swiftlang/swift

[SR-5457] Specific error message when user tries to compile Swift executable

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#48,029 opened on Jul 14, 2017

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compilergood first issueimprovementparser

Description
Previous ID SR-5457
Radar None
Original Reporter carlb (JIRA User)
Type Improvement
Votes 0
Component/s Compiler
Labels Improvement, Parser, StarterBug
Assignee None
Priority Medium

md5: 111feeb80ab569e4bee27d9d511be231

Issue Description:

I was talking to a new Swift programmer who came from the ruby/python world. He had this output:

$ swift .build/debug/helloWorld
.build/debug/helloWorld:1:1: error: invalid UTF-8 found in source file
�����x� H__PAGEZERO8__TEXT@@__text__TEXT Ͷ �__stubs__TEXT��
.build/debug/helloWorld:1:2: error: invalid UTF-8 found in source file
�����x� H__PAGEZERO8__TEXT@@__text__TEXT Ͷ �__stubs__TEXT��
.build/debug/helloWorld:1:3: error: invalid UTF-8 found in source file
�����x� H__PAGEZERO8__TEXT@@__text__TEXT Ͷ �__stubs__TEXT��
.build/debug/helloWorld:1:4: error: input files must be encoded as UTF-8 instead of UTF-16
�����x� H__PAGEZERO8__TEXT@@__text__TEXT Ͷ �__stubs__TEXT��

Because he had started with Swift scripts, where you put swift in front of the file.swift name.

The error message above is perfectly valid, but unhelpful in this case. I would guess enough new programmers would make this mistake that it's worth discussing a special-case error message if the file to be run is already a Swift executable.

Contributor guide

Tech stack
swift
Domain
developer experiencecli
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Swift programmingcompiler error handling
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80
Research direction
Investigate the Swift compiler's error handling for source files, specifically the code that produces the 'invalid UTF 8' and 'input files must be encoded as UTF 8' errors. Determine if the compiler can detect that the input file is an executable binary and provide a more helpful message. Look for related files in the Swift compiler repository, such as the parser or driver code.