Merge branch 'cli-suggestions' of https://github.com/thufschmitt/nix

This commit is contained in:
Eelco Dolstra 2022-03-07 19:47:45 +01:00
commit 30ddd37873
13 changed files with 385 additions and 25 deletions

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@ -27,3 +27,6 @@
* Templates can now define a `welcomeText` attribute, which is printed out by * Templates can now define a `welcomeText` attribute, which is printed out by
`nix flake {init,new} --template <template>`. `nix flake {init,new} --template <template>`.
* Nix will now helpfully suggest some valid inputs when the user mistypes
something on the command-line

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@ -272,9 +272,9 @@ void completeFlakeRefWithFragment(
auto attr = root->findAlongAttrPath(attrPath); auto attr = root->findAlongAttrPath(attrPath);
if (!attr) continue; if (!attr) continue;
for (auto & attr2 : attr->getAttrs()) { for (auto & attr2 : (*attr)->getAttrs()) {
if (hasPrefix(attr2, lastAttr)) { if (hasPrefix(attr2, lastAttr)) {
auto attrPath2 = attr->getAttrPath(attr2); auto attrPath2 = (*attr)->getAttrPath(attr2);
/* Strip the attrpath prefix. */ /* Strip the attrpath prefix. */
attrPath2.erase(attrPath2.begin(), attrPath2.begin() + attrPathPrefix.size()); attrPath2.erase(attrPath2.begin(), attrPath2.begin() + attrPathPrefix.size());
completions->add(flakeRefS + "#" + concatStringsSep(".", attrPath2)); completions->add(flakeRefS + "#" + concatStringsSep(".", attrPath2));
@ -568,15 +568,22 @@ std::tuple<std::string, FlakeRef, InstallableValue::DerivationInfo> InstallableF
auto cache = openEvalCache(*state, lockedFlake); auto cache = openEvalCache(*state, lockedFlake);
auto root = cache->getRoot(); auto root = cache->getRoot();
Suggestions suggestions;
for (auto & attrPath : getActualAttrPaths()) { for (auto & attrPath : getActualAttrPaths()) {
debug("trying flake output attribute '%s'", attrPath); debug("trying flake output attribute '%s'", attrPath);
auto attr = root->findAlongAttrPath( auto attrOrSuggestions = root->findAlongAttrPath(
parseAttrPath(*state, attrPath), parseAttrPath(*state, attrPath),
true true
); );
if (!attr) continue; if (!attrOrSuggestions) {
suggestions += attrOrSuggestions.getSuggestions();
continue;
}
auto attr = *attrOrSuggestions;
if (!attr->isDerivation()) if (!attr->isDerivation())
throw Error("flake output attribute '%s' is not a derivation", attrPath); throw Error("flake output attribute '%s' is not a derivation", attrPath);
@ -591,7 +598,7 @@ std::tuple<std::string, FlakeRef, InstallableValue::DerivationInfo> InstallableF
return {attrPath, lockedFlake->flake.lockedRef, std::move(drvInfo)}; return {attrPath, lockedFlake->flake.lockedRef, std::move(drvInfo)};
} }
throw Error("flake '%s' does not provide attribute %s", throw Error(suggestions, "flake '%s' does not provide attribute %s",
flakeRef, showAttrPaths(getActualAttrPaths())); flakeRef, showAttrPaths(getActualAttrPaths()));
} }
@ -610,17 +617,24 @@ std::pair<Value *, Pos> InstallableFlake::toValue(EvalState & state)
auto emptyArgs = state.allocBindings(0); auto emptyArgs = state.allocBindings(0);
Suggestions suggestions;
for (auto & attrPath : getActualAttrPaths()) { for (auto & attrPath : getActualAttrPaths()) {
try { try {
auto [v, pos] = findAlongAttrPath(state, attrPath, *emptyArgs, *vOutputs); auto [v, pos] = findAlongAttrPath(state, attrPath, *emptyArgs, *vOutputs);
state.forceValue(*v, pos); state.forceValue(*v, pos);
return {v, pos}; return {v, pos};
} catch (AttrPathNotFound & e) { } catch (AttrPathNotFound & e) {
suggestions += e.info().suggestions;
} }
} }
throw Error("flake '%s' does not provide attribute %s", throw Error(
flakeRef, showAttrPaths(getActualAttrPaths())); suggestions,
"flake '%s' does not provide attribute %s",
flakeRef,
showAttrPaths(getActualAttrPaths())
);
} }
std::vector<std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>> std::vector<std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>>
@ -635,7 +649,7 @@ InstallableFlake::getCursors(EvalState & state)
for (auto & attrPath : getActualAttrPaths()) { for (auto & attrPath : getActualAttrPaths()) {
auto attr = root->findAlongAttrPath(parseAttrPath(state, attrPath)); auto attr = root->findAlongAttrPath(parseAttrPath(state, attrPath));
if (attr) res.push_back({attr, attrPath}); if (attr) res.push_back({*attr, attrPath});
} }
return res; return res;

