected error during the `get` operation of an non-existing file.");
-    } else {
-        test:assertFail(msg = "Found a non-error response while accessing a non-existing file path");
     }
 }
 
@@ -101,11 +101,11 @@ public function testPutFileContentAtInvalidFileLocation() returns error? {
 }
 public function testIsDirectoryWithNonExistingDirectory() {
     boolean|Error receivedError = (<Client>clientEp)->isDirectory("/home/in/nonexisting");
-    if receivedError is Error {
-        test:assertEquals(receivedError.message(), "/home/in/nonexisting does not exists to check if it is a directory.",
+    test:assertTrue(receivedError is FileNotFoundError,
+        msg = "Expected FileNotFoundError when checking isDirectory on non-existing path");
+    if receivedError is FileNotFoundError {
+        test:assertEquals(receivedError.message(), "/home/in/nonexisting does not exist to check if it is a directory.",
             msg = "Unexpected error during the `isDirectory` operation of an non-existing directory. " + receivedError.message());
-    } else {
-        test:assertFail(msg = "Found a non-error response while accessing a non-existing directory path.");
     }
 }
 
@@ -130,11 +130,11 @@ public function testRenameNonExistingDirectory() {
     string newName = "/home/in/differentDirectory";
     Error? receivedError = (<Client>clientEp)->rename(existingName, newName);
 
-    if receivedError is Error {
+    test:assertTrue(receivedError is FileNotFoundError,
+        msg = "Expected FileNotFoundError when renaming non-existing file");
+    if receivedError is FileNotFoundError {
         test:assertTrue(receivedError.message().startsWith("Failed to rename file: "),
             msg = "Unexpected error during the `rename` operation of an non-existing file. " + receivedError.message());
-    } else {
-        test:assertFail(msg = "Found a non-error response while accessing a non existing directory path.");
     }
 }
 
@@ -169,11 +169,11 @@ public function testListFilesFromNonExistingDirectory() {
 }
 public function testDeleteFileAtNonExistingLocation() returns error? {
     Error? receivedError = (<Client>clientEp)->delete("/nonExistingFile");
-    if receivedError is Error {
+    test:assertTrue(receivedError is FileNotFoundError,
+        msg = "Expected FileNotFoundError when deleting non-existing file");
+    if receivedError is FileNotFoundError {
         test:assertTrue(receivedError.message().startsWith("Failed to delete file: "),
             msg = "Unexpected error during the `delete` operation of an non-existing file. " + receivedError.message());
-    } else {
-        test:assertFail(msg = "Found a non-error response while accessing a non-existing file path.");
     }
 }
 
@@ -182,11 +182,11 @@ public function testDeleteFileAtNonExistingLocation() returns error? {
 }
 public function testRemoveDirectoryWithWrongUrl() {
     Error? receivedError = (<Client>clientEp)->rmdir("/nonExistingDirectory");
-    if receivedError is Error {
+    test:assertTrue(receivedError is FileNotFoundError,
+        msg = "Expected FileNotFoundError when removing non-existing directory");
+    if receivedError is FileNotFoundError {
         test:assertTrue(receivedError.message().startsWith("Failed to delete directory: "),
             msg = "Unexpected error during the `rmdir` operation of a non-existing directory. " + receivedError.message());
-    } else {
-        test:assertFail(msg = "Found a non-error response while accessing a non-existing directory path.");
     }
 }
 
@@ -227,14 +227,14 @@ public function testConnectionWithNonExistingServerDetailedError() returns error
         auth: {credentials: {username: "wso2", password: "wso2123"}}
     };
     Client|Error nonExistingServerClientEp = new (nonExistingServerConfig);
-    if nonExistingServerClientEp is Error {
+    test:assertTrue(nonExistingServerClientEp is ConnectionError,
+        msg = "Expected ConnectionError when connecting to non-existing server");
+    if nonExistingServerClientEp is ConnectionError {
         test:assertTrue(nonExistingServerClientEp.message().startsWith("Error while connecting to the FTP server with URL: "),
             msg = "Unexpected error when tried to connect to a non existing server. " + nonExistingServerClientEp.message());
         // Verify that the error message contains additional details from the root cause
         test:assertTrue(nonExistingServerClientEp.message().length() > "Error while connecting to the FTP server with URL: ftp://wso2:***@127.0.0.1:21299".length(),
             msg = "Error message should contain detailed root cause information");
-    } else {
-        test:assertFail(msg = "Found a non-error response when tried to connect to a non existing server.");
     }
 }
 
