PHP error types and levels - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to display all errors except notices.

PHP

<?php
error_reporting([1]);
?>

Drag options to blanks, or click blank then click option'

AE_WARNING

BE_ERROR

CE_NOTICE

DE_ALL & ~E_NOTICE

Attempts:

3 left

💡 Hint

Common Mistakes

Using only E_ALL reports notices too.

Using E_NOTICE alone reports only notices.

The error_reporting function sets which errors are reported. Using E_ALL & ~E_NOTICE reports all errors except notices.

2fill in blank

medium

Complete the code to trigger a user error with a custom message.

PHP

<?php
trigger_error([1], E_USER_ERROR);
?>

Drag options to blanks, or click blank then click option'

A"Warning: Something went wrong"

B"Custom error occurred"

CE_USER_WARNING

DE_ERROR

Attempts:

3 left

💡 Hint

Common Mistakes

Passing error level constants instead of a message string.

Omitting quotes around the message.

The trigger_error function sends a user-generated error message. The first argument is the message string.

3fill in blank

hard

Fix the error in the code to set error reporting to show only warnings.

PHP

<?php
error_reporting([1]);
?>

Drag options to blanks, or click blank then click option'

AE_WARNING

BE_NOTICE

CE_ALL

DE_ERROR

Attempts:

3 left

💡 Hint

Common Mistakes

Using E_ALL reports all errors, not just warnings.

Using E_NOTICE reports notices, not warnings.

To report only warnings, use E_WARNING as the argument to error_reporting.

4fill in blank

hard

Fill both blanks to set error reporting to show all errors except deprecated and strict notices.

PHP

<?php
error_reporting(E_ALL & ~[1] & ~[2]);
?>

Drag options to blanks, or click blank then click option'

AE_DEPRECATED

BE_STRICT

CE_NOTICE

DE_WARNING

Attempts:

3 left

💡 Hint

Common Mistakes

Excluding E_NOTICE instead of E_DEPRECATED or E_STRICT.

Using bitwise OR instead of AND.

Using bitwise AND with the negation of E_DEPRECATED and E_STRICT excludes these error types from reporting.

5fill in blank

hard

Fill all three blanks to create a custom error handler function that handles warnings and notices.

PHP

<?php
function customErrorHandler([1], $errstr, $errfile, $errline) {
    if ($errNo & ([2] | [3])) {
        echo "Custom error: $errstr in $errfile on line $errline";
    }
}
set_error_handler('customErrorHandler');
?>

Drag options to blanks, or click blank then click option'

A$errNo

BE_WARNING

CE_NOTICE

D$errNo &

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect variable names for the error number.

Using bitwise AND incorrectly in the condition.

The error handler function receives the error number as the first argument. The condition checks if the error is a warning or notice using bitwise OR.

Practice

1. Which PHP error type indicates a problem that stops the script from running?

easy

A. Warning

B. Fatal error

C. Notice

D. Deprecated

Solution

1. Step 1: Understand PHP error types

   Fatal errors are serious problems that stop the script immediately.

2. Step 2: Compare with other error types

   Warnings and notices do not stop the script; deprecated warns about old code.

3. Final Answer:

   Fatal error -> Option B

4. Quick Check:

   Fatal error = stops script [OK]

Hint: Fatal errors stop scripts immediately, others do not [OK]

Common Mistakes:

• Confusing warnings with fatal errors
• Thinking notices stop script execution
• Mixing deprecated warnings with fatal errors

2. Which of the following is the correct way to set PHP to report all errors except notices?

easy

A. error_reporting(E_ALL & ~E_NOTICE);

B. error_reporting(E_ALL | E_NOTICE);

C. error_reporting(E_ALL & E_NOTICE);

D. error_reporting(E_ALL ^ E_NOTICE);

Solution

1. Step 1: Understand error_reporting flags

   E_ALL means all errors; ~E_NOTICE means exclude notices using bitwise NOT.

