Added invalid variable validation for build.buil-dir path templating.

This commit adds logic to check for unexpected variables in templated
paths like `build.build-dir`. Cargo will error if it finds a variable
that it does not know how to expand.

Author: ranger-ross

src/cargo/util/context/mod.rs

@@ -681,7 +681,17 @@ impl GlobalContext {
                 }),
             ];
 
-            let path = val.resolve_templated_path(self, replacements);
+            let path = val
+                .resolve_templated_path(self, replacements)
+                .map_err(|e| match e {
+                    path::ResolveTemplateError::UnexpectedVariable {
+                        variable,
+                        raw_template,
+                    } => anyhow!(
+                        "unexpected variable `{variable}` in build.build-dir path `{raw_template}`"
+                    ),
+                })?;
+
             // Check if the target directory is set to an empty string in the config.toml file.
             if val.raw_value().is_empty() {
                 bail!(

src/cargo/util/context/path.rs

@@ -1,4 +1,5 @@
 use super::{GlobalContext, StringList, Value};
+use regex::Regex;
 use serde::{de::Error, Deserialize};
 use std::path::PathBuf;
 
@@ -41,14 +42,23 @@ impl ConfigRelativePath {
         &self,
         gctx: &GlobalContext,
         replacements: impl IntoIterator<Item = (impl AsRef<str>, impl AsRef<str>)>,
-    ) -> PathBuf {
+    ) -> Result<PathBuf, ResolveTemplateError> {
         let mut value = self.0.val.clone();
 
         for (from, to) in replacements {
             value = value.replace(from.as_ref(), to.as_ref());
         }
 
-        self.0.definition.root(gctx).join(&value)
+        // Check for expected variables
+        let re = Regex::new(r"\{(.*)\}").unwrap();
+        if let Some(caps) = re.captures(&value) {
+            return Err(ResolveTemplateError::UnexpectedVariable {
+                variable: caps[1].to_string(),
+                raw_template: self.0.val.clone(),
+            });
+        };
+
+        Ok(self.0.definition.root(gctx).join(&value))
     }
 
     /// Resolves this configuration-relative path to either an absolute path or
@@ -122,3 +132,11 @@ impl PathAndArgs {
         }
     }
 }
+
+#[derive(Debug)]
+pub enum ResolveTemplateError {
+    UnexpectedVariable {
+        variable: String,
+        raw_template: String,
+    },
+}

tests/testsuite/build_dir.rs

@@ -12,7 +12,7 @@
 use std::path::PathBuf;
 
 use cargo_test_support::prelude::*;
-use cargo_test_support::{paths, project};
+use cargo_test_support::{paths, project, str};
 use std::env::consts::{DLL_PREFIX, DLL_SUFFIX, EXE_SUFFIX};
 
 #[cargo_test]
@@ -508,6 +508,11 @@ fn template_should_error_for_invalid_variables() {
     p.cargo("build -Z build-dir")
         .masquerade_as_nightly_cargo(&["build-dir"])
         .enable_mac_dsym()
+        .with_status(101)
+        .with_stderr_data(str![[r#"
+[ERROR] unexpected variable `fake` in build.build-dir path `{fake}/build-dir`
+
+"#]])
         .run();
 }