Merge remote-tracking branch 'origin/master' into detsys-main

tests/functional/characterisation/framework.sh

@@ -63,7 +63,7 @@ function characterisationTestExit() {
             echo ''
             echo 'You can rerun this test with:'
             echo ''
-            echo "    _NIX_TEST_ACCEPT=1 make tests/functional/${TEST_NAME}.test"
+            echo "    _NIX_TEST_ACCEPT=1 make tests/functional/${TEST_NAME}.sh.test"
             echo ''
             echo 'to regenerate the files containing the expected output,'
             echo 'and then view the git diff to decide whether a change is'

tests/functional/repl.sh

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 
 source common.sh
+source characterisation/framework.sh
 
 testDir="$PWD"
 cd "$TEST_ROOT"
@@ -73,21 +74,31 @@ testReplResponseGeneral () {
     local grepMode commands expectedResponse response
     grepMode="$1"; shift
     commands="$1"; shift
-    expectedResponse="$1"; shift
-    response="$(nix repl "$@" <<< "$commands" | stripColors)"
-    echo "$response" | grepQuiet "$grepMode" -s "$expectedResponse" \
-      || fail "repl command set:
+    # Expected response can contain newlines.
+    # grep can't handle multiline patterns, so replace newlines with TEST_NEWLINE
+    # in both expectedResponse and response.
+    # awk ORS always adds a trailing record separator, so we strip it with sed.
+    expectedResponse="$(printf '%s' "$1" | awk 1 ORS=TEST_NEWLINE | sed 's/TEST_NEWLINE$//')"; shift
+    # We don't need to strip trailing record separator here, since extra data is ok.
+    response="$(nix repl "$@" <<< "$commands" 2>&1 | stripColors | awk 1 ORS=TEST_NEWLINE)"
+    printf '%s' "$response" | grepQuiet "$grepMode" -s "$expectedResponse" \
+      || fail "$(echo "repl command set:
 
 $commands
 
 does not respond with:
 
+---
 $expectedResponse
+---
 
 but with:
 
+---
 $response
-"
+---
+
+" | sed 's/TEST_NEWLINE/\n/g')"
 }
 
 testReplResponse () {
@@ -189,7 +200,7 @@ testReplResponseNoRegex '
 let x = { y = { a = 1; }; inherit x; }; in x
 ' \
 '{
-  x = { ... };
+  x = «repeated»;
   y = { ... };
 }
 '
@@ -241,6 +252,45 @@ testReplResponseNoRegex '
 ' \
 '{
   x = «repeated»;
-  y = { a = 1 };
+  y = { a = 1; };
 }
 '
+
+# TODO: move init to characterisation/framework.sh
+badDiff=0
+badExitCode=0
+
+nixVersion="$(nix eval --impure --raw --expr 'builtins.nixVersion' --extra-experimental-features nix-command)"
+
+runRepl () {
+
+  # That is right, we are also filtering out the testdir _without underscores_.
+  # This is crazy, but without it, GHA will fail to run the tests, showing paths
+  # _with_ underscores in the set -x log, but _without_ underscores in the
+  # supposed nix repl output. I have looked in a number of places, but I cannot
+  # find a mechanism that could cause this to happen.
+  local testDirNoUnderscores
+  testDirNoUnderscores="${testDir//_/}"
+
+  # TODO: pass arguments to nix repl; see lang.sh
+  nix repl 2>&1 \
+    | stripColors \
+    | sed \
+      -e "s@$testDir@/path/to/tests/functional@g" \
+      -e "s@$testDirNoUnderscores@/path/to/tests/functional@g" \
+      -e "s@$nixVersion@<nix version>@g" \
+      -e "s@Added [0-9]* variables@Added <number omitted> variables@g" \
+    | grep -vF $'warning: you don\'t have Internet access; disabling some network-dependent features' \
+    ;
+}
+
+for test in $(cd "$testDir/repl"; echo *.in); do
+    test="$(basename "$test" .in)"
+    in="$testDir/repl/$test.in"
+    actual="$testDir/repl/$test.actual"
+    expected="$testDir/repl/$test.expected"
+    (cd "$testDir/repl"; set +x; runRepl 2>&1) < "$in" > "$actual"
+    diffAndAcceptInner "$test" "$actual" "$expected"
+done
+
+characterisationTestExit

tests/functional/repl/doc-comment-curried-args.expected

@@ -0,0 +1,24 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+Function curriedArgs
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:48:5
+
+    A documented function.
+
+
+"Note that users may not expect this to behave as it currently does"
+
+Function curriedArgs
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:50:5
+
+    The function returned by applying once
+
+"This won't produce documentation, because we can't actually document arbitrary values"
+
+error: value does not have documentation
+
+

