docs: clarify sdkmanrc distribution inference scope

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: brunoborges

README.md

@@ -36,9 +36,9 @@ For information about the latest releases, recent updates, and newly supported d
 
   - `java-version`: The Java version that is going to be set up. Takes a whole or [semver](#supported-version-syntax) Java version. If not specified, the action will expect `java-version-file` input to be specified.
 
-  - `java-version-file`: The path to a file containing java version. Supported file types are `.java-version` and `.tool-versions`. See more details in [about .java-version-file](docs/advanced-usage.md#Java-version-file).
+  - `java-version-file`: The path to a file containing java version. Supported file types are `.java-version`, `.tool-versions`, and `.sdkmanrc`. See more details in [about .java-version-file](docs/advanced-usage.md#Java-version-file).
 
-  - `distribution`: _(required)_ Java [distribution](#supported-distributions).
+  - `distribution`: Java [distribution](#supported-distributions). Required unless `java-version-file` points to `.sdkmanrc` with a recognized distribution suffix (for example `java=21.0.5-tem`).
 
   - `java-package`: The packaging variant of the chosen distribution. Possible values: `jdk`, `jre`, `jdk+fx`, `jre+fx`. Default value: `jdk`.
 

action.yml

@@ -10,7 +10,7 @@ inputs:
     description: 'The path to a file containing the Java version to set up (.java-version, .tool-versions, .sdkmanrc). Used when java-version is not set. See examples of supported syntax in README file'
     required: false
   distribution:
-    description: 'Java distribution. See the list of supported distributions in README file. When using .sdkmanrc with a distribution suffix (e.g., java=21.0.5-tem), this input is optional.'
+    description: 'Java distribution. See the list of supported distributions in README file. This input is required except when java-version-file points to .sdkmanrc with a recognized distribution suffix (e.g., java=21.0.5-tem).'
     required: false
   java-package:
     description: 'The package type (jdk, jre, jdk+fx, jre+fx)'

docs/advanced-usage.md

@@ -604,18 +604,17 @@ steps:
   Supported files are `.java-version`, `.tool-versions` and `.sdkmanrc`.
   * In `.java-version` file, only the version should be specified (e.g., 17.0.7). The `.java-version` file recognizes all variants of the version description according to [jenv](https://github.com/jenv/jenv).
   * In `.tool-versions` file, java version should be preceded by the java keyword (e.g., java 17.0.7). The `.tool-versions` file supports version specifications in accordance with [asdf](https://github.com/asdf-vm/asdf) standards, adhering to Semantic Versioning ([semver](https://semver.org/)).
-  * In `.sdkmanrc` file, java version should be preceded by the `java=` prefix (e.g., java=17.0.7-tem) and include the distribution. The `.sdkmanrc` file supports version specifications in accordance with [file format](https://sdkman.io/usage#env-command), see [Sdkman! documentation](https://sdkman.io/jdks) for more information.
+  * In `.sdkmanrc` file, java version should be preceded by the `java=` prefix (e.g., `java=17.0.7-tem`). When a recognized SDKMAN distribution suffix is present, setup-java can infer the `distribution` input automatically. Supported suffix mappings are: `tem` -> `temurin`, `sem` -> `semeru`, `albba`/`dragonwell` -> `dragonwell`, `zulu` -> `zulu`, `amzn` -> `corretto`, `graal`/`graalce` -> `graalvm`, `librca` -> `liberica`, `ms` -> `microsoft`, `oracle` -> `oracle`, `sapmchn` -> `sapmachine`, `jbr` -> `jetbrains`. Unrecognized suffixes require setting `distribution` explicitly. The `.sdkmanrc` file supports version specifications in accordance with [file format](https://sdkman.io/usage#env-command), see [Sdkman! documentation](https://sdkman.io/jdks) for more information.
 
 
   If both `java-version` and `java-version-file` **inputs** are provided, the `java-version` input will be used.
 
-**Example step using `Sdkman!`**:
+**Example step using `Sdkman!`** (distribution inferred from `.sdkmanrc`):
 ```yml
   - name: Setup java
     uses: actions/setup-java@v5
     with:
       java-version-file: '.sdkmanrc'
-      distribution: 'temurin'
 ```
 
 **Example `.sdkmanrc`**: