Deprecate overrides: local-overrides.json, add-override, remove-override

As explained in the changelog, overrides were a solution to a system
with version-only dependencies, which is long gone.

Author: Geod24

changelog/overrides_deprecated.dd

@@ -0,0 +1,9 @@
+The override system is deprecated
+
+Dub had an "override" system, allowing a specific version or version range
+to be overriden by a specific package.
+This override system was developed with a purely version-based approach in mind,
+however since its inception, more ways to specify dependencies have been added,
+making the override approach redundant and less flexible than other approaches.
+From this release, dub will warn you if it finds an override file,
+or when using the `dub add-override` / `dub remove-override` commands.

source/dub/commandline.d

@@ -2191,13 +2191,19 @@ class AddOverrideCommand : Command {
 		bool m_system = false;
 	}
 
+	static immutable string DeprecationMessage =
+		"This command is deprecated. Use path based dependency, custom cache path, " ~
+		"or edit `dub.selections.json` to achieve the same results.";
+
+
 	this() @safe pure nothrow
 	{
 		this.name = "add-override";
 		this.argumentsPattern = "<package> <version-spec> <target-path/target-version>";
 		this.description = "Adds a new package override.";
-		this.helpText = [
-		];
+
+		this.hidden = true;
+		this.helpText = [ DeprecationMessage ];
 	}
 
 	override void prepare(scope CommandArgs args)
@@ -2209,6 +2215,7 @@ class AddOverrideCommand : Command {
 
 	override int execute(Dub dub, string[] free_args, string[] app_args)
 	{
+		logWarn(DeprecationMessage);
 		enforceUsage(app_args.length == 0, "Unexpected application arguments.");
 		enforceUsage(free_args.length == 3, "Expected three arguments, not "~free_args.length.to!string);
 		auto scope_ = m_system ? PlacementLocation.system : PlacementLocation.user;
@@ -2217,11 +2224,11 @@ class AddOverrideCommand : Command {
 		if (existsFile(NativePath(free_args[2]))) {
 			auto target = NativePath(free_args[2]);
 			if (!target.absolute) target = NativePath(getcwd()) ~ target;
-			dub.packageManager.addOverride(scope_, pack, source, target);
+			dub.packageManager.addOverride_(scope_, pack, source, target);
 			logInfo("Added override %s %s => %s", pack, source, target);
 		} else {
 			auto target = Version(free_args[2]);
-			dub.packageManager.addOverride(scope_, pack, source, target);
+			dub.packageManager.addOverride_(scope_, pack, source, target);
 			logInfo("Added override %s %s => %s", pack, source, target);
 		}
 		return 0;
@@ -2238,8 +2245,9 @@ class RemoveOverrideCommand : Command {
 		this.name = "remove-override";
 		this.argumentsPattern = "<package> <version-spec>";
 		this.description = "Removes an existing package override.";
-		this.helpText = [
-		];
+
+		this.hidden = true;
+		this.helpText = [ AddOverrideCommand.DeprecationMessage ];
 	}
 
 	override void prepare(scope CommandArgs args)
@@ -2251,11 +2259,12 @@ class RemoveOverrideCommand : Command {
 
 	override int execute(Dub dub, string[] free_args, string[] app_args)
 	{
+		logWarn(AddOverrideCommand.DeprecationMessage);
 		enforceUsage(app_args.length == 0, "Unexpected application arguments.");
 		enforceUsage(free_args.length == 2, "Expected two arguments, not "~free_args.length.to!string);
 		auto scope_ = m_system ? PlacementLocation.system : PlacementLocation.user;
 		auto source = VersionRange.fromString(free_args[1]);
-		dub.packageManager.removeOverride(scope_, free_args[0], source);
+		dub.packageManager.removeOverride_(scope_, free_args[0], source);
 		return 0;
 	}
 }
@@ -2266,23 +2275,25 @@ class ListOverridesCommand : Command {
 		this.name = "list-overrides";
 		this.argumentsPattern = "";
 		this.description = "Prints a list of all local package overrides";
-		this.helpText = [
-			"Prints a list of all overridden packages added via \"dub add-override\"."
-		];
+
+		this.hidden = true;
+		this.helpText = [ AddOverrideCommand.DeprecationMessage ];
 	}
 	override void prepare(scope CommandArgs args) {}
 	override int execute(Dub dub, string[] free_args, string[] app_args)
 	{
-		void printList(in PackageOverride[] overrides, string caption)
+		logWarn(AddOverrideCommand.DeprecationMessage);
+
+		void printList(in PackageOverride_[] overrides, string caption)
 		{
 			if (overrides.length == 0) return;
 			logInfoNoTag("# %s", caption);
 			foreach (ovr; overrides)
 				ovr.target.match!(
 					t => logInfoNoTag("%s %s => %s", ovr.package_.color(Mode.bold), ovr.version_, t));
 		}
-		printList(dub.packageManager.getOverrides(PlacementLocation.user), "User wide overrides");
-		printList(dub.packageManager.getOverrides(PlacementLocation.system), "System wide overrides");
+		printList(dub.packageManager.getOverrides_(PlacementLocation.user), "User wide overrides");
+		printList(dub.packageManager.getOverrides_(PlacementLocation.system), "System wide overrides");
 		return 0;
 	}
 }

