nix repl: make symlinks with the :bl command

Requested by ppepino on the Matrix:
https://matrix.to/#/!KqkRjyTEzAGRiZFBYT:nixos.org/$Tb32BS3rVE2BSULAX4sPm0h6CDewX2hClOTGzTC7gwM?via=nixos.org&via=matrix.org&via=nixos.dev

This adds a new command, :bl, which works like :b but also creates
a GC root symlink to the various derivation outputs.

ckie@cookiemonster ~/git/nix -> ./outputs/out/bin/nix repl
Welcome to Nix 2.6.0. Type :? for help.

nix-repl> :l <nixpkgs>
Added 16118 variables.

nix-repl> :b runCommand "hello" {} "echo hi > $out"

This derivation produced the following outputs:
  ./repl-result-out -> /nix/store/kidqq2acdpi05c4a9mlbg2baikmzik44-hello
[1 built, 0.0 MiB DL]
ckie@cookiemonster ~/git/nix -> cat ./repl-result-out
hi
This commit is contained in:
mei (ckie) 2022-04-18 20:21:47 +03:00
parent ee57f91413
commit 0e2b01b14e
Signed by untrusted user: ckie
GPG key ID: 13E79449C0525215
4 changed files with 31 additions and 9 deletions

1
.gitignore vendored
View file

@ -79,6 +79,7 @@ perl/Makefile.config
/tests/shell.drv
/tests/config.nix
/tests/ca/config.nix
/tests/repl-result-out
# /tests/lang/
/tests/lang/*.out

View file

@ -1 +1,4 @@
# Release X.Y (202?-??-??)
* `nix repl` has a new build-'n-link (`:bl`) command that builds a derivation
while creating GC root symlinks.

View file

@ -33,6 +33,7 @@ extern "C" {
#include "command.hh"
#include "finally.hh"
#include "markdown.hh"
#include "local-fs-store.hh"
#if HAVE_BOEHMGC
#define GC_INCLUDE_NEW
@ -419,7 +420,8 @@ bool NixRepl::processLine(std::string line)
<< " <expr> Evaluate and print expression\n"
<< " <x> = <expr> Bind expression to variable\n"
<< " :a <expr> Add attributes from resulting set to scope\n"
<< " :b <expr> Build derivation\n"
<< " :b <expr> Build a derivation\n"
<< " :bl <expr> Build a derivation, creating GC roots in the working directory\n"
<< " :e <expr> Open package or function in $EDITOR\n"
<< " :i <expr> Build derivation, then install result into current profile\n"
<< " :l <path> Load Nix expression and add it to scope\n"
@ -502,18 +504,26 @@ bool NixRepl::processLine(std::string line)
runNix("nix-shell", {state->store->printStorePath(drvPath)});
}
else if (command == ":b" || command == ":i" || command == ":s" || command == ":log") {
else if (command == ":b" || command == ":bl" || command == ":i" || command == ":s" || command == ":log") {
Value v;
evalString(arg, v);
StorePath drvPath = getDerivationPath(v);
Path drvPathRaw = state->store->printStorePath(drvPath);
if (command == ":b") {
if (command == ":b" || command == ":bl") {
state->store->buildPaths({DerivedPath::Built{drvPath}});
auto drv = state->store->readDerivation(drvPath);
logger->cout("\nThis derivation produced the following outputs:");
for (auto & [outputName, outputPath] : state->store->queryDerivationOutputMap(drvPath))
logger->cout(" %s -> %s", outputName, state->store->printStorePath(outputPath));
for (auto & [outputName, outputPath] : state->store->queryDerivationOutputMap(drvPath)) {
auto localStore = state->store.dynamic_pointer_cast<LocalFSStore>();
if (localStore && command == ":bl") {
std::string symlink = "repl-result-" + outputName;
localStore->addPermRoot(outputPath, absPath(symlink));
logger->cout(" ./%s -> %s", symlink, state->store->printStorePath(outputPath));
} else {
logger->cout(" %s -> %s", outputName, state->store->printStorePath(outputPath));
}
}
} else if (command == ":i") {
runNix("nix-env", {"-i", drvPathRaw});
} else if (command == ":log") {

View file

@ -1,29 +1,37 @@
source common.sh
testDir="$PWD"
cd "$TEST_ROOT"
replCmds="
simple = 1
simple = import ./simple.nix
:b simple
simple = import $testDir/simple.nix
:bl simple
:log simple
"
replFailingCmds="
failing = import ./simple-failing.nix
failing = import $testDir/simple-failing.nix
:b failing
:log failing
"
replUndefinedVariable="
import ./undefined-variable.nix
import $testDir/undefined-variable.nix
"
testRepl () {
local nixArgs=("$@")
rm -rf repl-result-out || true # cleanup from other runs backed by a foreign nix store
local replOutput="$(nix repl "${nixArgs[@]}" <<< "$replCmds")"
echo "$replOutput"
local outPath=$(echo "$replOutput" |&
grep -o -E "$NIX_STORE_DIR/\w*-simple")
nix path-info "${nixArgs[@]}" "$outPath"
[ "$(realpath ./repl-result-out)" == "$outPath" ] || fail "nix repl :bl doesn't make a symlink"
# run it again without checking the output to ensure the previously created symlink gets overwritten
nix repl "${nixArgs[@]}" <<< "$replCmds" || fail "nix repl does not work twice with the same inputs"
# simple.nix prints a PATH during build
echo "$replOutput" | grep -qs 'PATH=' || fail "nix repl :log doesn't output logs"
local replOutput="$(nix repl "${nixArgs[@]}" <<< "$replFailingCmds" 2>&1)"