Forbid panic! in production code

Cargo.toml

@@ -664,6 +664,7 @@ non_zero_suggestions = "warn"
 nonstandard_macro_braces = "warn"
 option_as_ref_cloned = "warn"
 option_option = "warn"
+panic = "deny"
 path_buf_push_overwrite = "warn"
 pathbuf_init_then_push = "warn"
 precedence_bits = "warn"

clippy.toml

@@ -5,6 +5,7 @@
 
 msrv = "1.88"
 
+allow-panic-in-tests = true
 allow-unwrap-in-tests = true
 
 # https://doc.rust-lang.org/nightly/clippy/lint_configuration.html#avoid-breaking-exported-api

crates/build/re_build_tools/src/lib.rs

@@ -210,7 +210,10 @@ pub fn export_build_info_vars_for_crate(crate_name: &str) {
             // work just fine otherwise.
             Err(_err) if environment == Environment::UsedAsDependency => "<error>".to_owned(),
 
-            Err(err) => panic!("{err}"),
+            Err(err) => {
+                println!("cargo::error={err}");
+                return;
+            }
         };
 
         set_env("RE_BUILD_FEATURES", &features);

crates/build/re_build_tools/src/rebuild_detector.rs

@@ -76,7 +76,10 @@ pub fn is_tracked_env_var_set(env_var_name: &str) -> bool {
             "1" | "yes" | "true" => true,
             "0" | "no" | "false" => false,
             _ => {
-                panic!("Failed to understand boolean env-var {env_var_name}={value}");
+                println!(
+                    "cargo::error=Failed to understand boolean env-var {env_var_name}={value}"
+                );
+                false
             }
         },
     }
@@ -172,10 +175,11 @@ impl<'a> Packages<'a> {
     /// dependencies are properly tracked whether they are remote, in-workspace,
     /// or locally patched.
     pub fn track_implicit_dep(&self, pkg_name: &str, files_to_watch: &mut HashSet<PathBuf>) {
-        let pkg = self.pkgs.get(pkg_name).unwrap_or_else(|| {
+        let Some(pkg) = self.pkgs.get(pkg_name) else {
             let found_names: Vec<&str> = self.pkgs.values().map(|pkg| pkg.name.as_str()).collect();
-            panic!("Failed to find package {pkg_name:?} among {found_names:?}")
-        });
+            println!("cargo::error=Failed to find package {pkg_name:?} among {found_names:?}");
+            return;
+        };
 
         // Track the root package itself
         track_crate_files(&pkg.manifest_path, files_to_watch);

crates/build/re_dev_tools/src/main.rs

@@ -1,6 +1,10 @@
 //! Crate that combines several development utilities.
 //!
 //! To get an overview over all tools run `pixi run dev-tools --help`.
+
+// Exception for the build crates as it's not production code.
+#![allow(clippy::panic)]
+
 use argh::FromArgs;
 
 mod build_examples;

crates/build/re_protos_builder/src/lib.rs

@@ -3,7 +3,7 @@
 //! definitions in the same file.
 //!
 
-#![allow(clippy::unwrap_used, clippy::exit)]
+#![allow(clippy::unwrap_used, clippy::panic, clippy::exit)]
 
 use std::path::Path;
 

crates/build/re_types_builder/src/lib.rs

@@ -103,6 +103,8 @@
 
 // TODO(#6330): remove unwrap()
 #![allow(clippy::unwrap_used)]
+// Exception for the build crates as it's not production code.
+#![allow(clippy::panic)]
 
 // NOTE: Official generated code from flatbuffers; ignore _everything_.
 

crates/store/re_chunk/src/iter.rs

@@ -273,7 +273,7 @@ impl Chunk {
         let Some(struct_array) = list_array.values().downcast_array_ref::<ArrowStructArray>()
         else {
             if cfg!(debug_assertions) {
-                panic!("downcast failed for {component_descriptor}, data discarded");
+                panic_downcast_failed(component_descriptor);
             } else {
                 re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
             }
@@ -287,7 +287,7 @@ impl Chunk {
             .find_map(|(i, field)| (field.name() == field_name).then_some(i))
         else {
             if cfg!(debug_assertions) {
-                panic!("field {field_name} not found for {component_descriptor}, data discarded");
+                panic_field_not_found(component_descriptor, field_name);
             } else {
                 re_log::error_once!(
                     "field {field_name} not found for {component_descriptor}, data discarded"
@@ -298,7 +298,7 @@ impl Chunk {
 
         if field_idx >= struct_array.num_columns() {
             if cfg!(debug_assertions) {
-                panic!("field {field_name} not found for {component_descriptor}, data discarded");
+                panic_field_not_found(component_descriptor, field_name);
             } else {
                 re_log::error_once!(
                     "field {field_name} not found for {component_descriptor}, data discarded"
@@ -335,7 +335,6 @@ pub trait ChunkComponentSlicer {
 }
 