@@ -249,14 +249,14 @@ public function testConnectionWithInvalidHostDetailedError() returns error? {
         auth: {credentials: {username: "wso2", password: "wso2123"}}
     };
     Client|Error invalidHostClientEp = new (invalidHostConfig);
-    if invalidHostClientEp is Error {
+    test:assertTrue(invalidHostClientEp is ConnectionError,
+        msg = "Expected ConnectionError when connecting to invalid host");
+    if invalidHostClientEp is ConnectionError {
         test:assertTrue(invalidHostClientEp.message().startsWith("Error while connecting to the FTP server with URL: "),
             msg = "Unexpected error when tried to connect to an invalid host. " + invalidHostClientEp.message());
         // Verify that the error message contains additional details from the root cause
         test:assertTrue(invalidHostClientEp.message().length() > "Error while connecting to the FTP server with URL: ".length(),
             msg = "Error message should contain detailed root cause information");
-    } else {
-        test:assertFail(msg = "Found a non-error response when tried to connect to an invalid host.");
     }
 }
 
@@ -266,12 +266,13 @@ public function testConnectionWithInvalidHostDetailedError() returns error? {
 public function testMoveNonExistingFile() returns error? {
     string nonExistingPath = "/home/in/nonexistent_file_for_move.txt";
     string destinationPath = "/home/in/moved_nonexistent.txt";
-    // Note: VFS may not throw error for non-existing source in move/rename operations
-    // This test verifies that the operation completes without crashing
     Error? result = (<Client>clientEp)->move(nonExistingPath, destinationPath);
-    // If the VFS implementation doesn't throw an error, that's also acceptable
-    // The important thing is the client handles it gracefully
-    test:assertTrue(true, msg = "Move non-existing file handled");
+    test:assertTrue(result is FileNotFoundError,
+        msg = "Expected FileNotFoundError when moving non-existing file");
+    if result is FileNotFoundError {
+        test:assertTrue(result.message().includes("not found"),
+            msg = "Error message should indicate file not found");
+    }
 }
 
 @test:Config {
@@ -280,12 +281,13 @@ public function testMoveNonExistingFile() returns error? {
 public function testCopyNonExistingFile() returns error? {
     string nonExistingPath = "/home/in/nonexistent_file_for_copy.txt";
     string destinationPath = "/home/in/copied_nonexistent.txt";
-    // Note: VFS may not throw error for non-existing source in copy operations
-    // This test verifies that the operation completes without crashing
     Error? result = (<Client>clientEp)->copy(nonExistingPath, destinationPath);
-    // If the VFS implementation doesn't throw an error, that's also acceptable
-    // The important thing is the client handles it gracefully
-    test:assertTrue(true, msg = "Copy non-existing file handled");
+    test:assertTrue(result is FileNotFoundError,
+        msg = "Expected FileNotFoundError when copying non-existing file");
+    if result is FileNotFoundError {
+        test:assertTrue(result.message().includes("not found"),
+            msg = "Error message should indicate file not found");
+    }
 }
 
