From 1d278628ad7c16f85484d5315a9e4651b7dc67c2 Mon Sep 17 00:00:00 2001
From: "Jorge C. Leitao" <jorgecarleitao@gmail.com>
Date: Thu, 2 Dec 2021 19:34:37 +0000
Subject: [PATCH 1/2] Invalidate caches from CI.

---
 .github/workflows/security.yml | 2 ++
 .github/workflows/test.yml     | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/.github/workflows/security.yml b/.github/workflows/security.yml
index 6da87c38ea1..d40dea14b86 100644
--- a/.github/workflows/security.yml
+++ b/.github/workflows/security.yml
@@ -25,6 +25,8 @@ jobs:
           toolchain: nightly-2021-10-24
           override: true
       - uses: Swatinem/rust-cache@v1
+        with:
+          key: key1
       - name: Install Miri
         run: |
           rustup component add miri
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 43300789307..1dd6d1aaa9e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -77,6 +77,8 @@ jobs:
           toolchain: nightly-2021-10-24
           override: true
       - uses: Swatinem/rust-cache@v1
+        with:
+          key: key1
       - name: Install Miri
         run: |
           rustup component add miri
@@ -96,6 +98,8 @@ jobs:
           toolchain: nightly-2021-10-24
           override: true
       - uses: Swatinem/rust-cache@v1
+        with:
+          key: key1
       - name: Install Miri
         run: |
           rustup component add miri

From 6e7c5cf0f56579d08da7d8359e592cce7c733444 Mon Sep 17 00:00:00 2001
From: "Jorge C. Leitao" <jorgecarleitao@gmail.com>
Date: Thu, 2 Dec 2021 19:31:10 +0000
Subject: [PATCH 2/2] Avoid utf8 checks on MutableUtf8 -> Utf8

---
 src/array/utf8/mutable.rs | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/src/array/utf8/mutable.rs b/src/array/utf8/mutable.rs
index 4d33a3ef7af..6a269a88761 100644
--- a/src/array/utf8/mutable.rs
+++ b/src/array/utf8/mutable.rs
@@ -201,21 +201,31 @@ impl<O: Offset> MutableArray for MutableUtf8Array<O> {
     }
 
     fn as_box(&mut self) -> Box<dyn Array> {
-        Box::new(Utf8Array::from_data(
-            Self::default_data_type(),
-            std::mem::take(&mut self.offsets).into(),
-            std::mem::take(&mut self.values).into(),
-            std::mem::take(&mut self.validity).map(|x| x.into()),
-        ))
+        // Safety:
+        // `MutableUtf8Array` has the same invariants as `Utf8Array` and thus
+        // `Utf8Array` can be safely created from `MutableUtf8Array` without checks.
+        Box::new(unsafe {
+            Utf8Array::from_data_unchecked(
+                self.data_type.clone(),
+                std::mem::take(&mut self.offsets).into(),
+                std::mem::take(&mut self.values).into(),
+                std::mem::take(&mut self.validity).map(|x| x.into()),
+            )
+        })
     }
 
     fn as_arc(&mut self) -> Arc<dyn Array> {
-        Arc::new(Utf8Array::from_data(
-            Self::default_data_type(),
-            std::mem::take(&mut self.offsets).into(),
-            std::mem::take(&mut self.values).into(),
-            std::mem::take(&mut self.validity).map(|x| x.into()),
-        ))
+        // Safety:
+        // `MutableUtf8Array` has the same invariants as `Utf8Array` and thus
+        // `Utf8Array` can be safely created from `MutableUtf8Array` without checks.
+        Arc::new(unsafe {
+            Utf8Array::from_data_unchecked(
+                self.data_type.clone(),
+                std::mem::take(&mut self.offsets).into(),
+                std::mem::take(&mut self.values).into(),
+                std::mem::take(&mut self.validity).map(|x| x.into()),
+            )
+        })
     }
 
     fn data_type(&self) -> &DataType {
@@ -359,7 +369,7 @@ impl<O: Offset> MutableUtf8Array<O> {
         Self::from_data_unchecked(Self::default_data_type(), offsets, values, None)
     }
 
-    /// Creates a new [`Utf8Array`] from a [`TrustedLen`] of `&str`.
+    /// Creates a new [`MutableUtf8Array`] from a [`TrustedLen`] of `&str`.
     #[inline]
     pub fn from_trusted_len_values_iter<T: AsRef<str>, I: TrustedLen<Item = T>>(
         iterator: I,