Make stdio a feature

danielstuart14 · danielstuart14 · commit 84bdd8d4e39c · 2024-10-02T22:41:23.000-03:00
When embedding RustPython into a graphical windows application (where windows_subsystem = "windows"), it fails to create the RustPython VM. This happens because the VM will try to open stdin/stdout/stderr when initializing, but stdio isn't available for /SUBSYSTEM:WINDOWS apps. This commit makes stdio a feature, so it can be disabled when needed. https://doc.rust-lang.org/reference/runtime.html#the-windows_subsystem-attribute https://learn.microsoft.com/en-us/cpp/build/reference/subsystem-specify-subsystem?view=msvc-170 https://asawicki.info/news_1768_ways_to_print_and_capture_text_output_of_a_process
diff --git a/Cargo.toml b/Cargo.toml
@@ -10,9 +10,10 @@ repository.workspace = true
 license.workspace = true
 
 [features]
-default = ["threading", "stdlib", "zlib", "importlib"]
+default = ["threading", "stdlib", "stdio", "zlib", "importlib"]
 importlib = ["rustpython-vm/importlib"]
 encodings = ["rustpython-vm/encodings"]
+stdio = ["rustpython-vm/stdio"]
 stdlib = ["rustpython-stdlib", "rustpython-pylib", "encodings"]
 flame-it = ["rustpython-vm/flame-it", "flame", "flamescope"]
 freeze-stdlib = ["stdlib", "rustpython-vm/freeze-stdlib", "rustpython-pylib?/freeze-stdlib"]
diff --git a/vm/Cargo.toml b/vm/Cargo.toml
@@ -10,7 +10,8 @@ repository.workspace = true
 license.workspace = true
 
 [features]
-default = ["compiler", "wasmbind"]
+default = ["compiler", "wasmbind", "stdio"]
+stdio = []
 importlib = []
 encodings = ["importlib"]
 vm-tracing-logging = []
diff --git a/vm/src/vm/mod.rs b/vm/src/vm/mod.rs
@@ -305,25 +305,29 @@ impl VirtualMachine {
                 // builtins.open to io.OpenWrapper, but this is easier, since it doesn't
                 // require the Python stdlib to be present
                 let io = import::import_builtin(self, "_io")?;
-                let set_stdio = |name, fd, mode: &str| {
-                    let stdio = crate::stdlib::io::open(
-                        self.ctx.new_int(fd).into(),
-                        Some(mode),
-                        Default::default(),
-                        self,
-                    )?;
-                    let dunder_name = self.ctx.intern_str(format!("__{name}__"));
-                    self.sys_module.set_attr(
-                        dunder_name, // e.g. __stdin__
-                        stdio.clone(),
-                        self,
-                    )?;
-                    self.sys_module.set_attr(name, stdio, self)?;
-                    Ok(())
-                };
-                set_stdio("stdin", 0, "r")?;
-                set_stdio("stdout", 1, "w")?;
-                set_stdio("stderr", 2, "w")?;
+
+                #[cfg(feature = "stdio")]
+                {
+                    let set_stdio = |name, fd, mode: &str| {
+                        let stdio = crate::stdlib::io::open(
+                            self.ctx.new_int(fd).into(),
+                            Some(mode),
+                            Default::default(),
+                            self,
+                        )?;
+                        let dunder_name = self.ctx.intern_str(format!("__{name}__"));
+                        self.sys_module.set_attr(
+                            dunder_name, // e.g. __stdin__
+                            stdio.clone(),
+                            self,
+                        )?;
+                        self.sys_module.set_attr(name, stdio, self)?;
+                        Ok(())
+                    };
+                    set_stdio("stdin", 0, "r")?;
+                    set_stdio("stdout", 1, "w")?;
+                    set_stdio("stderr", 2, "w")?;
+                }
 
                 let io_open = io.get_attr("open", self)?;
                 self.builtins.set_attr("open", io_open, self)?;