 @test:Config {
@@ -294,27 +296,28 @@ public function testCopyNonExistingFile() returns error? {
 public function testCopyToExistingFile() returns error? {
     string sourcePath = "/home/in/test_copy_source.txt";
     string destinationPath = "/home/in/test_copy_dest.txt";
-    
+
     // Clean up any existing files first
     Error? cleanupResult1 = (<Client>clientEp)->delete(sourcePath);
     Error? cleanupResult2 = (<Client>clientEp)->delete(destinationPath);
-    
+
     // Create source file
     stream<io:Block, io:Error?> sourceStream = check io:fileReadBlocksAsStream(putFilePath, 5);
     check (<Client>clientEp)->put(sourcePath, sourceStream);
-    
+
     // Create destination file
     stream<io:Block, io:Error?> destStream = check io:fileReadBlocksAsStream(putFilePath, 5);
     check (<Client>clientEp)->put(destinationPath, destStream);
-    
-    // Copy to existing file should fail (VFS doesn't overwrite by default)
+
+    // Copy to existing file should fail with FileAlreadyExistsError
     Error? result = (<Client>clientEp)->copy(sourcePath, destinationPath);
-    test:assertTrue(result is Error, msg = "Copy to existing file should fail");
-    if result is Error {
-        test:assertTrue(result.message().includes("already exists"), 
+    test:assertTrue(result is FileAlreadyExistsError,
+        msg = "Expected FileAlreadyExistsError when copying to existing file");
+    if result is FileAlreadyExistsError {
+        test:assertTrue(result.message().includes("already exists"),
             msg = "Error message should indicate file already exists");
     }
-    
+
     // Cleanup
     Error? cleanup1 = (<Client>clientEp)->delete(sourcePath);
     Error? cleanup2 = (<Client>clientEp)->delete(destinationPath);
@@ -329,7 +332,89 @@ public function testExistsNonExistingFile() returns error? {
     if result is boolean {
         test:assertFalse(result, msg = "Non-existing file should return false");
     } else {
-        test:assertFail(msg = "Expected boolean result for exists on non-existing file, got error: " 
+        test:assertFail(msg = "Expected boolean result for exists on non-existing file, got error: "
             + result.message());
     }
 }
+
+// Invalid Configuration Tests
+
+@test:Config {}
+public function testListenerWithInvalidFileNamePattern() returns error? {
+    ListenerConfiguration invalidPatternConfig = {
+        protocol: FTP,
+        host: "127.0.0.1",
+        port: 21212,
+        auth: {credentials: {username: "wso2", password: "wso2123"}},
+        path: "/home/in",
+        pollingInterval: 2,
+        fileNamePattern: "[invalid(regex"  // Invalid regex pattern (unclosed bracket)
+    };
+    Listener|Error listenerResult = new (invalidPatternConfig);
+    test:assertTrue(listenerResult is InvalidConfigError,
+        msg = "Expected InvalidConfigError when creating listener with invalid fileNamePattern");
+    if listenerResult is InvalidConfigError {
+        test:assertTrue(listenerResult.message().includes("Invalid regex pattern"),
+            msg = "Error message should indicate invalid regex pattern. Got: " + listenerResult.message());
+        test:assertTrue(listenerResult.message().includes("fileNamePattern"),
+            msg = "Error message should mention fileNamePattern field");
+    }
+}
+
+@test:Config {}
+public function testListenerWithInvalidDependencyTargetPattern() returns error? {
+    ListenerConfiguration invalidDependencyConfig = {
+        protocol: FTP,
+        host: "127.0.0.1",
+        port: 21212,
+        auth: {credentials: {username: "wso2", password: "wso2123"}},
+        path: "/home/in",
+        pollingInterval: 2,
+        fileDependencyConditions: [
+            {
+                targetPattern: "*.txt[invalid",  // Invalid regex pattern
+                requiredFiles: ["done.txt"],
+                matchingMode: ALL,
+                requiredFileCount: 1
+            }
+        ]
+    };
+    Listener|Error listenerResult = new (invalidDependencyConfig);
+    test:assertTrue(listenerResult is InvalidConfigError,
+        msg = "Expected InvalidConfigError for invalid dependency targetPattern");
+    if listenerResult is InvalidConfigError {
+        test:assertTrue(listenerResult.message().includes("Invalid regex pattern"),
+            msg = "Error message should indicate invalid regex pattern. Got: " + listenerResult.message());
+        test:assertTrue(listenerResult.message().includes("targetPattern"),
+            msg = "Error message should mention targetPattern field");
+    }
+}
+
+@test:Config {}
+public function testListenerWithInvalidDependencyRequiredFilePattern() returns error? {
+    ListenerConfiguration invalidRequiredFileConfig = {
+        protocol: FTP,
+        host: "127.0.0.1",
+        port: 21212,
+        auth: {credentials: {username: "wso2", password: "wso2123"}},
+        path: "/home/in",
+        pollingInterval: 2,
+        fileDependencyConditions: [
+            {
+                targetPattern: ".*\\.txt",
+                requiredFiles: ["done[unclosed"],  // Invalid regex pattern
+                matchingMode: ALL,
+                requiredFileCount: 1
+            }
+        ]
+    };
+    Listener|Error listenerResult = new (invalidRequiredFileConfig);
+    test:assertTrue(listenerResult is InvalidConfigError,
+        msg = "Expected InvalidConfigError for invalid requiredFiles pattern");
+    if listenerResult is InvalidConfigError {
+        test:assertTrue(listenerResult.message().includes("Invalid regex pattern"),
+            msg = "Error message should indicate invalid regex pattern. Got: " + listenerResult.message());
+        test:assertTrue(listenerResult.message().includes("requiredFiles"),
+            msg = "Error message should mention requiredFiles field");
+    }
+}

ballerina/tests/client_endpoint_test.bal

@@ -938,7 +938,7 @@ public function testRenameDirectory() {
     boolean|Error response2 = (<Client>clientEp)->isDirectory(existingName);
     log:printInfo("Executed `isDirectory` operation on original directory after renaming a directory");
     if response2 is Error {
-        test:assertEquals(response2.message(), "/home/in/out does not exists to check if it is a directory.",
+        test:assertEquals(response2.message(), "/home/in/out does not exist to check if it is a directory.",
             msg = "Incorrect error message for non-existing file/directory at `isDirectory` operation");
     } else {
         test:assertFail("Error not created while invoking `isDirectory` operation after `rename` operation");
@@ -1247,7 +1247,7 @@ function testGenericRmdir(string path) returns error? {
         i += 1;
     }
     if response2 is Error {
-        test:assertEquals(response2.message(), path + " does not exists to check if it is a directory.",
+        test:assertEquals(response2.message(), path + " does not exist to check if it is a directory.",
             msg = "Incorrect error message for non-existing file/directory at `isDirectory` operation after `rmdir` operation");
     } else {
         // test:assertFail(msg = "Error not created while invoking `isDirectory` operation after `rmdir` operation on " + path );