From 12c2e2789e6407ae128e54297ed1bbf8cc7ee6f2 Mon Sep 17 00:00:00 2001
From: Julian Sommer <115516918+juliansommer@users.noreply.github.com>
Date: Thu, 26 Feb 2026 11:35:22 +1000
Subject: [PATCH] fix: skip diff coverage when instrumentable lines below
 minimum

The MIN_LOC=100 threshold checked total diff lines, not instrumentable
lines. A commit with many non-instrumentable lines (structs, comments)
but only 1-2 instrumentable lines would unfairly fail at 0% coverage.
Add a minimum instrumentable lines threshold (5) so the check skips
when the sample size is too small to be meaningful.
---
 scripts/diff-coverage.sh | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/scripts/diff-coverage.sh b/scripts/diff-coverage.sh
index 60110fafa..dca5c1b85 100755
--- a/scripts/diff-coverage.sh
+++ b/scripts/diff-coverage.sh
@@ -148,6 +148,12 @@ awk -v threshold="$THRESHOLD" '
             exit 0
         }
 
+        min_instrumentable = 5
+        if (total < min_instrumentable) {
+            printf "Only %d instrumentable lines (< %d minimum) — skipping diff coverage.\n", total, min_instrumentable
+            exit 0
+        }
+
         uncovered = total - covered
         pct = (covered / total) * 100