Add aliases for the old flake commands

Requires reworking a bit the existing alias mechanism to allow aliases
to be composite commands themselves

src/nix/flake.cc

@@ -638,142 +638,6 @@ struct CmdFlakeCheck : FlakeCommand
     }
 };
 
-struct CmdFlakeInitCommon : virtual Args, EvalCommand
-{
-    std::string templateUrl = "templates";
-    Path destDir;
-
-    const Strings attrsPathPrefixes{"templates."};
-    const LockFlags lockFlags{ .writeLockFile = false };
-
-    CmdFlakeInitCommon()
-    {
-        addFlag({
-            .longName = "template",
-            .shortName = 't',
-            .description = "The template to use.",
-            .labels = {"template"},
-            .handler = {&templateUrl},
-            .completer = {[&](size_t, std::string_view prefix) {
-                completeFlakeRefWithFragment(
-                    getEvalState(),
-                    lockFlags,
-                    attrsPathPrefixes,
-                    {"defaultTemplate"},
-                    prefix);
-            }}
-        });
-    }
-
-    void run(nix::ref<nix::Store> store) override
-    {
-        auto flakeDir = absPath(destDir);
-
-        auto evalState = getEvalState();
-
-        auto [templateFlakeRef, templateName] = parseFlakeRefWithFragment(templateUrl, absPath("."));
-
-        auto installable = InstallableFlake(nullptr,
-            evalState, std::move(templateFlakeRef),
-            Strings{templateName == "" ? "defaultTemplate" : templateName},
-            Strings(attrsPathPrefixes), lockFlags);
-
-        auto [cursor, attrPath] = installable.getCursor(*evalState);
-
-        auto templateDir = cursor->getAttr("path")->getString();
-
-        assert(store->isInStore(templateDir));
-
-        std::vector<Path> files;
-
-        std::function<void(const Path & from, const Path & to)> copyDir;
-        copyDir = [&](const Path & from, const Path & to)
-        {
-            createDirs(to);
-
-            for (auto & entry : readDirectory(from)) {
-                auto from2 = from + "/" + entry.name;
-                auto to2 = to + "/" + entry.name;
-                auto st = lstat(from2);
-                if (S_ISDIR(st.st_mode))
-                    copyDir(from2, to2);
-                else if (S_ISREG(st.st_mode)) {
-                    auto contents = readFile(from2);
-                    if (pathExists(to2)) {
-                        auto contents2 = readFile(to2);
-                        if (contents != contents2)
-                            throw Error("refusing to overwrite existing file '%s'", to2);
-                    } else
-                        writeFile(to2, contents);
-                }
-                else if (S_ISLNK(st.st_mode)) {
-                    auto target = readLink(from2);
-                    if (pathExists(to2)) {
-                        if (readLink(to2) != target)
-                            throw Error("refusing to overwrite existing symlink '%s'", to2);
-                    } else
-                          createSymlink(target, to2);
-                }
-                else
-                    throw Error("file '%s' has unsupported type", from2);
-                files.push_back(to2);
-            }
-        };
-
-        copyDir(templateDir, flakeDir);
-
-        if (pathExists(flakeDir + "/.git")) {
-            Strings args = { "-C", flakeDir, "add", "--intent-to-add", "--force", "--" };
-            for (auto & s : files) args.push_back(s);
-            runProgram("git", true, args);
-        }
-    }
-};
-
-struct CmdFlakeInit : CmdFlakeInitCommon
-{
-    std::string description() override
-    {
-        return "create a flake in the current directory from a template";
-    }
-
-    std::string doc() override
-    {
-        return
-          #include "flake-init.md"
-          ;
-    }
-
-    CmdFlakeInit()
-    {
-        destDir = ".";
-    }
-};
-
-struct CmdFlakeNew : CmdFlakeInitCommon
-{
-    std::string description() override
-    {
-        return "create a flake in the specified directory from a template";
-    }
-
-    std::string doc() override
-    {
-        return
-          #include "flake-new.md"
-          ;
-    }
-
-    CmdFlakeNew()
-    {
-        expectArgs({
-            .label = "dest-dir",
-            .handler = {&destDir},
-            .completer = completePath
-        });
-    }
-};
-
 struct CmdFlakeClone : FlakeCommand
 {
     Path destDir;
@@ -1125,8 +989,6 @@ struct CmdFlake : NixMultiCommand
                 {"metadata", []() { return make_ref<CmdFlakeMetadata>(); }},
                 {"info", []() { return make_ref<CmdFlakeInfo>(); }},
                 {"check", []() { return make_ref<CmdFlakeCheck>(); }},
-                {"init", []() { return make_ref<CmdFlakeInit>(); }},
-                {"new", []() { return make_ref<CmdFlakeNew>(); }},
                 {"clone", []() { return make_ref<CmdFlakeClone>(); }},
                 {"archive", []() { return make_ref<CmdFlakeArchive>(); }},
                 {"show", []() { return make_ref<CmdFlakeShow>(); }},

src/nix/main.cc

@@ -106,26 +106,28 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
         });
     }
 
