lix/src/nix/upgrade-nix.cc
Eelco Dolstra 8d4268d190 Improve error formatting
Changes:

* The divider lines are gone. These were in practice a bit confusing,
  in particular with --show-trace or --keep-going, since then there
  were multiple lines, suggesting a start/end which wasn't the case.

* Instead, multi-line error messages are now indented to align with
  the prefix (e.g. "error: ").

* The 'description' field is gone since we weren't really using it.

* 'hint' is renamed to 'msg' since it really wasn't a hint.

* The error is now printed *before* the location info.

* The 'name' field is no longer printed since most of the time it
  wasn't very useful since it was just the name of the exception (like
  EvalError). Ideally in the future this would be a unique, easily
  googleable error ID (like rustc).

* "trace:" is now just "…". This assumes error contexts start with
  something like "while doing X".

Example before:

  error: --- AssertionError ---------------------------------------------------------------------------------------- nix
  at: (7:7) in file: /home/eelco/Dev/nixpkgs/pkgs/applications/misc/hello/default.nix

       6|
       7|   x = assert false; 1;
        |       ^
       8|

  assertion 'false' failed
  ----------------------------------------------------- show-trace -----------------------------------------------------
  trace: while evaluating the attribute 'x' of the derivation 'hello-2.10'
  at: (192:11) in file: /home/eelco/Dev/nixpkgs/pkgs/stdenv/generic/make-derivation.nix

     191|         // (lib.optionalAttrs (!(attrs ? name) && attrs ? pname && attrs ? version)) {
     192|           name = "${attrs.pname}-${attrs.version}";
        |           ^
     193|         } // (lib.optionalAttrs (stdenv.hostPlatform != stdenv.buildPlatform && !dontAddHostSuffix && (attrs ? name || (attrs ? pname && attrs ? version)))) {

Example after:

  error: assertion 'false' failed

         at: (7:7) in file: /home/eelco/Dev/nixpkgs/pkgs/applications/misc/hello/default.nix

              6|
              7|   x = assert false; 1;
               |       ^
              8|

         … while evaluating the attribute 'x' of the derivation 'hello-2.10'

         at: (192:11) in file: /home/eelco/Dev/nixpkgs/pkgs/stdenv/generic/make-derivation.nix

            191|         // (lib.optionalAttrs (!(attrs ? name) && attrs ? pname && attrs ? version)) {
            192|           name = "${attrs.pname}-${attrs.version}";
               |           ^
            193|         } // (lib.optionalAttrs (stdenv.hostPlatform != stdenv.buildPlatform && !dontAddHostSuffix && (attrs ? name || (attrs ? pname && attrs ? version)))) {
2021-01-21 11:02:09 +01:00

152 lines
4.8 KiB
C++

#include "command.hh"
#include "common-args.hh"
#include "store-api.hh"
#include "filetransfer.hh"
#include "eval.hh"
#include "attr-path.hh"
#include "names.hh"
#include "progress-bar.hh"
using namespace nix;
struct CmdUpgradeNix : MixDryRun, StoreCommand
{
Path profileDir;
std::string storePathsUrl = "https://github.com/NixOS/nixpkgs/raw/master/nixos/modules/installer/tools/nix-fallback-paths.nix";
CmdUpgradeNix()
{
addFlag({
.longName = "profile",
.shortName = 'p',
.description = "The path to the Nix profile to upgrade.",
.labels = {"profile-dir"},
.handler = {&profileDir}
});
addFlag({
.longName = "nix-store-paths-url",
.description = "The URL of the file that contains the store paths of the latest Nix release.",
.labels = {"url"},
.handler = {&storePathsUrl}
});
}
std::string description() override
{
return "upgrade Nix to the latest stable version";
}
std::string doc() override
{
return
#include "upgrade-nix.md"
;
}
Category category() override { return catNixInstallation; }
void run(ref<Store> store) override
{
evalSettings.pureEval = true;
if (profileDir == "")
profileDir = getProfileDir(store);
printInfo("upgrading Nix in profile '%s'", profileDir);
auto storePath = getLatestNix(store);
auto version = DrvName(storePath.name()).version;
if (dryRun) {
stopProgressBar();
warn("would upgrade to version %s", version);
return;
}
{
Activity act(*logger, lvlInfo, actUnknown, fmt("downloading '%s'...", store->printStorePath(storePath)));
store->ensurePath(storePath);
}
{
Activity act(*logger, lvlInfo, actUnknown, fmt("verifying that '%s' works...", store->printStorePath(storePath)));
auto program = store->printStorePath(storePath) + "/bin/nix-env";
auto s = runProgram(program, false, {"--version"});
if (s.find("Nix") == std::string::npos)
throw Error("could not verify that '%s' works", program);
}
stopProgressBar();
{
Activity act(*logger, lvlInfo, actUnknown,
fmt("installing '%s' into profile '%s'...", store->printStorePath(storePath), profileDir));
runProgram(settings.nixBinDir + "/nix-env", false,
{"--profile", profileDir, "-i", store->printStorePath(storePath), "--no-sandbox"});
}
printInfo(ANSI_GREEN "upgrade to version %s done" ANSI_NORMAL, version);
}
/* Return the profile in which Nix is installed. */
Path getProfileDir(ref<Store> store)
{
Path where;
for (auto & dir : tokenizeString<Strings>(getEnv("PATH").value_or(""), ":"))
if (pathExists(dir + "/nix-env")) {
where = dir;
break;
}
if (where == "")
throw Error("couldn't figure out how Nix is installed, so I can't upgrade it");
printInfo("found Nix in '%s'", where);
if (hasPrefix(where, "/run/current-system"))
throw Error("Nix on NixOS must be upgraded via 'nixos-rebuild'");
Path profileDir = dirOf(where);
// Resolve profile to /nix/var/nix/profiles/<name> link.
while (canonPath(profileDir).find("/profiles/") == std::string::npos && isLink(profileDir))
profileDir = readLink(profileDir);
printInfo("found profile '%s'", profileDir);
Path userEnv = canonPath(profileDir, true);
if (baseNameOf(where) != "bin" ||
!hasSuffix(userEnv, "user-environment"))
throw Error("directory '%s' does not appear to be part of a Nix profile", where);
if (!store->isValidPath(store->parseStorePath(userEnv)))
throw Error("directory '%s' is not in the Nix store", userEnv);
return profileDir;
}
/* Return the store path of the latest stable Nix. */
StorePath getLatestNix(ref<Store> store)
{
Activity act(*logger, lvlInfo, actUnknown, "querying latest Nix version");
// FIXME: use nixos.org?
auto req = FileTransferRequest(storePathsUrl);
auto res = getFileTransfer()->download(req);
auto state = std::make_unique<EvalState>(Strings(), store);
auto v = state->allocValue();
state->eval(state->parseExprFromString(*res.data, "/no-such-path"), *v);
Bindings & bindings(*state->allocBindings(0));
auto v2 = findAlongAttrPath(*state, settings.thisSystem, bindings, *v).first;
return store->parseStorePath(state->forceString(*v2));
}
};
static auto rCmdUpgradeNix = registerCommand<CmdUpgradeNix>("upgrade-nix");