From 9b8e961c0cf3efd71a83c4658cc32a64f9bbf9a4 Mon Sep 17 00:00:00 2001
From: Max Bittman <max@npmjs.com>
Date: Fri, 22 Mar 2019 12:11:45 -0700
Subject: [PATCH] fix: Fix non-satisfiable ranges so they no longer intersect
 with anything

---
 semver.js     | 22 ++++++++++++++++++++--
 test/index.js |  8 ++++++--
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/semver.js b/semver.js
index a0a96c1b..1c3c4f96 100644
--- a/semver.js
+++ b/semver.js
@@ -935,8 +935,8 @@ Range.prototype.intersects = function (range, options) {
 
   return this.set.some(function (thisComparators) {
     return range.set.some(function (rangeComparators) {
-      return thisComparators.every(function (thisComparator) {
-        return rangeComparators.every(function (rangeComparator) {
+      return isSatisfiable(thisComparators, options) && thisComparators.every(function (thisComparator) {
+        return isSatisfiable(rangeComparators, options) && rangeComparators.every(function (rangeComparator) {
           return thisComparator.intersects(rangeComparator, options)
         })
       })
@@ -944,6 +944,24 @@ Range.prototype.intersects = function (range, options) {
   })
 }
 
+// take a set of comparators and determine whether there
+// exists a version which can satisfy it
+function isSatisfiable (comparators, options) {
+  var result = true
+  var remainingComparators = comparators.slice()
+  var testComparator = remainingComparators.pop()
+
+  while (result && remainingComparators.length) {
+    result = remainingComparators.every(function (otherComparator) {
+      return testComparator.intersects(otherComparator, options)
+    })
+
+    testComparator = remainingComparators.pop()
+  }
+
+  return result
+}
+
 // Mostly just for testing and legacy API reasons
 exports.toComparators = toComparators
 function toComparators (range, options) {
diff --git a/test/index.js b/test/index.js
index 56c13570..4922730d 100644
--- a/test/index.js
+++ b/test/index.js
@@ -875,7 +875,8 @@ test('missing comparator parameter in intersect comparators', function (t) {
 test('ranges intersect', function (t) {
   [
     ['1.3.0 || <1.0.0 >2.0.0', '1.3.0 || <1.0.0 >2.0.0', true],
-    ['<1.0.0 >2.0.0', '>0.0.0', true],
+    ['<1.0.0 >2.0.0', '>0.0.0', false],
+    ['>0.0.0', '<1.0.0 >2.0.0', false],
     ['<1.0.0 >2.0.0', '>1.4.0 <1.6.0', false],
     ['<1.0.0 >2.0.0', '>1.4.0 <1.6.0 || 2.0.0', false],
     ['>1.0.0 <=2.0.0', '2.0.0', true],
@@ -883,7 +884,10 @@ test('ranges intersect', function (t) {
     ['<1.0.0 >=2.0.0', '>1.4.0 <1.6.0 || 2.0.0', false],
     ['1.5.x', '<1.5.0 || >=1.6.0', false],
     ['<1.5.0 || >=1.6.0', '1.5.x', false],
-    ['<1.6.16 || >=1.7.0 <1.7.11 || >=1.8.0 <1.8.2', '>=1.6.16 <1.7.0 || >=1.7.11 <1.8.0 || >=1.8.2', false]
+    ['<1.6.16 || >=1.7.0 <1.7.11 || >=1.8.0 <1.8.2', '>=1.6.16 <1.7.0 || >=1.7.11 <1.8.0 || >=1.8.2', false],
+    ['<=1.6.16 || >=1.7.0 <1.7.11 || >=1.8.0 <1.8.2', '>=1.6.16 <1.7.0 || >=1.7.11 <1.8.0 || >=1.8.2', true],
+    ['>=1.0.0', '<=1.0.0', true],
+    ['>1.0.0 <1.0.0', '<=0.0.0', false]
   ].forEach(function (v) {
     var range1 = new Range(v[0])
     var range2 = new Range(v[1])