Fail early if required tools can't be found.

cargo-dist/src/errors.rs

@@ -361,6 +361,14 @@ pub enum DistError {
         tool: String,
     },
 
+    /// One or more required tools are missing.
+    #[error("The following tools are required to run this task, but are missing:\n- {}", tools.join("\n- "))]
+    #[diagnostic(help("Please install the tools mentioned above and try again."))]
+    EnvToolsMissing {
+        /// the names of the missing tools
+        tools: Vec<String>,
+    },
+
     /// Unknown target requested
     #[error(
         "A build was requested for {target}, but the standalone updater isn't available for it."

cargo-dist/src/lib.rs

@@ -57,8 +57,90 @@ pub mod tasks;
 #[cfg(test)]
 mod tests;
 
+/// dist env test -- make sure we have everything we need for a build.
+pub fn do_env_test(cfg: &Config) -> DistResult<()> {
+    let (dist, _manifest) = tasks::gather_work(cfg)?;
+
+    let builds = dist.config.builds;
+
+    let need_cargo_auditable = builds.cargo.cargo_auditable;
+    let need_cargo_cyclonedx = builds.cargo.cargo_cyclonedx;
+    let need_omnibor = builds.omnibor;
+    let mut need_xwin = false;
+    let mut need_zigbuild = false;
+
+    let tools = dist.tools;
+
+    let cargo = tools.cargo()?;
+    let host = cargo.host_target.parse()?;
+
+    for step in dist
+        .local_build_steps
+        .iter()
+        .chain(dist.global_build_steps.iter())
+    {
+        // Can't require cross-compilation tools if we aren't compiling.
+        if cfg.artifact_mode == ArtifactMode::Lies {
+            break;
+        }
+
+        match step {
+            BuildStep::Cargo(step) => {
+                let target = step.target_triple.parse()?;
+                let wrapper = tasks::build_wrapper_for_cross(&host, &target)?;
+
+                match wrapper {
+                    Some(CargoBuildWrapper::Xwin) => {
+                        need_xwin = true;
+                    }
+                    Some(CargoBuildWrapper::ZigBuild) => {
+                        need_zigbuild = true;
+                    }
+                    None => {}
+                }
+            }
+            _ => {}
+        }
+    }
+
+    // These are all of the tools we can check for.
+    //
+    // bool::then(f) returns an Option, so we start with a
+    // Vec<Option<Result<&Tool, DistResult>>>.
+    let all_tools: Vec<Option<DistResult<&Tool>>> = vec![
+        need_cargo_auditable.then(|| tools.cargo_auditable()),
+        need_cargo_cyclonedx.then(|| tools.cargo_cyclonedx()),
+        need_omnibor.then(|| tools.omnibor()),
+        need_xwin.then(|| tools.cargo_xwin()),
+        need_zigbuild.then(|| tools.cargo_zigbuild()),
+    ];
+
+    // Drop `None`s, then extract the values from the remaining `Option`s.
+    let needed_tools = all_tools.into_iter().flatten();
+
+    let missing: Vec<String> = needed_tools
+        .filter_map(|t| match t {
+            // The tool was found.
+            Ok(_) => None,
+            // The tool is missing
+            Err(DistError::ToolMissing { tool: ref name }) => Some(name.to_owned()),
+            // This should never happen, but I can't find a way to enforce
+            // it at the type system level. ;~; -@duckinator
+            Err(_) => unreachable!(
+                "do_env_test() got an Err that wasn't DistError::ToolMissing. This is a dist bug."
+            ),
+        })
+        .collect();
+
+    missing
+        .is_empty()
+        .then_some(())
+        .ok_or(DistError::EnvToolsMissing { tools: missing })
+}
+
 /// dist build -- actually build binaries and installers!
 pub fn do_build(cfg: &Config) -> DistResult<DistManifest> {
+    do_env_test(cfg)?;
     check_integrity(cfg)?;
 
     let (dist, mut manifest) = tasks::gather_work(cfg)?;

cargo-dist/src/tasks.rs

@@ -281,6 +281,14 @@ pub struct Tools {
     ///
     /// <https://www.ssl.com/guide/esigner-codesigntool-command-guide/>
     pub code_sign_tool: Option<Tool>,
+    /// cargo-auditable, used for auditable builds
+    pub cargo_auditable: Option<Tool>,
+    /// cargo-cyclonedx, for generating CycloneDX artifacts
+    pub cargo_cyclonedx: Option<Tool>,
+    /// cargo-xwin, for some cross builds
+    pub cargo_xwin: Option<Tool>,
+    /// cargo-zigbuild, for some cross builds
+    pub cargo_zigbuild: Option<Tool>,
 }
 
 impl Tools {
@@ -297,6 +305,34 @@ impl Tools {
             tool: "omnibor-cli".to_owned(),
         })
     }
+
+    /// Returns cargo-auditable info or an error
+    pub fn cargo_auditable(&self) -> DistResult<&Tool> {
+        self.cargo_auditable.as_ref().ok_or(DistError::ToolMissing {
+            tool: "cargo-auditable".to_owned(),
+        })
+    }
+
+    /// Returns cargo-cyclonedx info or an error
+    pub fn cargo_cyclonedx(&self) -> DistResult<&Tool> {
+        self.cargo_cyclonedx.as_ref().ok_or(DistError::ToolMissing {
+            tool: "cargo-cyclonedx".to_owned(),
+        })
+    }
+
+    /// Returns cargo-xwin info or an error
+    pub fn cargo_xwin(&self) -> DistResult<&Tool> {
+        self.cargo_xwin.as_ref().ok_or(DistError::ToolMissing {
+            tool: "cargo-xwin".to_owned(),
+        })
+    }
+
+    /// Returns cargo-zigbuild info or an error
+    pub fn cargo_zigbuild(&self) -> DistResult<&Tool> {
+        self.cargo_zigbuild.as_ref().ok_or(DistError::ToolMissing {
+            tool: "cargo-zigbuild".to_owned(),
+        })
+    }
 }
 
 /// Info about the cargo toolchain we're using
@@ -3180,6 +3216,29 @@ fn tool_info() -> DistResult<Tools> {
         omnibor: find_tool("omnibor", "--version"),
         // Computed later if needed
         code_sign_tool: None,
+
+        // NOTE: This doesn't actually give us cargo-auditable's version info,
+        // but it does confirm it's installed, which is what we care about.
+        cargo_auditable: find_tool2("cargo", "auditable", "--version"),
+
+        cargo_cyclonedx: find_tool2("cargo", "cyclonedx", "--version"),
+        cargo_xwin: find_tool2("cargo", "xwin", "--version"),
+        cargo_zigbuild: find_tool("cargo-zigbuild", "--version"),
+    })
+}
+
+fn find_tool2(name: &str, arg: &str, test_flag: &str) -> Option<Tool> {
+    let output = Cmd::new(name, "detect tool")
+        .arg(arg)
+        .arg(test_flag)
+        .check(false)
+        .output()
+        .ok()?;
+    let string_output = String::from_utf8(output.stdout).ok()?;
+    let version = string_output.lines().next()?;
+    Some(Tool {
+        cmd: format!("{} {}", name, arg),
+        version: version.to_owned(),
     })
 }
 

cargo-dist/src/tests/mock.rs

@@ -84,6 +84,10 @@ pub fn mock_tools() -> Tools {
         git: None,
         omnibor: None,
         code_sign_tool: None,
+        cargo_auditable: None,
+        cargo_cyclonedx: None,
+        cargo_xwin: None,
+        cargo_zigbuild: None,
     }
 }