lix/src/nix/develop.cc
regnat af99941279 Make experimental-features a proper type
Rather than having them plain strings scattered through the whole
codebase, create an enum containing all the known experimental features.

This means that
- Nix can now `warn` when an unkwown experimental feature is passed
  (making it much nicer to spot typos and spot deprecated features)
- It’s now easy to remove a feature altogether (once the feature isn’t
  experimental anymore or is dropped) by just removing the field for the
  enum and letting the compiler point us to all the now invalid usages
  of it.
2021-10-26 07:02:31 +02:00

564 lines
18 KiB
C++

#include "eval.hh"
#include "command.hh"
#include "common-args.hh"
#include "shared.hh"
#include "store-api.hh"
#include "path-with-outputs.hh"
#include "derivations.hh"
#include "affinity.hh"
#include "progress-bar.hh"
#include "run.hh"
#include <memory>
#include <nlohmann/json.hpp>
using namespace nix;
struct DevelopSettings : Config
{
Setting<std::string> bashPrompt{this, "", "bash-prompt",
"The bash prompt (`PS1`) in `nix develop` shells."};
Setting<std::string> bashPromptSuffix{this, "", "bash-prompt-suffix",
"Suffix appended to the `PS1` environment variable in `nix develop` shells."};
};
static DevelopSettings developSettings;
static GlobalConfig::Register rDevelopSettings(&developSettings);
struct BuildEnvironment
{
struct String
{
bool exported;
std::string value;
bool operator == (const String & other) const
{
return exported == other.exported && value == other.value;
}
};
using Array = std::vector<std::string>;
using Associative = std::map<std::string, std::string>;
using Value = std::variant<String, Array, Associative>;
std::map<std::string, Value> vars;
std::map<std::string, std::string> bashFunctions;
static BuildEnvironment fromJSON(std::string_view in)
{
BuildEnvironment res;
std::set<std::string> exported;
auto json = nlohmann::json::parse(in);
for (auto & [name, info] : json["variables"].items()) {
std::string type = info["type"];
if (type == "var" || type == "exported")
res.vars.insert({name, BuildEnvironment::String { .exported = type == "exported", .value = info["value"] }});
else if (type == "array")
res.vars.insert({name, (Array) info["value"]});
else if (type == "associative")
res.vars.insert({name, (Associative) info["value"]});
}
for (auto & [name, def] : json["bashFunctions"].items()) {
res.bashFunctions.insert({name, def});
}
return res;
}
std::string toJSON() const
{
auto res = nlohmann::json::object();
auto vars2 = nlohmann::json::object();
for (auto & [name, value] : vars) {
auto info = nlohmann::json::object();
if (auto str = std::get_if<String>(&value)) {
info["type"] = str->exported ? "exported" : "var";
info["value"] = str->value;
}
else if (auto arr = std::get_if<Array>(&value)) {
info["type"] = "array";
info["value"] = *arr;
}
else if (auto arr = std::get_if<Associative>(&value)) {
info["type"] = "associative";
info["value"] = *arr;
}
vars2[name] = std::move(info);
}
res["variables"] = std::move(vars2);
res["bashFunctions"] = bashFunctions;
auto json = res.dump();
assert(BuildEnvironment::fromJSON(json) == *this);
return json;
}
void toBash(std::ostream & out, const std::set<std::string> & ignoreVars) const
{
for (auto & [name, value] : vars) {
if (!ignoreVars.count(name)) {
if (auto str = std::get_if<String>(&value)) {
out << fmt("%s=%s\n", name, shellEscape(str->value));
if (str->exported)
out << fmt("export %s\n", name);
}
else if (auto arr = std::get_if<Array>(&value)) {
out << "declare -a " << name << "=(";
for (auto & s : *arr)
