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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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

Research direction
Look at the Swift driver source to find where the error message for invalid UTF 8 is generated, and add a check to detect if the input file is an executable (Mach O or ELF) and suggest using ./ instead.
Tech stack
swift
Domain
compilers
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
1
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Under 1 hour
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
SwiftBasic compiler understanding
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80