Handling type naming collisions

While most generated Golang types must have unique names by virtue of being based on their GraphQL type counterpart, which themselves must be unique, there are a few edge scenarios where conflicts can occur. This document describes how those collisions are handled.

Enum Constants

Enum type generation is a prime example of where naming collisions can occur, as we build the const names per value as a composite of the Enum name and each individual value.

Example Problem

Currently, enum types are transposed as such:

# graphql

enum MyEnum {
  value1
  value2
  value3
  value4
}

Which will result in the following Golang:

// golang

type MyEnum string

const (
	MyEnumValue1 MyEnum = "value1"
	MyEnumValue2 MyEnum = "value2"
	MyEnumValue3 MyEnum = "value3"
	MyEnumValue4 MyEnum = "value4"
)

However, those above enum values are just strings. What if you encounter a scenario where the following is necessary:

# graphql

enum MyEnum {
  value1
  value2
  value3
  value4
  Value4
  Value_4
}

The Value4 and Value_4 enum values cannot be directly transposed into the same "pretty" naming convention as their resulting constant names would conflict with the name for value4, as so:

// golang

type MyEnum string

const (
	MyEnumValue1 MyEnum = "value1"
	MyEnumValue2 MyEnum = "value2"
	MyEnumValue3 MyEnum = "value3"
	MyEnumValue4 MyEnum = "value4"
	MyEnumValue4 MyEnum = "Value4"
	MyEnumValue4 MyEnum = "Value_4"
)

Which immediately leads to compilation errors as we now have three constants with the same name, but different values.

Resolution

1. Store each name generated as part of a run for later comparison
2. Try to coerce name into CapitalCase. Use if no conflicts.
   • This process attempts to break apart identifiers into "words", identified by separating on capital letters, underscores, hyphens, and spaces.
   • Each "word" is capitalized and appended to previous word.
3. If non-composite name, append integer to end of name, starting at 0 and going to math.MaxInt
4. If composite name, in reverse order, the pieces of the name have a less opinionated converter applied
5. If all else fails, append integer to end of name, starting at 0 and going to math.MaxInt

The first step to produce a name that does not conflict with an existing name succeeds.

Examples

Example A

GraphQL:

# graphql

enum MyEnum {
  Value
  value
  TitleValue
  title_value
}

Go:

// golang

type MyEnum string

const (
	MyEnumValue MyEnum       = "Value"
	MyEnumvalue MyEnum       = "value"
	MyEnumTitleValue MyEnum  = "TitleValue"
	MyEnumtitle_value MyEnum = "title_value"
)

Example B

GraphQL:

# graphql

enum MyEnum {
  TitleValue
  title_value
  title_Value
  Title_Value
}

Go:

// golang

type MyEnum string

const (
	MyEnumTitleValue MyEnum  = "TitleValue"
	MyEnumtitle_value MyEnum = "title_value"
	MyEnumtitle_Value MyEnum = "title_Value"
	MyEnumTitle_Value MyEnum = "Title_Value"
)

Example C

GraphQL:

# graphql

enum MyEnum {
  value
  Value
}

Go:

// golang

type MyEnum string

const (
	MyEnumValue  = "value"
	MyEnumValue0 = "Value"
)

Warning

Name collision resolution is handled per-name, as they come in. If you change the order of an enum, you could very well end up with the same constant resolving to a different value.

Lets mutate Example C:

Example C - State A

GraphQL:

# graphql

enum MyEnum {
  value
  Value
}

Go:

// golang

type MyEnum string

const (
	MyEnumValue  = "value"
	MyEnumValue0 = "Value"
)

Example C - State B

GraphQL:

# graphql

enum MyEnum {
  Value
  value
}

Go:

// golang

type MyEnum string

const (
	MyEnumValue  = "Value"
	MyEnumValue0 = "value"
)

Notice how the constant names are the same, but the value that each applies to has changed.