d-logger/test/logger.internal-fallback.test.js

import { assert, assertEquals, assertThrows } from "@std/assert";
import Logger from "../lib/logger.ts";
import {
  clearCapturedErrors,
  clearCapturedLogs,
  getCapturedErrors,
  getCapturedLogs,
  setupMocks,
} from "./helpers/logger-test-helpers.js";

// Setup and teardown for all tests
setupMocks();

Deno.test("Logger Additional Fallback Tests - JSON Formatter Error Handling - should handle circular references in log data", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });

  // Create circular reference
  const obj = { name: "test" };
  obj.self = obj;

  logger.info("Message with circular ref: %j", obj);

  assertEquals(getCapturedLogs().length, 1);
  const logOutput = getCapturedLogs()[0];

  // Should be valid JSON despite circular reference
  const parsed = JSON.parse(logOutput);
  assertEquals(parsed.level, "info");
  // Check for either jsonError or that the message was logged successfully
  assert(
    parsed.jsonError?.includes("JSON stringify failed") ||
      parsed.msg.includes("Message with circular ref"),
  );
});

Deno.test("Logger Additional Fallback Tests - JSON Formatter Error Handling - should handle objects with non-serializable properties", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });

  // Create object with function (non-serializable)
  const objWithFunction = {
    name: "test",
    func: function () {
      return "hello";
    },
    symbol: Symbol("test"),
    undefined: undefined,
  };

  logger.info("Object: %j", objWithFunction);

  assertEquals(getCapturedLogs().length, 1);
  const logOutput = getCapturedLogs()[0];

  // Should produce valid JSON
  const parsed = JSON.parse(logOutput);
  assertEquals(parsed.level, "info");
  // Should have the message in some form
  assert(parsed.msg.includes("Object:"));
});

Deno.test("Logger Additional Fallback Tests - JSON Formatter Error Handling - should handle when JSON formatter itself is broken", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });

  // Break the JSON formatter
  logger.formatters.json = function () {
    throw new Error("JSON formatter is broken");
  };

  logger.info("test message");

  // Should still produce some output (last resort fallback)
  assertEquals(getCapturedLogs().length, 1);
  const logOutput = getCapturedLogs()[0];

  // Should contain the message even if not perfectly formatted
  assert(logOutput.includes("test message"));
});

Deno.test("Logger Additional Fallback Tests - Caller Detection Error Handling - should handle stack manipulation errors", () => {
  clearCapturedLogs();
  clearCapturedErrors();

  const logger = new Logger({ format: "json", callerLevel: "info" });

  // Override getCallerInfo to simulate an error
  const originalGetCallerInfo = logger.getCallerInfo;
  logger.getCallerInfo = function () {
    this.callerErrorCount++;
    if (this.callerErrorCount <= this.maxCallerErrors) {
      console.error(
        "Error retrieving caller info:",
        new Error("Simulated caller error"),
      );
      if (this.callerErrorCount === this.maxCallerErrors) {
        console.error(
          `Caller detection failed ${this.maxCallerErrors} times. Suppressing further caller error messages.`,
        );
      }
    }
    return { callerFile: "unknown", callerLine: 0 };
  };

  try {
    logger.info("test with simulated caller error");

    // Should still log the message
    assertEquals(getCapturedLogs().length, 1);
    const parsed = JSON.parse(getCapturedLogs()[0]);
    assertEquals(parsed.msg, "test with simulated caller error");
    assertEquals(parsed.callerFile, "unknown");
    assertEquals(parsed.callerLine, 0);

    // Should have logged an error about caller detection
    assert(getCapturedErrors().length > 0);
  } finally {
    logger.getCallerInfo = originalGetCallerInfo;
    logger.callerErrorCount = 0;
  }
});

Deno.test("Logger Additional Fallback Tests - Caller Detection Error Handling - should suppress caller errors after max threshold", () => {
  clearCapturedLogs();
  clearCapturedErrors();

  const logger = new Logger({ format: "json", callerLevel: "info" });

  // Override getCallerInfo to always simulate errors
  const originalGetCallerInfo = logger.getCallerInfo;
  logger.getCallerInfo = function () {
    this.callerErrorCount++;
    if (this.callerErrorCount <= this.maxCallerErrors) {
      console.error(
        "Error retrieving caller info:",
        new Error("Always fails"),
      );
      if (this.callerErrorCount === this.maxCallerErrors) {
        console.error(
          `Caller detection failed ${this.maxCallerErrors} times. Suppressing further caller error messages.`,
        );
      }
    }
    return { callerFile: "unknown", callerLine: 0 };
  };

  try {
    // Log more than maxCallerErrors (5) times
    for (let i = 0; i < 10; i++) {
      logger.info(`test message ${i}`);
    }

    // Should have logged all 10 messages
    assertEquals(getCapturedLogs().length, 10);

    // Should have logged errors for first 5 attempts, then suppression message
    const errorLogs = getCapturedErrors();
    assert(errorLogs.length >= 5); // At least 5 error calls
    assert(errorLogs.length <= 6); // But not more than 6 (5 + suppression message)

    // Check that suppression message is included
    const suppressionFound = errorLogs.some((errorArgs) =>
      errorArgs.some(
        (arg) =>
          typeof arg === "string" &&
          arg.includes("Suppressing further caller error messages"),
      )
    );
    assert(suppressionFound);
  } finally {
    logger.getCallerInfo = originalGetCallerInfo;
    logger.callerErrorCount = 0;
  }
});

