Improve hit-rate on buildcaches (#43272)

* Relax compiler and target mismatches

The mismatch occurs on an edge. Previously it was assigned
the parent priority, now it is assigned the child priority.

This should make reuse from buildcaches or store more likely,
since most mismatches will be counted with "reused" priority.

* Optimize version badness for runtimes at very low priority

We don't want to e.g. switch other attributes because we
cannot reuse an old installed runtime.

* Optimize runtime attributes at very low priority

This is such that the version of the runtime would
not influence whether we should reuse a spec.

Compiler mismatches are considered for runtimes,
to avoid situations where compiling foo%gcc@9
brings in gcc-runtime%gcc@13 if gcc@13 is among
the available compilers

* Exclude specs without runtimes from reuse

This should ensure that we do not reuse specs that
could be broken, as they expect the compiler to be
installed in a specific place.

15 files changed, 134 insertions, 51 deletions

diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index 5928886bdb..3c55941a56 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -3371,7 +3371,7 @@ def _is_reusable(spec: spack.spec.Spec, packages, local: bool) -> bool:
         return False
 
     if not spec.external:
-        return True
+        return _has_runtime_dependencies(spec)
 
     # Cray external manifest externals are always reusable
     if local:
@@ -3396,6 +3396,19 @@ def _is_reusable(spec: spack.spec.Spec, packages, local: bool) -> bool:
     return False
 
 
+def _has_runtime_dependencies(spec: spack.spec.Spec) -> bool:
+    if not WITH_RUNTIME:
+        return True
+
+    if spec.compiler.name == "gcc" and not spec.dependencies("gcc-runtime"):
+        return False
+
+    if spec.compiler.name == "oneapi" and not spec.dependencies("intel-oneapi-runtime"):
+        return False
+
+    return True
+
+
 class Solver:
     """This is the main external interface class for solving.
 
diff --git a/lib/spack/spack/solver/concretize.lp b/lib/spack/spack/solver/concretize.lp
index dd2a5afe02..1c6709602d 100644
--- a/lib/spack/spack/solver/concretize.lp
+++ b/lib/spack/spack/solver/concretize.lp
@@ -80,6 +80,7 @@ unification_set(SetID, VirtualNode)
 
 
 #defined multiple_unification_sets/1.
+#defined runtime/1.
 
 %----
 % Rules to break symmetry and speed-up searches
@@ -1494,18 +1495,20 @@ opt_criterion(40, "compiler mismatches that are not from CLI").
 #minimize{ 0@240: #true }.
 #minimize{ 0@40: #true }.
 #minimize{
-    1@40+Priority,PackageNode,DependencyNode
-    : compiler_mismatch(PackageNode, DependencyNode),
-      build_priority(PackageNode, Priority)
+    1@40+Priority,PackageNode,node(ID, Dependency)
+    : compiler_mismatch(PackageNode, node(ID, Dependency)),
+      build_priority(node(ID, Dependency), Priority),
+      not runtime(Dependency)
 }.
 
 opt_criterion(39, "compiler mismatches that are not from CLI").
 #minimize{ 0@239: #true }.
 #minimize{ 0@39: #true }.
 #minimize{
-    1@39+Priority,PackageNode,DependencyNode
-    : compiler_mismatch_required(PackageNode, DependencyNode),
-      build_priority(PackageNode, Priority)
+    1@39+Priority,PackageNode,node(ID, Dependency)
+    : compiler_mismatch_required(PackageNode, node(ID, Dependency)),
+      build_priority(node(ID, Dependency), Priority),
+      not runtime(Dependency)
 }.
 
 opt_criterion(30, "non-preferred OS's").
@@ -1522,9 +1525,10 @@ opt_criterion(25, "version badness").
 #minimize{ 0@225: #true }.
 #minimize{ 0@25: #true }.
 #minimize{
-    Weight@25+Priority,PackageNode
-    : version_weight(PackageNode, Weight),
-      build_priority(PackageNode, Priority)
+    Weight@25+Priority,node(X, Package)
+    : version_weight(node(X, Package), Weight),
+      build_priority(node(X, Package), Priority),
+      not runtime(Package)
 }.
 