out << shellEscape(s) << " ";
out << ")\n";
}
else if (auto arr = std::get_if<Associative>(&value)) {
out << "declare -A " << name << "=(";
for (auto & [n, v] : *arr)
out << "[" << shellEscape(n) << "]=" << shellEscape(v) << " ";
out << ")\n";
}
}
}
for (auto & [name, def] : bashFunctions) {
out << name << " ()\n{\n" << def << "}\n";
}
}
static std::string getString(const Value & value)
{
if (auto str = std::get_if<String>(&value))
return str->value;
else
throw Error("bash variable is not a string");
}
static Array getStrings(const Value & value)
{
if (auto str = std::get_if<String>(&value))
return tokenizeString<Array>(str->value);
else if (auto arr = std::get_if<Array>(&value)) {
return *arr;
} else if (auto assoc = std::get_if<Associative>(&value)) {
Array assocKeys;
std::for_each(assoc->begin(), assoc->end(), [&](auto & n) { assocKeys.push_back(n.first); });
return assocKeys;
}
else
throw Error("bash variable is not a string or array");
}
bool operator == (const BuildEnvironment & other) const
{
return vars == other.vars && bashFunctions == other.bashFunctions;
}
};
const static std::string getEnvSh =
#include "get-env.sh.gen.hh"
;
/* Given an existing derivation, return the shell environment as
initialised by stdenv's setup script. We do this by building a
modified derivation with the same dependencies and nearly the same
initial environment variables, that just writes the resulting
environment to a file and exits. */
static StorePath getDerivationEnvironment(ref<Store> store, ref<Store> evalStore, const StorePath & drvPath)
{
auto drv = evalStore->derivationFromPath(drvPath);
auto builder = baseNameOf(drv.builder);
if (builder != "bash")
throw Error("'nix develop' only works on derivations that use 'bash' as their builder");
auto getEnvShPath = evalStore->addTextToStore("get-env.sh", getEnvSh, {});
drv.args = {store->printStorePath(getEnvShPath)};
/* Remove derivation checks. */
drv.env.erase("allowedReferences");
drv.env.erase("allowedRequisites");
drv.env.erase("disallowedReferences");
drv.env.erase("disallowedRequisites");
/* Rehash and write the derivation. FIXME: would be nice to use
'buildDerivation', but that's privileged. */
drv.name += "-env";
drv.inputSrcs.insert(std::move(getEnvShPath));
if (settings.isExperimentalFeatureEnabled(Xp::CaDerivations)) {
for (auto & output : drv.outputs) {
output.second = {
.output = DerivationOutputDeferred{},
};
drv.env[output.first] = hashPlaceholder(output.first);
}
} else {
for (auto & output : drv.outputs) {
output.second = { .output = DerivationOutputInputAddressed { .path = StorePath::dummy } };
drv.env[output.first] = "";
}
Hash h = std::get<0>(hashDerivationModulo(*evalStore, drv, true));
for (auto & output : drv.outputs) {
auto outPath = store->makeOutputPath(output.first, h, drv.name);
output.second = { .output = DerivationOutputInputAddressed { .path = outPath } };
drv.env[output.first] = store->printStorePath(outPath);
}
}
auto shellDrvPath = writeDerivation(*evalStore, drv);
/* Build the derivation. */
store->buildPaths({DerivedPath::Built{shellDrvPath}}, bmNormal, evalStore);
for (auto & [_0, optPath] : evalStore->queryPartialDerivationOutputMap(shellDrvPath)) {
assert(optPath);
auto & outPath = *optPath;
assert(store->isValidPath(outPath));
auto outPathS = store->toRealPath(outPath);
if (lstat(outPathS).st_size)
return outPath;
}
throw Error("get-env.sh failed to produce an environment");
}
struct Common : InstallableCommand, MixProfile
{
std::set<std::string> ignoreVars{
"BASHOPTS",
"HOME", // FIXME: don't ignore in pure mode?