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@ -74,8 +74,14 @@ std::pair<Value *, Pos> findAlongAttrPath(EvalState & state, const std::string &
throw Error("empty attribute name in selection path '%1%'", attrPath); throw Error("empty attribute name in selection path '%1%'", attrPath);
Bindings::iterator a = v->attrs->find(state.symbols.create(attr)); Bindings::iterator a = v->attrs->find(state.symbols.create(attr));
if (a == v->attrs->end()) if (a == v->attrs->end()) {
throw AttrPathNotFound("attribute '%1%' in selection path '%2%' not found", attr, attrPath); std::set<std::string> attrNames;
for (auto & attr : *v->attrs)
attrNames.insert(attr.name);
auto suggestions = Suggestions::bestMatches(attrNames, attr);
throw AttrPathNotFound(suggestions, "attribute '%1%' in selection path '%2%' not found", attr, attrPath);
}
v = &*a->value; v = &*a->value;
pos = *a->pos; pos = *a->pos;
} }

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@ -406,6 +406,16 @@ Value & AttrCursor::forceValue()
return v; return v;
} }
Suggestions AttrCursor::getSuggestionsForAttr(Symbol name)
{
auto attrNames = getAttrs();
std::set<std::string> strAttrNames;
for (auto & name : attrNames)
strAttrNames.insert(std::string(name));
return Suggestions::bestMatches(strAttrNames, name);
}
std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErrors) std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErrors)
{ {
if (root->db) { if (root->db) {
@ -446,6 +456,11 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErro
return nullptr; return nullptr;
//throw TypeError("'%s' is not an attribute set", getAttrPathStr()); //throw TypeError("'%s' is not an attribute set", getAttrPathStr());
for (auto & attr : *v.attrs) {
if (root->db)
root->db->setPlaceholder({cachedValue->first, attr.name});
}
auto attr = v.attrs->get(name); auto attr = v.attrs->get(name);
if (!attr) { if (!attr) {
@ -464,7 +479,7 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErro
cachedValue2 = {root->db->setPlaceholder({cachedValue->first, name}), placeholder_t()}; cachedValue2 = {root->db->setPlaceholder({cachedValue->first, name}), placeholder_t()};
} }
return std::make_shared<AttrCursor>( return make_ref<AttrCursor>(
root, std::make_pair(shared_from_this(), name), attr->value, std::move(cachedValue2)); root, std::make_pair(shared_from_this(), name), attr->value, std::move(cachedValue2));
} }
@ -473,27 +488,31 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(std::string_view name)
return maybeGetAttr(root->state.symbols.create(name)); return maybeGetAttr(root->state.symbols.create(name));
} }
std::shared_ptr<AttrCursor> AttrCursor::getAttr(Symbol name, bool forceErrors) ref<AttrCursor> AttrCursor::getAttr(Symbol name, bool forceErrors)
{ {
auto p = maybeGetAttr(name, forceErrors); auto p = maybeGetAttr(name, forceErrors);
if (!p) if (!p)
throw Error("attribute '%s' does not exist", getAttrPathStr(name)); throw Error("attribute '%s' does not exist", getAttrPathStr(name));
return p; return ref(p);
} }
std::shared_ptr<AttrCursor> AttrCursor::getAttr(std::string_view name) ref<AttrCursor> AttrCursor::getAttr(std::string_view name)
{ {
return getAttr(root->state.symbols.create(name)); return getAttr(root->state.symbols.create(name));
} }
std::shared_ptr<AttrCursor> AttrCursor::findAlongAttrPath(const std::vector<Symbol> & attrPath, bool force) OrSuggestions<ref<AttrCursor>> AttrCursor::findAlongAttrPath(const std::vector<Symbol> & attrPath, bool force)
{ {
auto res = shared_from_this(); auto res = shared_from_this();
for (auto & attr : attrPath) { for (auto & attr : attrPath) {
res = res->maybeGetAttr(attr, force); auto child = res->maybeGetAttr(attr, force);
if (!res) return {}; if (!child) {
auto suggestions = res->getSuggestionsForAttr(attr);
return OrSuggestions<ref<AttrCursor>>::failed(suggestions);
}
res = child;
} }
return res; return ref(res);
} }
std::string AttrCursor::getString() std::string AttrCursor::getString()