tests/functional/repl/doc-comment-curried-args.in

@@ -0,0 +1,7 @@
+:l doc-comments.nix
+:doc curriedArgs
+x = curriedArgs 1        
+"Note that users may not expect this to behave as it currently does"
+:doc x
+"This won't produce documentation, because we can't actually document arbitrary values"
+:doc x 2

tests/functional/repl/doc-comment-formals.expected

@@ -0,0 +1,13 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+"Note that this is not yet complete"
+
+Function documentedFormals
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:57:5
+
+    Finds x
+
+

tests/functional/repl/doc-comment-formals.in

@@ -0,0 +1,3 @@
+:l doc-comments.nix
+"Note that this is not yet complete"
+:doc documentedFormals

tests/functional/repl/doc-comment-function.expected

@@ -0,0 +1,8 @@
+Nix <nix version>
+Type :? for help.
+Function defined at
+    /path/to/tests/functional/repl/doc-comment-function.nix:2:1
+
+    A doc comment for a file that only contains a function
+
+

tests/functional/repl/doc-comment-function.in

@@ -0,0 +1 @@
+:doc import ./doc-comment-function.nix

tests/functional/repl/doc-comment-function.nix

@@ -0,0 +1,3 @@
+/** A doc comment for a file that only contains a function */
+{ ... }:
+{ }

tests/functional/repl/doc-comments.nix

@@ -0,0 +1,60 @@
+{
+  /**
+    Perform *arithmetic* multiplication. It's kind of like repeated **addition**, very neat.
+
+    ```nix
+    multiply 2 3
+    => 6
+    ```
+   */
+  multiply = x: y: x * y;
+
+  /**👈 precisely this wide 👉*/
+  measurement = x: x;
+
+  floatedIn = /** This also works. */
+    x: y: x;
+
+  compact=/**boom*/x: x;
+
+  # https://github.com/NixOS/rfcs/blob/master/rfcs/0145-doc-strings.md#ambiguous-placement
+  /** Ignore!!! */
+  unambiguous = 
+    /** Very close */
+    x: x;
+
+  /** Firmly rigid. */
+  constant = true;
+
+  /** Immovably fixed. */
+  lib.version = "9000";
+
+  /** Unchangeably constant. */
+  lib.attr.empty = { };
+
+  lib.attr.undocumented = { };
+
+  nonStrict = /** My syntax is not strict, but I'm strict anyway. */ x: x;
+  strict = /** I don't have to be strict, but I am anyway. */ { ... }: null;
+  # Note that pre and post are the same here. I just had to name them somehow.
+  strictPre = /** Here's one way to do this */ a@{ ... }: a;
+  strictPost = /** Here's another way to do this */ { ... }@a: a;
+
+  # TODO
+
+  /** You won't see this. */
+  curriedArgs =
+    /** A documented function. */
+    x:
+    /** The function returned by applying once */
+    y:
+    /** A function body performing summation of two items */
+    x + y;
+
+  /** Documented formals (but you won't see this comment) */
+  documentedFormals =
+    /** Finds x */
+    { /** The x attribute */
+      x
+    }: x;
+}

tests/functional/repl/doc-compact.expected

@@ -0,0 +1,11 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+Function compact
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:18:20
+
+    boom
+
+

tests/functional/repl/doc-compact.in

@@ -0,0 +1,2 @@
+:l doc-comments.nix
+:doc compact

tests/functional/repl/doc-constant.expected

@@ -0,0 +1,102 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+error: value does not have documentation
+
+Attribute version
+
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:30:3
+
+    Immovably fixed.
+
+Attribute empty
+
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:33:3
+
+    Unchangeably constant.
+
+error:
+       … while evaluating the attribute 'attr.undocument'
+         at /path/to/tests/functional/repl/doc-comments.nix:33:3:
+           32|   /** Unchangeably constant. */
+           33|   lib.attr.empty = { };
+             |   ^
+           34|
+
+       error: attribute 'undocument' missing
+       at «string»:1:1:
+            1| lib.attr.undocument
+             | ^
+       Did you mean undocumented?
+
+Attribute constant
+
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:27:3
+
+    Firmly rigid.
+
+Attribute version
+
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:30:3
+
+    Immovably fixed.
+
+Attribute empty
+
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:33:3
+
+    Unchangeably constant.
+
+Attribute undocumented
+
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:35:3
+
+    No documentation found.
+
+error: undefined variable 'missing'
+       at «string»:1:1:
+            1| missing
+             | ^
+
+error: undefined variable 'constanz'
+       at «string»:1:1:
+            1| constanz
+             | ^
+
+error: undefined variable 'missing'
+       at «string»:1:1:
+            1| missing.attr
+             | ^
+
+error: attribute 'missing' missing
+       at «string»:1:1:
+            1| lib.missing
+             | ^
+
+error: attribute 'missing' missing
+       at «string»:1:1:
+            1| lib.missing.attr
+             | ^
+
+error:
+       … while evaluating the attribute 'attr.undocumental'
+         at /path/to/tests/functional/repl/doc-comments.nix:33:3:
+           32|   /** Unchangeably constant. */
+           33|   lib.attr.empty = { };
+             |   ^
+           34|
+
+       error: attribute 'undocumental' missing
+       at «string»:1:1:
+            1| lib.attr.undocumental
+             | ^
+       Did you mean undocumented?
+
+