 % Try to use all the default values of variants
@@ -1543,9 +1547,10 @@ opt_criterion(15, "non-preferred compilers").
 #minimize{ 0@215: #true }.
 #minimize{ 0@15: #true }.
 #minimize{
-    Weight@15+Priority,PackageNode
-    : node_compiler_weight(PackageNode, Weight),
-      build_priority(PackageNode, Priority)
+    Weight@15+Priority,node(X, Package)
+    : node_compiler_weight(node(X, Package), Weight),
+      build_priority(node(X, Package), Priority),
+      not runtime(Package)
 }.
 
 % Minimize the number of mismatches for targets in the DAG, try
@@ -1554,18 +1559,55 @@ opt_criterion(10, "target mismatches").
 #minimize{ 0@210: #true }.
 #minimize{ 0@10: #true }.
 #minimize{
-    1@10+Priority,PackageNode,Dependency
-    : node_target_mismatch(PackageNode, Dependency),
-      build_priority(PackageNode, Priority)
+    1@10+Priority,PackageNode,node(ID, Dependency)
+    : node_target_mismatch(PackageNode, node(ID, Dependency)),
+      build_priority(node(ID, Dependency), Priority),
+      not runtime(Dependency)
 }.
 
 opt_criterion(5, "non-preferred targets").
 #minimize{ 0@205: #true }.
 #minimize{ 0@5: #true }.
 #minimize{
-    Weight@5+Priority,PackageNode
-    : node_target_weight(PackageNode, Weight),
-      build_priority(PackageNode, Priority)
+    Weight@5+Priority,node(X, Package)
+    : node_target_weight(node(X, Package), Weight),
+      build_priority(node(X, Package), Priority),
+      not runtime(Package)
+}.
+
+
+% Minimize the number of compiler mismatches for runtimes
+opt_criterion(4, "compiler mismatches (runtimes)").
+#minimize{ 0@204: #true }.
+#minimize{ 0@4: #true }.
+#minimize{
+    1@4,PackageNode,node(ID, Dependency)
+    : compiler_mismatch(PackageNode, node(ID, Dependency)), runtime(Dependency)
+}.
+#minimize{
+    1@4,PackageNode,node(ID, Dependency)
+    : compiler_mismatch_required(PackageNode, node(ID, Dependency)), runtime(Dependency)
+}.
+
+
+% Choose more recent versions for runtimes
+opt_criterion(3, "version badness (runtimes)").
+#minimize{ 0@203: #true }.
+#minimize{ 0@3: #true }.
+#minimize{
+    Weight@3,node(X, Package)
+    : version_weight(node(X, Package), Weight),
+      runtime(Package)
+}.
+
+% Choose best target for runtimes
+opt_criterion(2, "non-preferred targets (runtimes)").
+#minimize{ 0@202: #true }.
+#minimize{ 0@2: #true }.
+#minimize{
+    Weight@2,node(X, Package)
+    : node_target_weight(node(X, Package), Weight),
+      runtime(Package)
 }.
 
 % Choose more recent versions for nodes
diff --git a/lib/spack/spack/target.py b/lib/spack/spack/target.py
index 8f9e6dcf51..8d0943c28a 100644
--- a/lib/spack/spack/target.py
+++ b/lib/spack/spack/target.py
@@ -142,7 +142,7 @@ class Target:
         # custom spec.
         compiler_version = compiler.version
         version_number, suffix = archspec.cpu.version_components(compiler.version)
-        if not version_number or suffix not in ("", "apple"):
+        if not version_number or suffix:
             # Try to deduce the underlying version of the compiler, regardless
             # of its name in compilers.yaml. Depending on where this function
             # is called we might get either a CompilerSpec or a fully fledged
diff --git a/lib/spack/spack/test/cmd/compiler.py b/lib/spack/spack/test/cmd/compiler.py
index 3b78720f08..46613b41fb 100644
--- a/lib/spack/spack/test/cmd/compiler.py
+++ b/lib/spack/spack/test/cmd/compiler.py
@@ -112,10 +112,10 @@ fi
 @pytest.mark.regression("37996")
 def test_compiler_remove(mutable_config, mock_packages):
     """Tests that we can remove a compiler from configuration."""
-    assert spack.spec.CompilerSpec("gcc@=4.8.0") in spack.compilers.all_compiler_specs()
-    args = spack.util.pattern.Bunch(all=True, compiler_spec="gcc@4.8.0", add_paths=[], scope=None)
+    assert spack.spec.CompilerSpec("gcc@=9.4.0") in spack.compilers.all_compiler_specs()
+    args = spack.util.pattern.Bunch(all=True, compiler_spec="gcc@9.4.0", add_paths=[], scope=None)
     spack.cmd.compiler.compiler_remove(args)
-    assert spack.spec.CompilerSpec("gcc@=4.8.0") not in spack.compilers.all_compiler_specs()
+    assert spack.spec.CompilerSpec("gcc@=9.4.0") not in spack.compilers.all_compiler_specs()
 
