* Strip off the `.nix' suffix from the attribute name for files in

~/.nix-defexpr,  otherwise the attribute cannot be selected with the
  `-A' option.  Useful if you want to stick a Nix expression directly
  in ~/.nix-defexpr.

src/libstore/derivations.cc

@@ -2,6 +2,7 @@
 #include "store-api.hh"
 #include "aterm.hh"
 #include "globals.hh"
+#include "util.hh"
 
 #include "derivations-ast.hh"
 #include "derivations-ast.cc"
@@ -163,9 +164,7 @@ ATerm unparseDerivation(const Derivation & drv)
 
 bool isDerivation(const string & fileName)
 {
-    return
+    return hasSuffix(fileName, drvExtension);
-        fileName.size() >= drvExtension.size() &&
-        string(fileName, fileName.size() - drvExtension.size()) == drvExtension;
 }
 
  

src/libutil/hash.cc

@@ -257,6 +257,7 @@ Hash hashString(HashType ht, const string & s)
     start(ht, ctx);
     update(ht, ctx, (const unsigned char *) s.c_str(), s.length());
     finish(ht, ctx, hash.hash);
+    //printMsg(lvlError, format("hashString %1% --> %2%:\n%3%\n===========END======") % s.size() % printHash(hash) % s);
     return hash;
 }
 

src/libutil/util.cc

@@ -1046,6 +1046,12 @@ bool string2Int(const string & s, long long & n)
 }
 
 
+bool hasSuffix(const string & s, const string & suffix)
+{
+    return s.size() >= suffix.size() && string(s, s.size() - suffix.size()) == suffix;
+}
+
+
 void ignoreException()
 {
     try {

src/libutil/util.hh

@@ -294,6 +294,10 @@ bool string2Int(const string & s, int & n);
 bool string2Int(const string & s, long long & n);
 
 
+/* Return true iff `s' ends in `suffix'. */
+bool hasSuffix(const string & s, const string & suffix);
+
+
 /* Exception handling in destructors: print an error message, then
    ignore the exception. */
 void ignoreException();

src/nix-env/nix-env.cc

@@ -115,18 +115,29 @@ static void getAllExprs(EvalState & state,
     const Path & path, ATermMap & attrs)
 {
     Strings names = readDirectory(path);
+    StringSet namesSorted(names.begin(), names.end());
 
-    for (Strings::iterator i = names.begin(); i != names.end(); ++i) {
+    foreach (StringSet::iterator, i, namesSorted) {
         Path path2 = path + "/" + *i;
         
         struct stat st;
         if (stat(path2.c_str(), &st) == -1)
             continue; // ignore dangling symlinks in ~/.nix-defexpr
         
-        if (isNixExpr(path2))
+        if (isNixExpr(path2)) {
-            attrs.set(toATerm(*i), makeAttrRHS(
+            /* Strip off the `.nix' filename suffix (if applicable),
+               otherwise the attribute cannot be selected with the
+               `-A' option.  Useful if you want to stick a Nix
+               expression directly in ~/.nix-defexpr. */
+            string attrName = *i;
+            if (hasSuffix(attrName, ".nix"))
+                attrName = string(attrName, 0, attrName.size() - 4);
+            attrs.set(toATerm(attrName), makeAttrRHS(
                     parseExprFromFile(state, absPath(path2)), makeNoPos()));
+        }
         else
+            /* `path2' is a directory (with no default.nix in it);
+               recurse into it. */
             getAllExprs(state, path2, attrs);
     }
 }