From 038b718390d1076c201eaa6c72bb2a2aff9633f5 Mon Sep 17 00:00:00 2001
From: delta17920 <pratik161106@gmail.com>
Date: Sat, 28 Feb 2026 07:53:55 +0000
Subject: [PATCH] Fix ICE on empty file with -Zquery-dep-graph

---
 compiler/rustc_middle/src/dep_graph/graph.rs | 8 +++++++-
 tests/ui/dep-graph/query-dep-graph-empty.rs  | 7 +++++++
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/dep-graph/query-dep-graph-empty.rs

diff --git a/compiler/rustc_middle/src/dep_graph/graph.rs b/compiler/rustc_middle/src/dep_graph/graph.rs
index 2ce01ab4c6650..0d515ed82bc89 100644
--- a/compiler/rustc_middle/src/dep_graph/graph.rs
+++ b/compiler/rustc_middle/src/dep_graph/graph.rs
@@ -826,7 +826,13 @@ impl DepGraph {
     where
         F: FnOnce() -> String,
     {
-        let dep_node_debug = &self.data.as_ref().unwrap().dep_node_debug;
+        // Early queries (e.g., `-Z query-dep-graph` on empty crates) can reach here
+        // before the graph is initialized. Return early to prevent an ICE.
+        let data = match &self.data {
+            Some(d) => d,
+            None => return,
+        };
+        let dep_node_debug = &data.dep_node_debug;
 
         if dep_node_debug.borrow().contains_key(&dep_node) {
             return;
diff --git a/tests/ui/dep-graph/query-dep-graph-empty.rs b/tests/ui/dep-graph/query-dep-graph-empty.rs
new file mode 100644
index 0000000000000..360dfd7f1126a
--- /dev/null
+++ b/tests/ui/dep-graph/query-dep-graph-empty.rs
@@ -0,0 +1,7 @@
+//@ build-pass
+//@ compile-flags: -Zquery-dep-graph --crate-type lib
+//@ edition: 2021
+
+// This file is intentionally left empty to reproduce issue #153199.
+// rustc used to ICE when generating a dependency graph for an empty file
+// because early queries would panic when unwrapping an uninitialized graph.