Review comments: downgrade to error-chain 0.8.1 for Send + Sync bound; use combine::primitive::Error.

Cargo.toml

@@ -18,7 +18,7 @@ rustc_version = "0.1.7"
 
 [dependencies]
 clap = "2.19.3"
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 nickel = "0.9.0"
 slog = "1.4.0"
 slog-scope = "0.2.2"

db/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 itertools = "0.5.9"
 lazy_static = "0.2.2"
 ordered-float = "0.4.0"

query-algebrizer/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 
 [dependencies.mentat_core]
 path = "../core"

query-parser/Cargo.toml

@@ -5,7 +5,7 @@ workspace = ".."
 
 [dependencies]
 combine = "2.2.2"
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 matches = "0.1"
 
 [dependencies.edn]

query-parser/src/parse.rs

@@ -353,15 +353,15 @@ enum FindQueryPart {
 }
 
 def_parser!(Find, vars, BTreeSet<Variable>, {
-    vector().of_exactly(many(Query::variable()).map(|vars: Vec<Variable>| {
+    vector().of_exactly(many(Query::variable()).and_then(|vars: Vec<Variable>| {
             let given = vars.len();
             let set: BTreeSet<Variable> = vars.into_iter().collect();
             if given != set.len() {
                 // TODO: find out what the variable is!
-                // TODO: figure out how to use `and_then` to return an error here.
+                let e = Box::new(Error::from_kind(ErrorKind::DuplicateVariableError));
-                panic!(Error::from_kind(ErrorKind::DuplicateVariableError));
+                Err(combine::primitives::Error::Other(e))
             } else {
-                set
+                Ok(set)
             }
     }))
 });
@@ -549,6 +549,33 @@ mod test {
                           vec![variable(e.clone())]);
     }
 
+    #[test]
+    fn test_repeated_vars() {
+        let e = edn::PlainSymbol::new("?e");
+        let f = edn::PlainSymbol::new("?f");
+        let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(e.clone()),
+                                            edn::Value::PlainSymbol(f.clone()),]);
+        assert_parses_to!(Find::vars, input,
+                          vec![variable(e.clone()), variable(f.clone())].into_iter().collect());
+
+        let g = edn::PlainSymbol::new("?g");
+        let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(g.clone()),
+                                            edn::Value::PlainSymbol(g.clone()),]);
+
+        let mut par = Find::vars();
+        let result = par.parse(input.with_spans().into_atom_stream())
+            .map(|x| x.0)
+            .map_err(|e| if let Some(combine::primitives::Error::Other(x)) = e.errors.into_iter().next() {
+                // Pattern matching on boxes is rocket science until Rust Nightly features hit
+                // stable.  ErrorKind isn't Clone, so convert to strings.  We could pattern match
+                // for exact comparison here.
+                x.downcast::<Error>().ok().map(|e| e.to_string())
+            } else {
+                None
+            });
+        assert_eq!(result, Err(Some("duplicates in variable list".to_string())));
+    }
+
     #[test]
     fn test_or() {
         let oj = edn::PlainSymbol::new("or");

query-projector/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 
 [dependencies.rusqlite]
 version = "0.10.1"

sql/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 ordered-float = "0.4.0"
 
 [dependencies.mentat_core]

tx-parser/Cargo.toml

@@ -5,7 +5,7 @@ workspace = ".."
 
 [dependencies]
 combine = "2.2.2"
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 
 [dependencies.edn]
 path = "../edn"