Dash `-` in `sourceName` gets changed to underscore `_` inside files but not in file names

From @petrroll on July 28, 2017 9:41

Steps to reproduce

1. dotnet new -i "Peachpie.Templates::*" (template’s config on GitHub)
2. dotnet new peachpie-web -n tst-tst // specifies a sourceName that gets replaced
3. dotnet restore

It should be reproducible with any template, didn’t have time to find any other that uses sourceName both in files and filenames, though.

Expected behavior

The original sourceName gets replaced either with tst-tst or tst_tst everywhere, i.e. both in the source files (including the .sln) and in file names (e.g. names of the .msbuildproj or folders).

Actual behavior

The original sourceName gets replaced with tst_tst inside source files (e.g. in the .sln file or the server’s Program.cs) but with tst-tst in file and folder names.

The mismatch between paths expected by the .sln file (it expects the projects in tst_tst.Server and tst_tst folders while they actually are in tst-tst.Server and tst-tst folders) breaks the .sln file and thus the template’s build.

Environment data

dotnet --info output:

Tested on both .NET SDK 1.0.4 on Windows and on .NET SDK 2.0 preview-2 on Ubuntu via WSL.

.NET Command Line Tools (2.0.0-preview2-006497)

Product Information:
 Version:            2.0.0-preview2-006497
 Commit SHA-1 hash:  06a2093335

Runtime Environment:
 OS Name:     ubuntu
 OS Version:  16.04
 OS Platform: Linux
 RID:         ubuntu.16.04-x64
 Base Path:   /usr/share/dotnet/sdk/2.0.0-preview2-006497/

Microsoft .NET Core Shared Framework Host

  Version  : 2.0.0-preview2-25407-01
  Build    : 40c565230930ead58a50719c0ec799df77bddee9

.NET Command Line Tools (1.0.4)

Product Information:
 Version:            1.0.4
 Commit SHA-1 hash:  af1e6684fd

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.15063
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\1.0.4

Copied from original issue: dotnet/cli#7307

[seancpeters]

Hi @petrroll, There is a way to slightly modify the template source to prevent this problem:

• In template.json, change the value of sourceName from “MyWebsite1” to “MyWebsite.1”.
• In Program.cs, change the namespace from “MyWebsite1.Server” to “MyWebsite._1.Server”.
• Change all other occurrences of “MyWebsite1” to “MyWebsite.1”, both in the file names and the file contents. (I believe the only file content changes are in MyWebste1.sln and MyWebsite1.Server.csproj)

With those changes, your template should work as expected - and should also work for other versions of dotnet new.

USing the -n tst-tst input, all occurrences of “MyWebsite.1” will be replaced with “tst-tst”, and the namespace in Program.cs will be replaced with “tst_tst”.

Please let me know if this solution works for you - if not, let me know the problem, and we’ll figure it out 😃

Partial explanation of what’s happening behind the scenes:

The reason this is necessary is because when the template engine creates an instance of a template, it makes variants on the input name that are meant to be safe to use in particular circumstances. For example it makes a variant that is a valid namespace, and another variant which is a valid class name. But the template engine doesn’t try to determine the semantic meaning of various symbols, so it doesn’t explicitly know when to use the namespace version. This is why we had to make the slightly different change in Program.cs.

The transformations used to make the variants are applied to both the sourceName value, and the user provided input value, and maps the results of the transformed sourceName to the transformed input name. The original values are also included in the mapping. In this case, with original values:

• sourceName = MyWebsite.1
• (input) name: tst-tst

The transformation for namespace results in:

• sourceName (variant) = MyWebsite._1
• name (variant) = tst_tst

And the transformation that could be used for class name (if you wanted that type of replacement) is:

• sourceName (variant) = MyWebsite__1
• name (variant) = tst_tst

These variants (and the original) are used to setup replacements from the template source to the output of:

• MyWebsite.1 -> tst-tst
• MyWebsite._1 -> tst_tst
• MyWebsite__1 -> tst_tst So anywhere in the template file contents where the value on the left appears, it gets replaced with the corresponding value on the right.

For the file names, we only replace the original sourceName value with the original user provided name value. We’re in the early stages of planning for more control of filename replacements, but don’t have anything concrete yet.

[cwensley]

For others looking at this issue, I’ve had success using the following symbol to support both the new and old sdk with a single template:

		"namespace-for-old-sdk": {
			"type": "generated",
			"generator": "coalesce",
			"parameters": {
				"sourceVariableName": "safe_namespace",
				"fallbackVariableName": "safe_name"
			},
			"replaces": "MyName._1"
		}

This doesn’t mean you can use ‘.’ or ‘-’ in the name with the old sdk, but they will work with the new sdk.

Hope this helps someone!