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@ -94,15 +94,17 @@ public:
std::string getAttrPathStr(Symbol name) const; std::string getAttrPathStr(Symbol name) const;
Suggestions getSuggestionsForAttr(Symbol name);
std::shared_ptr<AttrCursor> maybeGetAttr(Symbol name, bool forceErrors = false); std::shared_ptr<AttrCursor> maybeGetAttr(Symbol name, bool forceErrors = false);
std::shared_ptr<AttrCursor> maybeGetAttr(std::string_view name); std::shared_ptr<AttrCursor> maybeGetAttr(std::string_view name);
std::shared_ptr<AttrCursor> getAttr(Symbol name, bool forceErrors = false); ref<AttrCursor> getAttr(Symbol name, bool forceErrors = false);
std::shared_ptr<AttrCursor> getAttr(std::string_view name); ref<AttrCursor> getAttr(std::string_view name);
std::shared_ptr<AttrCursor> findAlongAttrPath(const std::vector<Symbol> & attrPath, bool force = false); OrSuggestions<ref<AttrCursor>> findAlongAttrPath(const std::vector<Symbol> & attrPath, bool force = false);
std::string getString(); std::string getString();

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@ -328,8 +328,13 @@ MultiCommand::MultiCommand(const Commands & commands_)
completions->add(name); completions->add(name);
} }
auto i = commands.find(s); auto i = commands.find(s);
if (i == commands.end()) if (i == commands.end()) {
throw UsageError("'%s' is not a recognised command", s); std::set<std::string> commandNames;
for (auto & [name, _] : commands)
commandNames.insert(name);
auto suggestions = Suggestions::bestMatches(commandNames, s);
throw UsageError(suggestions, "'%s' is not a recognised command", s);
}
command = {s, i->second()}; command = {s, i->second()};
command->second->parent = this; command->second->parent = this;
}} }}

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@ -282,6 +282,13 @@ std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool s
} }
} }
auto suggestions = einfo.suggestions.trim();
if (! suggestions.suggestions.empty()){
oss << "Did you mean " <<
suggestions.trim() <<
"?" << std::endl;
}
// traces // traces
if (showTrace && !einfo.traces.empty()) { if (showTrace && !einfo.traces.empty()) {
for (auto iter = einfo.traces.rbegin(); iter != einfo.traces.rend(); ++iter) { for (auto iter = einfo.traces.rbegin(); iter != einfo.traces.rend(); ++iter) {

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@ -1,5 +1,6 @@
#pragma once #pragma once
#include "suggestions.hh"
#include "ref.hh" #include "ref.hh"
#include "types.hh" #include "types.hh"
#include "fmt.hh" #include "fmt.hh"
@ -112,6 +113,8 @@ struct ErrorInfo {
std::optional<ErrPos> errPos; std::optional<ErrPos> errPos;
std::list<Trace> traces; std::list<Trace> traces;
Suggestions suggestions;
static std::optional<std::string> programName; static std::optional<std::string> programName;
}; };
@ -141,6 +144,11 @@ public:
: err { .level = lvlError, .msg = hintfmt(fs, args...) } : err { .level = lvlError, .msg = hintfmt(fs, args...) }
{ } { }
template<typename... Args>
BaseError(const Suggestions & sug, const Args & ... args)
: err { .level = lvlError, .msg = hintfmt(args...), .suggestions = sug }
{ }
BaseError(hintformat hint) BaseError(hintformat hint)
: err { .level = lvlError, .msg = hint } : err { .level = lvlError, .msg = hint }
{ } { }

