Add default gas limit value to cairo-run (#1003)

extensions/scarb-cairo-run/src/main.rs

@@ -38,6 +38,7 @@ struct Args {
 
 fn main() -> Result<()> {
     let args: Args = Args::parse();
+    let available_gas = GasLimit::parse(args.available_gas);
 
     let ui = Ui::new(Verbosity::default(), OutputFormat::Text);
 
@@ -76,16 +77,16 @@ fn main() -> Result<()> {
     .into_v1()
     .with_context(|| format!("failed to load Sierra program: {path}"))?;
 
-    if args.available_gas.is_none() && sierra_program.program.requires_gas_counter() {
+    if available_gas.is_disabled() && sierra_program.program.requires_gas_counter() {
         bail!("program requires gas counter, please provide `--available-gas` argument");
     }
 
     let runner = SierraCasmRunner::new(
         sierra_program.program,
-        if args.available_gas.is_some() {
-            Some(Default::default())
-        } else {
+        if available_gas.is_disabled() {
             None
+        } else {
+            Some(Default::default())
         },
         Default::default(),
     )?;
@@ -94,14 +95,15 @@ fn main() -> Result<()> {
         .run_function_with_starknet_context(
             runner.find_function("::main")?,
             &[],
-            args.available_gas,
+            available_gas.value(),
             StarknetState::default(),
         )
         .context("failed to run the function")?;
 
     ui.print(Summary {
         result,
         print_full_memory: args.print_full_memory,
+        gas_defined: available_gas.is_defined(),
     });
 
     Ok(())
@@ -110,6 +112,7 @@ fn main() -> Result<()> {
 struct Summary {
     result: RunResultStarknet,
     print_full_memory: bool,
+    gas_defined: bool,
 }
 
 impl Message for Summary {
@@ -133,8 +136,10 @@ impl Message for Summary {
             }
         }
 
-        if let Some(gas) = self.result.gas_counter {
-            println!("Remaining gas: {gas}");
+        if self.gas_defined {
+            if let Some(gas) = self.result.gas_counter {
+                println!("Remaining gas: {gas}");
+            }
         }
 
         if self.print_full_memory {
@@ -156,3 +161,34 @@ impl Message for Summary {
         todo!("JSON output is not implemented yet for this command")
     }
 }
+
+enum GasLimit {
+    Disabled,
+    Unlimited,
+    Limited(usize),
+}
+impl GasLimit {
+    pub fn parse(value: Option<usize>) -> Self {
+        match value {
+            Some(0) => GasLimit::Disabled,
+            Some(value) => GasLimit::Limited(value),
+            None => GasLimit::Unlimited,
+        }
+    }
+
+    pub fn is_disabled(&self) -> bool {
+        matches!(self, GasLimit::Disabled)
+    }
+
+    pub fn is_defined(&self) -> bool {
+        !matches!(self, GasLimit::Unlimited)
+    }
+
+    pub fn value(&self) -> Option<usize> {
+        match self {
+            GasLimit::Disabled => None,
+            GasLimit::Limited(value) => Some(*value),
+            GasLimit::Unlimited => Some(usize::MAX),
+        }
+    }
+}

extensions/scarb-cairo-run/tests/examples.rs

@@ -5,7 +5,7 @@ use snapbox::cmd::{cargo_bin, Command};
 use scarb_test_support::cargo::manifest_dir;
 
 #[test]
-fn hello_world() {
+fn scarb_build_is_called() {
     let example = manifest_dir()
         .parent()
         .unwrap()
@@ -16,17 +16,9 @@ fn hello_world() {
 
     let t = TempDir::new().unwrap();
 
-    Command::new(cargo_bin("scarb"))
-        .env("SCARB_TARGET_DIR", t.path())
-        .arg("build")
-        .current_dir(example.clone())
-        .assert()
-        .success();
     Command::new(cargo_bin("scarb"))
         .env("SCARB_TARGET_DIR", t.path())
         .arg("cairo-run")
-        .arg("--available-gas")
-        .arg("2000000")
         .current_dir(example)
         .assert()
         .success()
@@ -35,12 +27,37 @@ fn hello_world() {
                 Finished release target(s) in [..]
                  Running hello_world
             Run completed successfully, returning [987]
-            Remaining gas: 1953640
         "#});
 }
 
 #[test]
-fn scarb_build_is_called() {
+fn build_can_be_skipped() {
+    let example = manifest_dir()
+        .parent()
+        .unwrap()
+        .parent()
+        .unwrap()
+        .join("examples")
+        .join("hello_world");
+
+    let t = TempDir::new().unwrap();
+
+    Command::new(cargo_bin("scarb"))
+        .env("SCARB_TARGET_DIR", t.path())
+        .arg("cairo-run")
+        .arg("--no-build")
+        .current_dir(example)
+        .assert()
+        .failure()
+        .stderr_eq(indoc! {r#"
+            Error: package has not been compiled, file does not exist: hello_world.sierra.json
+            help: run `scarb build` to compile the package
+
+        "#});
+}
+
+#[test]
+fn can_limit_gas() {
     let example = manifest_dir()
         .parent()
         .unwrap()
@@ -55,7 +72,7 @@ fn scarb_build_is_called() {
         .env("SCARB_TARGET_DIR", t.path())
         .arg("cairo-run")
         .arg("--available-gas")
-        .arg("2000000")
+        .arg("100000")
         .current_dir(example)
         .assert()
         .success()
@@ -64,12 +81,12 @@ fn scarb_build_is_called() {
                 Finished release target(s) in [..]
                  Running hello_world
             Run completed successfully, returning [987]
-            Remaining gas: 1953640
+            Remaining gas: 53640
         "#});
 }
 
 #[test]
-fn build_can_be_skipped() {
+fn can_disable_gas() {
     let example = manifest_dir()
         .parent()
         .unwrap()
@@ -84,14 +101,11 @@ fn build_can_be_skipped() {
         .env("SCARB_TARGET_DIR", t.path())
         .arg("cairo-run")
         .arg("--available-gas")
-        .arg("2000000")
-        .arg("--no-build")
+        .arg("0")
         .current_dir(example)
         .assert()
         .failure()
         .stderr_eq(indoc! {r#"
-            Error: package has not been compiled, file does not exist: hello_world.sierra.json
-            help: run `scarb build` to compile the package
-
+            Error: program requires gas counter, please provide `--available-gas` argument
         "#});
 }

website/docs/extensions/cairo-run.md

@@ -4,4 +4,7 @@ The `scarb cairo-run` command executes the `main` function of a local package.
 It does automatically compile the cairo code within the package so using `scarb build` beforehand is not necessary.
 This automatically called build can be skipped with the `--no-build` flag.
 The extension accepts two optional parameters: `--available-gas` and `--print-full-memory`.
-The first one is used to set the available gas for the execution, and the second one prints the full memory after the execution.
+The first one is used to set the available gas for the execution.
+If not provided, a gas usage is not limited.
+Gas usage can be disallowed by setting the value to `0`.
+The second one prints the full memory after the execution.