chore: improve error message to suggest --project-manifest

crates/cargo_utils/src/workspace_members.rs

@@ -1,13 +1,13 @@
-use anyhow::Context;
 use cargo_metadata::{Metadata, Package};
 use std::path::Path;
 
-pub fn get_manifest_metadata(manifest_path: &Path) -> anyhow::Result<cargo_metadata::Metadata> {
+pub fn get_manifest_metadata(
+    manifest_path: &Path,
+) -> Result<cargo_metadata::Metadata, cargo_metadata::Error> {
     cargo_metadata::MetadataCommand::new()
         .no_deps()
         .manifest_path(manifest_path)
         .exec()
-        .with_context(|| format!("invalid manifest {manifest_path:?}"))
 }
 
 /// Lookup all members of the current workspace

crates/release_plz/src/args/repo_command.rs

@@ -16,7 +16,16 @@ pub trait RepoCommand {
     }
 
     fn cargo_metadata(&self) -> anyhow::Result<cargo_metadata::Metadata> {
-        cargo_utils::get_manifest_metadata(&self.project_manifest())
+        let manifest = &self.project_manifest();
+        cargo_utils::get_manifest_metadata(manifest).map_err(|e| match e {
+            cargo_metadata::Error::CargoMetadata { stderr } => {
+                let stderr = stderr.trim();
+                anyhow::anyhow!("{stderr}. Use --project-manifest to specify the path to the manifest file if it's not in the current directory.")
+            }
+            _ => {
+                anyhow::anyhow!(e)
+            }
+        })
     }
 
     fn get_repo_url(&self, config: &Config) -> anyhow::Result<RepoUrl> {