Dont remap dependency sources when building on CI services.

Use `-Dfabric.loom.ci=false` to force disable

src/main/java/net/fabricmc/loom/build/ModCompileRemapper.java

@@ -51,6 +51,7 @@ import net.fabricmc.loom.configuration.mods.ModProcessor;
 import net.fabricmc.loom.configuration.processors.dependency.ModDependencyInfo;
 import net.fabricmc.loom.configuration.processors.dependency.RemapData;
 import net.fabricmc.loom.util.Constants;
+import net.fabricmc.loom.util.OperatingSystem;
 import net.fabricmc.loom.util.SourceRemapper;
 
 @SuppressWarnings("UnstableApiUsage")
@@ -96,7 +97,7 @@ public class ModCompileRemapper {
 
 				File remappedSources = info.getRemappedOutput("sources");
 
-				if (!remappedSources.exists() || refreshDeps) {
+				if ((!remappedSources.exists() || refreshDeps) && !OperatingSystem.isCIBuild()) {
 					File sources = findSources(dependencies, artifact);
 
 					if (sources != null) {

src/main/java/net/fabricmc/loom/util/OperatingSystem.java

@@ -48,4 +48,15 @@ public class OperatingSystem {
 	public static boolean is64Bit() {
 		return System.getProperty("sun.arch.data.model").contains("64");
 	}
+
+	public static boolean isCIBuild() {
+		String loomProperty = System.getProperty("fabric.loom.ci");
+
+		if (loomProperty != null) {
+			return loomProperty.equalsIgnoreCase("true");
+		}
+
+		// CI seems to be set by most popular CI services
+		return System.getenv("CI") != null;
+	}
 }

src/main/java/net/fabricmc/loom/util/SourceRemapper.java

@@ -91,10 +91,12 @@ public class SourceRemapper {
 	}
 
 	public void remapAll() {
-		if (!remapTasks.isEmpty()) {
-			project.getLogger().lifecycle(":remapping sources");
+		if (remapTasks.isEmpty()) {
+			return;
 		}
 
+		project.getLogger().lifecycle(":remapping sources");
+
 		ProgressLogger progressLogger = ProgressLogger.getProgressFactory(project, SourceRemapper.class.getName());
 		progressLogger.start("Remapping dependency sources", "sources");