tests/functional/repl/doc-constant.in

@@ -0,0 +1,15 @@
+:l doc-comments.nix
+:doc constant
+:doc lib.version
+:doc lib.attr.empty
+:doc lib.attr.undocument
+:doc (import ./doc-comments.nix).constant
+:doc (import ./doc-comments.nix).lib.version
+:doc (import ./doc-comments.nix).lib.attr.empty
+:doc (import ./doc-comments.nix).lib.attr.undocumented
+:doc missing
+:doc constanz
+:doc missing.attr
+:doc lib.missing
+:doc lib.missing.attr
+:doc lib.attr.undocumental

tests/functional/repl/doc-floatedIn.expected

@@ -0,0 +1,11 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+Function floatedIn
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:16:5
+
+    This also works.
+
+

tests/functional/repl/doc-floatedIn.in

@@ -0,0 +1,2 @@
+:l doc-comments.nix
+:doc floatedIn

tests/functional/repl/doc-lambda-flavors.expected

@@ -0,0 +1,29 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+Function nonStrict
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:37:70
+
+    My syntax is not strict, but I'm strict anyway.
+
+Function strict
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:38:63
+
+    I don't have to be strict, but I am anyway.
+
+Function strictPre
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:40:48
+
+    Here's one way to do this
+
+Function strictPost
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:41:53
+
+    Here's another way to do this
+
+

tests/functional/repl/doc-lambda-flavors.in

@@ -0,0 +1,5 @@
+:l doc-comments.nix
+:doc nonStrict
+:doc strict
+:doc strictPre
+:doc strictPost

tests/functional/repl/doc-measurement.expected

@@ -0,0 +1,11 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+Function measurement
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:13:17
+
+    👈 precisely this wide 👉
+
+

tests/functional/repl/doc-measurement.in

@@ -0,0 +1,2 @@
+:l doc-comments.nix
+:doc measurement

tests/functional/repl/doc-multiply.expected

@@ -0,0 +1,15 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+Function multiply
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:10:14
+
+    Perform arithmetic multiplication. It's kind of like
+    repeated addition, very neat.
+
+      | multiply 2 3
+      | => 6
+
+

tests/functional/repl/doc-multiply.in

@@ -0,0 +1,2 @@
+:l doc-comments.nix
+:doc multiply

tests/functional/repl/doc-unambiguous.expected

@@ -0,0 +1,11 @@
+Nix <nix version>
+Type :? for help.
+Added <number omitted> variables.
+
+Function unambiguous
+    … defined at
+    /path/to/tests/functional/repl/doc-comments.nix:24:5
+
+    Very close
+
+

tests/functional/repl/doc-unambiguous.in

@@ -0,0 +1,2 @@
+:l doc-comments.nix
+:doc unambiguous

tests/functional/tarball.sh

@@ -71,3 +71,15 @@ test_tarball() {
 test_tarball '' cat
 test_tarball .xz xz
 test_tarball .gz gzip
+
+# Test hard links.
+# All entries in tree.tar.gz refer to the same file, and all have the same inode when unpacked by GNU tar.
+# We don't preserve the hard links, because that's an optimization we think is not worth the complexity,
+# so we only make sure that the contents are copied correctly.
+path="$(nix flake prefetch --json "tarball+file://$(pwd)/tree.tar.gz" | jq -r .storePath)"
+[[ $(cat "$path/a/b/foo") = bar ]]
+[[ $(cat "$path/a/b/xyzzy") = bar ]]
+[[ $(cat "$path/a/yyy") = bar ]]
+[[ $(cat "$path/a/zzz") = bar ]]
+[[ $(cat "$path/c/aap") = bar ]]
+[[ $(cat "$path/fnord") = bar ]]

tests/unit/libexpr-support/tests/libexpr.hh

@@ -4,12 +4,14 @@
 #include <gtest/gtest.h>
 #include <gmock/gmock.h>
 
+#include "fetch-settings.hh"
 #include "value.hh"
 #include "nixexpr.hh"
+#include "nixexpr.hh"
 #include "eval.hh"
+#include "eval-gc.hh"
 #include "eval-inline.hh"
 #include "eval-settings.hh"
-#include "store-api.hh"
 
