depot/patches/base/nix/nix-flake-default.patch

diff --git a/src/nix/installables.cc b/src/nix/installables.cc
index 4e6bf4a9a..ab672f8be 100644
--- a/src/libcmd/installables.cc
+++ b/src/libcmd/installables.cc
@@ -20,6 +20,10 @@
 
 namespace nix {
 
+const static std::regex attrPathRegex(
+    R"((?:[a-zA-Z0-9_"-][a-zA-Z0-9_".-]*))",
+    std::regex::ECMAScript);
+
 void completeFlakeInputPath(
     ref<EvalState> evalState,
     const FlakeRef & flakeRef,
@@ -215,10 +219,19 @@ void completeFlakeRefWithFragment(
     /* Look for flake output attributes that match the
        prefix. */
     try {
+        bool isAttrPath = std::regex_match(prefix.begin(), prefix.end(), attrPathRegex);
         auto hash = prefix.find('#');
-        if (hash != std::string::npos) {
-            auto fragment = prefix.substr(hash + 1);
-            auto flakeRefS = std::string(prefix.substr(0, hash));
+        if (isAttrPath || hash != std::string::npos) {
+            auto fragment =
+                isAttrPath
+                ? prefix
+                : prefix.substr(hash + 1);
+
+            auto flakeRefS =
+                isAttrPath
+                ? std::string("flake:default")
+                : std::string(prefix.substr(0, hash));
+
             // FIXME: do tilde expansion.
             auto flakeRef = parseFlakeRef(flakeRefS, absPath("."));
 
@@ -251,7 +264,10 @@ void completeFlakeRefWithFragment(
                         auto attrPath2 = attr->getAttrPath(attr2);
                         /* Strip the attrpath prefix. */
                         attrPath2.erase(attrPath2.begin(), attrPath2.begin() + attrPathPrefix.size());
-                        completions->add(flakeRefS + "#" + concatStringsSep(".", attrPath2));
+                        if (isAttrPath)
+                            completions->add(concatStringsSep(".", attrPath2));
+                        else
+                            completions->add(flakeRefS + "#" + concatStringsSep(".", attrPath2));
                     }
                 }
             }
@@ -626,7 +642,13 @@ std::vector<std::shared_ptr<Installable>> SourceExprCommand::parseInstallables(
             std::exception_ptr ex;
 
             try {
-                auto [flakeRef, fragment] = parseFlakeRefWithFragment(s, absPath("."));
+                bool isAttrPath = std::regex_match(s, attrPathRegex);
+
+                auto [flakeRef, fragment] =
+                    isAttrPath
+                    ? std::make_pair(parseFlakeRef("flake:default", absPath(".")), s)
+                    : parseFlakeRefWithFragment(s, absPath("."));
+
                 result.push_back(std::make_shared<InstallableFlake>(
                         getEvalState(), std::move(flakeRef),
                         fragment == "" ? getDefaultFlakeAttrPaths() : Strings{fragment},
diff --git a/src/nix/search.cc b/src/nix/search.cc
index 9f864b3a4..b21118ece 100644
--- a/src/nix/search.cc
+++ b/src/nix/search.cc
@@ -30,13 +30,32 @@ std::string hilite(const std::string & s, const std::smatch & m, std::string pos
           + std::string(m.suffix());
 }
 
-struct CmdSearch : InstallableCommand, MixJSON
+struct CmdSearch : SourceExprCommand, MixJSON
 {
+    std::string _installable{"flake:default"};
     std::vector<std::string> res;
 
     CmdSearch()
     {
-        expectArgs("regex", &res);
+        bool hasInstallable = false;
+
+        addFlag({
+            .longName = "installable",
+            .shortName = 'i',
+            .description = "Search within this installable",
+            .labels = {"installable"},
+            .handler = {[this, &hasInstallable](std::string ss) {
+                hasInstallable = true;
+                _installable = ss;
+            }},
+            .completer = completePath
+        });
+
+        if (hasInstallable && (file || expr)) {
+            throw UsageError("'--installable' cannot be used together with '--file' or '--expr'");
+        }
+
+        expectArgs("args", &res);
     }
 
     std::string description() override
@@ -63,6 +82,8 @@ struct CmdSearch : InstallableCommand, MixJSON
     {
         settings.readOnlyMode = true;
 
+        auto installable = parseInstallable(store, (file || expr) ? "" : _installable);
+
         // Empty search string should match all packages
         // Use "^" here instead of ".*" due to differences in resulting highlighting
         // (see #1893 -- libc++ claims empty search string is not in POSIX grammar)
diff --git a/tests/flakes.sh b/tests/flakes.sh
index 2b7bcdd68..f654b2f36 100644
--- a/tests/flakes.sh
+++ b/tests/flakes.sh
@@ -188,7 +188,7 @@ nix build -o $TEST_ROOT/result flake1#foo
 [[ -e $TEST_ROOT/result/hello ]]
 
 # Test defaultPackage.
-nix build -o $TEST_ROOT/result flake1
+nix build -o $TEST_ROOT/result flake1#
 [[ -e $TEST_ROOT/result/hello ]]
 
 nix build -o $TEST_ROOT/result $flake1Dir
diff --git a/tests/search.sh b/tests/search.sh
index ee3261687..e41963c2d 100644
--- a/tests/search.sh
+++ b/tests/search.sh
@@ -3,23 +3,23 @@ source common.sh
 clearStore
 clearCache
 
-(( $(nix search -f search.nix '' hello | wc -l) > 0 ))
+(( $(nix search -f search.nix hello | wc -l) > 0 ))
 
 # Check descriptions are searched
-(( $(nix search -f search.nix '' broken | wc -l) > 0 ))
+(( $(nix search -f search.nix broken | wc -l) > 0 ))
 
 # Check search that matches nothing
-(( $(nix search -f search.nix '' nosuchpackageexists | wc -l) == 0 ))
+(( $(nix search -f search.nix nosuchpackageexists | wc -l) == 0 ))
 
 # Search for multiple arguments
-(( $(nix search -f search.nix '' hello empty | wc -l) == 2 ))
+(( $(nix search -f search.nix hello empty | wc -l) == 2 ))
 
 # Multiple arguments will not exist
-(( $(nix search -f search.nix '' hello broken | wc -l) == 0 ))
+(( $(nix search -f search.nix hello broken | wc -l) == 0 ))
 
 ## Search expressions
 
 # Check that empty search string matches all
-nix search -f search.nix '' |grep -q foo
-nix search -f search.nix '' |grep -q bar
-nix search -f search.nix '' |grep -q hello
+nix search -f search.nix |grep -q foo
+nix search -f search.nix |grep -q bar
+nix search -f search.nix |grep -q hello