dub run <package> should search the registry on failure

changelog/dub-run.dd

@@ -0,0 +1,45 @@
+`dub run` will now automatically fetch a package if it's not found locally
+
+Starting with this release, `dub run <mypackage>` makes sure that the package is available locally.
+This means that now a `dub fetch <mypackage>` is no longer required and all a user of a library needs to run your dub package is `dub run`:
+
+$(CONSOLE
+> dub run gitcompatibledubpackage
+gitcompatibledubpackage wasn't found locally, but it's available online:
+---
+Description: Example of a DUB package also usable as git submodule. For DUB test suite.
+Version: 1.0.4
+---
+Do you want to fetch gitcompatibledubpackage? [Y/n]:
+)
+
+An optional `--yes` (`-y`) flag is provided for non-interactive use:
+
+$(CONSOLE
+> dub run --yes gitcompatibledubpackage
+gitcompatibledubpackage wasn't found locally, but it's available online:
+---
+Description: Example of a DUB package also usable as git submodule. For DUB test suite.
+Version: 1.0.4
+---
+Fetching gitcompatibledubpackage 1.0.4...
+Building package gitcompatibledubpackage in /home/seb/.dub/packages/gitcompatibledubpackage-1.0.4/gitcompatibledubpackage/
+Performing "debug" build using dmd for x86_64.
+gitcompatibledubpackage 1.0.4: building configuration "exe"...
+Linking...
+Running ../../.dub/packages/gitcompatibledubpackage-1.0.4/gitcompatibledubpackage/gitcompatibledubpackage
+Hello DUB
+)
+
+If one wants to run a specific version of a package, it can be passed to `dub run` too:
+
+$(CONSOLE
+> dub run gitcompatibledubpackage@1.0.3
+Fetching gitcompatibledubpackage 1.0.3...
+Building package gitcompatibledubpackage in /home/seb/.dub/packages/gitcompatibledubpackage-1.0.3/gitcompatibledubpackage/
+Performing "debug" build using dmd for x86_64.
+gitcompatibledubpackage 1.0.3: building configuration "exe"...
+Linking...
+Running ../../.dub/packages/gitcompatibledubpackage-1.0.3/gitcompatibledubpackage/gitcompatibledubpackage
+Hello DUB
+)

source/dub/commandline.d

@@ -517,7 +517,7 @@ class InitCommand : Command {
 			free_args = free_args[1 .. $];
 		}
 
-		string input(string caption, string default_value)
+		static string input(string caption, string default_value)
 		{
 			writef("%s [%s]: ", caption, default_value);
 			auto inp = readln();
@@ -829,6 +829,7 @@ class GenerateCommand : PackageBuildCommand {
 }
 
 class BuildCommand : GenerateCommand {
+	bool m_yes; // automatic yes to prompts;
 	this()
 	{
 		this.name = "build";
@@ -848,12 +849,70 @@ class BuildCommand : GenerateCommand {
 		args.getopt("f|force", &m_force, [
 			"Forces a recompilation even if the target is up to date"
 		]);
+		args.getopt("y|yes", &m_yes, [
+			`Automatic yes to prompts. Assume "yes" as answer to all prompts and run non-interactively.`
+		]);
 		super.prepare(args);
 		m_generator = "build";
 	}
 
 	override int execute(Dub dub, string[] free_args, string[] app_args)
 	{
+		// single package files don't need to be downloaded, they are on the disk.
+		if (free_args.length < 1 || m_single)
+		    return super.execute(dub, free_args, app_args);
+
+        const package_parts = splitPackageName(free_args[0]);
+        const package_name = package_parts.name;
+
+        static bool input(string caption, bool default_value = true) {
+            writef("%s [%s]: ", caption, default_value ? "Y/n" : "y/N");
+            auto inp = readln();
+            string userInput = "y";
+            if (inp.length > 1)
+                userInput = inp[0 .. $ - 1].toLower;
+
+            switch (userInput) {
+                case "no", "n", "0":
+                    return false;
+                case "yes", "y", "1":
+                default:
+                    return true;
+            }
+        }
+
+        Dependency dep;
+
+        if (package_parts.version_.length > 0) {
+            // the user provided a version manually
+            free_args[0] = package_name;
+            dep = Dependency(package_parts.version_);
+        } else {
+			const pack = dub.packageManager.getFirstPackage(package_name);
+			if (pack)
+				return super.execute(dub, free_args, app_args);
+
+            // search for the package and filter versions for exact matches
+            auto search = dub.searchPackages(package_name)
+                .map!(tup => tup[1].find!(p => p.name == package_name))
+                .filter!(ps => !ps.empty);
+            if (search.empty)
+                return 2;
+
+            const p = search.front.front;
+            logInfo("%s wasn't found locally, but it's available online:", package_name);
+            logInfo("---");
+            logInfo("Description: %s", p.description);
+            logInfo("Version: %s", p.version_);
+            logInfo("---");
+
+            const answer = m_yes ? true : input("Do you want to fetch %s?".format(package_name));
+            if (!answer)
+                return 0;
+            dep = Dependency(p.version_);
+        }
+
+        dub.fetch(package_name, dep, dub.defaultPlacementLocation, FetchOptions.none);
 		return super.execute(dub, free_args, app_args);
 	}
 }

test/issue877-auto-fetch-package-on-run.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+set -eu -o pipefail
+set -x
+$DUB remove --version="*" gitcompatibledubpackage || true
+
+# check whether the interactive run mode works
+echo "y" | $DUB run gitcompatibledubpackage | grep "Hello DUB"
+$DUB remove gitcompatibledubpackage
+
+! (echo "n" | $DUB run gitcompatibledubpackage | grep "Hello DUB")
+! $DUB remove gitcompatibledubpackage
+
+# check -y
+$DUB run --yes gitcompatibledubpackage | grep "Hello DUB"
+$DUB remove gitcompatibledubpackage
+
+# check --yes
+$DUB run -y gitcompatibledubpackage | grep "Hello DUB"
+$DUB remove gitcompatibledubpackage
+
+# check supplying versions directly
+dub_log="$($DUB run gitcompatibledubpackage@1.0.3)"
+echo "$dub_log" | grep "Hello DUB"
+echo "$dub_log" | grep "Fetching.*1.0.3"
+$DUB remove gitcompatibledubpackage
+
+# check supplying an invalid version
+(! $DUB run gitcompatibledubpackage@0.42.43) 2>&1 | \
+    grep 'No package gitcompatibledubpackage was found matching the dependency 0[.]42[.]43'
+
+! $DUB remove gitcompatibledubpackage