Find the subtle logic errors in code snippets. JS, Python, and SQL.

Sharpen your code review skills. Detailed snippets containing common pitfalls like off-by-one errors, floating point math, async race conditions, and mutation bugs.

What does `console.log(0.1 + 0.2 === 0.3)` output?

Bug in loop: `for (var i=0; i<5; i++) { setTimeout(() => console.log(i), 1000) }`

What is wrong? `const x = [1,2]; x.push(3); x = [4,5];`

Python: `def func(list=[]): list.append(1); return list` called twice?

SQL: `SELECT * FROM Users WHERE name = NULL` result?

What happens here? `x = 1; function x() {};`

Python: `a = 256; b = 256; a is b` vs `a = 257; b = 257; a is b`?

React: `array.map((item, index) => <li key={index}>)` issue?

Off-by-one: `let arr=[1,2,3]; for(let i=0; i<=arr.length; i++)`?

Async: `updates.forEach(async (u) => await update(u))` issue?

React: `setState(count + 1)` called 3 times in row?

JS: `parseInt('08')` in old browsers/strict mode?

Memory: `const leak = []; setInterval(() => leak.push(largeData), 100)`?

Git: Deleted file, committed, but still in history?

SQL Injection: `SELECT * FROM Users WHERE name = '" + input + "'`?

Python: `try: ... except:` (bare except)?

Promise: `.then(func())` vs `.then(func)`?

Closure loop bug: `for(var i...) addListener(()=>print(i))`?

Python: `x = 10; def f(): print(x); x += 1`?

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