added a source function to include the content of a template without rendering it

[fabpot]

Replaces #1230.

There is one question about the implementation: Should the content be considered safe (which is the current implementation)?

[TomiS]

@fabpot Great to see you were able to implement this! 👍

ps. I'm sorry I wasn't able to finish the PR I started in reasonable time. But client work must come first, as always. :/

[henrikbjorn]

+1 for considering it to be safe.

[Tobion]

Regarding the name source it makes sense to be considered safe. Otherwise it should be named something like file to only load the text representation in escaped form.

[stof]

@Tobion naming it file does not make sense. It does not load a file but the source of a template. There is 2 distinctions:

• templates are not always stored in files (see the ArrayLoader for instance), even if it is the most common setup
• the argument is not a filename but a template name (it is similar when the builtin FilesystemLoader without using the namespaced paths, but it is not anymore when using namespaced paths or the Symfony loader and its bundle convention)

[Tobion]

@stof I didn't suggest to name it file. If you read carefully, you'll see I only gave an argument for having source be considered safe.