Activating the gem puts the gem on the load path, where simply requiring
the file will search every gem that's installed until it can find a gem
that contains the `did_you_mean` file.
Calling RubyGems' `require` will search each installed gem until it can
find one that contains the file it should require. This means that the
more gems you have installed, the longer it can take to require that
gem.
To see this in action, lets compare the number of `stat` calls for a
"bare require" vs the number of `stat` calls for a require that follows
a gem activation by using these two programs:
```
[aaron@TC rubygems (master)]$ cat req_dym.rb
begin
require 'did_you_mean'
rescue LoadError
end
[aaron@TC rubygems (master)]$ cat gem_dym.rb
begin
gem 'did_you_mean'
require 'did_you_mean'
rescue Gem::LoadError, LoadError
end
```
The first program just requires the `did_you_mean` gem, where the second
one activates the gem, then requires it. We can count the number of
`stat` calls using `dtrace`:
```
[aaron@TC rubygems (master)]$ ruby -v
ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin15]
[aaron@TC rubygems (master)]$ sudo dtrace -q -n 'syscall::stat*:entry { printf("%s\n", copyinstr(arg0)); }' -c`rbenv which ruby`" --disable-did_you_mean req_dym.rb" | wc -l
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
283
[aaron@TC rubygems (master)]$ sudo dtrace -q -n 'syscall::stat*:entry { printf("%s\n", copyinstr(arg0)); }' -c`rbenv which ruby`" --disable-did_you_mean gem_dym.rb" | wc -l
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
13
```
The "bare require" version does over 10x the number of stat calls
compared to the "gem, then require" version. Of course the number for
the first one depends on the number of gems you have installed that sort
before the `did_you_mean` gem.
Lets also look at trunk Ruby:
```
[aaron@TC rubygems (master)]$ ruby -v
ruby 2.4.0dev (2016-02-25 trunk 53940) [x86_64-darwin15]
[aaron@TC rubygems (master)]$ sudo dtrace -q -n 'syscall::stat*:entry { printf("%s\n", copyinstr(arg0)); }' -c`rbenv which ruby`" --disable-did_you_mean req_dym.rb" | wc -l
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
2325
[aaron@TC rubygems (master)]$ sudo dtrace -q -n 'syscall::stat*:entry { printf("%s\n", copyinstr(arg0)); }' -c`rbenv which ruby`" --disable-did_you_mean gem_dym.rb" | wc -l
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
dtrace: error on enabled probe ID 3 (ID 826: syscall::stat64:entry): invalid user access in action #1 at DIF offset 24
685
```
This change will reduce the number of `stat` calls on trunk Ruby too,
but since this installation doesn't have the `did_you_mean` gem,
RubyGems is still reading every gem spec file so that it can raise a
`Gem::LoadError` exception with a nice error message. If we can modify
RubyGems a little, it may be possible to drop the number of stat calls
even on a Ruby installation that doesn't have the `did_you_mean` gem.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53941 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* eval_error.c (error_print): use same error position format when
no backtrace too.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53919 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* eval_error.c (error_pos): include a clone after the position.
* eval_error.c (error_print, error_handle): do not print a colon
if the error position is unavailable.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53917 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
space for titlecase indices; adding additional macros to add or
extract titlecase index; adding comments for better documentation.
* enc/unicode.c: Moving some macros to include/ruby/oniguruma.h;
activating use of titlecase indices.
(with Kimihito Matsui)
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53915 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* io.c (rb_io_gets_internal): read one line from an IO without
setting ARGF.lineno.
* parse.y (lex_io_gets): use rb_io_gets_internal not to affect
$. global variable.
* ruby.c (load_file): no longer reset $.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53913 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* numeric.c (flo_to_s, rb_fix2str): use rb_usascii_str_new instead
of rb_usascii_str_new_cstr, when the length can be calculated.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53910 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
data (new table, with indices from other tables).
* enc/unicode.c: Ignoring titlecase data indices for the moment.
(with Kimihito Matsui)
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53906 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* iseq.h (iseq_mark_ary_index): get rid of trailing comma and name
the magic number for iseq_mark_ary_create.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53905 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
start_stream call, caused strict parsers like on JRuby to err.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53899 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* ruby.c (process_options): remove unnecessary context.
rb_parser_append_print and rb_parser_while_loop just append some
nodes and do not depend on the context.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53893 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_core.h (CoreDataFromValue): split as an expression from
GetCoreDataFromValue, which can be a statement only.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53888 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* test/ruby/test_dir_m17n.rb (test_glob_encoding): get rid of
conversion when LC_ALL=C and filesystem encoding is ASCII-8BIT.
[ruby-core:73868] [Bug #12081]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53881 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* README.md: a few grammatical changes to the main Ruby README.md.
[Fix GH-1259]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53878 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* dir.c (push_pattern, push_glob): deal with read paths as UTF-8
to stat later, on Windows as well as OS X.
[ruby-core:73868] [Bug #12081]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53877 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* lib/find.rb (Find#find): raise with the given path name if it
does not exist. [ruby-dev:49497] [Bug #12087]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53874 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