 /// The actual implementation of `impl_native_type!`, so that we don't have to work in a macro.
-#[expect(clippy::needless_pass_by_value)] // The simplest way to avoid lifetime issues.
 fn slice_as_native<'a, P, T>(
     component_descriptor: ComponentDescriptor,
     array: &'a dyn ArrowArray,
@@ -347,7 +346,7 @@ where
 {
     let Some(values) = array.downcast_array_ref::<ArrowPrimitiveArray<P>>() else {
         if cfg!(debug_assertions) {
-            panic!("downcast failed for {component_descriptor}, data discarded");
+            panic_downcast_failed(component_descriptor);
         } else {
             re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
         }
@@ -395,7 +394,6 @@ impl_native_type!(arrow::array::types::Float32Type, f32);
 impl_native_type!(arrow::array::types::Float64Type, f64);
 
 /// The actual implementation of `impl_array_native_type!`, so that we don't have to work in a macro.
-#[expect(clippy::needless_pass_by_value)] // The simplest way to avoid lifetime issues.
 fn slice_as_array_native<'a, const N: usize, P, T>(
     component_descriptor: ComponentDescriptor,
     array: &'a dyn ArrowArray,
@@ -408,7 +406,7 @@ where
 {
     let Some(fixed_size_list_array) = array.downcast_array_ref::<ArrowFixedSizeListArray>() else {
         if cfg!(debug_assertions) {
-            panic!("downcast failed for {component_descriptor}, data discarded");
+            panic_downcast_failed(component_descriptor);
         } else {
             re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
         }
@@ -420,7 +418,7 @@ where
         .downcast_array_ref::<ArrowPrimitiveArray<P>>()
     else {
         if cfg!(debug_assertions) {
-            panic!("downcast failed for {component_descriptor}, data discarded");
+            panic_downcast_failed(component_descriptor);
         } else {
             re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
         }
@@ -475,7 +473,6 @@ impl_array_native_type!(arrow::array::types::Float32Type, f32);
 impl_array_native_type!(arrow::array::types::Float64Type, f64);
 
 /// The actual implementation of `impl_buffer_native_type!`, so that we don't have to work in a macro.
-#[expect(clippy::needless_pass_by_value)] // The simplest way to avoid lifetime issues.
 fn slice_as_buffer_native<'a, P, T>(
     component_descriptor: ComponentDescriptor,
     array: &'a dyn ArrowArray,
@@ -487,10 +484,7 @@ where
 {
     let Some(inner_list_array) = array.downcast_array_ref::<ArrowListArray>() else {
         if cfg!(debug_assertions) {
-            panic!(
-                "DEBUG BUILD: {component_descriptor} had unexpected datatype: {:?}",
-                array.data_type()
-            );
+            panic_unexpected_data_type(component_descriptor, array);
         } else {
             re_log::error_once!(
                 "{component_descriptor} had unexpected datatype: {:?}. Data discarded",
@@ -505,10 +499,7 @@ where
         .downcast_array_ref::<ArrowPrimitiveArray<P>>()
     else {
         if cfg!(debug_assertions) {
-            panic!(
-                "DEBUG BUILD: {component_descriptor} had unexpected datatype: {:?}",
-                array.data_type()
-            );
+            panic_unexpected_data_type(component_descriptor, array);
         } else {
             re_log::error_once!(
                 "{component_descriptor} had unexpected datatype: {:?}. Data discarded",
@@ -618,7 +609,6 @@ impl_buffer_native_type!(arrow::array::types::Float32Type, f32);
 impl_buffer_native_type!(arrow::array::types::Float64Type, f64);
 
