From e66ae3959deec6212d0f5c913105616e5b8a2354 Mon Sep 17 00:00:00 2001
From: Gregory Becker <becker33@llnl.gov>
Date: Mon, 21 Apr 2025 17:29:18 -0700
Subject: [PATCH] Spec.long_spec: update for conditional deps

Signed-off-by: Gregory Becker <becker33@llnl.gov>
---
 lib/spack/spack/spec.py | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index ea8809c2092..2c7139523aa 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -1639,20 +1639,26 @@ def edge_attributes(self) -> str:
 
         union = DependencySpec(parent=Spec(), spec=self, depflag=0, virtuals=())
         all_direct_edges = all(x.direct for x in edges)
+        dep_conditions = []
 
         for edge in edges:
             union.update_deptypes(edge.depflag)
             union.update_virtuals(edge.virtuals)
+            dep_conditions.append(edge.when)
 
         deptypes_str = ""
         if not all_direct_edges and union.depflag:
             deptypes_str = f"deptypes={','.join(dt.flag_to_tuple(union.depflag))}"
 
         virtuals_str = f"virtuals={','.join(union.virtuals)}" if union.virtuals else ""
-        if not deptypes_str and not virtuals_str:
-            return ""
-        result = f"{deptypes_str} {virtuals_str}".strip()
-        return f"[{result}]"
+
+        conditions = [str(c) for c in dep_conditions if c != Spec()]
+        when_str = f"when={','.join(conditions)}" if conditions else ""
+
+        result = f"{when_str} {deptypes_str} {virtuals_str}".strip()
+        if result:
+            result = f"[{result}]"
+        return result
 
     def dependencies(
         self,
@@ -2109,15 +2115,15 @@ def long_spec(self):
             new_name = spack.aliases.BUILTIN_TO_LEGACY_COMPILER.get(current_name, current_name)
             # note: depflag not allowed, currently, on "direct" edges
             edge_attributes = ""
-            if item.virtuals:
-                edge_attributes = item.spec.format("{edge_attributes}") + " "
+            if item.virtuals or item.when:
+                edge_attributes = item.spec.format("{edge_attributes}") + ""
 
             parts.append(f"%{edge_attributes}{item.spec.format()}".replace(current_name, new_name))
         for item in sorted(transitive, key=lambda x: x.spec.name):
             # Recurse to attach build deps in order
             edge_attributes = ""
-            if item.virtuals or item.depflag:
-                edge_attributes = item.spec.format("{edge_attributes}") + " "
+            if item.virtuals or item.depflag or item.when:
+                edge_attributes = item.spec.format("{edge_attributes}") + ""
             parts.append(f"^{edge_attributes}{str(item.spec)}")
         return " ".join(parts).strip()