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[Pratt Parser] Add support for options.error_recovery_limit #2154

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Merged
copybara-service merged 1 commit into from
Jul 24, 2026
Merged

[Pratt Parser] Add support for options.error_recovery_limit #2154

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6 changes: 4 additions & 2 deletions parser/internal/pratt_parser.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -50,9 +50,11 @@ namespace {
std::string DisplayParserError(const cel::Source& source,
SourceLocation location,
std::string_view message) {
int32_t display_column =
location.column >= 0 ? location.column + 1 : location.column;
return absl::StrCat(
absl::StrFormat("ERROR: %s:%zu:%zu: %s", source.description(),
location.line, location.column + 1, message),
absl::StrFormat("ERROR: %s:%d:%d: %s", source.description(),
location.line, display_column, message),
source.DisplayErrorLocation(location));
}

Expand Down
121 changes: 73 additions & 48 deletions parser/internal/pratt_parser_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1055,7 +1055,7 @@ std::string FormatIssues(const cel::Source& source,
issues, "\n", [&source](std::string* out, const cel::ParseIssue& issue) {
absl::StrAppend(
out,
absl::StrFormat("ERROR: %s:%zu:%zu: %s", source.description(),
absl::StrFormat("ERROR: %s:%d:%d: %s", source.description(),
issue.location().line, issue.location().column + 1,
issue.message()),
source.DisplayErrorLocation(issue.location()));
Expand Down Expand Up @@ -1576,53 +1576,6 @@ INSTANTIATE_TEST_SUITE_P(PrattParserMacroTest, PrattParserMacroTest,
testing::ValuesIn(GetMacroTestCases()),
TestName<MacroTestCase>);

TEST(PrattParserMacroErrorTest, ReportError) {
auto builder = NewPrattParserBuilder();
ASSERT_OK_AND_ASSIGN(
auto error_macro,
Macro::Global("bad_macro", 1,
[](MacroExprFactory& macro_factory,
absl::Span<Expr> args) -> std::optional<Expr> {
return macro_factory.ReportError("custom macro error");
}));

ASSERT_THAT(builder->AddMacro(error_macro), IsOk());
ASSERT_OK_AND_ASSIGN(auto parser, builder->Build());

ASSERT_OK_AND_ASSIGN(auto source, cel::NewSource("42 + bad_macro(x)"));
std::vector<cel::ParseIssue> issues;
auto ast = parser->Parse(*source, &issues);
EXPECT_THAT(ast, StatusIs(absl::StatusCode::kInvalidArgument));
EXPECT_EQ(FormatIssues(*source, issues),
"ERROR: <input>:1:6: custom macro error\n"
" | 42 + bad_macro(x)\n"
" | .....^");
}

TEST(PrattParserMacroErrorTest, ReportErrorAt) {
auto builder = NewPrattParserBuilder();
ASSERT_OK_AND_ASSIGN(
auto error_at_macro,
Macro::Global("bad_macro_at", 1,
[](MacroExprFactory& macro_factory,
absl::Span<Expr> args) -> std::optional<Expr> {
return macro_factory.ReportErrorAt(args[0],
"custom error at arg");
}));

ASSERT_THAT(builder->AddMacro(error_at_macro), IsOk());
ASSERT_OK_AND_ASSIGN(auto parser, builder->Build());

ASSERT_OK_AND_ASSIGN(auto source, cel::NewSource("bad_macro_at(x)"));
std::vector<cel::ParseIssue> issues;
auto ast = parser->Parse(*source, &issues);
EXPECT_THAT(ast, StatusIs(absl::StatusCode::kInvalidArgument));
EXPECT_EQ(FormatIssues(*source, issues),
"ERROR: <input>:1:14: custom error at arg\n"
" | bad_macro_at(x)\n"
" | .............^");
}

TEST(PrattParserMacroCallsTest, MacroCallsDisabledByDefault) {
cel::ParserOptions options;
options.add_macro_calls = false;
Expand Down Expand Up @@ -1737,5 +1690,77 @@ TEST(PrattParserMacroCallsTest, NestedMacroCallsUseCopyAndReplaceReplacer) {
)"));
}

