Upgrading to new versions

This file only lists breaking changes you need to be aware of when you upgrade to a new askama version. Please see our release notes to get a list of all changes and improvements that might be useful to you.

From askama v0.15 to askama v0.16

Variable creation without value cannot be done with let/set anymore. You need to use the new decl/declare instead:
```
{% decl variable_without_value %}
```
Duplicated blocks will now error and prevent compilation instead of emitting a warning.

From askama v0.14 to askama v0.15

The MSRV of this release is 1.88.

Filter functions now need to have the filter_fn proc-macro used on them. So if you had:

pub fn to_string(s: impl ToString, _: &dyn Values) -> Result<String> {
    Ok(s.to_string())
}

It now becomes:

#[askama::filter_fn]
pub fn to_string(s: impl ToString, _: &dyn Values) -> Result<String> {
    Ok(s.to_string())
}

Variables declared in the templates cannot be named caller anymore.

From askama v0.13 to askama v0.14

The MSRV of this release is 1.83.
When assigning a new variable ({% let var = … %}) with a local variable was value, it is moved or copied, not referenced.
Try expressions ({{ expr? }}) are not placed behind a reference.
FastWritable implementations have access to runtime values.
Custom filters have access to runtime values, and must add a second &dyn askama::Values argument as in the example.
|unique is a built-in filter; |titlecase is an alias for |title.

From askama v0.12 to askama v0.13

A blog post summarizing changes and also explaining the merge of rinja and askama is available here.

List of breaking changes:

The MSRV of this release is 1.81.
The integration crates were removed. Instead of depending on e.g. askama_axum / askama_axum, please use template.render() to render to a Result<String, askama::Error>.

Use e.g. .map_err(|err| err.into_io_error())? if your web-framework expects std::io::Errors, or err.into_box() if it expects Box<dyn std::error::Error + Send + Sync>.

Please read the documentation of your web-framework how to turn a String into a web-response.
The fields Template::EXTENSION and Template::MIME_TYPE were removed.
You may not give variables a name starting with __askama, or the name of a rust keyword.
#[derive(Template)] cannot be used with unions.
|linebreaks, |linebreaksbr and |paragraphbreaks escape their input automatically.
|json does not prettify its output by default anymore. Use e.g. |json(2) for readable output.
The binary operators |, & and ^ are now called bitor, bitand and xor, resp.
The feature "humansize" was removed. The filter |humansize is always available.
The feature "serde-json" is now called "serde_json".
The feature "markdown" was removed. Use comrak directly.
The feature "serde-yaml" was removed. Use e.g. yaml-rust2 directly.

From rinja v0.3 to askama v0.13

The MSRV of this release is 1.81.
The projects rinja and askama were re-unified into one project. You need to replace instances of rinja with askama, e.g.
```
-use rinja::Template;
+use askama::Template;
```
```
 [dependencies]
-rinja = "0.3.5"
+askama = "0.13.0"
```
The integration crates were removed. Instead of depending on e.g. rinja_axum / askama_axum, please use template.render() to render to a Result<String, askama::Error>.

Use e.g. .map_err(|err| err.into_io_error())? if your web-framework expects std::io::Errors, or err.into_box() if it expects Box<dyn std::error::Error + Send + Sync>.

Please read the documentation of your web-framework how to turn a String into a web-response.
The fields Template::EXTENSION and Template::MIME_TYPE were removed.
The feature "humansize" was removed. The filter |humansize is always available.
You may not give variables a name starting with __rinja, or the name of a rust keyword.
#[derive(Template)] cannot be used with unions.

From rinja v0.2 to rinja v0.3

You should be able to upgrade to v0.3 without changes.

From askama v0.12 to rinja v0.2

Have a look at our blog posts that highlight some of the best features of our releases, and give you more in-dept explanations: docs.rs switching jinja template framework from tera to rinja.

The MSRV of this release is 1.71.

You need to replace instances of askama with rinja, e.g.

-use askama::Template;
+use rinja::Template;

 [dependencies]
-askama = "0.12.1"
+rinja = "0.2.0"

|linebreaks, |linebreaksbr and |paragraphbreaks escape their input automatically.
|json does not prettify its output by default anymore. Use e.g. |json(2) for readable output.
The binary operators |, & and ^ are now called bitor, bitand and xor, resp.
Filter as_ref is now just ref
The feature "serde-json" is now called "serde_json".
The feature "markdown" was removed. Use comrak directly.
The feature "serde-yaml" was removed. Use e.g. yaml-rust2 directly.

From askama v0.11 to askama v0.12

The magic _parent field to access &**self was removed.
Integration implementations do not need an ext argument anymore.
The iron integration was removed.

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