7 files changed, 149 insertions, 5 deletions
diff --git a/src/libutil/args.cc b/src/libutil/args.cc
index f829415d1..afeaf4cea 100644
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@@ -217,10 +217,15 @@ MultiCommand::MultiCommand(const Commands & commands)
 {
     expectedArgs.push_back(ExpectedArg{"command", 1, true, [=](std::vector<std::string> ss) {
         assert(!command);
-        auto i = commands.find(ss[0]);
+        auto cmd = ss[0];
+        if (auto alias = get(deprecatedAliases, cmd)) {
+            warn("'%s' is a deprecated alias for '%s'", cmd, *alias);
+            cmd = *alias;
+        }
+        auto i = commands.find(cmd);
         if (i == commands.end())
-            throw UsageError("'%s' is not a recognised command", ss[0]);
-        command = {ss[0], i->second()};
+            throw UsageError("'%s' is not a recognised command", cmd);
+        command = {cmd, i->second()};
     }});
 
     categories[Command::catDefault] = "Available commands";
diff --git a/src/libutil/args.hh b/src/libutil/args.hh
index 1932e6a8a..154d1e6aa 100644
--- a/src/libutil/args.hh
+++ b/src/libutil/args.hh
@@ -234,6 +234,8 @@ public:
 
     std::map<Command::Category, std::string> categories;
 
+    std::map<std::string, std::string> deprecatedAliases;
+
     // Selected command, if any.
     std::optional<std::pair<std::string, ref<Command>>> command;
 
diff --git a/src/libutil/lru-cache.hh b/src/libutil/lru-cache.hh
index 8b83f842c..6ef4a3e06 100644
--- a/src/libutil/lru-cache.hh
+++ b/src/libutil/lru-cache.hh
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cassert>
 #include <map>
 #include <list>
 #include <optional>
diff --git a/src/libutil/tests/lru-cache.cc b/src/libutil/tests/lru-cache.cc
new file mode 100644
index 000000000..091d3d5ed
--- /dev/null
+++ b/src/libutil/tests/lru-cache.cc
@@ -0,0 +1,130 @@
+#include "lru-cache.hh"
+#include <gtest/gtest.h>
+
+namespace nix {
+
+    /* ----------------------------------------------------------------------------
+     * size
+     * --------------------------------------------------------------------------*/
+
+    TEST(LRUCache, sizeOfEmptyCacheIsZero) {
+        LRUCache<std::string, std::string> c(10);
+        ASSERT_EQ(c.size(), 0);
+    }
+
+    TEST(LRUCache, sizeOfSingleElementCacheIsOne) {
+        LRUCache<std::string, std::string> c(10);
+        c.upsert("foo", "bar");
+        ASSERT_EQ(c.size(), 1);
+    }
+
+    /* ----------------------------------------------------------------------------
+     * upsert / get
+     * --------------------------------------------------------------------------*/
+
+    TEST(LRUCache, getFromEmptyCache) {
+        LRUCache<std::string, std::string> c(10);
+        auto val = c.get("x");
+        ASSERT_EQ(val.has_value(), false);
+    }
+
+    TEST(LRUCache, getExistingValue) {
+        LRUCache<std::string, std::string> c(10);
+        c.upsert("foo", "bar");
+        auto val = c.get("foo");
+        ASSERT_EQ(val, "bar");
+    }
+
+    TEST(LRUCache, getNonExistingValueFromNonEmptyCache) {
+        LRUCache<std::string, std::string> c(10);
+        c.upsert("foo", "bar");
+        auto val = c.get("another");
+        ASSERT_EQ(val.has_value(), false);
+    }
+
+    TEST(LRUCache, upsertOnZeroCapacityCache) {
+        LRUCache<std::string, std::string> c(0);
+        c.upsert("foo", "bar");
+        auto val = c.get("foo");
+        ASSERT_EQ(val.has_value(), false);
+    }
+
+    TEST(LRUCache, updateExistingValue) {
+        LRUCache<std::string, std::string> c(1);
+        c.upsert("foo", "bar");
+
+        auto val = c.get("foo");
+        ASSERT_EQ(val.value_or("error"), "bar");
+        ASSERT_EQ(c.size(), 1);
+
+        c.upsert("foo", "changed");
+        val = c.get("foo");
+        ASSERT_EQ(val.value_or("error"), "changed");
+        ASSERT_EQ(c.size(), 1);
+    }
+
+    TEST(LRUCache, overwriteOldestWhenCapacityIsReached) {
+        LRUCache<std::string, std::string> c(3);
+        c.upsert("one", "eins");
+        c.upsert("two", "zwei");
+        c.upsert("three", "drei");
+
+        ASSERT_EQ(c.size(), 3);
+        ASSERT_EQ(c.get("one").value_or("error"), "eins");
+
+        // exceed capacity
+        c.upsert("another", "whatever");
+
+        ASSERT_EQ(c.size(), 3);
+        // Retrieving "one" makes it the most recent element thus
+        // two will be the oldest one and thus replaced.
+        ASSERT_EQ(c.get("two").has_value(), false);
+        ASSERT_EQ(c.get("another").value(), "whatever");
+    }
+
+    /* ----------------------------------------------------------------------------
+     * clear
+     * --------------------------------------------------------------------------*/
+
+    TEST(LRUCache, clearEmptyCache) {
+        LRUCache<std::string, std::string> c(10);
+        c.clear();
+        ASSERT_EQ(c.size(), 0);
+    }
+
+    TEST(LRUCache, clearNonEmptyCache) {
+        LRUCache<std::string, std::string> c(10);
+        c.upsert("one", "eins");
+        c.upsert("two", "zwei");
+        c.upsert("three", "drei");
+        ASSERT_EQ(c.size(), 3);
+        c.clear();
+        ASSERT_EQ(c.size(), 0);
+    }
+
+    /* ----------------------------------------------------------------------------
+     * erase
+     * --------------------------------------------------------------------------*/
+
+    TEST(LRUCache, eraseFromEmptyCache) {
+        LRUCache<std::string, std::string> c(10);
+        ASSERT_EQ(c.erase("foo"), false);
+        ASSERT_EQ(c.size(), 0);
+    }
+
+    TEST(LRUCache, eraseMissingFromNonEmptyCache) {
+        LRUCache<std::string, std::string> c(10);
+        c.upsert("one", "eins");
+        ASSERT_EQ(c.erase("foo"), false);
+        ASSERT_EQ(c.size(), 1);
+        ASSERT_EQ(c.get("one").value_or("error"), "eins");
+    }
+
+    TEST(LRUCache, eraseFromNonEmptyCache) {
+        LRUCache<std::string, std::string> c(10);
+        c.upsert("one", "eins");
+        ASSERT_EQ(c.erase("one"), true);
+        ASSERT_EQ(c.size(), 0);
+        ASSERT_EQ(c.get("one").value_or("empty"), "empty");
+    }
+}
diff --git a/src/libutil/url.cc b/src/libutil/url.cc
index 5d5328e5d..88c09eef9 100644
--- a/src/libutil/url.cc
+++ b/src/libutil/url.cc
@@ -4,6 +4,7 @@
 namespace nix {
 
