Fix info lookups from namespaces that don't yet exist

Currently when doing a `var-info` from a file before evaluating the `ns` form
always fails. The namespace object does not yet exist, and so none of the var
resolution strategies work.

However fully-qualified vars, namespace names, or built-ins (clojure.core
functions) could all be resolved, and it's frustrating that they aren't.

This adds a check to see if `(find-ns ns)` returns anything. If not then we are
initiating the lookup from a namespace that has not yet been defined, in which
case none of the lookup strategies will proceed, so we continue with doing the
lookup as if it had been initiated from `clojure.core`.

CHANGELOG.md

@@ -6,6 +6,10 @@
 
 * `orchard.namespace` functionality is now parallelized when possible.
 
+### Bugs Fixed
+
+* [#123](https://github.com/clojure-emacs/orchard/pull/123): Fix info lookups from namespaces that don't yet exist
+
 ## 0.7.1 (2021-04-18)
 
 ### Bugs Fixed

src/orchard/info.clj

@@ -63,30 +63,34 @@
 
 (defn clj-meta
   {:added "0.5"}
-  [{:keys [dialect ns sym computed-ns unqualified-sym]}]
+  [{:keys [dialect ns sym computed-ns unqualified-sym] :as opts}]
   {:pre [(= dialect :clj)]}
   (let [ns (or ns computed-ns)]
-    (or
-     ;; it's a special (special-symbol?)
-     (m/special-sym-meta sym)
-     ;; it's a var
-     (some-> ns (m/resolve-var sym) (m/var-meta))
-     ;; it's a Java constructor/static member symbol
-     (some-> ns (java/resolve-symbol sym))
-     ;; it's an unqualified sym maybe referred
-     (some-> ns (m/resolve-var unqualified-sym) (m/var-meta))
-     ;; it's a Java class/record type symbol
-     (some-> ns (java/resolve-type unqualified-sym))
-     ;; it's an alias for another ns
-     (some-> ns (m/resolve-aliases) (get sym) (m/ns-meta))
-     ;; We use :unqualified-sym *exclusively* here because because our :ns is
-     ;; too ambiguous.
-     ;;
-     ;; Observe the incorrect behavior (should return nil, there is a test):
-     ;;
-     ;;   (info '{:ns clojure.core :sym non-existing}) ;;=> {:author "Rich Hickey" :ns clojure.core ...}
-     ;;
-     (some-> (find-ns unqualified-sym) (m/ns-meta)))))
+    (if-not (and ns (find-ns ns))
+      ;; Lookups in files whose namespaces don't exist yet should still be able
+      ;; to resolve built-ins and fully-qualified syms
+      (recur (assoc opts :ns 'clojure.core))
+      (or
+       ;; it's a special (special-symbol?)
+       (m/special-sym-meta sym)
+       ;; it's a var
+       (some-> ns (m/resolve-var sym) (m/var-meta))
+       ;; it's a Java constructor/static member symbol
+       (some-> ns (java/resolve-symbol sym))
+       ;; it's an unqualified sym maybe referred
+       (some-> ns (m/resolve-var unqualified-sym) (m/var-meta))
+       ;; it's a Java class/record type symbol
+       (some-> ns (java/resolve-type unqualified-sym))
+       ;; it's an alias for another ns
+       (some-> ns (m/resolve-aliases) (get sym) (m/ns-meta))
+       ;; We use :unqualified-sym *exclusively* here because because our :ns is
+       ;; too ambiguous.
+       ;;
+       ;; Observe the incorrect behavior (should return nil, there is a test):
+       ;;
+       ;;   (info '{:ns clojure.core :sym non-existing}) ;;=> {:author "Rich Hickey" :ns clojure.core ...}
+       ;;
+       (some-> (find-ns unqualified-sym) (m/ns-meta))))))
 
 (defn cljs-meta
   {:added "0.5"}

test/orchard/info_test.clj

@@ -467,6 +467,22 @@
                :returns int}))
       (is (re-find #"Returns the greater of two" (:doc i))))))
 
+(deftest info-undefined-namespace-test
+  (testing "Fully qualified sym can still be resolved"
+    (is (= '{:added "1.2"
+             :ns clojure.string
+             :name upper-case
+             :file "clojure/string.clj"}
+           (select-keys (info/info* {:ns 'gibberish :sym 'clojure.string/upper-case})
+                        [:added :ns :name :file]))))
+  (testing "clojure.core syms can still be resolved"
+    (is (= '{:added "1.0"
+             :ns clojure.core
+             :name merge
+             :file "clojure/core.clj"}
+           (select-keys (info/info* {:ns 'gibberish :sym 'merge})
+                        [:added :ns :name :file])))))
+
 (deftest javadoc-info-unit-test
   (testing "Get an HTTP URL for a Sun/Oracle Javadoc"
     (testing "Javadoc 1.7 format"