Use System's path separator for classpaths

smithy-cli/src/main/java/software/amazon/smithy/cli/BuildParameterBuilder.java

@@ -65,6 +65,7 @@ public final class BuildParameterBuilder {
     private static final Logger LOGGER = Logger.getLogger(BuildParameterBuilder.class.getName());
     private static final String SMITHY_TAG_PROPERTY = "Smithy-Tags";
     private static final String SOURCE = "source";
+    private static final String PATH_SEPARATOR = "path.separator";
 
     private String projectionSource = SOURCE;
     private Set<String> projectionSourceTags = new LinkedHashSet<>();
@@ -135,7 +136,7 @@ public BuildParameterBuilder addSourcesIfExists(Collection<String> sources) {
      * @return Returns the builder.
      */
     public BuildParameterBuilder buildClasspath(String buildClasspath) {
-        this.buildClasspath.addAll(splitAndFilterString(":", buildClasspath));
+        this.buildClasspath.addAll(splitAndFilterString(System.getProperty(PATH_SEPARATOR), buildClasspath));
         return this;
     }
 
@@ -157,7 +158,7 @@ private static Set<String> splitAndFilterString(String delimiter, String value)
      * @return Returns the builder.
      */
     public BuildParameterBuilder libClasspath(String libClasspath) {
-        this.libClasspath.addAll(splitAndFilterString(":", libClasspath));
+        this.libClasspath.addAll(splitAndFilterString(System.getProperty(PATH_SEPARATOR), libClasspath));
         return this;
     }
 
@@ -357,7 +358,9 @@ private Result configureSourceProjection() {
         Set<String> combined = new LinkedHashSet<>(libClasspath);
         combined.addAll(buildClasspath);
 
-        return new Result(this, String.join(":", computedDiscovery), String.join(":", combined), sources);
+        String discoveryClasspath = String.join(System.getProperty(PATH_SEPARATOR), computedDiscovery);
+        String classpath = String.join(System.getProperty(PATH_SEPARATOR), combined);
+        return new Result(this, discoveryClasspath, classpath, sources);
     }
 
     /**
@@ -373,7 +376,7 @@ private Result configureProjection() {
             LOGGER.warning("No projection source tags were set for the projection `" + projection + "`, so the "
                            + "projection will not have any sources in it other than files found in the sources of "
                            + "the package being built.");
-            String buildCp = String.join(":", buildClasspath);
+            String buildCp = String.join(System.getProperty(PATH_SEPARATOR), buildClasspath);
             return new Result(this, buildCp, buildCp, sources);
         }
 
@@ -390,8 +393,9 @@ private Result configureProjection() {
         Set<String> computedDiscovery = new LinkedHashSet<>(buildClasspath);
         computedDiscovery.removeAll(computedSources);
 
-        return new Result(this, String.join(":", computedDiscovery),
-                String.join(":", buildClasspath), computedSources);
+        String discoveryClasspath = String.join(System.getProperty(PATH_SEPARATOR), computedDiscovery);
+        String classpath = String.join(System.getProperty(PATH_SEPARATOR), buildClasspath);
+        return new Result(this, discoveryClasspath, classpath, computedSources);
     }
 
     /**

smithy-cli/src/main/java/software/amazon/smithy/cli/commands/CommandUtils.java

@@ -70,7 +70,9 @@ private static void handleModelDiscovery(Arguments arguments, ModelAssembler ass
     private static void discoverModelsWithClasspath(Arguments arguments, ModelAssembler assembler) {
         String rawClasspath = arguments.parameter(SmithyCli.DISCOVER_CLASSPATH);
         LOGGER.finer("Discovering models with classpath: " + rawClasspath);
-        String[] classpath = rawClasspath.split(":");
+
+        // Use System.getProperty here each time since it allows the value to be changed.
+        String[] classpath = rawClasspath.split(System.getProperty("path.separator"));
         URL[] urls = new URL[classpath.length];
 
         for (int i = 0; i < classpath.length; i++) {

smithy-cli/src/test/java/software/amazon/smithy/cli/BuildParameterBuilderTest.java

@@ -217,7 +217,8 @@ public void findsProjectionJarsWithSourceTags() {
         String a = getClass().getResource("jars/a/a.jar").getPath();
         String b = getClass().getResource("jars/b/b.jar").getPath();
         String c = getClass().getResource("jars/c/c.jar").getPath();
-        String buildCp = a + ":" + b + ":" + c;
+        String separator = System.getProperty("path.separator");
+        String buildCp = a + separator + b + separator + c;
 
         BuildParameterBuilder.Result result = new BuildParameterBuilder()
                 .projectionSource("foo")
@@ -230,8 +231,35 @@ public void findsProjectionJarsWithSourceTags() {
         // The classpath keeps all of the JARs.
         assertThat(result.classpath, equalTo(buildCp));
         // The discovery classpath removes a because it's JAR matched the source tag.
-        assertThat(result.discoveryClasspath, equalTo(b + ":" + c));
+        assertThat(result.discoveryClasspath, equalTo(b + separator + c));
         // The sources now contains a because it matched a source tag.
         assertThat(result.sources, contains(a));
     }
+
+    @Test
+    public void usesCustomSeparator() {
+        String currentSeparator = System.getProperty("path.separator");
+
+        try {
+            System.setProperty("path.separator", "|");
+            String a = getClass().getResource("jars/a/a.jar").getPath();
+            String b = getClass().getResource("jars/b/b.jar").getPath();
+            String c = getClass().getResource("jars/c/c.jar").getPath();
+            String buildCp = a + "|" + b + "|" + c;
+
+            BuildParameterBuilder.Result result = new BuildParameterBuilder()
+                    .projectionSource("foo")
+                    .projectionSourceTags("X, Blah")
+                    .libClasspath("abc.jar")
+                    .buildClasspath(buildCp)
+                    .discover(true)
+                    .build();
+
+            assertThat(result.classpath, equalTo(buildCp));
+            assertThat(result.discoveryClasspath, equalTo(b + "|" + c));
+            assertThat(result.sources, contains(a));
+        } finally {
+            System.setProperty("path.separator", currentSeparator);
+        }
+    }
 }