 #include "tests/libstore.hh"
 
@@ -24,7 +26,7 @@ namespace nix {
         protected:
             LibExprTest()
                 : LibStoreTest()
-                , state({}, store, evalSettings, nullptr)
+                , state({}, store, fetchSettings, evalSettings, nullptr)
             {
                 evalSettings.nixPath = {};
             }
@@ -43,6 +45,7 @@ namespace nix {
             }
 
             bool readOnlyMode = true;
+            fetchers::Settings fetchSettings{};
             EvalSettings evalSettings{readOnlyMode};
             EvalState state;
     };

tests/unit/libfetchers/git-utils.cc

@@ -0,0 +1,112 @@
+#include "git-utils.hh"
+#include "file-system.hh"
+#include "gmock/gmock.h"
+#include <git2/global.h>
+#include <git2/repository.h>
+#include <git2/types.h>
+#include <gtest/gtest.h>
+#include "fs-sink.hh"
+#include "serialise.hh"
+
+namespace nix {
+
+class GitUtilsTest : public ::testing::Test
+{
+    // We use a single repository for all tests.
+    Path tmpDir;
+    std::unique_ptr<AutoDelete> delTmpDir;
+
+public:
+    void SetUp() override
+    {
+        tmpDir = createTempDir();
+        delTmpDir = std::make_unique<AutoDelete>(tmpDir, true);
+
+        // Create the repo with libgit2
+        git_libgit2_init();
+        git_repository * repo = nullptr;
+        auto r = git_repository_init(&repo, tmpDir.c_str(), 0);
+        ASSERT_EQ(r, 0);
+        git_repository_free(repo);
+    }
+
+    void TearDown() override
+    {
+        // Destroy the AutoDelete, triggering removal
+        // not AutoDelete::reset(), which would cancel the deletion.
+        delTmpDir.reset();
+    }
+
+    ref<GitRepo> openRepo()
+    {
+        return GitRepo::openRepo(tmpDir, true, false);
+    }
+};
+
+void writeString(CreateRegularFileSink & fileSink, std::string contents, bool executable)
+{
+    if (executable)
+        fileSink.isExecutable();
+    fileSink.preallocateContents(contents.size());
+    fileSink(contents);
+}
+
+TEST_F(GitUtilsTest, sink_basic)
+{
+    auto repo = openRepo();
+    auto sink = repo->getFileSystemObjectSink();
+
+    // TODO/Question: It seems a little odd that we use the tarball-like convention of requiring a top-level directory
+    // here
+    //                The sync method does not document this behavior, should probably renamed because it's not very
+    //                general, and I can't imagine that "non-conventional" archives or any other source to be handled by
+    //                this sink.
+
+    sink->createDirectory(CanonPath("foo-1.1"));
+
+    sink->createRegularFile(CanonPath("foo-1.1/hello"), [](CreateRegularFileSink & fileSink) {
+        writeString(fileSink, "hello world", false);
+    });
+    sink->createRegularFile(CanonPath("foo-1.1/bye"), [](CreateRegularFileSink & fileSink) {
+        writeString(fileSink, "thanks for all the fish", false);
+    });
+    sink->createSymlink(CanonPath("foo-1.1/bye-link"), "bye");
+    sink->createDirectory(CanonPath("foo-1.1/empty"));
+    sink->createDirectory(CanonPath("foo-1.1/links"));
+    sink->createHardlink(CanonPath("foo-1.1/links/foo"), CanonPath("foo-1.1/hello"));
+
+    // sink->createHardlink("foo-1.1/links/foo-2", CanonPath("foo-1.1/hello"));
+
+    auto result = sink->sync();
+    auto accessor = repo->getAccessor(result, false);
+    auto entries = accessor->readDirectory(CanonPath::root);
+    ASSERT_EQ(entries.size(), 5);
+    ASSERT_EQ(accessor->readFile(CanonPath("hello")), "hello world");
+    ASSERT_EQ(accessor->readFile(CanonPath("bye")), "thanks for all the fish");
+    ASSERT_EQ(accessor->readLink(CanonPath("bye-link")), "bye");
+    ASSERT_EQ(accessor->readDirectory(CanonPath("empty")).size(), 0);
+    ASSERT_EQ(accessor->readFile(CanonPath("links/foo")), "hello world");
+};
+
+TEST_F(GitUtilsTest, sink_hardlink)
+{
+    auto repo = openRepo();
+    auto sink = repo->getFileSystemObjectSink();
+
+    sink->createDirectory(CanonPath("foo-1.1"));
+
+    sink->createRegularFile(CanonPath("foo-1.1/hello"), [](CreateRegularFileSink & fileSink) {
+        writeString(fileSink, "hello world", false);
+    });
+
+    try {
+        sink->createHardlink(CanonPath("foo-1.1/link"), CanonPath("hello"));
+        FAIL() << "Expected an exception";
+    } catch (const nix::Error & e) {
+        ASSERT_THAT(e.msg(), testing::HasSubstr("invalid hard link target"));
+        ASSERT_THAT(e.msg(), testing::HasSubstr("/hello"));
+        ASSERT_THAT(e.msg(), testing::HasSubstr("foo-1.1/link"));
+    }
+};
+
+} // namespace nix

