Fix issue where insert size metrics failed on a sample without adapters

Author: rhpvorderman

CHANGELOG.rst

@@ -7,6 +7,11 @@ Changelog
 .. This document is user facing. Please word the changes in such a way
 .. that users understand how the changes affect the new version.
 
+version 0.9.1
+-----------------
++ Fix an issue where the insert size metrics module would crash when no
+  adapters where present.
+
 version 0.9.0
 -----------------
 + MultiQC support since MultiQC version 1.22

src/sequali/report_modules.py

@@ -1843,8 +1843,8 @@ def from_insert_size_metrics(cls, metrics: InsertSizeMetrics):
                 metrics.adapters_read1())
         adapters_read2 = AdapterFromOverlapReport.select_relevant_adapters(
             metrics.adapters_read2())
-        longest_adapter_read1 = adapters_read1[-1][0]
-        longest_adapter_read2 = adapters_read2[-1][0]
+        longest_adapter_read1 = adapters_read1[-1][0] if adapters_read1 else ""
+        longest_adapter_read2 = adapters_read2[-1][0] if adapters_read2 else ""
         longest_adapter_read1_match = identify_sequence_builtin(
             longest_adapter_read1)[2]
         longest_adapter_read2_match = identify_sequence_builtin(