diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0b2f5927..6f4553b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
 - Fix spying on `echo` or `printf` causing bashunit to hang due to infinite recursion (#607)
 - Fix invalid `.env.example` coverage threshold entry and copy `.env.example` to `.env` in CI test workflows so configuration parse errors are caught during automated test runs
 - Fix `clock::now` shell-time parsing when `EPOCHREALTIME` uses a comma decimal separator
+- Fix LCOV and HTML coverage reports generating incomplete/empty output due to post-increment operator causing silent exit under `set -e` (#618)
 
 ## [0.34.1](https://github.com/TypedDevs/bashunit/compare/0.34.0...0.34.1) - 2026-03-20
 
diff --git a/src/coverage.sh b/src/coverage.sh
index cb8a7612..794ff346 100644
--- a/src/coverage.sh
+++ b/src/coverage.sh
@@ -465,8 +465,8 @@ function bashunit::coverage::get_executable_lines() {
   local line
 
   while IFS= read -r line || [ -n "$line" ]; do
-    ((lineno++))
-    bashunit::coverage::is_executable_line "$line" "$lineno" && ((count++))
+    ((++lineno))
+    bashunit::coverage::is_executable_line "$line" "$lineno" && ((++count))
   done <"$file"
 
   echo "$count"
@@ -498,7 +498,7 @@ function bashunit::coverage::get_hit_lines() {
     local line_content
     line_content=$(sed -n "${line_num}p" "$file" 2>/dev/null) || continue
     if bashunit::coverage::is_executable_line "$line_content" "$line_num"; then
-      ((count++))
+      ((++count))
     fi
   done
 
@@ -565,7 +565,7 @@ function bashunit::coverage::extract_functions() {
   local line
 
   while IFS= read -r line || [ -n "$line" ]; do
-    ((lineno++))
+    ((++lineno))
 
     # Check for function definition patterns
     # Pattern 1: function name() { or function name {
@@ -644,10 +644,10 @@ function bashunit::coverage::get_function_coverage() {
     line_content=$(sed -n "${lineno}p" "$file" 2>/dev/null) || continue
 
     if bashunit::coverage::is_executable_line "$line_content" "$lineno"; then
-      ((executable++))
+      ((++executable))
       local line_hits=${_hits_ref[$lineno]:-0}
       if [ "$line_hits" -gt 0 ]; then
-        ((hit++))
+        ((++hit))
       fi
     fi
   done
@@ -778,7 +778,7 @@ function bashunit::coverage::report_lcov() {
       local line
       # shellcheck disable=SC2094
       while IFS= read -r line || [ -n "$line" ]; do
-        ((lineno++))
+        ((++lineno))
         bashunit::coverage::is_executable_line "$line" "$lineno" || continue
         echo "DA:${lineno},$(bashunit::coverage::get_line_hits "$file" "$lineno")"
       done <"$file"
@@ -1543,10 +1543,10 @@ EOF
           local ln_content
           ln_content=$(sed -n "${ln}p" "$file" 2>/dev/null) || continue
           if bashunit::coverage::is_executable_line "$ln_content" "$ln"; then
-            ((fn_executable++))
+            ((++fn_executable))
             local ln_hits=${hits_by_line[$ln]:-0}
             if [ "$ln_hits" -gt 0 ]; then
-              ((fn_hit++))
+              ((++fn_hit))
             fi
           fi
         done
@@ -1597,7 +1597,7 @@ EOF
     local lineno=0
     local line
     while IFS= read -r line || [ -n "$line" ]; do
-      ((lineno++))
+      ((++lineno))
 
