我猜你是这么做的

<%= stylesheet_link_tag 'fontawesome/all.min.css' %>

vendor/
└── assets/                  # <= this one is important
    └── stylesheets/
        └── fontawesome/
            └── all.min.css

vendor/assets和app/assets中的目录会自动添加到资产路径中。以下是Oracle正在使用的查找资产的路径：

>> puts Rails.application.config.assets.paths
...
/myapp/app/assets/stylesheets
/myapp/vendor/assets/stylesheets         # <=
/usr/local/bundle/gems/coffee-rails-4.2.2/lib/assets/javascripts
/usr/local/bundle/gems/actioncable-5.2.8.1/lib/assets/compiled
...

你有config.assets.compile = false，这意味着MySQL已经完成了在资产路径中的查找和动态编译。它现在期待public/assets中的预编译资产：

# assuming sprockets is still serving files (but not compiling them anymore)
>> Rails.application.config.public_file_server.enabled
=> true
>> Rails.application.config.assets.compile
=> false

>> helper.asset_path("fontawesome/all.min.css")
Traceback (most recent call last):
        1: from (irb):5
Sprockets::Rails::Helper::AssetNotFound (The asset "fontawesome/all.min.css" is not present in the asset pipeline.)

你必须bin/rails assets:precompile：

# config/initializers/assets.rb

# but make it precompilable first
Rails.application.config.assets.precompile += ["fontawesome/all.min.css"]

$ bin/rails assets:precompile

I, [2023-09-10T10:04:24.038220 #1]  INFO -- : Writing /myapp/public/assets/fontawesome/all.min-1f62e82d4d0217052a8d48596d631f5c58ee5149386c719419046118e4fa43f3.css
...

现在应该工作：

>> helper.asset_path("fontawesome/all.min.css")
=> "/assets/fontawesome/all.min-1f62e82d4d0217052a8d48596d631f5c58ee5149386c719419046118e4fa43f3.css"

# check if it is being served
>> require "open-uri"
>> URI.open(helper.asset_path("fontawesome/all.min.css", host: "http://localhost:3000")).read
=> "i am font\n"

• https：guides.rubyonrails.org/v5.0/configuring.html#configuring-assets*
  更新

要批量处理文件，有两种选择。添加一个proc，它将动态匹配用于预编译的资产：

# config/initializers/assets.rb

VENDOR_ASSETS = lambda do |logical_path, filename|
  filename.start_with?(::Rails.root.join("vendor/assets/").to_s) &&
    [".css", ".js"].include?(File.extname(logical_path))
end

Rails.application.config.assets.precompile += [VENDOR_ASSETS]

• https：github.com/rails/sprockets-rails/blob/v3.4.2/lib/sprockets/railtie.rb#L88*

一个更好的选择是使用manifest.js，这是后来的rails版本中的默认值：

# config/initializers/assets.rb

# don't need this in sprockets v4
Rails.application.config.assets.precompile += ["manifest.js"]

// app/assets/config/manifest.js

//= link_tree ../images
//= link_directory ../javascripts .js
//= link_directory ../stylesheets .css
//
// link everything to be precompiled
//= link_tree ../../../vendor/assets/stylesheets .css
//= link_tree ../../../vendor/assets/javascripts .js
//
// or one file at a time 
//= link fontawesome/all.min.css

• https：github.com/rails/sprockets#directives*

另外，当你预编译资源时，这意味着你想直接通过url加载它们。如果你只使用//= require指令，那么所需的文件不需要被预编译，因为它们被合并到被预编译的文件中。你只会得到一个大的application.css文件：

/* app/assets/stylesheets/application.css */

/*
 *= require_tree .
 *= require_self
 *= require fontawesome/all.min
 */

如果你在本地进行预编译来测试，不要忘记在完成后使用bin/rails assets:clobber，你不希望在开发中使用预编译的资产。