 std::regex refRegex(refRegexS, std::regex::ECMAScript);
+std::regex badGitRefRegex(badGitRefRegexS, std::regex::ECMAScript);
 std::regex revRegex(revRegexS, std::regex::ECMAScript);
 std::regex flakeIdRegex(flakeIdRegexS, std::regex::ECMAScript);
 
diff --git a/src/libutil/url.hh b/src/libutil/url.hh
index 1503023a2..4a0d4071b 100644
--- a/src/libutil/url.hh
+++ b/src/libutil/url.hh
@@ -49,6 +49,12 @@ const static std::string pathRegex = "(?:" + segmentRegex + "(?:/" + segmentRege
 const static std::string refRegexS = "[a-zA-Z0-9][a-zA-Z0-9_.-]*"; // FIXME: check
 extern std::regex refRegex;
 
+// Instead of defining what a good Git Ref is, we define what a bad Git Ref is
+// This is because of the definition of a ref in refs.c in https://github.com/git/git
+// See tests/fetchGitRefs.sh for the full definition
+const static std::string badGitRefRegexS = "//|^[./]|/\\.|\\.\\.|[[:cntrl:][:space:]:?^~\[]|\\\\|\\*|\\.lock$|\\.lock/|@\\{|[/.]$|^@$|^$";
+extern std::regex badGitRefRegex;
+
 // A Git revision (a SHA-1 commit hash).
 const static std::string revRegexS = "[0-9a-fA-F]{40}";
 extern std::regex revRegex;
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index a63ee05b3..4b117f9bc 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -459,8 +459,7 @@ string base64Encode(const string & s);
 string base64Decode(const string & s);
 
 
-/* Get a value for the specified key from an associate container, or a
-   default value if the key doesn't exist. */
+/* Get a value for the specified key from an associate container. */
 template <class T>
 std::optional<typename T::mapped_type> get(const T & map, const typename T::key_type & key)
 {