diff --git a/postgresql_archive/src/error.rs b/postgresql_archive/src/error.rs
index 6cc7ea8..e6683d4 100644
--- a/postgresql_archive/src/error.rs
+++ b/postgresql_archive/src/error.rs
@@ -22,6 +22,9 @@ pub enum Error {
     /// Parse error
     #[error(transparent)]
     ParseError(anyhow::Error),
+    /// Poisoned lock
+    #[error("poisoned lock '{0}'")]
+    PoisonedLock(String),
     /// Repository failure
     #[error("{0}")]
     RepositoryFailure(String),
diff --git a/postgresql_archive/src/hasher/registry.rs b/postgresql_archive/src/hasher/registry.rs
index cf6709b..90f3264 100644
--- a/postgresql_archive/src/hasher/registry.rs
+++ b/postgresql_archive/src/hasher/registry.rs
@@ -1,4 +1,5 @@
 use crate::hasher::{blake2b_512, blake2s_256, sha2_256, sha2_512, sha3_256, sha3_512};
+use crate::Error::PoisonedLock;
 use crate::Result;
 use lazy_static::lazy_static;
 use std::collections::HashMap;
@@ -33,13 +34,29 @@ impl HasherRegistry {
     }
 
     /// Get a hasher for the specified extension.
-    fn get<S: AsRef<str>>(&self, extension: S) -> Option<HasherFn> {
+    ///
+    /// # Errors
+    /// * If the registry is poisoned.
+    fn get<S: AsRef<str>>(&self, extension: S) -> Result<Option<HasherFn>> {
         let extension = extension.as_ref().to_string();
         if let Some(hasher) = self.hashers.get(&extension) {
-            return Some(*hasher.read().unwrap());
+            let hasher = *hasher
+                .read()
+                .map_err(|error| PoisonedLock(error.to_string()))?;
+            return Ok(Some(hasher));
         }
 
-        None
+        Ok(None)
+    }
+
+    /// Get the number of hashers in the registry.
+    fn len(&self) -> usize {
+        self.hashers.len()
+    }
+
+    /// Check if the registry is empty.
+    fn is_empty(&self) -> bool {
+        self.hashers.is_empty()
     }
 }
 
@@ -60,29 +77,56 @@ impl Default for HasherRegistry {
 /// Registers a hasher for an extension. Newly registered hashers with the same extension will
 /// override existing ones.
 ///
-/// # Panics
+/// # Errors
 /// * If the registry is poisoned.
 #[allow(dead_code)]
-pub fn register<S: AsRef<str>>(extension: S, hasher_fn: HasherFn) {
-    let mut registry = REGISTRY.lock().unwrap();
+pub fn register<S: AsRef<str>>(extension: S, hasher_fn: HasherFn) -> Result<()> {
+    let mut registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
     registry.register(extension, hasher_fn);
+    Ok(())
 }
 
 /// Get a hasher for the specified extension.
 ///
-/// # Panics
+/// # Errors
 /// * If the registry is poisoned.
-pub fn get<S: AsRef<str>>(extension: S) -> Option<HasherFn> {
-    let registry = REGISTRY.lock().unwrap();
+pub fn get<S: AsRef<str>>(extension: S) -> Result<Option<HasherFn>> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
     registry.get(extension)
 }
 
+/// Get the number of matchers in the registry.
+///
+/// # Errors
+/// * If the registry is poisoned.
+pub fn len() -> Result<usize> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
+    Ok(registry.len())
+}
+
+/// Check if the registry is empty.
+///
+/// # Errors
+/// * If the registry is poisoned.
+pub fn is_empty() -> Result<bool> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
+    Ok(registry.is_empty())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
     fn test_hasher(extension: &str, expected: &str) -> Result<()> {
-        let hasher = get(extension).unwrap();
+        let hasher = get(extension)?.unwrap();
         let data = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 0];
         let hash = hasher(&data)?;
         assert_eq!(expected, hash);
@@ -92,12 +136,16 @@ mod tests {
     #[test]
     fn test_register() -> Result<()> {
         let extension = "sha256";
-        let hashers = REGISTRY.lock().unwrap().hashers.len();
-        assert!(!REGISTRY.lock().unwrap().hashers.is_empty());
-        REGISTRY.lock().unwrap().hashers.remove(extension);
-        assert_ne!(hashers, REGISTRY.lock().unwrap().hashers.len());
-        register(extension, sha2_256::hash);
-        assert_eq!(hashers, REGISTRY.lock().unwrap().hashers.len());
+        let hashers = len()?;
+        assert!(!is_empty()?);
+        REGISTRY
+            .lock()
+            .map_err(|error| PoisonedLock(error.to_string()))?
+            .hashers
+            .remove(extension);
+        assert_ne!(hashers, len()?);
+        register(extension, sha2_256::hash)?;
+        assert_eq!(hashers, len()?);
 
         test_hasher(
             extension,
diff --git a/postgresql_archive/src/matcher/registry.rs b/postgresql_archive/src/matcher/registry.rs
index 3793b03..98671bb 100644
--- a/postgresql_archive/src/matcher/registry.rs
+++ b/postgresql_archive/src/matcher/registry.rs
@@ -1,4 +1,5 @@
 use crate::matcher::{default, postgresql_binaries};
+use crate::Error::PoisonedLock;
 use crate::{Result, DEFAULT_POSTGRESQL_URL};
 use lazy_static::lazy_static;
 use semver::Version;
@@ -34,16 +35,35 @@ impl MatchersRegistry {
 
