[BUG] limit version prefix to optional `v`

[mbtools]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

The following "ranges" are currently considered valid: > v=1.2.3, > vvv1.2.3, > v==1.2.3, > v=vv==v1.x

The validation is not strict enough and allows =, v=, and nonsensical prefixes as well.

Expected Behavior

With next major semver, the version prefix should be limited to a single, optional v. Other prefixes shall not be permitted anymore.

Suggested change:

// createToken('LOOSEPLAIN', `[v=\\s]*${src[t.MAINVERSIONLOOSE] // old
createToken('LOOSEPLAIN', `v?\\s*${src[t.MAINVERSIONLOOSE] // new

// createToken('XRANGEPLAIN', `[v=\\s]*(${src[t.XRANGEIDENTIFIER]})` +  // old
createToken('XRANGEPLAIN', `v?(${src[t.XRANGEIDENTIFIER]})` +// new

// createToken('XRANGEPLAINLOOSE', `[v=\\s]*(${src[t.XRANGEIDENTIFIERLOOSE]})` + // old
createToken('XRANGEPLAINLOOSE', `v?\\s*(${src[t.XRANGEIDENTIFIERLOOSE]})` + // new

Steps To Reproduce

validRange('> v=1.2.3') 

Environment

• node-semver: 7.6.0

[wraithgar]

Added this to #501

[mbtools]

I have done some analysis of all versions, dependencies and engine ranges used in the top 5200 npm package.json files:

Type of Range	Count
^	52049
semver	14049
>=	2934
~	1979
||	841
*	730
x	502
major	348
=	162
"latest"	154
npm:	101
git:	69
-	60
file:	44
>	25
major.minor	24
"next"	15
http/s:	12
link:	7
portal:	3
<	3
.	3
v1.1.0	1
./	1
workspace:	1
v1.13.4	1
Grand Total	74118

The use of v or v= prefixes is extremely rare. It's only 2 cases (which could be tags and valid).

I would suggest to put up a deprecation notice of these semver v1 notations and then completely stick to semver v2 (i.e. no prefixes, not even a v) with the next major.

[ljharb]

why even bother removing the v? there's nothing conceptually wrong with it; npm doesn't comply with semver v2 anyways; and https://semver.org/#is-v123-a-semantic-version supports its use as an optional prefix.

[mbtools]

Agree. Removing v won't make a difference. Stats are interesting nevertheless 😃