Add `@TestOnly` annotation to `Composer.disableSourceInformation()`

`disableSourceInformation()` can only be safely called in a test and
should never be called outside a test as it will change the result
of the composition in unpredictable ways. For this reason it should
have been marked `@TestOnly`.

Also added documentation about when this function can be called and
what the function does.

Test: N/A - annotation and documentation change only
Fixes: 260595475
Relnote: "Added `@TestOnly` to `Composer.disableSourceInformation()`
as this function is only safe to call in a test."

Change-Id: I896c84a91e1ec01f0107c52def0900196e2cde45

diff --git a/compose/runtime/runtime/api/current.txt b/compose/runtime/runtime/api/current.txt
index 20f83f5eb..1339ac2 100644
--- a/compose/runtime/runtime/api/current.txt
+++ b/compose/runtime/runtime/api/current.txt

@@ -113,7 +113,7 @@
     method @androidx.compose.runtime.ComposeCompilerApi public <T> void createNode(kotlin.jvm.functions.Function0<? extends T> factory);
     method @androidx.compose.runtime.ComposeCompilerApi public void deactivateToEndGroup(boolean changed);
     method @androidx.compose.runtime.ComposeCompilerApi public void disableReusing();
-    method public void disableSourceInformation();
+    method @org.jetbrains.annotations.TestOnly public void disableSourceInformation();
     method @androidx.compose.runtime.ComposeCompilerApi public void enableReusing();
     method @androidx.compose.runtime.ComposeCompilerApi public void endDefaults();
     method @androidx.compose.runtime.ComposeCompilerApi public void endMovableGroup();

diff --git a/compose/runtime/runtime/api/public_plus_experimental_current.txt b/compose/runtime/runtime/api/public_plus_experimental_current.txt
index 20810fc..46fdaad 100644
--- a/compose/runtime/runtime/api/public_plus_experimental_current.txt
+++ b/compose/runtime/runtime/api/public_plus_experimental_current.txt

@@ -120,7 +120,7 @@
     method @androidx.compose.runtime.ComposeCompilerApi public <T> void createNode(kotlin.jvm.functions.Function0<? extends T> factory);
     method @androidx.compose.runtime.ComposeCompilerApi public void deactivateToEndGroup(boolean changed);
     method @androidx.compose.runtime.ComposeCompilerApi public void disableReusing();
-    method public void disableSourceInformation();
+    method @org.jetbrains.annotations.TestOnly public void disableSourceInformation();
     method @androidx.compose.runtime.ComposeCompilerApi public void enableReusing();
     method @androidx.compose.runtime.ComposeCompilerApi public void endDefaults();
     method @androidx.compose.runtime.ComposeCompilerApi public void endMovableGroup();

diff --git a/compose/runtime/runtime/api/restricted_current.txt b/compose/runtime/runtime/api/restricted_current.txt
index 3cc2fcc..d14716b 100644
--- a/compose/runtime/runtime/api/restricted_current.txt
+++ b/compose/runtime/runtime/api/restricted_current.txt

@@ -115,7 +115,7 @@
     method @androidx.compose.runtime.ComposeCompilerApi public <T> void createNode(kotlin.jvm.functions.Function0<? extends T> factory);
     method @androidx.compose.runtime.ComposeCompilerApi public void deactivateToEndGroup(boolean changed);
     method @androidx.compose.runtime.ComposeCompilerApi public void disableReusing();
-    method public void disableSourceInformation();
+    method @org.jetbrains.annotations.TestOnly public void disableSourceInformation();
     method @androidx.compose.runtime.ComposeCompilerApi public void enableReusing();
     method @androidx.compose.runtime.ComposeCompilerApi public void endDefaults();
     method @androidx.compose.runtime.ComposeCompilerApi public void endMovableGroup();

diff --git a/compose/runtime/runtime/src/commonMain/kotlin/androidx/compose/runtime/Composer.kt b/compose/runtime/runtime/src/commonMain/kotlin/androidx/compose/runtime/Composer.kt
index 9d387be..19c83cc 100644
--- a/compose/runtime/runtime/src/commonMain/kotlin/androidx/compose/runtime/Composer.kt
+++ b/compose/runtime/runtime/src/commonMain/kotlin/androidx/compose/runtime/Composer.kt

@@ -1059,6 +1059,15 @@
     val composition: ControlledComposition
         @TestOnly get
 
+    /**
+     * Disable the collection of source information, that may introduce groups to store the source
+     * information, in order to be able to more accurately calculate the actual number of groups a
+     * composable function generates in a release build.
+     *
+     * This function is only safe to call in a test and will produce incorrect composition results
+     * if called on a composer not under test.
+     */
+    @TestOnly
     fun disableSourceInformation()
 
     companion object {