     /// Get a matcher for the specified URL, or the default matcher if no matcher is
     /// registered for the URL.
-    fn get<S: AsRef<str>>(&self, url: S) -> MatcherFn {
+    ///
+    /// # Errors
+    /// * If the registry is poisoned.
+    fn get<S: AsRef<str>>(&self, url: S) -> Result<MatcherFn> {
         let url = Some(url.as_ref().to_string());
         if let Some(matcher) = self.matchers.get(&url) {
-            return *matcher.read().unwrap();
+            let matcher = *matcher
+                .read()
+                .map_err(|error| PoisonedLock(error.to_string()))?;
+            return Ok(matcher);
         }
 
-        match self.matchers.get(&None) {
-            Some(matcher) => *matcher.read().unwrap(),
+        let matcher = match self.matchers.get(&None) {
+            Some(matcher) => *matcher
+                .read()
+                .map_err(|error| PoisonedLock(error.to_string()))?,
             None => default::matcher,
-        }
+        };
+        Ok(matcher)
+    }
+
+    /// Get the number of matchers in the registry.
+    fn len(&self) -> usize {
+        self.matchers.len()
+    }
+
+    /// Check if the registry is empty.
+    fn is_empty(&self) -> bool {
+        self.matchers.is_empty()
     }
 }
 
@@ -60,39 +80,71 @@ impl Default for MatchersRegistry {
 /// Registers a matcher for a URL. Newly registered matchers with the same url will override
 /// existing ones.
 ///
-/// # Panics
+/// # Errors
 /// * If the registry is poisoned.
 #[allow(dead_code)]
-pub fn register<S: AsRef<str>>(url: Option<S>, matcher_fn: MatcherFn) {
-    let mut registry = REGISTRY.lock().unwrap();
+pub fn register<S: AsRef<str>>(url: Option<S>, matcher_fn: MatcherFn) -> Result<()> {
+    let mut registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
     registry.register(url, matcher_fn);
+    Ok(())
 }
 
 /// Get a matcher for the specified URL, or the default matcher if no matcher is
 /// registered for the URL.
 ///
-/// # Panics
+/// # Errors
 /// * If the registry is poisoned.
-pub fn get<S: AsRef<str>>(url: S) -> MatcherFn {
-    let registry = REGISTRY.lock().unwrap();
+pub fn get<S: AsRef<str>>(url: S) -> Result<MatcherFn> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
     registry.get(url)
 }
 
+/// Get the number of matchers in the registry.
+///
+/// # Errors
+/// * If the registry is poisoned.
+pub fn len() -> Result<usize> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
+    Ok(registry.len())
+}
+
+/// Check if the registry is empty.
+///
+/// # Errors
+/// * If the registry is poisoned.
+pub fn is_empty() -> Result<bool> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
+    Ok(registry.is_empty())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::Error::PoisonedLock;
     use std::env;
 
     #[test]
     fn test_register() -> Result<()> {
-        let matchers = REGISTRY.lock().unwrap().matchers.len();
-        assert!(!REGISTRY.lock().unwrap().matchers.is_empty());
-        REGISTRY.lock().unwrap().matchers.remove(&None::<String>);
-        assert_ne!(matchers, REGISTRY.lock().unwrap().matchers.len());
-        register(None::<&str>, default::matcher);
-        assert_eq!(matchers, REGISTRY.lock().unwrap().matchers.len());
-
-        let matcher = get(DEFAULT_POSTGRESQL_URL);
+        let matchers = len()?;
+        assert!(!is_empty()?);
+        REGISTRY
+            .lock()
+            .map_err(|error| PoisonedLock(error.to_string()))?
+            .matchers
+            .remove(&None::<String>);
+        assert_ne!(matchers, len()?);
+        register(None::<&str>, default::matcher)?;
+        assert_eq!(matchers, len()?);
+
+        let matcher = get(DEFAULT_POSTGRESQL_URL)?;
         let version = Version::new(16, 3, 0);
         let target = target_triple::TARGET;
         let name = format!("postgresql-{version}-{target}.tar.gz");
@@ -103,7 +155,7 @@ mod tests {
 