-    std::map<std::string, std::vector<std::string>> aliases = {
-        {"add-to-store", {"store", "add-path"}},
-        {"cat-nar", {"nar", "cat"}},
-        {"cat-store", {"store", "cat"}},
-        {"copy-sigs", {"store", "copy-sigs"}},
-        {"dev-shell", {"develop"}},
-        {"diff-closures", {"store", "diff-closures"}},
-        {"dump-path", {"store", "dump-path"}},
-        {"hash-file", {"hash", "file"}},
-        {"hash-path", {"hash", "path"}},
-        {"ls-nar", {"nar", "ls"}},
-        {"ls-store", {"store", "ls"}},
-        {"make-content-addressable", {"store", "make-content-addressable"}},
-        {"optimise-store", {"store", "optimise"}},
-        {"ping-store", {"store", "ping"}},
-        {"sign-paths", {"store", "sign"}},
-        {"to-base16", {"hash", "to-base16"}},
-        {"to-base32", {"hash", "to-base32"}},
-        {"to-base64", {"hash", "to-base64"}},
-        {"verify", {"store", "verify"}},
+    std::map<std::vector<std::string>, std::vector<std::string>> aliases = {
+        {{"add-to-store"}, {"store", "add-path"}},
+        {{"cat-nar"}, {"nar", "cat"}},
+        {{"cat-store"}, {"store", "cat"}},
+        {{"copy-sigs"}, {"store", "copy-sigs"}},
+        {{"dev-shell"}, {"develop"}},
+        {{"diff-closures"}, {"store", "diff-closures"}},
+        {{"dump-path"}, {"store", "dump-path"}},
+        {{"hash-file"}, {"hash", "file"}},
+        {{"hash-path"}, {"hash", "path"}},
+        {{"ls-nar"}, {"nar", "ls"}},
+        {{"ls-store"}, {"store", "ls"}},
+        {{"make-content-addressable"}, {"store", "make-content-addressable"}},
+        {{"optimise-store"}, {"store", "optimise"}},
+        {{"ping-store"}, {"store", "ping"}},
+        {{"sign-paths"}, {"store", "sign"}},
+        {{"to-base16"}, {"hash", "to-base16"}},
+        {{"to-base32"}, {"hash", "to-base32"}},
+        {{"to-base64"}, {"hash", "to-base64"}},
+        {{"verify"}, {"store", "verify"}},
+        {{"flake", "init"}, {"init"}},
+        {{"flake", "new"}, {"new"}},
     };
 
     bool aliasUsed = false;
@@ -134,14 +136,33 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
     {
         if (aliasUsed || command || pos == args.end()) return pos;
         auto arg = *pos;
-        auto i = aliases.find(arg);
-        if (i == aliases.end()) return pos;
-        warn("'%s' is a deprecated alias for '%s'",
-            arg, concatStringsSep(" ", i->second));
-        pos = args.erase(pos);
-        for (auto j = i->second.rbegin(); j != i->second.rend(); ++j)
-            pos = args.insert(pos, *j);
-        aliasUsed = true;
+
+        // Loop through the aliases to see whether the current cli corresponds
+        // to one of them.
+        for (auto & [from, to] : aliases) {
+            auto i = pos;
+            bool isCurrentAlias = true;
+            // Is the current alias a prefix of the args?
+            for (auto & fromItem : from) {
+                if (i == args.end() || *i != fromItem) {
+                    // The current alias doesn’t match the args
+                    isCurrentAlias = false;
+                    break;
+                }
+                i++;
+            }
+            // If we went through to the end of the previous loop, then we match
+            // the currently considered alias.
+            // So rewrite the alias in the current args.
+            if (isCurrentAlias) {
+                warn("'%s' is a deprecated alias for '%s'",
+                    concatStringsSep(" ", from), concatStringsSep(" ", to));
+                pos = args.erase(pos, i);
+                pos = args.insert(pos, to.begin(), to.end());
+                aliasUsed = true;
+                return pos;
+            }
+        }
         return pos;
     }
 