"NIX_BUILD_TOP",
"NIX_ENFORCE_PURITY",
"NIX_LOG_FD",
"NIX_REMOTE",
"PPID",
"SHELLOPTS",
"SSL_CERT_FILE", // FIXME: only want to ignore /no-cert-file.crt
"TEMP",
"TEMPDIR",
"TERM",
"TMP",
"TMPDIR",
"TZ",
"UID",
};
std::vector<std::pair<std::string, std::string>> redirects;
Common()
{
addFlag({
.longName = "redirect",
.description = "Redirect a store path to a mutable location.",
.labels = {"installable", "outputs-dir"},
.handler = {[&](std::string installable, std::string outputsDir) {
redirects.push_back({installable, outputsDir});
}}
});
}
std::string makeRcScript(
ref<Store> store,
const BuildEnvironment & buildEnvironment,
const Path & outputsDir = absPath(".") + "/outputs")
{
std::ostringstream out;
out << "unset shellHook\n";
out << "nix_saved_PATH=\"$PATH\"\n";
buildEnvironment.toBash(out, ignoreVars);
out << "PATH=\"$PATH:$nix_saved_PATH\"\n";
out << "export NIX_BUILD_TOP=\"$(mktemp -d -t nix-shell.XXXXXX)\"\n";
for (auto & i : {"TMP", "TMPDIR", "TEMP", "TEMPDIR"})
out << fmt("export %s=\"$NIX_BUILD_TOP\"\n", i);
out << "eval \"$shellHook\"\n";
auto script = out.str();
/* Substitute occurrences of output paths. */
auto outputs = buildEnvironment.vars.find("outputs");
assert(outputs != buildEnvironment.vars.end());
// FIXME: properly unquote 'outputs'.
StringMap rewrites;
for (auto & outputName : BuildEnvironment::getStrings(outputs->second)) {
auto from = buildEnvironment.vars.find(outputName);
assert(from != buildEnvironment.vars.end());
// FIXME: unquote
rewrites.insert({BuildEnvironment::getString(from->second), outputsDir + "/" + outputName});
}
/* Substitute redirects. */
for (auto & [installable_, dir_] : redirects) {
auto dir = absPath(dir_);
auto installable = parseInstallable(store, installable_);
auto builtPaths = toStorePaths(
getEvalStore(), store, Realise::Nothing, OperateOn::Output, {installable});
for (auto & path: builtPaths) {
auto from = store->printStorePath(path);
if (script.find(from) == std::string::npos)
warn("'%s' (path '%s') is not used by this build environment", installable->what(), from);
else {
printInfo("redirecting '%s' to '%s'", from, dir);
rewrites.insert({from, dir});
}
}
}
return rewriteStrings(script, rewrites);
}
Strings getDefaultFlakeAttrPaths() override
{
return {"devShell." + settings.thisSystem.get(), "defaultPackage." + settings.thisSystem.get()};
}
Strings getDefaultFlakeAttrPathPrefixes() override
{
auto res = SourceExprCommand::getDefaultFlakeAttrPathPrefixes();
res.emplace_front("devShells." + settings.thisSystem.get() + ".");
return res;
}
StorePath getShellOutPath(ref<Store> store)
{
auto path = installable->getStorePath();
if (path && hasSuffix(path->to_string(), "-env"))
return *path;
else {
auto drvs = toDerivations(store, {installable});
if (drvs.size() != 1)
throw Error("'%s' needs to evaluate to a single derivation, but it evaluated to %d derivations",
installable->what(), drvs.size());
auto & drvPath = *drvs.begin();
return getDerivationEnvironment(store, getEvalStore(), drvPath);
}
}
std::pair<BuildEnvironment, std::string> getBuildEnvironment(ref<Store> store)
{
auto shellOutPath = getShellOutPath(store);
auto strPath = store->printStorePath(shellOutPath);
updateProfile(shellOutPath);
debug("reading environment file '%s'", strPath);
return {BuildEnvironment::fromJSON(readFile(store->toRealPath(shellOutPath))), strPath};
}
};
struct CmdDevelop : Common, MixEnvironment
{
std::vector<std::string> command;
std::optional<std::string> phase;
CmdDevelop()
{
addFlag({
.longName = "command",
.shortName = 'c',
.description = "Instead of starting an interactive shell, start the specified command and arguments.",
.labels = {"command", "args"},
.handler = {[&](std::vector<std::string> ss) {
if (ss.empty()) throw UsageError("--command requires at least one argument");
command = ss;
}}
});
addFlag({
.longName = "phase",
.description = "The stdenv phase to run (e.g. `build` or `configure`).",
.labels = {"phase-name"},
.handler = {&phase},
});
addFlag({
.longName = "unpack",
.description = "Run the `unpack` phase.",
.handler = {&phase, {"unpack"}},
});
addFlag({
.longName = "configure",
.description = "Run the `configure` phase.",
.handler = {&phase, {"configure"}},
});
addFlag({
.longName = "build",
.description = "Run the `build` phase.",
.handler = {&phase, {"build"}},
});
addFlag({
.longName = "check",
.description = "Run the `check` phase.",
.handler = {&phase, {"check"}},
});
addFlag({
.longName = "install",
.description = "Run the `install` phase.",
.handler = {&phase, {"install"}},
});
addFlag({
.longName = "installcheck",
.description = "Run the `installcheck` phase.",
.handler = {&phase, {"installCheck"}},
});
}
std::string description() override
{
return "run a bash shell that provides the build environment of a derivation";
}
std::string doc() override
{
return
#include "develop.md"
;
}
void run(ref<Store> store) override
{
auto [buildEnvironment, gcroot] = getBuildEnvironment(store);
auto [rcFileFd, rcFilePath] = createTempFile("nix-shell");
auto script = makeRcScript(store, buildEnvironment);
if (verbosity >= lvlDebug)
script += "set -x\n";
script += fmt("command rm -f '%s'\n", rcFilePath);
if (phase) {
if (!command.empty())
throw UsageError("you cannot use both '--command' and '--phase'");
// FIXME: foundMakefile is set by buildPhase, need to get
// rid of that.
