Apollo-ios: Trailing newline thrash with Xcode 10.2

[erikstrottmann]

I’m setting up Apollo in an app for the first time, and I have noticed that Apollo and Xcode 10.2 disagree about whether a file should end in a trailing newline, causing the file to be modified every time it is opened or the project is built.

Intended outcome:
Apollo should generate an API.swift with a newline \n character at the end of the file.

Actual outcome:
Apollo generates an API.swift that does not have a newline \n character at the end of the file. Every time Xcode 10.2 opens the file, it adds a newline to the end of the file. Every time the project is built, Apollo removes the trailing newline.

How to reproduce the issue:

• Use Apollo 0.10.1 and Xcode 10.2
• Add your Apollo-generated API.swift to your Xcode project
• Open API.swift in Xcode, and see that Xcode adds a newline to API.swift
• Build the project, and see that Apollo regenerates API.swift without a newline

[michaelnisi]

What Text Editing Preferences are you using? I could not reproduce this with Xcode Version 10.2.1 (10E1001).

Anyone else seeing this issue?

[erikstrottmann]

It looks like, while Xcode automatically modifies the file when it’s opened (see screenshot indicating modified file), I still have to save the file for the additional whitespace to be reflected on the filesystem.

I have “Automatically trim trailing whitespace” and “Including whitespace-only lines” enabled, but “Convert existing files on save” disabled. However, I still experience the issue if I copy your settings exactly. I also experience the issue when I use Xcode 10.1.

To better illustrate my issue, here’s the end of the output of cat API.swift as generated by Apollo:

And here’s the end of the output of cat API.swift after Xcode appends a trailing newline:

Note how the last brace of the Apollo-generated file appears on the same line as my command prompt, while the last brace of the Xcode-modified file appears on its own line, as expected.

According to the POSIX standard, each line in a file, including the last line, should end in a newline \n character. GNU and Unix tools like cat expect this behavior, so they don’t behave nicely when a file does not end in a trailing newline.

[michaelnisi]

Thank you for the detailed follow-up. Sounds like I should be able to reproduce it. However, there’s some subtlety to it, a freshly generated file looks fine here.

[erikstrottmann]

When I use Vim with :set list!, my freshly generated file shows a newline $ too, but if I save the file from Vim, Git shows that there’s now a new line. It looks like Vim also inserts the newline if it isn’t already present.

I think that’s default behavior, but just in case, here’s my ~/.vimrc:

syntax enable

set incsearch
set hlsearch

autocmd FileType gitcommit setlocal spell textwidth=72

[michaelnisi]

Confirmed 😅

[michaelnisi]

Although, from a quick glance, I reckon this is not Swift specific, I will try expose this issue with a test for apollographql/apollo-tooling/packages/apollo-codegen-swift.

[michaelnisi]

I guess writing TypeScript is a thing I do now. 🤷‍♂️

[designatednerd]

This has been addressed by switching to the updated code generation in 0.13.0!