forked from lix-project/lix
350 lines
10 KiB
C++
350 lines
10 KiB
C++
#include "eval.hh"
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#include "command.hh"
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#include "common-args.hh"
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#include "shared.hh"
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#include "store-api.hh"
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#include "derivations.hh"
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#include "affinity.hh"
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#include "progress-bar.hh"
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#include <regex>
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using namespace nix;
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struct Var
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{
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bool exported = true;
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bool associative = false;
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std::string value; // quoted string or array
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};
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struct BuildEnvironment
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{
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std::map<std::string, Var> env;
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std::string bashFunctions;
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};
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BuildEnvironment readEnvironment(const Path & path)
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{
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BuildEnvironment res;
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std::set<std::string> exported;
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debug("reading environment file '%s'", path);
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auto file = readFile(path);
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auto pos = file.cbegin();
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static std::string varNameRegex =
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R"re((?:[a-zA-Z_][a-zA-Z0-9_]*))re";
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static std::regex declareRegex(
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"^declare -x (" + varNameRegex + ")" +
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R"re((?:="((?:[^"\\]|\\.)*)")?\n)re");
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static std::string simpleStringRegex =
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R"re((?:[a-zA-Z0-9_/:\.\-\+=]*))re";
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static std::string quotedStringRegex =
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R"re((?:\$?'(?:[^'\\]|\\[abeEfnrtv\\'"?])*'))re";
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static std::string indexedArrayRegex =
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R"re((?:\(( *\[[0-9]+]="(?:[^"\\]|\\.)*")**\)))re";
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static std::regex varRegex(
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"^(" + varNameRegex + ")=(" + simpleStringRegex + "|" + quotedStringRegex + "|" + indexedArrayRegex + ")\n");
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/* Note: we distinguish between an indexed and associative array
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using the space before the closing parenthesis. Will
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undoubtedly regret this some day. */
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static std::regex assocArrayRegex(
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"^(" + varNameRegex + ")=" + R"re((?:\(( *\[[^\]]+\]="(?:[^"\\]|\\.)*")* *\)))re" + "\n");
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static std::regex functionRegex(
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"^" + varNameRegex + " \\(\\) *\n");
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while (pos != file.end()) {
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std::smatch match;
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if (std::regex_search(pos, file.cend(), match, declareRegex)) {
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pos = match[0].second;
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exported.insert(match[1]);
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}
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else if (std::regex_search(pos, file.cend(), match, varRegex)) {
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pos = match[0].second;
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res.env.insert({match[1], Var { .exported = exported.count(match[1]) > 0, .value = match[2] }});
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}
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else if (std::regex_search(pos, file.cend(), match, assocArrayRegex)) {
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pos = match[0].second;
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res.env.insert({match[1], Var { .associative = true, .value = match[2] }});
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}
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else if (std::regex_search(pos, file.cend(), match, functionRegex)) {
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res.bashFunctions = std::string(pos, file.cend());
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break;
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}
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else throw Error("shell environment '%s' has unexpected line '%s'",
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path, file.substr(pos - file.cbegin(), 60));
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}
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return res;
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}
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const static std::string getEnvSh =
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#include "get-env.sh.gen.hh"
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;
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/* Given an existing derivation, return the shell environment as
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initialised by stdenv's setup script. We do this by building a
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modified derivation with the same dependencies and nearly the same
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initial environment variables, that just writes the resulting
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environment to a file and exits. */
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StorePath getDerivationEnvironment(ref<Store> store, const StorePath & drvPath)
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{
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auto drv = store->derivationFromPath(drvPath);
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auto builder = baseNameOf(drv.builder);
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if (builder != "bash")
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throw Error("'nix develop' only works on derivations that use 'bash' as their builder");
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auto getEnvShPath = store->addTextToStore("get-env.sh", getEnvSh, {});
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drv.args = {store->printStorePath(getEnvShPath)};
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/* Remove derivation checks. */
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drv.env.erase("allowedReferences");
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drv.env.erase("allowedRequisites");
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drv.env.erase("disallowedReferences");
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drv.env.erase("disallowedRequisites");
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/* Rehash and write the derivation. FIXME: would be nice to use
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'buildDerivation', but that's privileged. */
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auto drvName = std::string(drvPath.name());
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assert(hasSuffix(drvName, ".drv"));
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drvName.resize(drvName.size() - 4);
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drvName += "-env";
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for (auto & output : drv.outputs)
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drv.env.erase(output.first);
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drv.env["out"] = "";
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drv.env["outputs"] = "out";
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drv.inputSrcs.insert(std::move(getEnvShPath));
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Hash h = hashDerivationModulo(*store, drv, true);
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auto shellOutPath = store->makeOutputPath("out", h, drvName);
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drv.outputs.insert_or_assign("out", DerivationOutput {
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.path = shellOutPath,
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.hash = FileSystemHash {
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FileIngestionMethod::Flat, Hash { }
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},
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});
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drv.env["out"] = store->printStorePath(shellOutPath);
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auto shellDrvPath2 = writeDerivation(store, drv, drvName);
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/* Build the derivation. */
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store->buildPaths({{shellDrvPath2}});
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assert(store->isValidPath(shellOutPath));
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return shellOutPath;
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}
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struct Common : InstallableCommand, MixProfile
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{
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std::set<string> ignoreVars{
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"BASHOPTS",
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"EUID",
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"HOME", // FIXME: don't ignore in pure mode?