 /// The actual implementation of `impl_array_list_native_type!`, so that we don't have to work in a macro.
-#[expect(clippy::needless_pass_by_value)] // The simplest way to avoid lifetime issues.
 fn slice_as_array_list_native<'a, const N: usize, P, T>(
     component_descriptor: ComponentDescriptor,
     array: &'a dyn ArrowArray,
@@ -631,7 +621,7 @@ where
 {
     let Some(inner_list_array) = array.downcast_array_ref::<ArrowListArray>() else {
         if cfg!(debug_assertions) {
-            panic!("downcast failed for {component_descriptor}, data discarded");
+            panic_downcast_failed(component_descriptor);
         } else {
             re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
         }
@@ -646,7 +636,7 @@ where
         .downcast_array_ref::<ArrowFixedSizeListArray>()
     else {
         if cfg!(debug_assertions) {
-            panic!("downcast failed for {component_descriptor}, data discarded");
+            panic_downcast_failed(component_descriptor);
         } else {
             re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
         }
@@ -658,7 +648,7 @@ where
         .downcast_array_ref::<ArrowPrimitiveArray<P>>()
     else {
         if cfg!(debug_assertions) {
-            panic!("downcast failed for {component_descriptor}, data discarded");
+            panic_downcast_failed(component_descriptor);
         } else {
             re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
         }
@@ -729,7 +719,7 @@ impl ChunkComponentSlicer for String {
     ) -> impl Iterator<Item = Vec<ArrowString>> + 'a {
         let Some(utf8_array) = array.downcast_array_ref::<ArrowStringArray>() else {
             if cfg!(debug_assertions) {
-                panic!("downcast failed for {component_descriptor}, data discarded");
+                panic_downcast_failed(component_descriptor);
             } else {
                 re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
             }
@@ -761,7 +751,7 @@ impl ChunkComponentSlicer for bool {
     ) -> impl Iterator<Item = Self::Item<'a>> + 'a {
         let Some(values) = array.downcast_array_ref::<ArrowBooleanArray>() else {
             if cfg!(debug_assertions) {
-                panic!("downcast failed for {component_descriptor}, data discarded");
+                panic_downcast_failed(component_descriptor);
             } else {
                 re_log::error_once!("downcast failed for {component_descriptor}, data discarded");
             }
@@ -950,11 +940,7 @@ impl Chunk {
             Ok(values) => values,
             Err(err) => {
                 if cfg!(debug_assertions) {
-                    panic!(
-                        "[DEBUG-ONLY] deserialization failed for {}, data discarded: {}",
-                        C::name(),
-                        re_error::format_ref(&err),
-                    );
+                    panic_deserialization_failed::<C, _>(err);
                 } else {
                     re_log::error_once!(
                         "deserialization failed for {}, data discarded: {}",
@@ -977,6 +963,36 @@ impl Chunk {
     }
 }
 
+#[expect(clippy::panic, clippy::needless_pass_by_value)]
+fn panic_downcast_failed(component_descriptor: ComponentDescriptor) -> ! {
+    panic!("downcast failed for {component_descriptor}, data discarded")
+}
+
+#[expect(clippy::panic, clippy::needless_pass_by_value)]
+fn panic_field_not_found(component_descriptor: ComponentDescriptor, field_name: &str) -> ! {
+    panic!("field {field_name} not found for {component_descriptor}, data discarded")
+}
+
+#[expect(clippy::panic, clippy::needless_pass_by_value)]
+fn panic_unexpected_data_type(
+    component_descriptor: ComponentDescriptor,
+    array: &dyn ArrowArray,
+) -> ! {
+    panic!(
+        "DEBUG BUILD: {component_descriptor} had unexpected datatype: {:?}",
+        array.data_type()
+    )
+}
+
+#[expect(clippy::panic)]
+fn panic_deserialization_failed<C: Component, E: std::error::Error>(err: E) -> ! {
+    panic!(
+        "[DEBUG-ONLY] deserialization failed for {}, data discarded: {}",
+        C::name(),
+        re_error::format_ref(&err),
+    )
+}
+
 // ---
 
