buildProduction is doing too much and is slow

I have been exposing buildProduction to some more use cases. One of them is https://github.com/jsconf/2014.jsconf.eu

I've cloned the repos and built the page with jekyll. Then ran buildProduction like so:

munter at pollex in ~/git/2014.jsconf.eu on gh-pages
$ buildProduction _site/*.html --outroot build
Guessing --root from input files: file:///home/munter/git/2014.jsconf.eu/_site
 ✔ 0.002 secs: logEvents
 ✔ 0.001 secs: registerRequireJsConfig
 ✔ 0.005 secs: registerLabelsAsCustomProtocols
 ✔ 1.277 secs: loadAssets
 ✔ 0.154 secs: populate
 ✔ 0.011 secs: assumeRequireJsConfigHasBeenFound
 ⚠ WARN: _site/sponsors/images/bloomberg.svg: Parse error in _site/sponsors/images/bloomberg.svg
         entity not found:&ns_svg;
         @#[line:undefined,col:undefined]
 ✔ 187.192 secs: populate
 ✔ 0.045 secs: fixBaseAssetsOfUnresolvedOutgoingRelationsFromHtmlFragments
 ✔ 0.007 secs: assumeThatAllHtmlFragmentAssetsWithoutIncomingRelationsAreNotTemplates
 ✔ 27.597 secs: populate
 ✔ 0.034 secs: removeRelations
 ✔ 0.065 secs: addDataVersionAttributeToHtmlElement
 ✔ 0.018 secs: replaceDartWithJavaScript
 ✔ 0.012 secs: populate
 ✔ 0.035 secs: compileLessToCss
 ✔ 0.039 secs: removeRelations
 ✔ 28.996 secs: populate
 ✔ 29.004 secs: compileJsxToJs
 ✔ 0.098 secs: stripDebug
 ✔ 0.020 secs: removeRelations
 ✔ 2.270 secs: externalizeRelations
 ✔ 0.006 secs: mergeIdenticalAssets
 ✔ 0.131 secs: processImages
 ✔ 0.038 secs: spriteBackgroundImages
 ✔ 0.115 secs: processImages
 ℹ INFO: minifySvgAssetsWithSvgo: Found 2 svg asset(s), but no svgo module is available. Please use npm to install svgo in your project so minifySvgAssetsWithSvgo can require it.
 ✔ 0.041 secs: minifySvgAssetsWithSvgo
 ✔ 63.806 secs: inlineKnockoutJsTemplates
 ✔ 0.407 secs: liftUpJavaScriptRequireJsCommonJsCompatibilityRequire
 ✔ 12.199 secs: flattenRequireJs
 ✔ 3.135 secs: removeUnreferencedAssets
 ✔ 4.384 secs: convertCssImportsToHtmlStyles
 ✔ 0.106 secs: removeDuplicateHtmlStyles
 ✔ 6.176 secs: mergeIdenticalAssets
 ✔ 30.558 secs: bundleRelations
 ✔ 0.040 secs: splitCssIfIeLimitIsReached
 ✔ 0.057 secs: replaceRequireJsWithAlmond
 ✔ 24.387 secs: bundleRelations
 ✔ 12.394 secs: mergeIdenticalAssets
 ✔ 2.216 secs: ngmin
 ✔ 0.020 secs: removeNobundleAttribute
 ✔ 9.192 secs: inlineCssImagesWithLegacyFallback
 ✔ 0.018 secs: mergeIdenticalAssets
 ✔ 121.220 secs: minifyAssets
 ✔ 0.006 secs: replaceSymbolsInJavaScript
 ✔ 0.364 secs: compressJavaScript
 ✔ 0.005 secs: removeEmptyJavaScripts
 ✔ 0.023 secs: removeEmptyStylesheets
 ✔ 15.349 secs: inlineRelations
 ✔ 75.147 secs: inlineAngularJsTemplates
 ✔ 2.068 secs: duplicateFavicon
 ✔ 0.000 secs: setAsyncOrDeferOnHtmlScripts
 ✔ 0.028 secs: omitFunctionCall
 ✔ 0.033 secs: inlineRelations
 ✔ 5.033 secs: moveAssetsInOrder
 ✔ 636.133 secs: buildProduction
 ✔ 2.855 secs: writeAssetsToDisc
  Html 153  6.6 MB
   Css   1 11.1 KB
   Ico   2 13.4 KB
   Png  36  4.9 MB
  Jpeg  70 18.4 MB
 Asset   4 41.0 KB
   Svg   2 38.6 KB
Total: 268 30.1 MB
 ✔ 0.022 secs: writeStatsToStderr

Note all the time spent in transforms that should have no impact at all. The does not use neither Knockout nor Angular nor React, yet a lot of time is spent in those transforms. Why?

assetgraph / assetgraph-builder

buildProduction is doing too much and is slow #144