2. Step 2: Analyze each option

   error_reporting(E_ALL & ~E_NOTICE); uses bitwise AND with NOT (~) to exclude notices correctly.

3. Final Answer:

   error_reporting(E_ALL & ~E_NOTICE); -> Option A

4. Quick Check:

   Exclude notices with & ~E_NOTICE [OK]

Hint: Use & ~E_NOTICE to exclude notices from all errors [OK]

Common Mistakes:

• Using | instead of & ~ to exclude errors
• Confusing ^ (XOR) with exclusion
• Using & E_NOTICE which includes only notices

3. What will be the output of this PHP code?

<?php
error_reporting(E_ERROR | E_WARNING);
echo $undefined_variable;
include('missing_file.php');
?>

medium

A. Warning about missing file only

B. Fatal error about missing file

C. Notice about undefined variable and warning about missing file

D. No output, script runs silently

Solution

1. Step 1: Check error_reporting level

   Only E_ERROR and E_WARNING are reported; notices are not shown.

2. Step 2: Analyze code behavior

   Undefined variable triggers a notice (not shown). Missing file triggers a warning (shown).

3. Final Answer:

   Warning about missing file only -> Option A

4. Quick Check:

   E_WARNING shown, notices hidden [OK]

Hint: Only errors and warnings show; notices are hidden [OK]

Common Mistakes:

• Expecting notice output when it's excluded
• Confusing warning with fatal error
• Thinking script stops on warning

4. Identify the error in this PHP code snippet:

<?php
error_reporting(E_ALL);
ini_set('display_errors', 0);
echo $undefined_var;
?>

medium

A. Errors will be displayed despite display_errors set to 0

B. No errors will be reported because error_reporting is off

C. Syntax error due to missing semicolon

D. Errors are reported but not displayed due to display_errors=0

Solution

1. Step 1: Understand error_reporting and display_errors

   error_reporting(E_ALL) enables all error reporting; display_errors=0 hides errors from output.

2. Step 2: Analyze code behavior

   Errors are logged/reported internally but not shown on screen because display_errors is off.

3. Final Answer:

   Errors are reported but not displayed due to display_errors=0 -> Option D

4. Quick Check:

   display_errors=0 hides errors, reporting still active [OK]

Hint: display_errors=0 hides errors; error_reporting controls reporting [OK]

Common Mistakes:

• Thinking errors won't be reported at all
• Confusing display_errors with error_reporting
• Assuming syntax error due to missing semicolon

5. You want to show all errors except deprecated warnings during development but hide all errors on the live site. Which code setup achieves this best?

hard

A. error_reporting(E_ALL); ini_set('display_errors', 1);

B. error_reporting(E_ALL & ~E_NOTICE); ini_set('display_errors', 0);

C. if (ENV == 'dev') { error_reporting(E_ALL & ~E_DEPRECATED); ini_set('display_errors', 1); } else { error_reporting(0); ini_set('display_errors', 0); }

D. if (ENV == 'prod') { error_reporting(E_ALL); ini_set('display_errors', 1); } else { error_reporting(0); ini_set('display_errors', 0); }

Solution

1. Step 1: Understand environment-based error settings

   During development (dev), show all errors except deprecated; on live (prod), hide all errors.

2. Step 2: Analyze each option

   if (ENV == 'dev') { error_reporting(E_ALL & ~E_DEPRECATED); ini_set('display_errors', 1); } else { error_reporting(0); ini_set('display_errors', 0); } correctly uses error_reporting with exclusion and display_errors on dev, off on live.

3. Final Answer:

   if (ENV == 'dev') { error_reporting(E_ALL & ~E_DEPRECATED); ini_set('display_errors', 1); } else { error_reporting(0); ini_set('display_errors', 0); } -> Option C

4. Quick Check:

   Dev shows errors except deprecated; live hides all [OK]

Hint: Use environment check to toggle error reporting and display [OK]

Common Mistakes:

• Showing errors on live site
• Not excluding deprecated warnings during dev
• Confusing environment variable names