 #[cfg(test)]

crates/store/re_types/src/datatypes/mat3x3_ext.rs

@@ -19,6 +19,7 @@ impl Mat3x3 {
     ///
     /// Panics if `index` is greater than 2.
     #[inline]
+    #[expect(clippy::panic)]
     pub fn col(&self, index: usize) -> Vec3D {
         match index {
             0 => [self.0[0], self.0[1], self.0[2]].into(),

crates/store/re_types/src/datatypes/mat4x4_ext.rs

@@ -20,6 +20,7 @@ impl Mat4x4 {
     ///
     /// Panics if `index` is greater than 3.
     #[inline]
+    #[expect(clippy::panic)]
     pub fn col(&self, index: usize) -> Vec4D {
         match index {
             0 => [self.0[0], self.0[1], self.0[2], self.0[3]].into(),

crates/store/re_types/src/view_coordinates.rs

@@ -100,6 +100,7 @@ impl Axis3 {
     /// * 1 => [`Self::Y`]
     /// * 2 => [`Self::Z`]
     #[inline]
+    #[expect(clippy::panic)]
     pub fn from_dim(dim: usize) -> Self {
         match dim {
             0 => Self::X,

crates/store/re_types_core/src/arrow_zip_validity.rs

@@ -186,27 +186,3 @@ where
     V: ExactSizeIterator<Item = bool>,
 {
 }
-
-impl<T, I, V> ZipValidity<T, I, V>
-where
-    I: Iterator<Item = T>,
-    V: Iterator<Item = bool>,
-{
-    /// Unwrap into an iterator that has no null values.
-    pub fn unwrap_required(self) -> I {
-        if let Self::Required(i) = self {
-            i
-        } else {
-            panic!("Could not 'unwrap_required'. 'ZipValidity' iterator has nulls.");
-        }
-    }
-
-    /// Unwrap into an iterator that has null values.
-    pub fn unwrap_optional(self) -> ZipValidityIter<T, I, V> {
-        if let Self::Optional(i) = self {
-            i
-        } else {
-            panic!("Could not 'unwrap_optional'. 'ZipValidity' iterator has no nulls.");
-        }
-    }
-}

crates/store/re_types_core/src/component_batch.rs

@@ -56,6 +56,7 @@ pub trait ComponentBatch {
             Ok(array) => Some(array),
 
             #[cfg(debug_assertions)]
+            #[expect(clippy::panic)]
             Err(err) => {
                 panic!(
                     "failed to serialize data for {}: {}",

crates/store/re_types_core/src/lib.rs

@@ -158,6 +158,7 @@ pub fn try_serialize_field<L: Loggable>(
         Ok(array) => Some(SerializedComponentBatch::new(array, descriptor)),
 
         #[cfg(debug_assertions)]
+        #[expect(clippy::panic)]
         Err(err) => {
             panic!(
                 "failed to serialize data for {descriptor}: {}",

crates/utils/re_log/src/result_extensions.rs

@@ -59,6 +59,7 @@ where
     #[track_caller]
     fn unwrap_debug_or_log_error(self) -> Option<T> {
         if cfg!(debug_assertions) {
+            #[expect(clippy::panic)]
             match self {
                 Ok(value) => Some(value),
                 Err(err) => {

crates/utils/re_log/src/setup.rs

@@ -156,6 +156,8 @@ impl log::Log for PanicOnWarn {
         }
     }
 
+    // Panic is expected only in this method as the logger requires it while the rest of the code must be panic-free.
+    #[expect(clippy::panic)]
     fn log(&self, record: &log::Record<'_>) {
         // `enabled` isn't called automatically by the `log!` macros, so we have to call it here.
         // (it is only used by `log_enabled!`)

crates/utils/re_video/src/demux/mp4.rs

@@ -146,6 +146,7 @@ impl VideoDataDescription {
             mp4_tracks,
         };
 
+        #[expect(clippy::panic)]
         if cfg!(debug_assertions)
             && let Err(err) = video_data_description.sanity_check()
         {

crates/viewer/re_renderer/src/file_system.rs

@@ -18,10 +18,12 @@ pub trait FileSystem {
 
     fn exists(&self, path: impl AsRef<Path>) -> bool;
 
+    #[expect(clippy::panic)]
     fn create_dir_all(&self, _path: impl AsRef<Path>) -> anyhow::Result<()> {
         panic!("create_dir_all() is not supported on this backend")
     }
 
+    #[expect(clippy::panic)]
     fn create_file(
         &self,
         _path: impl AsRef<Path>,