114
src/libutil/suggestions.cc Normal file
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@ -0,0 +1,114 @@
#include "suggestions.hh"
#include "ansicolor.hh"
#include "util.hh"
#include <algorithm>
namespace nix {
int levenshteinDistance(std::string_view first, std::string_view second)
{
// Implementation borrowed from
// https://en.wikipedia.org/wiki/Levenshtein_distance#Iterative_with_two_matrix_rows
int m = first.size();
int n = second.size();
auto v0 = std::vector<int>(n+1);
auto v1 = std::vector<int>(n+1);
for (auto i = 0; i <= n; i++)
v0[i] = i;
for (auto i = 0; i < m; i++) {
v1[0] = i+1;
for (auto j = 0; j < n; j++) {
auto deletionCost = v0[j+1] + 1;
auto insertionCost = v1[j] + 1;
auto substitutionCost = first[i] == second[j] ? v0[j] : v0[j] + 1;
v1[j+1] = std::min({deletionCost, insertionCost, substitutionCost});
}
std::swap(v0, v1);
}
return v0[n];
}
Suggestions Suggestions::bestMatches (
std::set<std::string> allMatches,
std::string query)
{
std::set<Suggestion> res;
for (const auto & possibleMatch : allMatches) {
res.insert(Suggestion {
.distance = levenshteinDistance(query, possibleMatch),
.suggestion = possibleMatch,
});
}
return Suggestions { res };
}
Suggestions Suggestions::trim(int limit, int maxDistance) const
{
std::set<Suggestion> res;
int count = 0;
for (auto & elt : suggestions) {
if (count >= limit || elt.distance > maxDistance)
break;
count++;
res.insert(elt);
}
return Suggestions{res};
}
std::string Suggestion::to_string() const
{
return ANSI_WARNING + filterANSIEscapes(suggestion) + ANSI_NORMAL;
}
std::string Suggestions::to_string() const
{
switch (suggestions.size()) {
case 0:
return "";
case 1:
return suggestions.begin()->to_string();
default: {
std::string res = "one of ";
auto iter = suggestions.begin();
res += iter->to_string(); // Iter cant be end() because the container isnt null
iter++;
auto last = suggestions.end(); last--;
for ( ; iter != suggestions.end() ; iter++) {
res += (iter == last) ? " or " : ", ";
res += iter->to_string();
}
return res;
}
}
}
Suggestions & Suggestions::operator+=(const Suggestions & other)
{
suggestions.insert(
other.suggestions.begin(),
other.suggestions.end()
);
return *this;
}
std::ostream & operator<<(std::ostream & str, const Suggestion & suggestion)
{
return str << suggestion.to_string();
}
std::ostream & operator<<(std::ostream & str, const Suggestions & suggestions)
{
return str << suggestions.to_string();
}
}

102
src/libutil/suggestions.hh Normal file
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@ -0,0 +1,102 @@
#pragma once
#include "comparator.hh"
#include "types.hh"
#include <set>
namespace nix {
int levenshteinDistance(std::string_view first, std::string_view second);
/**
* A potential suggestion for the cli interface.
*/
class Suggestion {
public:
int distance; // The smaller the better
std::string suggestion;
std::string to_string() const;
GENERATE_CMP(Suggestion, me->distance, me->suggestion)
};
class Suggestions {
public:
std::set<Suggestion> suggestions;
std::string to_string() const;
Suggestions trim(
int limit = 5,
int maxDistance = 2
) const;
static Suggestions bestMatches (
std::set<std::string> allMatches,
std::string query
);
Suggestions& operator+=(const Suggestions & other);
};
std::ostream & operator<<(std::ostream & str, const Suggestion &);
std::ostream & operator<<(std::ostream & str, const Suggestions &);
// Either a value of type `T`, or some suggestions
template<typename T>
class OrSuggestions {
public:
using Raw = std::variant<T, Suggestions>;
Raw raw;
T* operator ->()
{
return &**this;
}
T& operator *()
{
return std::get<T>(raw);
}
operator bool() const noexcept
{
return std::holds_alternative<T>(raw);
}
OrSuggestions(T t)
: raw(t)
{
}
OrSuggestions()
: raw(Suggestions{})
{
}
static OrSuggestions<T> failed(const Suggestions & s)
{
auto res = OrSuggestions<T>();
res.raw = s;
return res;
}
static OrSuggestions<T> failed()
{
return OrSuggestions<T>::failed(Suggestions{});
}
const Suggestions & getSuggestions()
{
static Suggestions noSuggestions;
if (const auto & suggestions = std::get_if<Suggestions>(&raw))
return *suggestions;
else
return noSuggestions;
}
};
}