tests/unit/libfetchers/local.mk

@@ -29,7 +29,7 @@ libfetchers-tests_LIBS = \
     libstore-test-support libutil-test-support \
     libfetchers libstore libutil
 
-libfetchers-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS)
+libfetchers-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS) $(LIBGIT2_LIBS)
 
 ifdef HOST_WINDOWS
   # Increase the default reserved stack size to 65 MB so Nix doesn't run out of space

tests/unit/libflake/flakeref.cc

@@ -1,5 +1,6 @@
 #include <gtest/gtest.h>
 
+#include "fetch-settings.hh"
 #include "flake/flakeref.hh"
 
 namespace nix {
@@ -11,8 +12,9 @@ namespace nix {
      * --------------------------------------------------------------------------*/
 
     TEST(to_string, doesntReencodeUrl) {
+        fetchers::Settings fetchSettings;
         auto s = "http://localhost:8181/test/+3d.tar.gz";
-        auto flakeref = parseFlakeRef(s);
+        auto flakeref = parseFlakeRef(fetchSettings, s);
         auto parsed = flakeref.to_string();
         auto expected = "http://localhost:8181/test/%2B3d.tar.gz";
 

tests/unit/libstore/legacy-ssh-store.cc

@@ -0,0 +1,26 @@
+#include <gtest/gtest.h>
+
+#include "legacy-ssh-store.hh"
+
+namespace nix {
+
+TEST(LegacySSHStore, constructConfig)
+{
+    LegacySSHStoreConfig config{
+        "ssh",
+        "localhost",
+        StoreConfig::Params{
+            {
+                "remote-program",
+                // TODO #11106, no more split on space
+                "foo bar",
+            },
+        }};
+    EXPECT_EQ(
+        config.remoteProgram.get(),
+        (Strings{
+            "foo",
+            "bar",
+        }));
+}
+}

tests/unit/libstore/meson.build

@@ -58,6 +58,7 @@ sources = files(
   'derivation.cc',
   'derived-path.cc',
   'downstream-placeholder.cc',
+  'legacy-ssh-store.cc',
   'machines.cc',
   'nar-info-disk-cache.cc',
   'nar-info.cc',
@@ -67,6 +68,7 @@ sources = files(
   'path.cc',
   'references.cc',
   'serve-protocol.cc',
+  'ssh-store.cc',
   'store-reference.cc',
   'worker-protocol.cc',
 )

tests/unit/libstore/path-info.cc

@@ -26,9 +26,9 @@ static UnkeyedValidPathInfo makeEmpty()
     };
 }
 
-static UnkeyedValidPathInfo makeFull(const Store & store, bool includeImpureInfo)
+static ValidPathInfo makeFullKeyed(const Store & store, bool includeImpureInfo)
 {
-    UnkeyedValidPathInfo info = ValidPathInfo {
+    ValidPathInfo info = ValidPathInfo {
         store,
         "foo",
         FixedOutputInfo {
@@ -57,6 +57,9 @@ static UnkeyedValidPathInfo makeFull(const Store & store, bool includeImpureInfo
     }
     return info;
 }
+static UnkeyedValidPathInfo makeFull(const Store & store, bool includeImpureInfo) {
+    return makeFullKeyed(store, includeImpureInfo);
+}
 
 #define JSON_TEST(STEM, OBJ, PURE)                                        \
     TEST_F(PathInfoTest, PathInfo_ ## STEM ## _from_json) {               \
@@ -86,4 +89,13 @@ JSON_TEST(empty_impure, makeEmpty(), true)
 JSON_TEST(pure, makeFull(*store, false), false)
 JSON_TEST(impure, makeFull(*store, true), true)
 
