* Get rid of the substitutes database table (NIX-47). Instead, if we

  need any info on substitutable paths, we just call the substituters
  (such as download-using-manifests.pl) directly.  This means that
  it's no longer necessary for nix-pull to register substitutes or for
  nix-channel to clear them, which makes those operations much faster
  (NIX-95).  Also, we don't have to worry about keeping nix-pull
  manifests (in /nix/var/nix/manifests) and the database in sync with
  each other.

  The downside is that there is some overhead in calling an external
  program to get the substitutes info.  For instance, "nix-env -qas"
  takes a bit longer.

  Abolishing the substitutes table also makes the logic in
  local-store.cc simpler, as we don't need to store info for invalid
  paths.  On the downside, you cannot do things like "nix-store -qR"
  on a substitutable but invalid path (but nobody did that anyway).

* Never catch interrupts (the Interrupted exception).

1 files changed, 7 insertions, 1 deletions

diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc
index ebdbeb11e1..a606f0dae3 100644
--- a/src/libmain/shared.cc
+++ b/src/libmain/shared.cc
@@ -113,6 +113,12 @@ static void initAndRun(int argc, char * * argv)
     nixLibexecDir = canonPath(getEnv("NIX_LIBEXEC_DIR", NIX_LIBEXEC_DIR));
     nixBinDir = canonPath(getEnv("NIX_BIN_DIR", NIX_BIN_DIR));
 
+    string subs = getEnv("NIX_SUBSTITUTERS", "default");
+    if (subs == "default")
+        substituters.push_back(nixLibexecDir + "/nix/download-using-manifests.pl");
+    else
+        substituters = tokenizeString(subs, ":");
+
     /* Get some settings from the configuration file. */
     thisSystem = querySetting("system", SYSTEM);
     maxBuildJobs = queryIntSetting("build-max-jobs", 1);
@@ -320,7 +326,7 @@ int main(int argc, char * * argv)
                 "Try `%2% --help' for more information.")
             % e.what() % programId);
         return 1;
-    } catch (Error & e) {
+    } catch (BaseError & e) {
         printMsg(lvlError, format("error: %1%") % e.msg());
         return 1;
     } catch (std::exception & e) {