From 01d4ad3c0160b97be1786ad2dbaa9ee8945e7f8f Mon Sep 17 00:00:00 2001
From: Mike Schmidt <schmidmt@gmail.com>
Date: Tue, 6 Feb 2024 09:02:18 -0700
Subject: [PATCH] feat(python): Improved errors from type conversions.

---
 CHANGELOG.md        |  1 +
 pylace/src/utils.rs | 17 ++++++++++-------
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f3cdca13..665e2885 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 - Added parallelism to `Slice` row reassignment kernel. Run time is ~6x faster.
+- (Python) Improved errors in type conversions.
 
 ### Fixed
 - Initializing an engine with a codebook that has a different number of rows than the data will result in an error instead of printing a bunch on nonsense.
diff --git a/pylace/src/utils.rs b/pylace/src/utils.rs
index 32fd63d3..0e45a1f0 100644
--- a/pylace/src/utils.rs
+++ b/pylace/src/utils.rs
@@ -532,7 +532,11 @@ pub(crate) fn value_to_datum(val: &PyAny, ftype: FType) -> PyResult<Datum> {
 
     match ftype {
         FType::Continuous => {
-            let x: f64 = val.extract().unwrap();
+            let x: f64 = val.extract().map_err(|err| {
+                PyTypeError::new_err(format!(
+                    "Expected real number, got `{val}` ({err})"
+                ))
+            })?;
             if x.is_nan() {
                 Ok(Datum::Missing)
             } else {
@@ -543,10 +547,9 @@ pub(crate) fn value_to_datum(val: &PyAny, ftype: FType) -> PyResult<Datum> {
             let x = pyany_to_category(val)?;
             Ok(Datum::Categorical(x))
         }
-        FType::Count => Ok(Datum::Count(val.extract().unwrap())),
-        ftype => Err(PyErr::new::<PyValueError, _>(format!(
-            "Unsupported ftype: {:?}",
-            ftype
+        FType::Count => Ok(Datum::Count(val.extract()?)),
+        ftype => Err(PyTypeError::new_err(format!(
+            "Unsupported ftype: `{ftype:?}`"
         ))),
     }
 }
@@ -556,7 +559,7 @@ pub(crate) fn value_to_name(
     indexer: &Indexer,
 ) -> PyResult<String> {
     val.extract::<String>().or_else(|_| {
-        let ix: usize = val.extract().unwrap();
+        let ix: usize = val.extract()?;
         if let Some(name) = indexer.to_name.get(&ix) {
             Ok(name.to_owned())
         } else {
@@ -570,7 +573,7 @@ pub(crate) fn value_to_index(
     indexer: &Indexer,
 ) -> PyResult<usize> {
     val.extract::<usize>().or_else(|_| {
-        let s: &str = val.extract().unwrap();
+        let s: &str = val.extract()?;
         if let Some(ix) = indexer.to_ix.get(s) {
             Ok(*ix)
         } else {