+TEST_F(PathInfoTest, PathInfo_full_shortRefs) {
+    ValidPathInfo it = makeFullKeyed(*store, true);
+    // it.references = unkeyed.references;
+    auto refs = it.shortRefs();
+    ASSERT_EQ(refs.size(), 2);
+    ASSERT_EQ(*refs.begin(), "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar");
+    ASSERT_EQ(*++refs.begin(), "n5wkd9frr45pa74if5gpz9j7mifg27fh-foo");
 }
+
+} // namespace nix

tests/unit/libstore/ssh-store.cc

@@ -0,0 +1,26 @@
+#include <gtest/gtest.h>
+
+#include "ssh-store.hh"
+
+namespace nix {
+
+TEST(SSHStore, constructConfig)
+{
+    SSHStoreConfig config{
+        "ssh",
+        "localhost",
+        StoreConfig::Params{
+            {
+                "remote-program",
+                // TODO #11106, no more split on space
+                "foo bar",
+            },
+        }};
+    EXPECT_EQ(
+        config.remoteProgram.get(),
+        (Strings{
+            "foo",
+            "bar",
+        }));
+}
+}

tests/unit/libutil-support/tests/tracing-file-system-object-sink.cc

@@ -0,0 +1,34 @@
+#include <iostream>
+#include "tracing-file-system-object-sink.hh"
+
+namespace nix::test {
+
+void TracingFileSystemObjectSink::createDirectory(const CanonPath & path)
+{
+    std::cerr << "createDirectory(" << path << ")\n";
+    sink.createDirectory(path);
+}
+
+void TracingFileSystemObjectSink::createRegularFile(
+    const CanonPath & path, std::function<void(CreateRegularFileSink &)> fn)
+{
+    std::cerr << "createRegularFile(" << path << ")\n";
+    sink.createRegularFile(path, [&](CreateRegularFileSink & crf) {
+        // We could wrap this and trace about the chunks of data and such
+        fn(crf);
+    });
+}
+
+void TracingFileSystemObjectSink::createSymlink(const CanonPath & path, const std::string & target)
+{
+    std::cerr << "createSymlink(" << path << ", target: " << target << ")\n";
+    sink.createSymlink(path, target);
+}
+
+void TracingExtendedFileSystemObjectSink::createHardlink(const CanonPath & path, const CanonPath & target)
+{
+    std::cerr << "createHardlink(" << path << ", target: " << target << ")\n";
+    sink.createHardlink(path, target);
+}
+
+} // namespace nix::test

tests/unit/libutil-support/tests/tracing-file-system-object-sink.hh

@@ -0,0 +1,41 @@
+#pragma once
+#include "fs-sink.hh"
+
+namespace nix::test {
+
+/**
+ * A `FileSystemObjectSink` that traces calls, writing to stderr.
+ */
+class TracingFileSystemObjectSink : public virtual FileSystemObjectSink
+{
+    FileSystemObjectSink & sink;
+public:
+    TracingFileSystemObjectSink(FileSystemObjectSink & sink)
+        : sink(sink)
+    {
+    }
+
+    void createDirectory(const CanonPath & path) override;
+
+    void createRegularFile(const CanonPath & path, std::function<void(CreateRegularFileSink &)> fn) override;
+
+    void createSymlink(const CanonPath & path, const std::string & target) override;
+};
+
+/**
+ * A `ExtendedFileSystemObjectSink` that traces calls, writing to stderr.
+ */
+class TracingExtendedFileSystemObjectSink : public TracingFileSystemObjectSink, public ExtendedFileSystemObjectSink
+{
+    ExtendedFileSystemObjectSink & sink;
+public:
+    TracingExtendedFileSystemObjectSink(ExtendedFileSystemObjectSink & sink)
+        : TracingFileSystemObjectSink(sink)
+        , sink(sink)
+    {
+    }
+
+    void createHardlink(const CanonPath & path, const CanonPath & target) override;
+};
+
+}

tests/unit/libutil/git.cc

@@ -229,7 +229,7 @@ TEST_F(GitTest, both_roundrip) {
 
     mkSinkHook(CanonPath::root, root.hash, BlobMode::Regular);
 