script += fmt("foundMakefile=1\n");
script += fmt("runHook %1%Phase\n", *phase);
}
else if (!command.empty()) {
std::vector<std::string> args;
for (auto s : command)
args.push_back(shellEscape(s));
script += fmt("exec %s\n", concatStringsSep(" ", args));
}
else {
script = "[ -n \"$PS1\" ] && [ -e ~/.bashrc ] && source ~/.bashrc;\n" + script;
if (developSettings.bashPrompt != "")
script += fmt("[ -n \"$PS1\" ] && PS1=%s;\n", shellEscape(developSettings.bashPrompt));
if (developSettings.bashPromptSuffix != "")
script += fmt("[ -n \"$PS1\" ] && PS1+=%s;\n", shellEscape(developSettings.bashPromptSuffix));
}
writeFull(rcFileFd.get(), script);
setEnviron();
// prevent garbage collection until shell exits
setenv("NIX_GCROOT", gcroot.data(), 1);
Path shell = "bash";
try {
auto state = getEvalState();
auto nixpkgsLockFlags = lockFlags;
nixpkgsLockFlags.inputOverrides = {};
nixpkgsLockFlags.inputUpdates = {};
auto bashInstallable = std::make_shared<InstallableFlake>(
this,
state,
installable->nixpkgsFlakeRef(),
Strings{"bashInteractive"},
Strings{"legacyPackages." + settings.thisSystem.get() + "."},
nixpkgsLockFlags);
shell = store->printStorePath(
toStorePath(getEvalStore(), store, Realise::Outputs, OperateOn::Output, bashInstallable)) + "/bin/bash";
} catch (Error &) {
ignoreException();
}
// If running a phase or single command, don't want an interactive shell running after
// Ctrl-C, so don't pass --rcfile
auto args = phase || !command.empty() ? Strings{std::string(baseNameOf(shell)), rcFilePath}
: Strings{std::string(baseNameOf(shell)), "--rcfile", rcFilePath};
// Need to chdir since phases assume in flake directory
if (phase) {
// chdir if installable is a flake of type git+file or path
auto installableFlake = std::dynamic_pointer_cast<InstallableFlake>(installable);
if (installableFlake) {
auto sourcePath = installableFlake->getLockedFlake()->flake.resolvedRef.input.getSourcePath();
if (sourcePath) {
if (chdir(sourcePath->c_str()) == -1) {
throw SysError("chdir to '%s' failed", *sourcePath);
}
}
}
}
runProgramInStore(store, shell, args);
}
};
struct CmdPrintDevEnv : Common, MixJSON
{
std::string description() override
{
return "print shell code that can be sourced by bash to reproduce the build environment of a derivation";
}
std::string doc() override
{
return
#include "print-dev-env.md"
;
}
Category category() override { return catUtility; }
void run(ref<Store> store) override
{
auto buildEnvironment = getBuildEnvironment(store).first;
stopProgressBar();
logger->writeToStdout(
json
? buildEnvironment.toJSON()
: makeRcScript(store, buildEnvironment));
}
};
static auto rCmdPrintDevEnv = registerCommand<CmdPrintDevEnv>("print-dev-env");
static auto rCmdDevelop = registerCommand<CmdDevelop>("develop");