 
 @pytest.mark.regression("37996")
@@ -124,10 +124,10 @@ def test_removing_compilers_from_multiple_scopes(mutable_config, mock_packages):
     site_config = spack.config.get("compilers", scope="site")
     spack.config.set("compilers", site_config, scope="user")
 
-    assert spack.spec.CompilerSpec("gcc@=4.8.0") in spack.compilers.all_compiler_specs()
-    args = spack.util.pattern.Bunch(all=True, compiler_spec="gcc@4.8.0", add_paths=[], scope=None)
+    assert spack.spec.CompilerSpec("gcc@=9.4.0") in spack.compilers.all_compiler_specs()
+    args = spack.util.pattern.Bunch(all=True, compiler_spec="gcc@9.4.0", add_paths=[], scope=None)
     spack.cmd.compiler.compiler_remove(args)
-    assert spack.spec.CompilerSpec("gcc@=4.8.0") not in spack.compilers.all_compiler_specs()
+    assert spack.spec.CompilerSpec("gcc@=9.4.0") not in spack.compilers.all_compiler_specs()
 
 
 @pytest.mark.not_on_windows("Cannot execute bash script on Windows")
diff --git a/lib/spack/spack/test/cmd/spec.py b/lib/spack/spack/test/cmd/spec.py
index 718a5e08d4..6dfc024f47 100644
--- a/lib/spack/spack/test/cmd/spec.py
+++ b/lib/spack/spack/test/cmd/spec.py
@@ -31,7 +31,7 @@ def test_spec():
 
 
 @pytest.mark.only_clingo("Known failure of the original concretizer")
-def test_spec_concretizer_args(mutable_config, mutable_database):
+def test_spec_concretizer_args(mutable_config, mutable_database, do_not_check_runtimes_on_reuse):
     """End-to-end test of CLI concretizer prefs.
 
     It's here to make sure that everything works from CLI
diff --git a/lib/spack/spack/test/concretize.py b/lib/spack/spack/test/concretize.py
index cd1b189961..81d4f3190f 100644
--- a/lib/spack/spack/test/concretize.py
+++ b/lib/spack/spack/test/concretize.py
@@ -254,7 +254,7 @@ def gcc11_with_flags(compiler_factory):
 # This must use the mutable_config fixture because the test
 # adjusting_default_target_based_on_compiler uses the current_host fixture,
 # which changes the config.
-@pytest.mark.usefixtures("mutable_config", "mock_packages")
+@pytest.mark.usefixtures("mutable_config", "mock_packages", "do_not_check_runtimes_on_reuse")
 class TestConcretize:
     def test_concretize(self, spec):
         check_concretize(spec)
@@ -614,7 +614,7 @@ class TestConcretize:
         spec.normalize()
         spec.concretize()
 