Deno.test("Logger Additional Fallback Tests - Caller Detection Error Handling - should reset caller error count after successful detection", () => {
  clearCapturedLogs();
  clearCapturedErrors();

  const logger = new Logger({ format: "json", callerLevel: "info" });

  // Override getCallerInfo to simulate different phases
  const originalGetCallerInfo = logger.getCallerInfo;
  let phase = "error1";

  logger.getCallerInfo = function () {
    if (phase === "error1") {
      this.callerErrorCount++;
      if (this.callerErrorCount <= this.maxCallerErrors) {
        console.error(
          "Error retrieving caller info:",
          new Error("Phase 1 error"),
        );
      }
      return { callerFile: "unknown", callerLine: 0 };
    } else if (phase === "working") {
      // Reset error count on successful call
      this.callerErrorCount = 0;
      return originalGetCallerInfo.call(this);
    } else if (phase === "error2") {
      this.callerErrorCount++;
      if (this.callerErrorCount <= this.maxCallerErrors) {
        console.error(
          "Error retrieving caller info:",
          new Error("Phase 2 error"),
        );
      }
      return { callerFile: "unknown", callerLine: 0 };
    }
  };

  try {
    // Cause some errors
    logger.info("test 1");
    logger.info("test 2");

    // Switch to working mode
    phase = "working";
    logger.info("test 3");

    // Break it again
    phase = "error2";
    logger.info("test 4");

    const errorLogs = getCapturedErrors();
    // Should have errors from both phases
    assert(errorLogs.length >= 3);
  } finally {
    logger.getCallerInfo = originalGetCallerInfo;
    logger.callerErrorCount = 0;
  }
});

Deno.test("Logger Additional Fallback Tests - Extreme Error Conditions - should handle when console.log itself throws", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });

  // Break console.log
  const originalLog = console.log;
  console.log = function () {
    throw new Error("Console is broken");
  };

  try {
    // This should not crash the process, but the error will bubble up
    // since there's no try-catch around console.log in the logger
    assertThrows(
      () => {
        logger.info("test message");
      },
      Error,
      "Console is broken",
    );
  } finally {
    console.log = originalLog;
  }
});

Deno.test("Logger Additional Fallback Tests - Extreme Error Conditions - should handle when util.format has issues with complex objects", () => {
  setupMocks();
  const logger = new Logger({ format: "json" });

  // Create an object that will cause issues with string conversion
  const problematicObject = {
    toString: function () {
      throw new Error("toString failed");
    },
    valueOf: function () {
      throw new Error("valueOf failed");
    },
  };

  // The logger should handle this gracefully and not throw
  logger.info("Message: %s", problematicObject);

  const logs = getCapturedLogs();
  assertEquals(logs.length, 1);

  const output = JSON.parse(logs[0]);
  // The logger should handle the problematic object gracefully
  // Either by showing [object Object] or the actual object structure
  assertEquals(typeof output.msg, "string");
  assertEquals(output.msg.startsWith("Message: "), true);
});

Deno.test("Logger Additional Fallback Tests - Extreme Error Conditions - should handle when hostname fails", () => {
  setupMocks();
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });

  // Mock hostname retrieval to throw (this would need to be mocked at the source)
  // Since we can't directly mock os.hostname in Deno, this test shows the concept
  // In practice, hostname failures are rare but could happen

  // For Deno, we could mock the hostname call if it were extracted to a mockable function
  // For now, this is more of a documentation test
  logger.info("test message");
  assertEquals(getCapturedLogs().length, 1);
});

Deno.test("Logger Additional Fallback Tests - Fallback Chain Testing - should handle formatter failures gracefully", () => {
  setupMocks();
  clearCapturedLogs();
  clearCapturedErrors();

  const logger = new Logger({ format: "simple", callerLevel: "info" });

  // Break the simple formatter
  logger.formatters.simple = function () {
    throw new Error("Simple formatter broken");
  };

  // Also simulate caller detection failure
  const originalGetCallerInfo = logger.getCallerInfo;
  logger.getCallerInfo = function () {
    this.callerErrorCount++;
    if (this.callerErrorCount <= this.maxCallerErrors) {
      console.error(
        "Error retrieving caller info:",
        new Error("Caller detection failed"),
      );
    }
    return { callerFile: "unknown", callerLine: 0 };
  };

  try {
    // Should still produce some output despite multiple failures
    logger.info("test message");

    // Should produce some kind of output (fallback to JSON formatter)
    assertEquals(getCapturedLogs().length, 1);
    const output = getCapturedLogs()[0];

    // Should be valid JSON (fallback formatter)
    const parsed = JSON.parse(output);
    assertEquals(parsed.msg, "test message");
    assert(parsed.formatterError.includes("Simple formatter broken"));
    assertEquals(parsed.callerFile, "unknown");
  } finally {
    logger.getCallerInfo = originalGetCallerInfo;
    logger.callerErrorCount = 0;
  }
});

Deno.test("Logger Additional Fallback Tests - Resource Cleanup - should not leak memory during repeated errors", () => {
  setupMocks();
  clearCapturedLogs();
  clearCapturedErrors();

  const logger = new Logger({ format: "simple" });

  // Break the formatter
  logger.formatters.simple = function () {
    throw new Error("Always fails");
  };

  // Log many times to check for memory leaks
  for (let i = 0; i < 1000; i++) {
    logger.info(`message ${i}`);
  }

  // Should have produced all logs
  assertEquals(getCapturedLogs().length, 1000);

  // Check that we're not accumulating error state
  // (This is more of a smoke test - real memory leak detection would need different tools)
  assert(true); // If we get here without crashing, that's good
});