From a6eb86da71e0db1386f2b013eba31f12c53cc6b5 Mon Sep 17 00:00:00 2001
From: berik <berik@mobile.dev>
Date: Tue, 23 Aug 2022 15:02:19 +0200
Subject: [PATCH] Add recoverCatching

recoverCatching tries to recover, exceptions in transformation cause an error result.
---
 build.gradle.kts                              |  5 ++++
 .../com/github/michaelbull/result/Or.kt       | 21 +++++++++++++
 .../com/github/michaelbull/result/OrTest.kt   | 30 +++++++++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/build.gradle.kts b/build.gradle.kts
index c83c04f..86bc6d4 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -195,6 +195,11 @@ subprojects {
                             name.set("Dmitry Suzdalev")
                             url.set("https://github.com/dimsuz")
                         }
+
+                        contributor {
+                            name.set("Berik Visschers")
+                            url.set("https://visschers.nu/")
+                        }
                     }
 
                     scm {
diff --git a/kotlin-result/src/commonMain/kotlin/com/github/michaelbull/result/Or.kt b/kotlin-result/src/commonMain/kotlin/com/github/michaelbull/result/Or.kt
index e61116b..b6d6ed7 100644
--- a/kotlin-result/src/commonMain/kotlin/com/github/michaelbull/result/Or.kt
+++ b/kotlin-result/src/commonMain/kotlin/com/github/michaelbull/result/Or.kt
@@ -66,6 +66,27 @@ public inline infix fun <V, E> Result<V, E>.recover(transform: (E) -> V): Ok<V>
     }
 }
 
+/**
+ * Returns the [transformation][transform] of the [error][Err.error], catching and encapsulating any
+ * thrown exception as a failure if this [Result] is [Err], otherwise this [Ok].
+ */
+public inline infix fun <V, E> Result<V, E>.recoverCatching(transform: (E) -> V): Result<V, Throwable> {
+    contract {
+        callsInPlace(transform, InvocationKind.AT_MOST_ONCE)
+    }
+
+    return when (this) {
+        is Ok -> this
+        is Err -> {
+            try {
+                Ok(transform(error))
+            } catch (e: Throwable) {
+                Err(e)
+            }
+        }
+    }
+}
+
 /**
  * Returns the [transformation][transform] of the [error][Err.error] if this [Result] is [Err]
  * and satisfies the given [predicate], otherwise this [Result].
diff --git a/kotlin-result/src/commonTest/kotlin/com/github/michaelbull/result/OrTest.kt b/kotlin-result/src/commonTest/kotlin/com/github/michaelbull/result/OrTest.kt
index 6abb300..bb20c46 100644
--- a/kotlin-result/src/commonTest/kotlin/com/github/michaelbull/result/OrTest.kt
+++ b/kotlin-result/src/commonTest/kotlin/com/github/michaelbull/result/OrTest.kt
@@ -82,6 +82,36 @@ class OrTest {
         }
     }
 
+    class RecoverCatching {
+        @Test
+        fun returnsValueIfOk() {
+            assertEquals(
+                expected = Ok(3000),
+                actual = Ok(3000).recoverCatching { 4000 }
+            )
+        }
+
+        @Test
+        fun returnsTransformedValueIfErr() {
+            assertEquals(
+                expected = Ok(2000),
+                actual = Err(4000).recoverCatching { 2000 }
+            )
+        }
+
+        @Test
+        fun returnsErrorIfTransformerThrows() {
+            val exception = IllegalArgumentException("throw me")
+
+            assertEquals(
+                expected = exception,
+                actual = Err(4000)
+                    .recoverCatching { throw exception }
+                    .getError()
+            )
+        }
+    }
+
     class RecoverIf {
         @Test
         fun returnsValueIfOk() {