source/dub/packagemanager.d

@@ -491,7 +491,13 @@ class PackageManager {
 
 	/** Returns a list of all package overrides for the given scope.
 	*/
+	deprecated(OverrideDepMsg)
 	const(PackageOverride)[] getOverrides(PlacementLocation scope_)
+	const {
+		return cast(typeof(return)) this.getOverrides_(scope_);
+	}
+
+	package(dub) const(PackageOverride_)[] getOverrides_(PlacementLocation scope_)
 	const {
 		return m_repositories[scope_].overrides;
 	}
@@ -513,15 +519,28 @@ class PackageManager {
 	}
 
 	/// Ditto
+	deprecated(OverrideDepMsg)
 	void addOverride(PlacementLocation scope_, string package_, VersionRange source, Version target)
 	{
-		m_repositories[scope_].overrides ~= PackageOverride(package_, source, target);
-		m_repositories[scope_].writeOverrides();
+		this.addOverride_(scope_, package_, source, target);
 	}
 	/// ditto
+	deprecated(OverrideDepMsg)
 	void addOverride(PlacementLocation scope_, string package_, VersionRange source, NativePath target)
 	{
-		m_repositories[scope_].overrides ~= PackageOverride(package_, source, target);
+		this.addOverride_(scope_, package_, source, target);
+	}
+
+	// Non deprecated version that is used by `commandline`. Do not use!
+	package(dub) void addOverride_(PlacementLocation scope_, string package_, VersionRange source, Version target)
+	{
+		m_repositories[scope_].overrides ~= PackageOverride_(package_, source, target);
+		m_repositories[scope_].writeOverrides();
+	}
+	// Non deprecated version that is used by `commandline`. Do not use!
+	package(dub) void addOverride_(PlacementLocation scope_, string package_, VersionRange source, NativePath target)
+	{
+		m_repositories[scope_].overrides ~= PackageOverride_(package_, source, target);
 		m_repositories[scope_].writeOverrides();
 	}
 
@@ -536,7 +555,13 @@ class PackageManager {
 		);
 	}
 
+	deprecated(OverrideDepMsg)
 	void removeOverride(PlacementLocation scope_, string package_, VersionRange src)
+	{
+		this.removeOverride_(scope_, package_, src);
+	}
+
+	package(dub) void removeOverride_(PlacementLocation scope_, string package_, VersionRange src)
 	{
 		Location* rep = &m_repositories[scope_];
 		foreach (i, ovr; rep.overrides) {
@@ -838,9 +863,11 @@ class PackageManager {
 	}
 }
 
-struct PackageOverride {
-	private alias ResolvedDep = SumType!(NativePath, Version);
+deprecated(OverrideDepMsg)
+alias PackageOverride = PackageOverride_;
 
+package(dub) struct PackageOverride_ {
+	private alias ResolvedDep = SumType!(NativePath, Version);
 	string package_;
 	VersionRange source;
 	ResolvedDep target;
@@ -943,7 +970,7 @@ private struct Location {
 	Package[] localPackages;
 
 	/// List of overrides stored at this `Location`
-	PackageOverride[] overrides;
+	PackageOverride_[] overrides;
 
 	this(NativePath path) @safe pure nothrow @nogc
 	{
@@ -955,8 +982,11 @@ private struct Location {
 		this.overrides = null;
 		auto ovrfilepath = this.packagePath ~ LocalOverridesFilename;
 		if (existsFile(ovrfilepath)) {
+			logWarn("Found local override file: %s", ovrfilepath);
+			logWarn(OverrideDepMsg);
+			logWarn("Replace with a path-based dependency in your project or a custom cache path");
 			foreach (entry; jsonFromFile(ovrfilepath)) {
-				PackageOverride ovr;
+				PackageOverride_ ovr;
 				ovr.package_ = entry["name"].get!string;
 				ovr.source = VersionRange.fromString(entry["version"].get!string);
 				if (auto pv = "targetVersion" in entry) ovr.target = Version(pv.get!string);
@@ -1122,3 +1152,6 @@ private struct Location {
 			logDiagnostic("Failed to enumerate %s packages: %s", path.toNativeString(), e.toString());
 	}
 }
+
+private immutable string OverrideDepMsg =
+	"Overrides are deprecated as they are redundant with more fine-grained approaches";