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@ -0,0 +1,43 @@
#include "suggestions.hh"
#include <gtest/gtest.h>
namespace nix {
struct LevenshteinDistanceParam {
std::string s1, s2;
int distance;
};
class LevenshteinDistanceTest :
public testing::TestWithParam<LevenshteinDistanceParam> {
};
TEST_P(LevenshteinDistanceTest, CorrectlyComputed) {
auto params = GetParam();
ASSERT_EQ(levenshteinDistance(params.s1, params.s2), params.distance);
ASSERT_EQ(levenshteinDistance(params.s2, params.s1), params.distance);
}
INSTANTIATE_TEST_SUITE_P(LevenshteinDistance, LevenshteinDistanceTest,
testing::Values(
LevenshteinDistanceParam{"foo", "foo", 0},
LevenshteinDistanceParam{"foo", "", 3},
LevenshteinDistanceParam{"", "", 0},
LevenshteinDistanceParam{"foo", "fo", 1},
LevenshteinDistanceParam{"foo", "oo", 1},
LevenshteinDistanceParam{"foo", "fao", 1},
LevenshteinDistanceParam{"foo", "abc", 3}
)
);
TEST(Suggestions, Trim) {
auto suggestions = Suggestions::bestMatches({"foooo", "bar", "fo", "gao"}, "foo");
auto onlyOne = suggestions.trim(1);
ASSERT_EQ(onlyOne.suggestions.size(), 1);
ASSERT_TRUE(onlyOne.suggestions.begin()->suggestion == "fo");
auto closest = suggestions.trim(999, 2);
ASSERT_EQ(closest.suggestions.size(), 3);
}
}

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@ -92,8 +92,9 @@ nix_tests = \
bash-profile.sh \ bash-profile.sh \
pass-as-file.sh \ pass-as-file.sh \
describe-stores.sh \ describe-stores.sh \
store-ping.sh \ nix-profile.sh \
nix-profile.sh suggestions.sh \
store-ping.sh
ifeq ($(HAVE_LIBCPUID), 1) ifeq ($(HAVE_LIBCPUID), 1)
nix_tests += compute-levels.sh nix_tests += compute-levels.sh

36
tests/suggestions.sh Normal file
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@ -0,0 +1,36 @@
source common.sh
clearStore
cd "$TEST_HOME"
cat <<EOF > flake.nix
{
outputs = a: {
packages.$system = {
foo = 1;
fo1 = 1;
fo2 = 1;
fooo = 1;
foooo = 1;
fooooo = 1;
fooooo1 = 1;
fooooo2 = 1;
fooooo3 = 1;
fooooo4 = 1;
fooooo5 = 1;
fooooo6 = 1;
};
};
}
EOF
# Probable typo in the requested attribute path. Suggest some close possibilities
NIX_BUILD_STDERR_WITH_SUGGESTIONS=$(! nix build .\#fob 2>&1 1>/dev/null)
[[ "$NIX_BUILD_STDERR_WITH_SUGGESTIONS" =~ "Did you mean one of fo1, fo2, foo or fooo?" ]] || \
fail "The nix build stderr should suggest the three closest possiblities"
# None of the possible attributes is close to `bar`, so shouldnt suggest anything
NIX_BUILD_STDERR_WITH_NO_CLOSE_SUGGESTION=$(! nix build .\#bar 2>&1 1>/dev/null)
[[ ! "$NIX_BUILD_STDERR_WITH_NO_CLOSE_SUGGESTION" =~ "Did you mean" ]] || \
fail "The nix build stderr shouldnt suggest anything if theres nothing relevant to suggest"