-    ASSERT_EQ(*files, *files2);
+    ASSERT_EQ(files->root, files2->root);
 }
 
 TEST(GitLsRemote, parseSymrefLineWithReference) {

tests/unit/libutil/position.cc

@@ -0,0 +1,122 @@
+#include <gtest/gtest.h>
+
+#include "position.hh"
+
+namespace nix {
+
+inline Pos::Origin makeStdin(std::string s)
+{
+    return Pos::Stdin{make_ref<std::string>(s)};
+}
+
+TEST(Position, getSnippetUpTo_0)
+{
+    Pos::Origin o = makeStdin("");
+    Pos p(1, 1, o);
+    ASSERT_EQ(p.getSnippetUpTo(p), "");
+}
+TEST(Position, getSnippetUpTo_1)
+{
+    Pos::Origin o = makeStdin("x");
+    {
+        // NOTE: line and column are actually 1-based indexes
+        Pos start(0, 0, o);
+        Pos end(99, 99, o);
+        ASSERT_EQ(start.getSnippetUpTo(start), "");
+        ASSERT_EQ(start.getSnippetUpTo(end), "x");
+        ASSERT_EQ(end.getSnippetUpTo(end), "");
+        ASSERT_EQ(end.getSnippetUpTo(start), std::nullopt);
+    }
+    {
+        // NOTE: line and column are actually 1-based indexes
+        Pos start(0, 99, o);
+        Pos end(99, 0, o);
+        ASSERT_EQ(start.getSnippetUpTo(start), "");
+
+        // "x" might be preferable, but we only care about not crashing for invalid inputs
+        ASSERT_EQ(start.getSnippetUpTo(end), "");
+
+        ASSERT_EQ(end.getSnippetUpTo(end), "");
+        ASSERT_EQ(end.getSnippetUpTo(start), std::nullopt);
+    }
+    {
+        Pos start(1, 1, o);
+        Pos end(1, 99, o);
+        ASSERT_EQ(start.getSnippetUpTo(start), "");
+        ASSERT_EQ(start.getSnippetUpTo(end), "x");
+        ASSERT_EQ(end.getSnippetUpTo(end), "");
+        ASSERT_EQ(end.getSnippetUpTo(start), "");
+    }
+    {
+        Pos start(1, 1, o);
+        Pos end(99, 99, o);
+        ASSERT_EQ(start.getSnippetUpTo(start), "");
+        ASSERT_EQ(start.getSnippetUpTo(end), "x");
+        ASSERT_EQ(end.getSnippetUpTo(end), "");
+        ASSERT_EQ(end.getSnippetUpTo(start), std::nullopt);
+    }
+}
+TEST(Position, getSnippetUpTo_2)
+{
+    Pos::Origin o = makeStdin("asdf\njkl\nqwer");
+    {
+        Pos start(1, 1, o);
+        Pos end(1, 2, o);
+        ASSERT_EQ(start.getSnippetUpTo(start), "");
+        ASSERT_EQ(start.getSnippetUpTo(end), "a");
+        ASSERT_EQ(end.getSnippetUpTo(end), "");
+
+        // nullopt? I feel like changing the column handling would just make it more fragile
+        ASSERT_EQ(end.getSnippetUpTo(start), "");
+    }
+    {
+        Pos start(1, 2, o);
+        Pos end(1, 3, o);
+        ASSERT_EQ(start.getSnippetUpTo(end), "s");
+    }
+    {
+        Pos start(1, 2, o);
+        Pos end(2, 2, o);
+        ASSERT_EQ(start.getSnippetUpTo(end), "sdf\nj");
+    }
+    {
+        Pos start(1, 2, o);
+        Pos end(3, 2, o);
+        ASSERT_EQ(start.getSnippetUpTo(end), "sdf\njkl\nq");
+    }
+    {
+        Pos start(1, 2, o);
+        Pos end(2, 99, o);
+        ASSERT_EQ(start.getSnippetUpTo(end), "sdf\njkl");
+    }
+    {
+        Pos start(1, 4, o);
+        Pos end(2, 99, o);
+        ASSERT_EQ(start.getSnippetUpTo(end), "f\njkl");
+    }
+    {
+        Pos start(1, 5, o);
+        Pos end(2, 99, o);
+        ASSERT_EQ(start.getSnippetUpTo(end), "\njkl");
+    }
+    {
+        Pos start(1, 6, o); // invalid: starting column past last "line character", ie at the newline
+        Pos end(2, 99, o);
+        ASSERT_EQ(start.getSnippetUpTo(end), "\njkl"); // jkl might be acceptable for this invalid start position
+    }
+    {
+        Pos start(1, 1, o);
+        Pos end(2, 0, o); // invalid
+        ASSERT_EQ(start.getSnippetUpTo(end), "asdf\n");
+    }
+}
+
+TEST(Position, example_1)
+{
+    Pos::Origin o = makeStdin("  unambiguous = \n    /** Very close */\n    x: x;\n# ok\n");
+    Pos start(2, 5, o);
+    Pos end(2, 22, o);
+    ASSERT_EQ(start.getSnippetUpTo(end), "/** Very close */");
+}
+
+} // namespace nix

