Fixed #24: Fixed edge case issue where constraint "> 0" does not hand…

…le "0.0.1-alpha" properly.

CHANGELOG.md

@@ -1,3 +1,9 @@
+# Release 1.2.1 (unreleased)
+
+## Fixed:
+- #24: Fixed edge case issue where constraint "> 0" does not handle "0.0.1-alpha"
+  properly.
+
 # Release 1.2.0 (2016-11-04)
 
 ## Added

constraints.go

@@ -155,14 +155,6 @@ type constraint struct {
 
 // Check if a version meets the constraint
 func (c *constraint) check(v *Version) bool {
-
-	// If there is a pre-release on the version but the constraint isn't looking
-	// for them assume that pre-releases are not compatible. See issue 21 for
-	// more details.
-	if v.Prerelease() != "" && c.con.Prerelease() == "" {
-		return false
-	}
-
 	return c.function(v, c)
 }
 
@@ -212,6 +204,14 @@ func parseConstraint(c string) (*constraint, error) {
 // Constraint functions
 func constraintNotEqual(v *Version, c *constraint) bool {
 	if c.dirty {
+
+		// If there is a pre-release on the version but the constraint isn't looking
+		// for them assume that pre-releases are not compatible. See issue 21 for
+		// more details.
+		if v.Prerelease() != "" && c.con.Prerelease() == "" {
+			return false
+		}
+
 		if c.con.Major() != v.Major() {
 			return true
 		}
@@ -228,10 +228,31 @@ func constraintNotEqual(v *Version, c *constraint) bool {
 }
 
 func constraintGreaterThan(v *Version, c *constraint) bool {
+
+	// An edge case the constraint is 0.0.0 and the version is 0.0.0-someprerelease
+	// exists. This that case.
+	if !isNonZero(c.con) && isNonZero(v) {
+		return true
+	}
+
+	// If there is a pre-release on the version but the constraint isn't looking
+	// for them assume that pre-releases are not compatible. See issue 21 for
+	// more details.
+	if v.Prerelease() != "" && c.con.Prerelease() == "" {
+		return false
+	}
+
 	return v.Compare(c.con) == 1
 }
 
 func constraintLessThan(v *Version, c *constraint) bool {
+	// If there is a pre-release on the version but the constraint isn't looking
+	// for them assume that pre-releases are not compatible. See issue 21 for
+	// more details.
+	if v.Prerelease() != "" && c.con.Prerelease() == "" {
+		return false
+	}
+
 	if !c.dirty {
 		return v.Compare(c.con) < 0
 	}
@@ -246,10 +267,30 @@ func constraintLessThan(v *Version, c *constraint) bool {
 }
 
 func constraintGreaterThanEqual(v *Version, c *constraint) bool {
+	// An edge case the constraint is 0.0.0 and the version is 0.0.0-someprerelease
+	// exists. This that case.
+	if !isNonZero(c.con) && isNonZero(v) {
+		return true
+	}
+
+	// If there is a pre-release on the version but the constraint isn't looking
+	// for them assume that pre-releases are not compatible. See issue 21 for
+	// more details.
+	if v.Prerelease() != "" && c.con.Prerelease() == "" {
+		return false
+	}
+
 	return v.Compare(c.con) >= 0
 }
 
 func constraintLessThanEqual(v *Version, c *constraint) bool {
+	// If there is a pre-release on the version but the constraint isn't looking
+	// for them assume that pre-releases are not compatible. See issue 21 for
+	// more details.
+	if v.Prerelease() != "" && c.con.Prerelease() == "" {
+		return false
+	}
+
 	if !c.dirty {
 		return v.Compare(c.con) <= 0
 	}
@@ -270,6 +311,13 @@ func constraintLessThanEqual(v *Version, c *constraint) bool {
 // ~1.2.3, ~>1.2.3 --> >=1.2.3, <1.3.0
 // ~1.2.0, ~>1.2.0 --> >=1.2.0, <1.3.0
 func constraintTilde(v *Version, c *constraint) bool {
+	// If there is a pre-release on the version but the constraint isn't looking
+	// for them assume that pre-releases are not compatible. See issue 21 for
+	// more details.
+	if v.Prerelease() != "" && c.con.Prerelease() == "" {
+		return false
+	}
+
 	if v.LessThan(c.con) {
 		return false
 	}
@@ -294,6 +342,13 @@ func constraintTilde(v *Version, c *constraint) bool {
 // When there is a .x (dirty) status it automatically opts in to ~. Otherwise
 // it's a straight =
 func constraintTildeOrEqual(v *Version, c *constraint) bool {
+	// If there is a pre-release on the version but the constraint isn't looking
+	// for them assume that pre-releases are not compatible. See issue 21 for
+	// more details.
+	if v.Prerelease() != "" && c.con.Prerelease() == "" {
+		return false
+	}
+
 	if c.dirty {
 		c.msg = constraintMsg["~"]
 		return constraintTilde(v, c)
@@ -309,6 +364,13 @@ func constraintTildeOrEqual(v *Version, c *constraint) bool {
 // ^1.2.3 --> >=1.2.3, <2.0.0
 // ^1.2.0 --> >=1.2.0, <2.0.0
 func constraintCaret(v *Version, c *constraint) bool {
+	// If there is a pre-release on the version but the constraint isn't looking
+	// for them assume that pre-releases are not compatible. See issue 21 for
+	// more details.
+	if v.Prerelease() != "" && c.con.Prerelease() == "" {
+		return false
+	}
+
 	if v.LessThan(c.con) {
 		return false
 	}
@@ -348,3 +410,12 @@ func rewriteRange(i string) string {
 
 	return o
 }
+
+// Detect if a version is not zero (0.0.0)
+func isNonZero(v *Version) bool {
+	if v.major != 0 || v.minor != 0 || v.patch != 0 || v.pre != "" {
+		return true
+	}
+
+	return false
+}

constraints_test.go

@@ -72,6 +72,10 @@ func TestConstraintCheck(t *testing.T) {
 		{"<=1.1", "0.1.0", true},
 		{"<=1.1", "1.1.0", true},
 		{"<=1.1", "1.1.1", false},
+		{">0", "0.0.1-alpha", true},
+		{">=0", "0.0.1-alpha", true},
+		{">0", "0", false},
+		{">=0", "0", true},
 	}
 
 	for _, tc := range tests {
@@ -89,7 +93,7 @@ func TestConstraintCheck(t *testing.T) {
 
 		a := c.check(v)
 		if a != tc.check {
-			t.Errorf("Constraint '%s' failing", tc.constraint)
+			t.Errorf("Constraint %q failing with %q", tc.constraint, tc.version)
 		}
 	}
 }