     #[test]
     fn test_default_matcher() -> Result<()> {
-        let matcher = get("https://foo.com");
+        let matcher = get("https://foo.com")?;
         let version = Version::new(16, 3, 0);
         let os = env::consts::OS;
         let arch = env::consts::ARCH;
diff --git a/postgresql_archive/src/repository/github/repository.rs b/postgresql_archive/src/repository/github/repository.rs
index 7e73277..c97f31e 100644
--- a/postgresql_archive/src/repository/github/repository.rs
+++ b/postgresql_archive/src/repository/github/repository.rs
@@ -174,7 +174,7 @@ impl GitHub {
         version: &Version,
         release: &Release,
     ) -> Result<(Asset, Option<Asset>, Option<HasherFn>)> {
-        let matcher = matcher::registry::get(&self.url);
+        let matcher = matcher::registry::get(&self.url)?;
         let mut release_asset: Option<Asset> = None;
         for asset in &release.assets {
             if matcher(asset.name.as_str(), version)? {
@@ -199,7 +199,7 @@ impl GitHub {
                 .strip_prefix(format!("{}.", asset.name.as_str()).as_str())
                 .unwrap_or_default();
 
-            if let Some(hasher_fn) = hasher::registry::get(extension) {
+            if let Some(hasher_fn) = hasher::registry::get(extension)? {
                 asset_hash = Some(release_asset.clone());
                 asset_hasher_fn = Some(hasher_fn);
                 break;
diff --git a/postgresql_archive/src/repository/registry.rs b/postgresql_archive/src/repository/registry.rs
index 3ca4dce..5406645 100644
--- a/postgresql_archive/src/repository/registry.rs
+++ b/postgresql_archive/src/repository/registry.rs
@@ -1,6 +1,6 @@
 use crate::repository::github::repository::GitHub;
 use crate::repository::model::Repository;
-use crate::Error::UnsupportedRepository;
+use crate::Error::{PoisonedLock, UnsupportedRepository};
 use crate::Result;
 use lazy_static::lazy_static;
 use std::sync::{Arc, Mutex, RwLock};
@@ -39,17 +39,34 @@ impl RepositoryRegistry {
     }
 
     /// Gets a repository that supports the specified URL
+    ///
+    /// # Errors
+    /// * If the URL is not supported.
     fn get(&self, url: &str) -> Result<Box<dyn Repository>> {
         for (supports_fn, new_fn) in &self.repositories {
-            let supports_function = supports_fn.read().unwrap();
+            let supports_function = supports_fn
+                .read()
+                .map_err(|error| PoisonedLock(error.to_string()))?;
             if supports_function(url) {
-                let new_function = new_fn.read().unwrap();
+                let new_function = new_fn
+                    .read()
+                    .map_err(|error| PoisonedLock(error.to_string()))?;
                 return new_function(url);
             }
         }
 
         Err(UnsupportedRepository(url.to_string()))
     }
+
+    /// Get the number of repositories in the registry.
+    fn len(&self) -> usize {
+        self.repositories.len()
+    }
+
+    /// Check if the registry is empty.
+    fn is_empty(&self) -> bool {
+        self.repositories.is_empty()
+    }
 }
 
 impl Default for RepositoryRegistry {
@@ -63,38 +80,66 @@ impl Default for RepositoryRegistry {
 
 /// Registers a repository. Newly registered repositories can override existing ones.
 ///
-/// # Panics
-/// * If the repository registry is poisoned.
+/// # Errors
+/// * If the registry is poisoned.
 #[allow(dead_code)]
-pub fn register(supports_fn: Box<SupportsFn>, new_fn: Box<NewFn>) {
-    let mut registry = REGISTRY.lock().unwrap();
+pub fn register(supports_fn: Box<SupportsFn>, new_fn: Box<NewFn>) -> Result<()> {
+    let mut registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
     registry.register(supports_fn, new_fn);
+    Ok(())
 }
 
 /// Gets a repository that supports the specified URL
 ///
 /// # Errors
 /// * If the URL is not supported.
-///
-/// # Panics
-/// * If the repository registry is poisoned.
 pub fn get(url: &str) -> Result<Box<dyn Repository>> {
-    let registry = REGISTRY.lock().unwrap();
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
     registry.get(url)
 }
 
+/// Get the number of repositories in the registry.
+///
+/// # Errors
+/// * If the registry is poisoned.
+pub fn len() -> Result<usize> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
+    Ok(registry.len())
+}
+
+/// Check if the registry is empty.
+///
+/// # Errors
+/// * If the registry is poisoned.
+pub fn is_empty() -> Result<bool> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
+    Ok(registry.is_empty())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
     #[tokio::test]
     async fn test_register() -> Result<()> {
-        let repositories = REGISTRY.lock().unwrap().repositories.len();
-        assert!(!REGISTRY.lock().unwrap().repositories.is_empty());
-        REGISTRY.lock().unwrap().repositories.truncate(0);
-        assert_ne!(repositories, REGISTRY.lock().unwrap().repositories.len());
-        register(Box::new(GitHub::supports), Box::new(GitHub::new));
-        assert_eq!(repositories, REGISTRY.lock().unwrap().repositories.len());
+        let repositories = len()?;
+        assert!(!is_empty()?);
+        REGISTRY
+            .lock()
+            .map_err(|error| PoisonedLock(error.to_string()))?
+            .repositories
+            .truncate(0);
+        assert_ne!(repositories, len()?);
+        register(Box::new(GitHub::supports), Box::new(GitHub::new))?;
+        assert_eq!(repositories, len()?);
 
         let url = "https://github.com/theseus-rs/postgresql-binaries";
         let result = get(url);