Check if source is empty when constructing hal::DebugSource

[teoxoy]

Fixes #4569

[robtfm]

this still crashes for me at the same place.

you can try with cargo test on this branch if it helps, i changed the cargo.toml like so:

diff --git a/Cargo.toml b/Cargo.toml
index c7b8c62..51671ae 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,7 +17,7 @@ prune = []
 allow_deprecated = []
 
 [dependencies]
-naga = { version = "0.14", features = ["wgsl-in", "wgsl-out", "clone", "span"] }
+naga = { git = "https://github.com/gfx-rs/wgpu", branch = "check-if-source-is-empty", features = ["wgsl-in", "wgsl-out", "clone", "span"] }
 tracing = "0.1"
 regex = "1.8"
 regex-syntax = "0.7"
@@ -34,3 +34,6 @@ indexmap = "2"
 wgpu = { version = "0.18", features = ["naga"] }
 futures-lite = "1"
 tracing-subscriber = { version = "0.3", features = ["std", "fmt"] }
+
+[patch.crates-io]
+naga = { git = "https://github.com/gfx-rs/wgpu", branch = "check-if-source-is-empty" }

i don't see any base naga in my tree so i think that worked.

[teoxoy]

The fix is in wgpu, not naga.

[robtfm]

apologies, works perfectly.