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"NIX_BUILD_TOP",
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"NIX_ENFORCE_PURITY",
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"NIX_LOG_FD",
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"PPID",
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"PWD",
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"SHELLOPTS",
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"SHLVL",
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"SSL_CERT_FILE", // FIXME: only want to ignore /no-cert-file.crt
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"TEMP",
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"TEMPDIR",
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"TERM",
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"TMP",
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"TMPDIR",
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"TZ",
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"UID",
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};
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void makeRcScript(const BuildEnvironment & buildEnvironment, std::ostream & out)
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{
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out << "unset shellHook\n";
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out << "nix_saved_PATH=\"$PATH\"\n";
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for (auto & i : buildEnvironment.env) {
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if (!ignoreVars.count(i.first) && !hasPrefix(i.first, "BASH_")) {
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if (i.second.associative)
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out << fmt("declare -A %s=(%s)\n", i.first, i.second.value);
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else {
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out << fmt("%s=%s\n", i.first, i.second.value);
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if (i.second.exported)
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out << fmt("export %s\n", i.first);
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}
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}
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}
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out << "PATH=\"$PATH:$nix_saved_PATH\"\n";
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out << buildEnvironment.bashFunctions << "\n";
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// FIXME: set outputs
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out << "export NIX_BUILD_TOP=\"$(mktemp -d --tmpdir nix-shell.XXXXXX)\"\n";
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for (auto & i : {"TMP", "TMPDIR", "TEMP", "TEMPDIR"})
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out << fmt("export %s=\"$NIX_BUILD_TOP\"\n", i);
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out << "eval \"$shellHook\"\n";
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}
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StorePath getShellOutPath(ref<Store> store)
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{
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auto path = installable->getStorePath();
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if (path && hasSuffix(path->to_string(), "-env"))
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return *path;
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else {
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auto drvs = toDerivations(store, {installable});
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if (drvs.size() != 1)
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throw Error("'%s' needs to evaluate to a single derivation, but it evaluated to %d derivations",
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installable->what(), drvs.size());
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auto & drvPath = *drvs.begin();
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return getDerivationEnvironment(store, drvPath);
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}
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}
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std::pair<BuildEnvironment, std::string> getBuildEnvironment(ref<Store> store)
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{
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auto shellOutPath = getShellOutPath(store);
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auto strPath = store->printStorePath(shellOutPath);
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updateProfile(shellOutPath);
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return {readEnvironment(strPath), strPath};
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}
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};
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struct CmdDevelop : Common, MixEnvironment
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{
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std::vector<std::string> command;
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CmdDevelop()
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{
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addFlag({
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.longName = "command",
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.shortName = 'c',
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.description = "command and arguments to be executed insted of an interactive shell",
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.labels = {"command", "args"},
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.handler = {[&](std::vector<std::string> ss) {
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if (ss.empty()) throw UsageError("--command requires at least one argument");
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command = ss;
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}}
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});
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}
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std::string description() override
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{
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return "run a bash shell that provides the build environment of a derivation";
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}
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Examples examples() override
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{
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return {
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Example{
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"To get the build environment of GNU hello:",
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"nix develop nixpkgs.hello"
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},
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Example{
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"To store the build environment in a profile:",
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"nix develop --profile /tmp/my-shell nixpkgs.hello"
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},
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Example{
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"To use a build environment previously recorded in a profile:",
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"nix develop /tmp/my-shell"
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},
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};
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}
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void run(ref<Store> store) override
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{
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auto [buildEnvironment, gcroot] = getBuildEnvironment(store);
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auto [rcFileFd, rcFilePath] = createTempFile("nix-shell");
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std::ostringstream ss;
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makeRcScript(buildEnvironment, ss);
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ss << fmt("rm -f '%s'\n", rcFilePath);
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if (!command.empty()) {
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std::vector<std::string> args;
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for (auto s : command)
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args.push_back(shellEscape(s));
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ss << fmt("exec %s\n", concatStringsSep(" ", args));
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}
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writeFull(rcFileFd.get(), ss.str());
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stopProgressBar();
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auto shell = getEnv("SHELL").value_or("bash");
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setEnviron();
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// prevent garbage collection until shell exits
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setenv("NIX_GCROOT", gcroot.data(), 1);
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auto args = Strings{std::string(baseNameOf(shell)), "--rcfile", rcFilePath};
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restoreAffinity();
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restoreSignals();
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execvp(shell.c_str(), stringsToCharPtrs(args).data());
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throw SysError("executing shell '%s'", shell);
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}
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};
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struct CmdPrintDevEnv : Common
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{
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std::string description() override
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{
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return "print shell code that can be sourced by bash to reproduce the build environment of a derivation";
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}
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Examples examples() override
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{
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return {
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Example{
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"To apply the build environment of GNU hello to the current shell:",
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". <(nix print-dev-env nixpkgs.hello)"
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},
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};
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}
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Category category() override { return catUtility; }
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void run(ref<Store> store) override
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{
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auto buildEnvironment = getBuildEnvironment(store).first;
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stopProgressBar();
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makeRcScript(buildEnvironment, std::cout);
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}
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};
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static auto r1 = registerCommand<CmdPrintDevEnv>("print-dev-env");
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static auto r2 = registerCommand<CmdDevelop>("develop");
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