From d6b3e9199abf9dea69d9f7afd8e1945b49c8d5bc Mon Sep 17 00:00:00 2001
From: Paul Calande <paul.luap09@gmail.com>
Date: Fri, 19 Jan 2024 12:29:20 -0600
Subject: [PATCH] fix(rust): don't return NaN as available memory fraction

---
 crates/polars-pipe/src/executors/sinks/memory.rs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/crates/polars-pipe/src/executors/sinks/memory.rs b/crates/polars-pipe/src/executors/sinks/memory.rs
index 6ee627830af9..987ce08b955a 100644
--- a/crates/polars-pipe/src/executors/sinks/memory.rs
+++ b/crates/polars-pipe/src/executors/sinks/memory.rs
@@ -58,10 +58,15 @@ impl MemTracker {
     }
 
     pub(super) fn free_memory_fraction_since_start(&self) -> f64 {
-        // we divide first to reduce the precision loss in floats
-        let available_at_start = (self.available_at_start / TO_MB) as f64;
-        let available = (self.get_available() / TO_MB) as f64;
-        available / available_at_start
+        if self.available_at_start == 0 {
+            // This branch exists to prevent division by 0 so we don't return NaN.
+            0.0
+        } else {
+            // We divide first to reduce the precision loss in floats.
+            let available_at_start = (self.available_at_start / TO_MB) as f64;
+            let available = (self.get_available() / TO_MB) as f64;
+            available / available_at_start
+        }
     }
 
     /// Increment the used memory and return the previous value.