Regex string allocation

[ericproulx]

While memory profilling our app, I found these strange memory allocations :

1442  "(?<_"
974  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
468  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

983  ")"
974  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 9  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/mustermann-grape-1.0.0/lib/mustermann/grape.rb:20

974  ">"
974  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41

468  ">)"
468  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53
12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:a|%61)(?:c|%63)(?:c|%63)(?:o|%6f|%6F)(?:u|%75)(?:n|%6e|%6E)(?:t|%74)(?:s|%73)\\/(?<account_id>[^\\/\\?#.]+)\\/(?:m|%6d|%6D)(?:e|%65)(?:s|%73)(?"
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:a|%61)(?:p|%70)(?:p|%70)(?:o|%6f|%6F)(?:i|%69)(?:n|%6e|%6E)(?:t|%74)(?:m|%6d|%6D)(?:e|%65)(?:n|%6e|%6E)(?:t|%74)(?:s|%73)\\/(?:a|%61)(?:v|%7"
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:c|%63)(?:h|%68)(?:a|%61)(?:n|%6e|%6E)(?:g|%67)(?:e|%65)(?:_|%5f|%5F)(?:r|%72)(?:e|%65)(?:q|%71)(?:u|%75)(?:e|%65)(?:s|%73)(?:t|%74)(?:s|%73"
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:c|%63)(?:o|%6f|%6F)(?:n|%6e|%6E)(?:v|%76)(?:e|%65)(?:r|%72)(?:s|%73)(?:a|%61)(?:t|%74)(?:i|%69)(?:o|%6f|%6F)(?:n|%6e|%6E)(?:s|%73)\\/(?<conv"
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:g|%67)(?:r|%72)(?:o|%6f|%6F)(?:u|%75)(?:p|%70)(?:s|%73)\\/(?<group_id>[^\\/\\?#.]+)\\/(?:a|%61)(?:p|%70)(?:p|%70)(?:o|%6f|%6F)(?:i|%69)(?:n|%6e"
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:g|%67)(?:r|%72)(?:o|%6f|%6F)(?:u|%75)(?:p|%70)(?:s|%73)\\/(?<group_id>[^\\/\\?#.]+)\\/(?:f|%66)(?:o|%6f|%6F)(?:r|%72)(?:m|%6d|%6D)(?:s|%73)\\/(?"
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:g|%67)(?:r|%72)(?:o|%6f|%6F)(?:u|%75)(?:p|%70)(?:s|%73)\\/(?<group_id>[^\\/\\?#.]+)\\/(?:m|%6d|%6D)(?:a|%61)(?:n|%6e|%6E)(?:a|%61)(?:g|%67)(?:e"
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:g|%67)(?:r|%72)(?:o|%6f|%6F)(?:u|%75)(?:p|%70)(?:s|%73)\\/(?<group_id>[^\\/\\?#.]+)\\/(?:t|%74)(?:e|%65)(?:a|%61)(?:m|%6d|%6D)(?:s|%73)(?:(?:\\."
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:h|%68)(?:o|%6f|%6F)(?:s|%73)(?:p|%70)(?:i|%69)(?:t|%74)(?:a|%61)(?:l|%6c|%6C)(?:s|%73)\\/(?<hospital_id>[^\\/\\?#.]+)\\/(?:c|%63)(?:o|%6f|%6F)("
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

12  "(?-mix:\\A(?-mix:\\/(?<version>(?-mix:(?:v|%76)(?:2|%32)))\\/(?:s|%73)(?:c|%63)(?:h|%68)(?:e|%65)(?:d|%64)(?:u|%75)(?:l|%6c|%6C)(?:e|%65)\\/(?:g|%67)(?:r|%72)(?:o|%6f|%6F)(?:u|%75)(?:p|%70)(?:s|%73)\\/(?<i"
10  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:41
 2  /Users/eproulx/.rbenv/versions/2.4.9/lib/ruby/gems/2.4.0/gems/grape-1.2.6/lib/grape/router.rb:53

Turns out, its 2 regex defined in router.rb with interpolation. I replaced the 2 lliteral regexs by the Regexp constructor. Therefore, the strings above (memory profiling) are just allocated once and benefits from the frozen_string_literal

[grape-bot]

	1 Warning
⚠️	There’re library changes, but not tests. That’s OK as long as you’re refactoring existing code.

Generated by 🚫 danger

[dblock]

Nitpick, this should describe what it does, eg. "Reduce number of regex string allocations"

[dblock]

Great work. Rebase, I'll merge.

[dblock]

Missing * so danger complains.

[dblock]

Merged thank you