Fixed #6330, minor ticks were not applied outside major ticks on a lo…

…garithmic axis.

js/parts/Axis.js

@@ -727,23 +727,31 @@ H.Axis.prototype = {
 			minorTickInterval = axis.minorTickInterval,
 			minorTickPositions = [],
 			pos,
-			i,
 			pointRangePadding = axis.pointRangePadding || 0,
 			min = axis.min - pointRangePadding, // #1498
 			max = axis.max + pointRangePadding, // #1498
-			range = max - min,
-			len;
+			range = max - min;
 
 		// If minor ticks get too dense, they are hard to read, and may cause long running script. So we don't draw them.
 		if (range && range / minorTickInterval < axis.len / 3) { // #3875
 
 			if (axis.isLog) {
-				len = tickPositions.length;
-				for (i = 1; i < len; i++) {
-					minorTickPositions = minorTickPositions.concat(
-						axis.getLogTickPositions(minorTickInterval, tickPositions[i - 1], tickPositions[i], true)
-					);
-				}
+				// For each interval in the major ticks, compute the minor ticks
+				// separately.
+				each(this.paddedTicks, function (pos, i, paddedTicks) {
+					if (i) {
+						minorTickPositions.push.apply(
+							minorTickPositions, 
+							axis.getLogTickPositions(
+								minorTickInterval,
+								paddedTicks[i - 1],
+								paddedTicks[i],
+								true
+							)
+						);
+					}
+				});
+
 			} else if (axis.isDatetimeAxis && options.minorTickInterval === 'auto') { // #1314
 				minorTickPositions = minorTickPositions.concat(
 					axis.getTimeTicks(
@@ -1300,7 +1308,8 @@ H.Axis.prototype = {
 
 		}
 
-		// reset min/max or remove extremes based on start/end on tick
+		// Reset min/max or remove extremes based on start/end on tick
+		this.paddedTicks = tickPositions.slice(0); // Used for logarithmic minor
 		this.trimTicks(tickPositions, startOnTick, endOnTick);
 		if (!this.isLinked) {
 

js/parts/Utilities.js

@@ -1533,9 +1533,10 @@ H.stop = function (el, prop) {
  * @function #each
  * @memberOf Highcharts
  * @param {Array} arr - The array to iterate over.
- * @param {Function} fn - The iterator callback. It passes two arguments:
+ * @param {Function} fn - The iterator callback. It passes three arguments:
  * * item - The array item.
  * * index - The item's index in the array.
+ * * arr - The array that each is being applied to.
  * @param {Object} [ctx] The context.
  */
 H.each = function (arr, fn, ctx) { // modern browsers

samples/unit-tests/axis/type-logarithmic/demo.js

@@ -45,4 +45,44 @@ QUnit.test('Minor ticks should not affect extremes (#6330)', function (assert) {
         'Y axis max is bigger than data'
     );
 
-});
+});
+
+QUnit.test(
+    'Minor ticks should extend past major ticks (#6330)',
+    function (assert) {
+        var chart = Highcharts.chart('container', {
+            chart: {
+                width: 600,
+                height: 300
+            },
+
+            xAxis: {
+                type: 'logarithmic',
+                minorTickInterval: 'auto'
+            },
+
+            series: [{
+                data: [
+                    [0.42, 1],
+                    [1.7, 2]
+                ]
+            }]
+        });
+
+        var gridLines = chart.container.querySelectorAll(
+            '.highcharts-grid-line'
+        );
+        var minorGridLines = chart.container.querySelectorAll(
+            '.highcharts-minor-grid-line'
+        );
+        assert.ok(
+            minorGridLines[0].getBBox().x < gridLines[0].getBBox().x,
+            'Minor grid lines outside major grid lines'
+        );
+        assert.ok(
+            minorGridLines[minorGridLines.length - 1].getBBox().x >
+                gridLines[gridLines.length - 1].getBBox().x,
+            'Minor grid lines outside major grid lines'
+        );
+    }
+);