When prefix starts with a whitespace, the suggestion will disappear after typing first two letters

[yubaoquan]

Prerequisites

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  • Followed all applicable steps in the debugging guide: http://flight-manual.atom.io/hacking-atom/sections/debugging/
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Description

If the first letter of a snippet's prefix is whitespace, the suggestion will disappear after user typing the first two letters of prefix. If taking whitespace character as a part of snippets prefix is not recommended, it should report an error when user save the snippets file, otherwise the suggestions should show when the prefix matches one of the snippets.

Steps to Reproduce

1. Add a snippet, be sure the first letter of the prefix is a whitespace, like this:

'propertyFunction':
        prefix: ' pf'
        body: '''
            ($1) {
                $2
            },
        '''

2. Open an empty js file in text editor, type a letter a and a whitespace.
3. Look at the suggestions.
4. Follow the whitespace, type the letter p.
5. Look at the suggestions.

Expected behavior:
After typing letter p, the suggestion item propertyFunction still shows in the suggestion list.

Actual behavior: The suggestion item propertyFunction disappeared.

Reproduces how often: 100%

Versions

Atom : 1.22.0-beta0
Electron: 1.6.9
Chrome : 56.0.2924.87
Node : 7.4.0

apm 1.18.4
npm 3.10.10
node 6.9.5 x64
python 3.6.1
git 2.13.5

OS: MacOS Sierra 10.12.6

Additional Information

After typing a whitespace:

After typing a whitespace and a letter p:

[50Wliu]

Pretty sure it's because the prefix now becomes pf instead of <space>pf.

[Aerijo]

I imagine this is (sort of) intentional behaviour. Otherwise, it may as well consider the entire line to be part of the prefix (seeing as word breaks would be ignored), a change in behaviour of which could be annoying to those other packages that rely on the prefix provided by the autocomplete-plus package. Although the snippets package does allow arbitrary prefixes, I believe allowing this in autocomplete-snippets could lead to unexpected or desirable results.

The way the snippets package seems to handle it is to look at all snippets and make the prefix regex require one or more of any observed characters to be present (so if spaces are present in a snippet definition, they will be allowed). This could probably be adpated here too, but good luck finding someone who will put in the time to do this. It seems like a lot of work to put in, especially when considering how annoying it would be to have whitespace in snippets anyway. As it is, autocomplete-snippets currently relies on the prefix provided by autocomplete-plus, as seen here.

[yubaoquan]

Conclusion: People should avoid using whitespace as a part of snippet.