src/nix/new.cc

@@ -0,0 +1,150 @@
+#include "command.hh"
+#include "common-args.hh"
+#include "shared.hh"
+#include "store-api.hh"
+#include "local-fs-store.hh"
+#include "fs-accessor.hh"
+#include "eval-cache.hh"
+
+using namespace nix;
+using namespace nix::flake;
+
+struct CmdFlakeInitCommon : virtual Args, EvalCommand
+{
+    std::string templateUrl = "templates";
+    Path destDir;
+
+    const Strings attrsPathPrefixes{"templates."};
+    const LockFlags lockFlags{ .writeLockFile = false };
+
+    CmdFlakeInitCommon()
+    {
+        addFlag({
+            .longName = "template",
+            .shortName = 't',
+            .description = "The template to use.",
+            .labels = {"template"},
+            .handler = {&templateUrl},
+            .completer = {[&](size_t, std::string_view prefix) {
+                completeFlakeRefWithFragment(
+                    getEvalState(),
+                    lockFlags,
+                    attrsPathPrefixes,
+                    {"defaultTemplate"},
+                    prefix);
+            }}
+        });
+    }
+
+    void run(nix::ref<nix::Store> store) override
+    {
+        auto flakeDir = absPath(destDir);
+
+        auto evalState = getEvalState();
+
+        auto [templateFlakeRef, templateName] = parseFlakeRefWithFragment(templateUrl, absPath("."));
+
+        auto installable = InstallableFlake(nullptr,
+            evalState, std::move(templateFlakeRef),
+            Strings{templateName == "" ? "defaultTemplate" : templateName},
+            Strings(attrsPathPrefixes), lockFlags);
+
+        auto [cursor, attrPath] = installable.getCursor(*evalState);
+
+        auto templateDir = cursor->getAttr("path")->getString();
+
+        assert(store->isInStore(templateDir));
+
+        std::vector<Path> files;
+
+        std::function<void(const Path & from, const Path & to)> copyDir;
+        copyDir = [&](const Path & from, const Path & to)
+        {
+            createDirs(to);
+
+            for (auto & entry : readDirectory(from)) {
+                auto from2 = from + "/" + entry.name;
+                auto to2 = to + "/" + entry.name;
+                auto st = lstat(from2);
+                if (S_ISDIR(st.st_mode))
+                    copyDir(from2, to2);
+                else if (S_ISREG(st.st_mode)) {
+                    auto contents = readFile(from2);
+                    if (pathExists(to2)) {
+                        auto contents2 = readFile(to2);
+                        if (contents != contents2)
+                            throw Error("refusing to overwrite existing file '%s'", to2);
+                    } else
+                        writeFile(to2, contents);
+                }
+                else if (S_ISLNK(st.st_mode)) {
+                    auto target = readLink(from2);
+                    if (pathExists(to2)) {
+                        if (readLink(to2) != target)
+                            throw Error("refusing to overwrite existing symlink '%s'", to2);
+                    } else
+                          createSymlink(target, to2);
+                }
+                else
+                    throw Error("file '%s' has unsupported type", from2);
+                files.push_back(to2);
+            }
+        };
+
+        copyDir(templateDir, flakeDir);
+
+        if (pathExists(flakeDir + "/.git")) {
+            Strings args = { "-C", flakeDir, "add", "--intent-to-add", "--force", "--" };
+            for (auto & s : files) args.push_back(s);
+            runProgram("git", true, args);
+        }
+    }
+};
+
+struct CmdFlakeInit : CmdFlakeInitCommon
+{
+    std::string description() override
+    {
+        return "create a flake in the current directory from a template";
+    }
+
+    std::string doc() override
+    {
+        return
+          #include "init.md"
+          ;
+    }
+
+    CmdFlakeInit()
+    {
+        destDir = ".";
+    }
+};
+
+struct CmdFlakeNew : CmdFlakeInitCommon
+{
+    std::string description() override
+    {
+        return "create a flake in the specified directory from a template";
+    }
+
+    std::string doc() override
+    {
+        return
+          #include "new.md"
+          ;
+    }
+
+    CmdFlakeNew()
+    {
+        expectArgs({
+            .label = "dest-dir",
+            .handler = {&destDir},
+            .completer = completePath
+        });
+    }
+};
+
+static auto r0 = registerCommand<CmdFlakeInit>("init");
+static auto r1 = registerCommand<CmdFlakeNew>("new");
+