perf: Generating files from a list which is not a simple string rather a List<Map<String, dynamic>> takes over 30 minutes

[absar]

Generating files from a list which is not a simple string rather a List<Map<String, dynamic>> takes exponentially greater time. For example {{#updateMethods}}{{{usecaseName.snakeCase()}}}.dart{{/updateMethods}} takes over 30 minutes to generate 4 files on Windows 10 i7 processor with 16gb RAM, the process consumes only around 25% CPU and negligible disk and memory activity, however if you change the name extraction from triple { to double e.g. {{#updateMethods}}{{usecaseName.snakeCase()}}.dart{{/updateMethods}} then it generates in 5 seconds, however it only generates a single file by appending all names, with all the content meant for the 4 files.
Using latest mason CLI, Flutter 3.16.9

Sample input data:

{
  "project_name": "Project1",
  "feature_name": "Wallet",
  "updateMethods": [
    { "usecaseName": "UpdateBalance", "paramsToUpdate": [{"paramName": "balance", "paramType": "double"}]},
    { "usecaseName": "RewardA", "paramsToUpdate": [{"paramName": "balance", "paramType": "double"}, {"paramName": "rewardedCoins", "paramType": "double"}, {"paramName": "rewardedAt", "paramType": "DateTime"}]},
    { "usecaseName": "RewardB", "paramsToUpdate": [{"paramName": "balance", "paramType": "double"}, {"paramName": "rewardedCoins", "paramType": "double"}, {"paramName": "rewardedAt", "paramType": "DateTime"}]},
    { "usecaseName": "UpdateName", "paramsToUpdate": [{"paramName": "name", "paramType": "String"}]}
  ]
}

[felangel]

Hi @absar 👋
Thanks for opening an issue!

It would be super helpful if you could provide a link to a minimal reproduction sample, thanks!

[absar]

Hi @felangel here you go https://github.com/absar/mason_performance_issue_1257
Check the readme for additional comments and reproduction steps