Allow pre-releases when the range uses them

README.md

@@ -85,7 +85,8 @@ differences to notes between these two methods of comparison.
    different set of rules that are common for ranges with tools like npm/js
    and Rust/Cargo. This includes considering prereleases to be invalid if the
    ranges does not include one. If you want to have it include pre-releases a
-   simple solution is to include `-0` in your range.
+   simple solution is to include `-0` in your range. For example, `~1.2.3-0` or
+   `1.2.3-0 - 1.5.0`.
 3. Constraint ranges can have some complex rules including the shorthand use of
    ~ and ^. For more details on those see the options below.
 

constraints.go

@@ -19,7 +19,7 @@ type Constraints struct {
 func NewConstraint(c string) (*Constraints, error) {
 
 	// Rewrite - ranges into a comparison operation.
-	c = rewriteRange(c)
+	c, rangesWithPrerelease := rewriteRange(c)
 
 	ors := strings.Split(c, "||")
 	or := make([][]*constraint, len(ors))
@@ -43,6 +43,13 @@ func NewConstraint(c string) (*Constraints, error) {
 				return nil, err
 			}
 
+			// When we parse a constraint we lose information about if it was part of a range
+			// Use rangesWithPrerelease to check if the range originally used a pre-release
+			pcStr := pc.string()
+			if _, ok := rangesWithPrerelease[pcStr]; ok {
+				pc.allowPrerelease = true
+			}
+
 			result[i] = pc
 		}
 		or[k] = result
@@ -224,6 +231,10 @@ type constraint struct {
 	minorDirty bool
 	dirty      bool
 	patchDirty bool
+
+	// allowPrerelease indicates if the constraint should allow pre-releases,
+	// such as when part of a range constraint that uses pre-releases
+	allowPrerelease bool
 }
 
 // Check if a version meets the constraint
@@ -279,6 +290,7 @@ func parseConstraint(c string) (*constraint, error) {
 		cs.minorDirty = minorDirty
 		cs.patchDirty = patchDirty
 		cs.dirty = dirty
+		cs.allowPrerelease = cs.con.Prerelease() != ""
 
 		return cs, nil
 	}
@@ -411,7 +423,7 @@ func constraintGreaterThanEqual(v *Version, c *constraint) (bool, error) {
 	// 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() == "" {
+	if v.Prerelease() != "" && !c.allowPrerelease {
 		return false, fmt.Errorf("%s is a prerelease version and the constraint is only looking for release versions", v)
 	}
 
@@ -426,7 +438,7 @@ func constraintLessThanEqual(v *Version, c *constraint) (bool, error) {
 	// 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() == "" {
+	if v.Prerelease() != "" && !c.allowPrerelease {
 		return false, fmt.Errorf("%s is a prerelease version and the constraint is only looking for release versions", v)
 	}
 
@@ -459,7 +471,7 @@ func constraintTilde(v *Version, c *constraint) (bool, error) {
 	// 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() == "" {
+	if v.Prerelease() != "" && !c.allowPrerelease {
 		return false, fmt.Errorf("%s is a prerelease version and the constraint is only looking for release versions", v)
 	}
 
@@ -491,7 +503,7 @@ func constraintTildeOrEqual(v *Version, c *constraint) (bool, error) {
 	// 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() == "" {
+	if v.Prerelease() != "" && !c.allowPrerelease {
 		return false, fmt.Errorf("%s is a prerelease version and the constraint is only looking for release versions", v)
 	}
 
@@ -520,7 +532,7 @@ func constraintCaret(v *Version, c *constraint) (bool, error) {
 	// 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() == "" {
+	if v.Prerelease() != "" && !c.allowPrerelease {
 		return false, fmt.Errorf("%s is a prerelease version and the constraint is only looking for release versions", v)
 	}
 
@@ -579,16 +591,27 @@ func isX(x string) bool {
 	}
 }
 
-func rewriteRange(i string) string {
+func rewriteRange(i string) (string, map[string]struct{}) {
 	m := constraintRangeRegex.FindAllStringSubmatch(i, -1)
 	if m == nil {
-		return i
+		return i, nil
 	}
 	o := i
+	allowPrerelease := make(map[string]struct{}, 0)
 	for _, v := range m {
 		t := fmt.Sprintf(">= %s, <= %s ", v[1], v[11])
 		o = strings.Replace(o, v[0], t, 1)
+
+		// Check if any part of the range uses a pre-release
+		rangeUsesPrerelease := v[5] != "" || v[15] != ""
+		if rangeUsesPrerelease {
+			// do not use spaces, so that we can compare this later against a parsed constraint
+			lower := fmt.Sprintf(">=%s", v[1])
+			upper := fmt.Sprintf("<=%s", v[11])
+			allowPrerelease[lower] = struct{}{}
+			allowPrerelease[upper] = struct{}{}
+		}
 	}
 
-	return o
+	return o, allowPrerelease
 }

constraints_test.go

@@ -400,6 +400,15 @@ func TestConstraintsCheck(t *testing.T) {
 		// Ranges should work in conjunction with other constraints anded together.
 		{"1.0.0 - 2.0.0 <=2.0.0", "1.5.0", true},
 		{"1.0.0 - 2.0.0, <=2.0.0", "1.5.0", true},
+
+		// Should fail because 1.5.0 is AND'd with the range and since it does not allow prereleases, the entire constraint fails
+		{"1.0.0-alpha.1 - 1.0.0, <= 1.5.0", "1.0.0-beta.2", false},
+		// Should fail because only the first range should allow prereleases (detects if we are allowing prereleases for more than the affected range
+		{"1.0.0-alpha.1 - 1.0.0 || <= 1.5.0", "1.5.0-beta.2", false},
+		// When the lower part of the range allows prereleases, the upper should also allow prereleases
+		{"1.0.0-alpha.1 - 1.0.0", "1.0.0-beta.2", true},
+		// When the upper part of the range allows prereleases, the lower should also allow prereleases
+		{"1.0.0 - 2.0.0-beta.3", "2.0.0-beta.2", true},
 	}
 
 	for _, tc := range tests {
@@ -435,7 +444,7 @@ func TestRewriteRange(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		o := rewriteRange(tc.c)
+		o, _ := rewriteRange(tc.c)
 
 		if o != tc.nc {
 			t.Errorf("Range %s rewritten incorrectly as %q instead of expected %q", tc.c, o, tc.nc)