-    @pytest.mark.parametrize("compiler_str", ["clang", "gcc", "gcc@10.2.1", "clang@:12.0.0"])
+    @pytest.mark.parametrize("compiler_str", ["clang", "gcc", "gcc@10.2.1", "clang@:15.0.0"])
     def test_compiler_inheritance(self, compiler_str):
         spec_str = "mpileaks %{0}".format(compiler_str)
         spec = Spec(spec_str).concretized()
@@ -877,7 +877,7 @@ class TestConcretize:
             # Unconstrained versions select default compiler (gcc@4.5.0)
             ("bowtie@1.4.0", "%gcc@10.2.1"),
             # Version with conflicts and no valid gcc select another compiler
-            ("bowtie@1.3.0", "%clang@12.0.0"),
+            ("bowtie@1.3.0", "%clang@15.0.0"),
             # If a higher gcc is available still prefer that
             ("bowtie@1.2.2 os=redhat6", "%gcc@11.1.0"),
         ],
@@ -1439,7 +1439,7 @@ class TestConcretize:
     @pytest.mark.regression("22718")
     @pytest.mark.parametrize(
         "spec_str,expected_compiler",
-        [("mpileaks", "%gcc@10.2.1"), ("mpileaks ^mpich%clang@12.0.0", "%clang@12.0.0")],
+        [("mpileaks", "%gcc@10.2.1"), ("mpileaks ^mpich%clang@15.0.0", "%clang@15.0.0")],
     )
     def test_compiler_is_unique(self, spec_str, expected_compiler):
         s = Spec(spec_str).concretized()
@@ -1727,7 +1727,7 @@ class TestConcretize:
         [
             (["libelf", "libelf@0.8.10"], 1),
             (["libdwarf%gcc", "libelf%clang"], 2),
-            (["libdwarf%gcc", "libdwarf%clang"], 4),
+            (["libdwarf%gcc", "libdwarf%clang"], 3),
             (["libdwarf^libelf@0.8.12", "libdwarf^libelf@0.8.13"], 4),
             (["hdf5", "zmpi"], 3),
             (["hdf5", "mpich"], 2),
diff --git a/lib/spack/spack/test/concretize_compiler_runtimes.py b/lib/spack/spack/test/concretize_compiler_runtimes.py
index ed91c01df8..3e13fd8e56 100644
--- a/lib/spack/spack/test/concretize_compiler_runtimes.py
+++ b/lib/spack/spack/test/concretize_compiler_runtimes.py
@@ -7,6 +7,8 @@ import os
 
 import pytest
 
+import archspec.cpu
+
 import spack.paths
 import spack.repo
 import spack.solver.asp
@@ -24,9 +26,7 @@ def _concretize_with_reuse(*, root_str, reused_str):
     reused_spec = spack.spec.Spec(reused_str).concretized()
     setup = spack.solver.asp.SpackSolverSetup(tests=False)
     driver = spack.solver.asp.PyclingoDriver()
-    result, _, _ = driver.solve(
-        setup, [spack.spec.Spec(f"{root_str} ^{reused_str}")], reuse=[reused_spec]
-    )
+    result, _, _ = driver.solve(setup, [spack.spec.Spec(f"{root_str}")], reuse=[reused_spec])
     root = result.specs[0]
     return root, reused_spec
 
@@ -47,7 +47,7 @@ def enable_runtimes():
 
 
 def test_correct_gcc_runtime_is_injected_as_dependency(runtime_repo):
-    s = spack.spec.Spec("a%gcc@10.2.1 ^b%gcc@4.8.0").concretized()
+    s = spack.spec.Spec("a%gcc@10.2.1 ^b%gcc@9.4.0").concretized()
     a, b = s["a"], s["b"]
 