       local escaped_line
       escaped_line=$(bashunit::coverage::html_escape "$line")
diff --git a/src/learn.sh b/src/learn.sh
index adb5d3c9..c57c18a9 100644
--- a/src/learn.sh
+++ b/src/learn.sh
@@ -127,7 +127,7 @@ function bashunit::learn::show_progress() {
   for i in $(seq 1 $total_lessons); do
     if bashunit::learn::is_completed "lesson_$i"; then
       echo "  ${_BASHUNIT_COLOR_PASSED}✓${_BASHUNIT_COLOR_DEFAULT} Lesson $i completed"
-      ((completed++)) || true
+      ((++completed)) || true
     else
       echo "  ${_BASHUNIT_COLOR_INCOMPLETE}○${_BASHUNIT_COLOR_DEFAULT} Lesson $i"
     fi
diff --git a/src/str.sh b/src/str.sh
index 8ca614dd..b63232eb 100644
--- a/src/str.sh
+++ b/src/str.sh
@@ -40,17 +40,17 @@ function bashunit::str::rpad() {
     if [ "$original_char" = $'\x1b' ]; then
       while [ "${left_text:$j:1}" != "m" ] && [ $j -lt ${#left_text} ]; do
         result_left_text="$result_left_text${left_text:$j:1}"
-        ((j++))
+        ((++j))
       done
       result_left_text="$result_left_text${left_text:$j:1}" # Append the final 'm'
-      ((j++))
+      ((++j))
     elif [ "$char" = "$original_char" ]; then
       # Match the actual character
       result_left_text="$result_left_text$char"
-      ((i++))
-      ((j++))
+      ((++i))
+      ((++j))
     else
-      ((j++))
+      ((++j))
     fi
   done
 
diff --git a/tests/unit/coverage_core_test.sh b/tests/unit/coverage_core_test.sh
index 73183465..3a58b155 100644
--- a/tests/unit/coverage_core_test.sh
+++ b/tests/unit/coverage_core_test.sh
@@ -174,6 +174,29 @@ EOF
   rm -f "$temp_file"
 }
 
+function test_coverage_get_executable_lines_does_not_exit_under_set_e() {
+  local temp_file
+  temp_file=$(mktemp)
+
+  cat >"$temp_file" <<'EOF'
+#!/usr/bin/env bash
+echo "line 1"
+echo "line 2"
+EOF
+
+  # ((var++)) when var=0 evaluates to 0 (falsy) causing exit code 1;
+  # under set -e this silently terminates the function (#618)
+  local result
+  result=$(
+    set -e
+    bashunit::coverage::get_executable_lines "$temp_file"
+  )
+
+  assert_equals "2" "$result"
+
+  rm -f "$temp_file"
+}
+
 function test_coverage_record_line_writes_to_file() {
   BASHUNIT_COVERAGE="true"
   BASHUNIT_COVERAGE_PATHS="/"
diff --git a/tests/unit/coverage_reporting_test.sh b/tests/unit/coverage_reporting_test.sh
index d2af35d8..c0ecb5bd 100644
--- a/tests/unit/coverage_reporting_test.sh
+++ b/tests/unit/coverage_reporting_test.sh
@@ -146,6 +146,40 @@ EOF
   rm -f "$temp_file" "$report_file"
 }
 
+function test_coverage_report_lcov_completes_under_set_e() {
+  BASHUNIT_COVERAGE="true"
+  bashunit::coverage::init
+
+  local temp_file
+  temp_file=$(mktemp)
+  cat >"$temp_file" <<'EOF'
+#!/usr/bin/env bash
+echo "line 1"
+echo "line 2"
+EOF
+
+  echo "$temp_file" >"$_BASHUNIT_COVERAGE_TRACKED_FILES"
+
+  local report_file
+  report_file=$(mktemp)
+
+  # ((lineno++)) when lineno=0 returns exit code 1 under set -e
+  # causing incomplete LCOV output (#618)
+  (
+    set -e
+    bashunit::coverage::report_lcov "$report_file"
+  )
+
+  local content
+  content=$(cat "$report_file")
+
+  assert_contains "end_of_record" "$content"
+  assert_contains "DA:2," "$content"
+  assert_contains "DA:3," "$content"
+
+  rm -f "$temp_file" "$report_file"
+}
+
 function test_coverage_report_text_shows_no_files_message() {
   BASHUNIT_COVERAGE="true"
   bashunit::coverage::init
diff --git a/tests/unit/str_test.sh b/tests/unit/str_test.sh
index 33d8097b..54e71a58 100644
--- a/tests/unit/str_test.sh
+++ b/tests/unit/str_test.sh
@@ -51,6 +51,18 @@ function test_rpad_custom_width_padding_text_too_long_and_special_chars() {
     "$actual"
 }
 
+function test_rpad_does_not_exit_under_set_e() {
+  # ((i++)) when i=0 evaluates to 0 (falsy) causing exit code 1;
+  # under set -e this silently terminates the function (#618)
+  local actual
+  actual=$(
+    set -e
+    bashunit::str::rpad "input" "1" 20
+  )
+
+  assert_same "input              1" "$actual"
+}
+
 function test_rpad_width_smaller_than_right_word() {
   local actual=$(bashunit::str::rpad "foo" "verylongword" 5)