Fix a parser hang on invalid CSS (#2276)

Previously invalid CSS with unbalanced parentheses could cause esbuild's CSS parser to hang. An example of such an input is the CSS file :x(. This hang has been fixed.

Add support for custom log message levels

This release allows you to override the default log level of esbuild's individual log messages. For example, CSS syntax errors are treated as warnings instead of errors by default because CSS grammar allows for rules containing syntax errors to be ignored. However, if you would like for esbuild to consider CSS syntax errors to be build errors, you can now configure that like this:

• CLI

  $ esbuild example.css --log-override:css-syntax-error=error

• JS API

  let result = await esbuild.build({
    entryPoints: ['example.css'],
    logOverride: {
      'css-syntax-error': 'error',
    },
  })

• Go API

  result := api.Build(api.BuildOptions{
    EntryPoints: []string{"example.ts"},
    LogOverride: map[string]api.LogLevel{
      "css-syntax-error": api.LogLevelError,
    },
  })

You can also now use this feature to silence warnings that you are not interested in. Log messages are referred to by their identifier. Each identifier is stable (i.e. shouldn't change over time) except there is no guarantee that the log message will continue to exist. A given log message may potentially be removed in the future, in which case esbuild will ignore log levels set for that identifier. The current list of supported log level identifiers for use with this feature can be found below:

JavaScript:

• assign-to-constant
• call-import-namespace
• commonjs-variable-in-esm
• delete-super-property
• direct-eval
• duplicate-case
• duplicate-object-key
• empty-import-meta
• equals-nan
• equals-negative-zero
• equals-new-object
• html-comment-in-js
• impossible-typeof
• private-name-will-throw
• semicolon-after-return
• suspicious-boolean-not
• this-is-undefined-in-esm
• unsupported-dynamic-import
• unsupported-jsx-comment
• unsupported-regexp
• unsupported-require-call

CSS:

• css-syntax-error
• invalid-@charset
• invalid-@import
• invalid-@nest
• invalid-@layer
• invalid-calc
• js-comment-in-css
• unsupported-@charset
• unsupported-@namespace
• unsupported-css-property

Bundler:

• different-path-case
• ignored-bare-import
• ignored-dynamic-import
• import-is-undefined
• package.json
• require-resolve-not-external
• tsconfig.json

Source maps:

• invalid-source-mappings
• sections-in-source-map
• missing-source-map
• unsupported-source-map-comment

Documentation about which identifiers correspond to which log messages will be added in the future, but hasn't been written yet. Note that it's not possible to configure the log level for a build error. This is by design because changing that would cause esbuild to incorrectly proceed in the building process generate invalid build output. You can only configure the log level for non-error log messages (although you can turn non-errors into errors).