tests/unit/libutil/references.cc

@@ -15,7 +15,7 @@ struct RewriteParams {
             strRewrites.insert(from + "->" + to);
         return os <<
             "OriginalString: " << bar.originalString << std::endl <<
-            "Rewrites: " << concatStringsSep(",", strRewrites) << std::endl <<
+            "Rewrites: " << dropEmptyInitThenConcatStringsSep(",", strRewrites) << std::endl <<
             "Expected result: " << bar.finalString;
     }
 };

tests/unit/libutil/strings.cc

@@ -0,0 +1,83 @@
+#include <gtest/gtest.h>
+
+#include "strings.hh"
+
+namespace nix {
+
+using Strings = std::vector<std::string>;
+
+/* ----------------------------------------------------------------------------
+ * concatStringsSep
+ * --------------------------------------------------------------------------*/
+
+TEST(concatStringsSep, empty)
+{
+    Strings strings;
+
+    ASSERT_EQ(concatStringsSep(",", strings), "");
+}
+
+TEST(concatStringsSep, justOne)
+{
+    Strings strings;
+    strings.push_back("this");
+
+    ASSERT_EQ(concatStringsSep(",", strings), "this");
+}
+
+TEST(concatStringsSep, emptyString)
+{
+    Strings strings;
+    strings.push_back("");
+
+    ASSERT_EQ(concatStringsSep(",", strings), "");
+}
+
+TEST(concatStringsSep, emptyStrings)
+{
+    Strings strings;
+    strings.push_back("");
+    strings.push_back("");
+
+    ASSERT_EQ(concatStringsSep(",", strings), ",");
+}
+
+TEST(concatStringsSep, threeEmptyStrings)
+{
+    Strings strings;
+    strings.push_back("");
+    strings.push_back("");
+    strings.push_back("");
+
+    ASSERT_EQ(concatStringsSep(",", strings), ",,");
+}
+
+TEST(concatStringsSep, buildCommaSeparatedString)
+{
+    Strings strings;
+    strings.push_back("this");
+    strings.push_back("is");
+    strings.push_back("great");
+
+    ASSERT_EQ(concatStringsSep(",", strings), "this,is,great");
+}
+
+TEST(concatStringsSep, buildStringWithEmptySeparator)
+{
+    Strings strings;
+    strings.push_back("this");
+    strings.push_back("is");
+    strings.push_back("great");
+
+    ASSERT_EQ(concatStringsSep("", strings), "thisisgreat");
+}
+
+TEST(concatStringsSep, buildSingleString)
+{
+    Strings strings;
+    strings.push_back("this");
+
+    ASSERT_EQ(concatStringsSep(",", strings), "this");
+}
+
+} // namespace nix

tests/unit/libutil/tests.cc

@@ -227,32 +227,32 @@ namespace nix {
     }
 
     /* ----------------------------------------------------------------------------
-     * concatStringsSep
+     * dropEmptyInitThenConcatStringsSep
      * --------------------------------------------------------------------------*/
 
-    TEST(concatStringsSep, buildCommaSeparatedString) {
+    TEST(dropEmptyInitThenConcatStringsSep, buildCommaSeparatedString) {
         Strings strings;
         strings.push_back("this");
         strings.push_back("is");
         strings.push_back("great");
 
-        ASSERT_EQ(concatStringsSep(",", strings), "this,is,great");
+        ASSERT_EQ(dropEmptyInitThenConcatStringsSep(",", strings), "this,is,great");
     }
 
-    TEST(concatStringsSep, buildStringWithEmptySeparator) {
+    TEST(dropEmptyInitThenConcatStringsSep, buildStringWithEmptySeparator) {
         Strings strings;
         strings.push_back("this");
         strings.push_back("is");
         strings.push_back("great");
 
-        ASSERT_EQ(concatStringsSep("", strings), "thisisgreat");
+        ASSERT_EQ(dropEmptyInitThenConcatStringsSep("", strings), "thisisgreat");
     }
 
-    TEST(concatStringsSep, buildSingleString) {
+    TEST(dropEmptyInitThenConcatStringsSep, buildSingleString) {
         Strings strings;
         strings.push_back("this");
 
-        ASSERT_EQ(concatStringsSep(",", strings), "this");
+        ASSERT_EQ(dropEmptyInitThenConcatStringsSep(",", strings), "this");
     }
 
     /* ----------------------------------------------------------------------------