TEST(PrattParserMacroErrorTest, ReportError) {
auto builder = NewPrattParserBuilder();
ASSERT_OK_AND_ASSIGN(
auto error_macro,
Macro::Global("bad_macro", 1,
[](MacroExprFactory& macro_factory,
absl::Span<Expr> args) -> std::optional<Expr> {
return macro_factory.ReportError("custom macro error");
}));

ASSERT_THAT(builder->AddMacro(error_macro), IsOk());
ASSERT_OK_AND_ASSIGN(auto parser, builder->Build());

ASSERT_OK_AND_ASSIGN(auto source, cel::NewSource("42 + bad_macro(x)"));
std::vector<cel::ParseIssue> issues;
auto ast = parser->Parse(*source, &issues);
EXPECT_THAT(ast, StatusIs(absl::StatusCode::kInvalidArgument));
EXPECT_EQ(FormatIssues(*source, issues),
"ERROR: <input>:1:6: custom macro error\n"
" | 42 + bad_macro(x)\n"
" | .....^");
}

TEST(PrattParserMacroErrorTest, ReportErrorAt) {
auto builder = NewPrattParserBuilder();
ASSERT_OK_AND_ASSIGN(
auto error_at_macro,
Macro::Global("bad_macro_at", 1,
[](MacroExprFactory& macro_factory,
absl::Span<Expr> args) -> std::optional<Expr> {
return macro_factory.ReportErrorAt(args[0],
"custom error at arg");
}));

ASSERT_THAT(builder->AddMacro(error_at_macro), IsOk());
ASSERT_OK_AND_ASSIGN(auto parser, builder->Build());

ASSERT_OK_AND_ASSIGN(auto source, cel::NewSource("bad_macro_at(x)"));
std::vector<cel::ParseIssue> issues;
auto ast = parser->Parse(*source, &issues);
EXPECT_THAT(ast, StatusIs(absl::StatusCode::kInvalidArgument));
EXPECT_EQ(FormatIssues(*source, issues),
"ERROR: <input>:1:14: custom error at arg\n"
" | bad_macro_at(x)\n"
" | .............^");
}

TEST(PrattParserErrorRecoveryTest, ErrorRecoveryLimitZero) {
cel::ParserOptions options;
options.error_recovery_limit = 0;
std::vector<cel::ParseIssue> issues;
auto result = Parse("......", options, &issues);
EXPECT_THAT(result, StatusIs(absl::StatusCode::kInvalidArgument));
ASSERT_OK_AND_ASSIGN(auto source, cel::NewSource("......"));
EXPECT_EQ(FormatIssues(*source, issues),
"ERROR: <input>:-1:0: Error recovery limit (0) exceeded");
}

TEST(PrattParserErrorRecoveryTest, ErrorRecoveryLimitOne) {
cel::ParserOptions options;
options.error_recovery_limit = 1;
std::vector<cel::ParseIssue> issues;
auto result = Parse("......", options, &issues);
EXPECT_THAT(result, StatusIs(absl::StatusCode::kInvalidArgument));
ASSERT_OK_AND_ASSIGN(auto source, cel::NewSource("......"));
EXPECT_EQ(FormatIssues(*source, issues),
"ERROR: <input>:1:2: expected identifier\n"
" | ......\n"
" | .^\n"
"ERROR: <input>:-1:0: Error recovery limit (1) exceeded");
}

} // namespace
} // namespace cel::parser_internal
32 changes: 28 additions & 4 deletions parser/internal/pratt_parser_worker.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@

#include "absl/base/nullability.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_format.h"
#include "absl/strings/string_view.h"
#include "common/source.h"
#include "parser/internal/lexer.h"
Expand Down Expand Up @@ -50,20 +51,30 @@ std::string ParserWorker::GetTokenText(const Token& tok) const {
}

Token ParserWorker::NextSignificantToken() {
if (is_recovery_limit_exceeded()) {
return Token{.type = TokenType::kEnd, .start = 0, .end = 0};
}
while (true) {
Token tok = lexer_.Lex();
if (tok.type == TokenType::kWhitespace || tok.type == TokenType::kComment) {
continue;
}
if (tok.type == TokenType::kError) {
ReportError(tok, lexer_.GetError().message);
if (is_recovery_limit_exceeded()) {
return Token{.type = TokenType::kEnd, .start = 0, .end = 0};
}
}
return tok;
}
}

