Add 'nix store gc' command

src/nix/store-gc.cc

@@ -0,0 +1,43 @@
+#include "command.hh"
+#include "common-args.hh"
+#include "shared.hh"
+#include "store-api.hh"
+
+using namespace nix;
+
+struct CmdStoreGC : StoreCommand, MixDryRun
+{
+    GCOptions options;
+
+    CmdStoreGC()
+    {
+        addFlag({
+            .longName = "max",
+            .description = "stop after freeing `n` bytes of disk space",
+            .labels = {"n"},
+            .handler = {&options.maxFreed}
+        });
+    }
+
+    std::string description() override
+    {
+        return "perform garbage collection on a Nix store";
+    }
+
+    std::string doc() override
+    {
+        return
+          #include "store-gc.md"
+          ;
+    }
+
+    void run(ref<Store> store) override
+    {
+        options.action = dryRun ? GCOptions::gcReturnDead : GCOptions::gcDeleteDead;
+        GCResults results;
+        PrintFreed freed(options.action == GCOptions::gcDeleteDead, results);
+        store->collectGarbage(options, results);
+    }
+};
+
+static auto rCmdStoreGC = registerCommand2<CmdStoreGC>({"store", "gc"});

src/nix/store-gc.md

@@ -0,0 +1,21 @@
+R""(
+
+# Examples
+
+* Delete unreachable paths in the Nix store:
+
+  ```console
+  # nix store gc
+  ```
+
+* Delete up to 1 gigabyte of garbage:
+
+  ```console
+  # nix store gc --max 1G
+  ```
+
+# Description
+
+This command deletes unreachable paths in the Nix store.
+
+)""

tests/flakes.sh

@@ -276,18 +276,18 @@ git -C $flake3Dir commit -m 'Add lockfile'
 # Test whether registry caching works.
 nix registry list --flake-registry file://$registry | grep -q flake3
 mv $registry $registry.tmp
-nix-store --gc
+nix store gc
 nix registry list --flake-registry file://$registry --refresh | grep -q flake3
 mv $registry.tmp $registry
 
 # Test whether flakes are registered as GC roots for offline use.
 # FIXME: use tarballs rather than git.
 rm -rf $TEST_HOME/.cache
-nix-store --gc # get rid of copies in the store to ensure they get fetched to our git cache
+nix store gc # get rid of copies in the store to ensure they get fetched to our git cache
 _NIX_FORCE_HTTP=1 nix build -o $TEST_ROOT/result git+file://$flake2Dir#bar
 mv $flake1Dir $flake1Dir.tmp
 mv $flake2Dir $flake2Dir.tmp
-nix-store --gc
+nix store gc
 _NIX_FORCE_HTTP=1 nix build -o $TEST_ROOT/result git+file://$flake2Dir#bar
 _NIX_FORCE_HTTP=1 nix build -o $TEST_ROOT/result git+file://$flake2Dir#bar --refresh
 mv $flake1Dir.tmp $flake1Dir