diff --git a/lib/spack/spack/fetch_strategy.py b/lib/spack/spack/fetch_strategy.py
index f08316bc9d2..5e0dc4cfe02 100644
--- a/lib/spack/spack/fetch_strategy.py
+++ b/lib/spack/spack/fetch_strategy.py
@@ -270,7 +270,7 @@ def __init__(self, *, url: str, checksum: Optional[str] = None, **kwargs) -> Non
         self._effective_url: Optional[str] = None
 
     def spec_attrs(self):
-        attrs = super(URLFetchStrategy, self).spec_attrs()
+        attrs = super().spec_attrs()
         if self.digest:
             try:
                 hash_type = spack.util.crypto.hash_algo_for_digest(self.digest)
@@ -759,6 +759,16 @@ def __init__(self, **kwargs):
         self.get_full_repo = kwargs.get("get_full_repo", False)
         self.git_sparse_paths = kwargs.get("git_sparse_paths", None)
 
+    def spec_attrs(self):
+        attrs = super().spec_attrs()
+
+        # need to fully resolve submodule callbacks for node dicts
+        submodules = attrs.get("submodules", None)
+        if submodules and callable(submodules):
+            attrs["submodules"] = submodules(self.package)
+
+        return attrs
+
     @property
     def git_version(self):
         return GitFetchStrategy.version_from_git(self.git)
diff --git a/lib/spack/spack/test/spec_yaml.py b/lib/spack/spack/test/spec_yaml.py
index 5b64822b382..ee685078b6c 100644
--- a/lib/spack/spack/test/spec_yaml.py
+++ b/lib/spack/spack/test/spec_yaml.py
@@ -96,6 +96,22 @@ def test_invalid_json_spec(invalid_json, error_message):
         # Virtuals on edges
         "callpath",
         "mpileaks",
+        # all types of git versions
+        # ensure that we try to serialize all the things that might be in the node dict,
+        # e.g., submodule callbacks can fail serialization if they're not fully resolved.
+        "git-url-top-level@develop",
+        "git-url-top-level@submodules",
+        "git-url-top-level@submodules_callback",
+        "git-url-top-level@3.4",
+        "git-url-top-level@3.3",
+        "git-url-top-level@3.2",
+        "git-url-top-level@3.1",
+        "git-url-top-level@3.0",
+        "git-url-top-level@2.3",
+        "git-url-top-level@2.2",
+        "git-url-top-level@2.1",
+        "git-url-top-level@2.0",
+        "git-url-top-level@2.3",
     ],
 )
 def test_roundtrip_concrete_specs(abstract_spec, default_mock_concretization):
diff --git a/var/spack/repos/builtin.mock/packages/git-url-top-level/package.py b/var/spack/repos/builtin.mock/packages/git-url-top-level/package.py
index 7e3009d7dc9..ac5bdf669b2 100644
--- a/var/spack/repos/builtin.mock/packages/git-url-top-level/package.py
+++ b/var/spack/repos/builtin.mock/packages/git-url-top-level/package.py
@@ -6,6 +6,11 @@
 from spack.package import *
 
 
+def use_submodules(pkg):
+    """test example of a submodule callback"""
+    return ["a", "b"]
+
+
 class GitUrlTopLevel(Package):
     """Mock package that top-level git and url attributes.
 
@@ -22,6 +27,7 @@ class GitUrlTopLevel(Package):
     # These resolve to git fetchers
     version("develop", branch="develop")
     version("submodules", submodules=True)
+    version("submodules_callback", submodules=use_submodules)
     version("3.4", commit="abc34")
     version("3.3", branch="releases/v3.3", commit="abc33")
     version("3.2", branch="releases/v3.2")