decompile generates incorrect code for empty concat string

[NeilMacMullen]

Bicep version
2.23.0
Describe the bug

When concatenating an empty string, BICEP decompiler gets very confused and generates invalid BICEP...

Source ARM

 "variables": {
    "apiSiteName": "[concat(parameters('siteName'), '')]",
    "apiAppInsightsName": "[concat(parameters('siteName'), 'Insights')]"
  },

Output BICEP

var apiSiteName_var = 'siteName${
var apiAppInsightsName_var = '${siteName}Insights'

[alex-frankel]

Interesting - first can you double check the version number? Bicep's latest release is 0.3.255.

What is the scenario in which you'd want to concat an empty string? isn't that a no-op?

[NeilMacMullen]

➜ az bicep version
Bicep CLI version 0.3.255 (589f0375df)

What is the scenario in which you'd want to concat an empty string? isn't that a no-op?

Yes it is. It was just a manual tweak to an ARM template that was originally catting some text to a parameter. I wanted to temporary sidestep the catting and it was quicker to cat an empty string than remove the entire concat call.

It's a fairly unlikely case in practice but may indicate a more general problem with empty strings....

[majastrz]

I think we should fix this regardless of the validity of the scenario. Most likely a super simple fix.