Empty values in inline mapping result in error

[ericcornelissen]

Bug Report

• wordrow version: v0.5.0-beta
• Operating system: Ubuntu 19.04

Description

Providing an incorrect mapping from the CLI (i.e. with a empty string on either side of the mapping) results in a crash.

Actual Behaviour

A program crash.

Expected Behaviour

The mapping is not used and the program potentially halts with an error message.

Working Example

Use the program with a CLI specified mapping such as --map "foo," or --map ",bar".

Log Output

$ wordrow --map "foo," inputfile.txt
panic: 1

goroutine 1 [running]:
github.com/ericcornelissen/wordrow/internal/wordmaps.(*WordMap).AddOne(0xc0000b7d78, 0x7ffc0fad0cbf, 0x3, 0x7ffc0fad0cbf, 0x0)
        /media/win/workspace/wordrow/internal/wordmaps/wordmap.go:49 +0x230
main.processInlineMapping(0x7ffc0fad0cbf, 0x4, 0xc0000b7d78, 0x1, 0x1)
        /media/win/workspace/wordrow/cmd/wordrow/wordmap.go:98 +0x189
main.processInlineMappings(0xc00005e3b0, 0x1, 0x1, 0xc0000b7d78, 0x0, 0x0)
        /media/win/workspace/wordrow/cmd/wordrow/wordmap.go:108 +0xe8
main.getWordMap(0x0, 0x0, 0x0, 0xc00005e3b0, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, ...)
        /media/win/workspace/wordrow/cmd/wordrow/wordmap.go:128 +0xba
main.run(0x0, 0x0, 0x0, 0xc00005e3c0, 0x1, 0x1, 0x0, 0x0, 0x0, 0xc00005e3b0, ...)
        /media/win/workspace/wordrow/cmd/wordrow/main.go:12 +0x81
main.main()
        /media/win/workspace/wordrow/cmd/wordrow/main.go:51 +0xf7