     # Both a and b should depend on the same gcc-runtime directly
@@ -78,9 +78,28 @@ def test_external_nodes_do_not_have_runtimes(runtime_repo, mutable_config, tmp_p
     "root_str,reused_str,expected,nruntime",
     [
         # The reused runtime is older than we need, thus we'll add a more recent one for a
-        ("a%gcc@10.2.1", "b%gcc@4.8.0", {"a": "gcc-runtime@10.2.1", "b": "gcc-runtime@4.8.0"}, 2),
+        ("a%gcc@10.2.1", "b%gcc@9.4.0", {"a": "gcc-runtime@10.2.1", "b": "gcc-runtime@9.4.0"}, 2),
         # The root is compiled with an older compiler, thus we'll reuse the runtime from b
-        ("a%gcc@4.8.0", "b%gcc@10.2.1", {"a": "gcc-runtime@10.2.1", "b": "gcc-runtime@10.2.1"}, 1),
+        ("a%gcc@9.4.0", "b%gcc@10.2.1", {"a": "gcc-runtime@10.2.1", "b": "gcc-runtime@10.2.1"}, 1),
+        # Same as before, but tests that we can reuse from a more generic target
+        pytest.param(
+            "a%gcc@9.4.0",
+            "b%gcc@10.2.1 target=x86_64",
+            {"a": "gcc-runtime@10.2.1 target=x86_64", "b": "gcc-runtime@10.2.1 target=x86_64"},
+            1,
+            marks=pytest.mark.skipif(
+                str(archspec.cpu.host().family) != "x86_64", reason="test data is x86_64 specific"
+            ),
+        ),
+        pytest.param(
+            "a%gcc@10.2.1",
+            "b%gcc@9.4.0 target=x86_64",
+            {"a": "gcc-runtime@10.2.1 target=x86_64", "b": "gcc-runtime@9.4.0 target=x86_64"},
+            2,
+            marks=pytest.mark.skipif(
+                str(archspec.cpu.host().family) != "x86_64", reason="test data is x86_64 specific"
+            ),
+        ),
     ],
 )
 def test_reusing_specs_with_gcc_runtime(root_str, reused_str, expected, nruntime, runtime_repo):
@@ -104,8 +123,8 @@ def test_reusing_specs_with_gcc_runtime(root_str, reused_str, expected, nruntime
     [
         # Ensure that, whether we have multiple runtimes in the DAG or not,
         # we always link only the latest version
-        ("a%gcc@10.2.1", "b%gcc@4.8.0", ["gcc-runtime@10.2.1"], ["gcc-runtime@4.8.0"]),
-        ("a%gcc@4.8.0", "b%gcc@10.2.1", ["gcc-runtime@10.2.1"], ["gcc-runtime@4.8.0"]),
+        ("a%gcc@10.2.1", "b%gcc@9.4.0", ["gcc-runtime@10.2.1"], ["gcc-runtime@9.4.0"]),
+        ("a%gcc@9.4.0", "b%gcc@10.2.1", ["gcc-runtime@10.2.1"], ["gcc-runtime@9.4.0"]),
     ],
 )
 def test_views_can_handle_duplicate_runtime_nodes(
diff --git a/lib/spack/spack/test/concretize_preferences.py b/lib/spack/spack/test/concretize_preferences.py
index fb53374be6..a7683bf65f 100644
--- a/lib/spack/spack/test/concretize_preferences.py
+++ b/lib/spack/spack/test/concretize_preferences.py
@@ -105,7 +105,7 @@ class TestConcretizePreferences:
 
     @pytest.mark.parametrize(
         "compiler_str,spec_str",
-        [("gcc@=4.8.0", "mpileaks"), ("clang@=12.0.0", "mpileaks"), ("gcc@=4.8.0", "openmpi")],
+        [("gcc@=9.4.0", "mpileaks"), ("clang@=15.0.0", "mpileaks"), ("gcc@=9.4.0", "openmpi")],
     )
     def test_preferred_compilers(self, compiler_str, spec_str):
         """Test preferred compilers are applied correctly"""
diff --git a/lib/spack/spack/test/conftest.py b/lib/spack/spack/test/conftest.py
index e491cb436c..7a38d4ccba 100644
--- a/lib/spack/spack/test/conftest.py
+++ b/lib/spack/spack/test/conftest.py
@@ -2013,3 +2013,12 @@ def compiler_factory():
 def host_architecture_str():
     """Returns the broad architecture family (x86_64, aarch64, etc.)"""
     return str(archspec.cpu.host().family)
+
+
+def _true(x):
+    return True
+
+
+@pytest.fixture()
+def do_not_check_runtimes_on_reuse(monkeypatch):
+    monkeypatch.setattr(spack.solver.asp, "_has_runtime_dependencies", _true)
diff --git a/lib/spack/spack/test/data/config/compilers.yaml b/lib/spack/spack/test/data/config/compilers.yaml
index e8a709dc85..0d5345130a 100644
--- a/lib/spack/spack/test/data/config/compilers.yaml
+++ b/lib/spack/spack/test/data/config/compilers.yaml
@@ -1,6 +1,6 @@
 compilers:
 - compiler:
-    spec: gcc@=4.8.0
+    spec: gcc@=9.4.0
     operating_system: {linux_os.name}{linux_os.version}
     paths:
       cc: /path/to/gcc
@@ -10,7 +10,7 @@ compilers:
     modules: []
     target: {target}
 - compiler:
-    spec: gcc@=4.8.0
+    spec: gcc@=9.4.0
     operating_system: redhat6
     paths:
       cc: /path/to/gcc
@@ -20,7 +20,7 @@ compilers:
     modules: []
     target: {target}
 - compiler:
-    spec: clang@=12.0.0
+    spec: clang@=15.0.0
     operating_system: {linux_os.name}{linux_os.version}
     paths:
       cc: /path/to/clang
diff --git a/lib/spack/spack/test/data/config/packages.yaml b/lib/spack/spack/test/data/config/packages.yaml
index c6ff731a7e..3d5cac7664 100644
--- a/lib/spack/spack/test/data/config/packages.yaml
+++ b/lib/spack/spack/test/data/config/packages.yaml
@@ -16,7 +16,7 @@ packages:
   externalvirtual:
     buildable: False
     externals:
-    - spec: externalvirtual@2.0%clang@12.0.0
+    - spec: externalvirtual@2.0%clang@15.0.0
       prefix: /path/to/external_virtual_clang
     - spec: externalvirtual@1.0%gcc@10.2.1
       prefix: /path/to/external_virtual_gcc
diff --git a/lib/spack/spack/test/data/modules/lmod/complex_hierarchy.yaml b/lib/spack/spack/test/data/modules/lmod/complex_hierarchy.yaml
index 39515b3856..91adfd92e6 100644
--- a/lib/spack/spack/test/data/modules/lmod/complex_hierarchy.yaml
+++ b/lib/spack/spack/test/data/modules/lmod/complex_hierarchy.yaml
@@ -4,7 +4,7 @@ lmod:
   hash_length: 0
 
