50 Shades of Go: Traps, Gotchas, and Common Mistakes for New Golang Devs

Opening Brace Can't Be Placed on a Separate Line

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Unused Variables

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Unused Imports

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Short Variable Declarations Can Be Used Only Inside Functions

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Redeclaring Variables Using Short Variable Declarations

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Can't Use Short Variable Declarations to Set Field Values

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Accidental Variable Shadowing

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Can't Use "nil" to Initialize a Variable Without an Explicit Type

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Using "nil" Slices and Maps

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Map Capacity

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Strings Can't Be "nil"

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Array Function Arguments

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Unexpected Values in Slice and Array "range" Clauses

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Slices and Arrays Are One-Dimensional

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Accessing Non-Existing Map Keys

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Strings Are Immutable

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Conversions Between Strings and Byte Slices

Strings and Index Operator

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Strings Are Not Always UTF8 Text

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String Length

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Missing Comma In Multi-Line Slice, Array, and Map Literals

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log.Fatal and log.Panic Do More Than Log

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Built-in Data Structure Operations Are Not Synchronized

Iteration Values For Strings in "range" Clauses

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Iterating Through a Map Using a "for range" Clause

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Fallthrough Behavior in "switch" Statements

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Increments and Decrements

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Bitwise NOT Operator

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Operator Precedence Differences

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Unexported Structure Fields Are Not Encoded

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App Exits With Active Goroutines

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Sending to an Unbuffered Channel Returns As Soon As the Target Receiver Is Ready

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Sending to an Closed Channel Causes a Panic

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Using "nil" Channels

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Methods with Value Receivers Can't Change the Original Value

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Closing HTTP Response Body

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Closing HTTP Connections

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JSON Encoder Adds a Newline Character

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JSON Package Escapes Special HTML Characters in Keys and String Values

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Unmarshalling JSON Numbers into Interface Values

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JSON String Values Will Not Be Ok with Hex or Other non-UTF8 Escape Sequences

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Comparing Structs, Arrays, Slices, and Maps

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Recovering From a Panic

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Updating and Referencing Item Values in Slice, Array, and Map "range" Clauses

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"Hidden" Data in Slices

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Slice Data "Corruption"

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"Stale" Slices

Type Declarations and Methods

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Breaking Out of "for switch" and "for select" Code Blocks

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Iteration Variables and Closures in "for" Statements

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Deferred Function Call Argument Evaluation

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Deferred Function Call Execution

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Failed Type Assertions

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Blocked Goroutines and Resource Leaks

Same Address for Different Zero-sized Variables

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The First Use of iota Doesn't Always Start with Zero

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Using Pointer Receiver Methods On Value Instances

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Updating Map Value Fields

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"nil" Interfaces and "nil" Interfaces Values

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Stack and Heap Variables

GOMAXPROCS, Concurrency, and Parallelism

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Read and Write Operation Reordering

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Preemptive Scheduling

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Import C and Multiline Import Blocks

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No blank lines Between Import C and Cgo Comments

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Can't Call C Functions with Variable Arguments

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