Merge pull request #12144 from NixOS/mergify/bp/2.24-maintenance/pr-12046

CLI symlink fixes (backport #12046)

tests/functional/add.sh

@@ -29,6 +29,47 @@ echo "$hash2"
 
 test "$hash1" = "sha256:$hash2"
 
+# The contents can be accessed through a symlink, and this symlink has no effect on the hash
+# https://github.com/NixOS/nix/issues/11941
+test_issue_11941() {
+    local expected actual
+    mkdir -p "$TEST_ROOT/foo/bar" && ln -s "$TEST_ROOT/foo" "$TEST_ROOT/foo-link"
+
+    # legacy
+    expected=$(nix-store --add-fixed --recursive sha256 "$TEST_ROOT/foo/bar")
+    actual=$(nix-store --add-fixed --recursive sha256 "$TEST_ROOT/foo-link/bar")
+    [[ "$expected" == "$actual" ]]
+    actual=$(nix-store --add "$TEST_ROOT/foo-link/bar")
+    [[ "$expected" == "$actual" ]]
+
+    # nix store add
+    actual=$(nix store add --hash-algo sha256 --mode nar "$TEST_ROOT/foo/bar")
+    [[ "$expected" == "$actual" ]]
+
+    # cleanup
+    rm -r "$TEST_ROOT/foo" "$TEST_ROOT/foo-link"
+}
+test_issue_11941
+
+# A symlink is added to the store as a symlink, not as a copy of the target
+test_add_symlink() {
+    ln -s /bin "$TEST_ROOT/my-bin"
+
+    # legacy
+    path=$(nix-store --add-fixed --recursive sha256 "$TEST_ROOT/my-bin")
+    [[ "$(readlink "$path")" == /bin ]]
+    path=$(nix-store --add "$TEST_ROOT/my-bin")
+    [[ "$(readlink "$path")" == /bin ]]
+
+    # nix store add
+    path=$(nix store add --hash-algo sha256 --mode nar "$TEST_ROOT/my-bin")
+    [[ "$(readlink "$path")" == /bin ]]
+
+    # cleanup
+    rm "$TEST_ROOT/my-bin"
+}
+test_add_symlink
+
 #### New style commands
 
 clearStoreIfPossible

tests/functional/hash-path.sh

@@ -92,3 +92,32 @@ try2 md5 "20f3ffe011d4cfa7d72bfabef7882836"
 rm "$TEST_ROOT/hash-path/hello"
 ln -s x "$TEST_ROOT/hash-path/hello"
 try2 md5 "f78b733a68f5edbdf9413899339eaa4a"
+
+# Flat mode supports process substitution
+h=$(nix hash path --mode flat --type sha256 --base32 <(printf "SMASH THE STATE"))
+[[ 0d9n3r2i4m1zgy0wpqbsyabsfzgs952066bfp8gwvcg4mkr4r5g8 == "$h" ]]
+
+# Flat mode supports process substitution (hash file)
+h=$(nix hash file --type sha256 --base32 <(printf "SMASH THE STATE"))
+[[ 0d9n3r2i4m1zgy0wpqbsyabsfzgs952066bfp8gwvcg4mkr4r5g8 == "$h" ]]
+
+# Symlinks in the ancestry are ok and don't affect the result
+mkdir -p "$TEST_ROOT/simple" "$TEST_ROOT/try/to/mess/with/it"
+echo hi > "$TEST_ROOT/simple/hi"
+ln -s "$TEST_ROOT/simple" "$TEST_ROOT/try/to/mess/with/it/simple-link"
+h=$(nix hash path --type sha256 --base32 "$TEST_ROOT/simple/hi")
+[[ 1xmr8jicvzszfzpz46g37mlpvbzjl2wpwvl2b05psipssyp1sm8h == "$h" ]]
+h=$(nix hash path --type sha256 --base32 "$TEST_ROOT/try/to/mess/with/it/simple-link/hi")
+[[ 1xmr8jicvzszfzpz46g37mlpvbzjl2wpwvl2b05psipssyp1sm8h == "$h" ]]
+
+# nix hash --mode nar does not canonicalize a symlink argument.
+#   Otherwise it can't generate a NAR whose root is a symlink.
+#   If you want to follow the symlink, pass $(realpath -s ...) instead.
+ln -s /non-existent-48cujwe8ndf4as0bne "$TEST_ROOT/symlink-to-nowhere"
+h=$(nix hash path --mode nar --type sha256 --base32 "$TEST_ROOT/symlink-to-nowhere")
+[[ 1bl5ry3x1fcbwgr5c2x50bn572iixh4j1p6ax5isxly2ddgn8pbp == "$h" ]]  # manually verified hash
+if [[ -e /bin ]]; then
+    ln -s /bin "$TEST_ROOT/symlink-to-bin"
+    h=$(nix hash path --mode nar --type sha256 --base32 "$TEST_ROOT/symlink-to-bin")
+    [[ 0z2mdmkd43l0ijdxfbj1y8vzli15yh9b09n3a3rrygmjshbyypsw == "$h" ]] # manually verified hash
+fi

tests/nixos/default.nix

@@ -145,6 +145,8 @@ in
 
   functional_root = runNixOSTestFor "x86_64-linux" ./functional/as-root.nix;
 
+  functional_symlinked-home = runNixOSTestFor "x86_64-linux" ./functional/symlinked-home.nix;
+
   user-sandboxing = runNixOSTestFor "x86_64-linux" ./user-sandboxing;
 
   fetchurl = runNixOSTestFor "x86_64-linux" ./fetchurl.nix;

tests/nixos/functional/symlinked-home.nix

@@ -0,0 +1,36 @@
+/**
+  This test runs the functional tests on a NixOS system where the home directory
+  is symlinked to another location.
+
+  The purpose of this test is to find cases where Nix uses low-level operations
+  that don't support symlinks on paths that include them.
+
+  It is not a substitute for more intricate, use case-specific tests, but helps
+  catch common issues.
+*/
+# TODO: add symlinked tmpdir
+{ ... }:
+{
+  name = "functional-tests-on-nixos_user_symlinked-home";
+
+  imports = [ ./common.nix ];
+
+  nodes.machine = {
+    users.users.alice = { isNormalUser = true; };
+  };
+
+  testScript = ''
+    machine.wait_for_unit("multi-user.target")
+    with subtest("prepare symlinked home"):
+      machine.succeed("""
+        (
+          set -x
+          mv /home/alice /home/alice.real
+          ln -s alice.real /home/alice
+        ) 1>&2
+      """)
+    machine.succeed("""
+      su --login --command "run-test-suite" alice >&2
+    """)
+  '';
+}