   core_compilers:
-    - 'clang@12.0.0'
+    - 'clang@15.0.0'
 
   core_specs:
     - 'mpich@3.0.1'
diff --git a/lib/spack/spack/test/data/modules/lmod/core_compilers.yaml b/lib/spack/spack/test/data/modules/lmod/core_compilers.yaml
index 60d461d10a..0070f42bec 100644
--- a/lib/spack/spack/test/data/modules/lmod/core_compilers.yaml
+++ b/lib/spack/spack/test/data/modules/lmod/core_compilers.yaml
@@ -2,4 +2,4 @@ enable:
   - lmod
 lmod:
   core_compilers:
-    - 'clang@12.0.0'
+    - 'clang@15.0.0'
diff --git a/lib/spack/spack/test/data/modules/lmod/core_compilers_at_equal.yaml b/lib/spack/spack/test/data/modules/lmod/core_compilers_at_equal.yaml
index d4b22dccf1..5a69c98bb5 100644
--- a/lib/spack/spack/test/data/modules/lmod/core_compilers_at_equal.yaml
+++ b/lib/spack/spack/test/data/modules/lmod/core_compilers_at_equal.yaml
@@ -2,4 +2,4 @@ enable:
   - lmod
 lmod:
   core_compilers:
-    - 'clang@=12.0.0'
+    - 'clang@=15.0.0'
diff --git a/lib/spack/spack/test/modules/lmod.py b/lib/spack/spack/test/modules/lmod.py
index 5b38931c06..9038d8c9f6 100644
--- a/lib/spack/spack/test/modules/lmod.py
+++ b/lib/spack/spack/test/modules/lmod.py
@@ -29,7 +29,7 @@ pytestmark = [
 ]
 
 
-@pytest.fixture(params=["clang@=12.0.0", "gcc@=10.2.1"])
+@pytest.fixture(params=["clang@=15.0.0", "gcc@=10.2.1"])
 def compiler(request):
     return request.param
 
@@ -59,7 +59,7 @@ class TestLmod:
         we can use both ``compiler@version`` and ``compiler@=version`` to specify a core compiler.
         """
         module_configuration(modules_config)
-        module, spec = factory("libelf%clang@12.0.0")
+        module, spec = factory("libelf%clang@15.0.0")
         assert "Core" in module.layout.available_path_parts
 
     def test_file_layout(self, compiler, provider, factory, module_configuration):
@@ -78,7 +78,7 @@ class TestLmod:
         # is transformed to r"Core" if the compiler is listed among core
         # compilers
         # Check that specs listed as core_specs are transformed to "Core"
-        if compiler == "clang@=12.0.0" or spec_string == "mpich@3.0.1":
+        if compiler == "clang@=15.0.0" or spec_string == "mpich@3.0.1":
             assert "Core" in layout.available_path_parts
         else:
             assert compiler.replace("@=", "/") in layout.available_path_parts