Token ParserWorker::NextToken() {
current_token_ = peek_token_;
if (is_recovery_limit_exceeded()) {
peek_token_ = Token{.type = TokenType::kEnd, .start = 0, .end = 0};
return current_token_;
}
if (peek_token_.type != TokenType::kEnd) {
peek_token_ = NextSignificantToken();
}
Expand All @@ -75,6 +86,9 @@ bool ParserWorker::Expect(TokenType type, absl::string_view msg) {
NextToken();
return true;
}
if (is_recovery_limit_exceeded()) {
return false;
}
if (peek_token_.type != TokenType::kError) {
std::string err_msg;
if (msg.empty()) {
Expand All @@ -98,9 +112,7 @@ bool ParserWorker::Expect(TokenType type, absl::string_view msg) {

void ParserWorker::SynchronizeOnDelimiter() {
if (is_recovery_limit_exceeded()) {
while (peek_token_.type != TokenType::kEnd) {
NextToken();
}
peek_token_ = Token{.type = TokenType::kEnd, .start = 0, .end = 0};
return;
}
while (peek_token_.type != TokenType::kEnd) {
Expand Down Expand Up @@ -149,8 +161,20 @@ void ParserWorker::ReportError(int32_t position, absl::string_view msg) {

void ParserWorker::ReportError(const SourceLocation& loc,
absl::string_view msg) {
if (error_count_ > options_.error_recovery_limit) {
return;
}
error_count_++;
if (parse_issues_ != nullptr) {
if (error_count_ == options_.error_recovery_limit + 1) {
if (parse_issues_ != nullptr) {
parse_issues_->push_back(
cel::ParseIssue(absl::StrFormat("Error recovery limit (%d) exceeded",
options_.error_recovery_limit)));
}
peek_token_ = Token{.type = TokenType::kEnd, .start = 0, .end = 0};
}
if (parse_issues_ != nullptr &&
error_count_ <= options_.error_recovery_limit) {
parse_issues_->push_back(cel::ParseIssue(loc, std::string(msg)));
}
}
Expand Down
6 changes: 3 additions & 3 deletions parser/internal/pratt_parser_worker.h
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Original file line number Diff line number Diff line change
Expand Up @@ -81,7 +81,7 @@ class ParserWorker {

// Error reporting and recovery
bool is_recovery_limit_exceeded() const {
return error_count_ >= options_.error_recovery_limit;
return error_count_ > options_.error_recovery_limit;
}
void ReportError(int32_t position, absl::string_view msg);
void ReportError(const SourceLocation& loc, absl::string_view msg);
Expand Down Expand Up @@ -214,7 +214,7 @@ class PrattParserWorker : public ParserWorker {
template <typename ExprNode>
ExprNode PrattParserWorker<ExprNode>::Parse() {
ExprNode expr = ParseExpr();
if (is_recursion_limit_exceeded()) {
if (is_recursion_limit_exceeded() || is_recovery_limit_exceeded()) {
return expr;
}
if (peek_token_.type != TokenType::kEnd &&
Expand All @@ -226,7 +226,7 @@ ExprNode PrattParserWorker<ExprNode>::Parse() {

template <typename ExprNode>
ExprNode PrattParserWorker<ExprNode>::ParseExpr() {
if (recursion_limit_exceeded_) {
if (recursion_limit_exceeded_ || is_recovery_limit_exceeded()) {
return ExprNode();
}
if (recursion_depth_ > options_.max_recursion_depth) {
Expand Down
2 changes: 1 addition & 1 deletion parser/parser_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1584,7 +1584,7 @@ TEST(ExpressionTest, TsanOom) {
.IgnoreError();
}

TEST(ExpressionTest, ErrorRecoveryLimits) {
TEST_P(ExpressionTest, ErrorRecoveryLimits) {
ParserOptions options;
options.error_recovery_limit = 1;
auto result = Parse("......", "", options);
Expand Down
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