What does the ~> symbol mean in a bundler Gemfile?

Question

What does the -> mean next to a version number in a Gemfile?

For example:

gem 'sass-rails',   '~> 3.1.5'

No sweat! There is plenty of space on Interwebs. A little duplication is rather good. :) — Waseem, Jan 02 '12 at 19:20
While we're mentioning duplicates, here's the oldest question that it's a dupe of: https://stackoverflow.com/q/3414337 — ReinstateMonica3167040, Jan 09 '20 at 13:36

score 99 · Accepted Answer · edited May 05 '20 at 21:50

99

From the bundler website:

The specifier ~> has a special meaning, best shown by example:
'~> 2.0.3' is identical to '>= 2.0.3' and '< 2.1.'
'~> 2.1' is identical to '>= 2.1' and '< 3.0'.
'~> 2.2.beta' will match prerelease versions like '2.2.beta.12'.

See https://bundler.io/gemfile.html and http://guides.rubygems.org/patterns/#pessimistic-version-constraint

edited May 05 '20 at 21:50

Luke Abel

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answered Jan 02 '12 at 10:53

Tim Brandes

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Yes, you're right and I was way too fast with my answer and was in editing already, sorry! – Tim Brandes Jan 02 '12 at 11:00
Okay, I had been reading the gemfile manual which didn't seem to have that info. Should have just stuck to the pretty pages! – brad Jan 02 '12 at 11:04

score 22 · Answer 2 · edited May 05 '20 at 13:56

22

You usually use this to tell bundler that it's ok to install some minor updates (last digit specified can vary) but not to install some major update.

SO

~> 2.0.3 means >= 2.0.3 ∩ < 2.1

and

~> 2.1 means >= 2.1 ∩ < 3.0

Read more at https://bundler.io/gemfile.html

edited May 05 '20 at 13:56

Luke Abel

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answered Jan 02 '12 at 10:51

Uko

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What does the ~> symbol mean in a bundler Gemfile?

2 Answers2

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