[clang] [clang-tools-extra] [clang-tidy] Add `IgnoreValueCalls` option to bugprone-unchecked-optional-access (PR #167209)
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Sun Nov 9 01:14:37 PST 2025
https://github.com/zeyi2 created https://github.com/llvm/llvm-project/pull/167209
Add a new option `IgnoreValueCalls` to `bugprone-unchecked-optional-access`
Closes [#163831](https://github.com/llvm/llvm-project/issues/163831)
>From a33d0c02f8a31fdabf2a678fd02c7e6b4ca4a274 Mon Sep 17 00:00:00 2001
From: mtx <mitchell.xu2 at gmail.com>
Date: Sun, 9 Nov 2025 17:01:11 +0800
Subject: [PATCH] [clang-tidy] Add `IgnoreValueCalls` option to
bugprone-unchecked-optional-access
---
.../bugprone/UncheckedOptionalAccessCheck.h | 4 ++-
clang-tools-extra/docs/ReleaseNotes.rst | 5 +++-
.../bugprone/unchecked-optional-access.rst | 19 ++++++++++++++
...unchecked-optional-access-ignore-value.cpp | 25 +++++++++++++++++++
.../Models/UncheckedOptionalAccessModel.h | 7 ++++++
.../Models/UncheckedOptionalAccessModel.cpp | 15 +++++++++++
6 files changed, 73 insertions(+), 2 deletions(-)
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/unchecked-optional-access-ignore-value.cpp
diff --git a/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessCheck.h b/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessCheck.h
index 11086fb4bfda1..62bf42da4f9f9 100644
--- a/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessCheck.h
@@ -25,7 +25,8 @@ class UncheckedOptionalAccessCheck : public ClangTidyCheck {
public:
UncheckedOptionalAccessCheck(StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
- ModelOptions{Options.get("IgnoreSmartPointerDereference", false)} {}
+ ModelOptions{Options.get("IgnoreSmartPointerDereference", false),
+ Options.get("IgnoreValueCalls", false)} {}
void registerMatchers(ast_matchers::MatchFinder *Finder) override;
void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
@@ -34,6 +35,7 @@ class UncheckedOptionalAccessCheck : public ClangTidyCheck {
void storeOptions(ClangTidyOptions::OptionMap &Opts) override {
Options.store(Opts, "IgnoreSmartPointerDereference",
ModelOptions.IgnoreSmartPointerDereference);
+ Options.store(Opts, "IgnoreValueCalls", ModelOptions.IgnoreValueCalls);
}
private:
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 666865cfb2fcd..7e1e1802ade22 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -351,7 +351,10 @@ Changes in existing checks
- Improved :doc:`bugprone-unchecked-optional-access
<clang-tidy/checks/bugprone/unchecked-optional-access>` check by supporting
``NullableValue::makeValue`` and ``NullableValue::makeValueInplace`` to
- prevent false-positives for ``BloombergLP::bdlb::NullableValue`` type.
+ prevent false-positives for ``BloombergLP::bdlb::NullableValue`` type, and by
+ adding the ``IgnoreValueCalls`` option to suppress diagnostics for
+ ``optional::value()`` while still diagnosing UB-prone dereferences via
+ ``operator*`` and ``operator->``.
- Improved :doc:`bugprone-unhandled-self-assignment
<clang-tidy/checks/bugprone/unhandled-self-assignment>` check by adding
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/unchecked-optional-access.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/unchecked-optional-access.rst
index 552e6db699696..76078571f8c2d 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/unchecked-optional-access.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/unchecked-optional-access.rst
@@ -308,3 +308,22 @@ advantages:
* Performance. A single check can cover many or even all accesses within
scope. This gives the user the best of both worlds -- the safety of a
dynamic check, but without incurring redundant costs.
+
+Options
+-------
+
+.. option:: IgnoreSmartPointerDereference
+
+ If set to ``true`` (default is ``false``), the check ignores optionals that
+ are reached through overloaded smart-pointer-like dereference (``operator*``,
+ ``operator->``) on classes other than the optional type itself. This helps
+ avoid false positives where the analysis cannot equate results across such
+ calls. Note: This does not cover access through ``operator[]``.
+
+.. option:: IgnoreValueCalls
+
+ If set to ``true`` (default is ``false``), the check does not diagnose calls
+ to ``optional::value()``. Diagnostics for ``operator*()`` and
+ ``operator->()`` remain enabled. This is useful for codebases that
+ intentionally rely on ``value()`` for defined, guarded access while still
+ flagging UB-prone operator dereferences.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/unchecked-optional-access-ignore-value.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/unchecked-optional-access-ignore-value.cpp
new file mode 100644
index 0000000000000..f54621269f8c0
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/unchecked-optional-access-ignore-value.cpp
@@ -0,0 +1,25 @@
+// RUN: %check_clang_tidy %s bugprone-unchecked-optional-access %t -- \
+// RUN: -config="{CheckOptions: \
+// RUN: {bugprone-unchecked-optional-access.IgnoreValueCalls: true}}" -- \
+// RUN: -I %S/Inputs/unchecked-optional-access
+
+#include "absl/types/optional.h"
+
+struct Foo {
+ void foo() const {}
+};
+
+void unchecked_value_access(const absl::optional<int> &opt) {
+ opt.value(); // no-warning
+}
+
+void unchecked_deref_operator_access(const absl::optional<int> &opt) {
+ *opt;
+ // CHECK-MESSAGES: :[[@LINE-1]]:4: warning: unchecked access to optional value
+}
+
+void unchecked_arrow_operator_access(const absl::optional<Foo> &opt) {
+ opt->foo();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: unchecked access to optional value
+}
+
diff --git a/clang/include/clang/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.h b/clang/include/clang/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.h
index 696c9f4a6cf5c..07fa95fe81059 100644
--- a/clang/include/clang/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.h
+++ b/clang/include/clang/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.h
@@ -46,6 +46,13 @@ struct UncheckedOptionalAccessModelOptions {
/// are confident in this const accessor caching, we shouldn't need the
/// IgnoreSmartPointerDereference option anymore.
bool IgnoreSmartPointerDereference = false;
+
+ /// In generating diagnostics, ignore calls to `optional::value()`.
+ ///
+ /// Projects that intentionally use `value()` as a guarded access pattern may
+ /// set this to true to suppress diagnostics for `value()` while continuing to
+ /// diagnose UB-prone operator accesses (`operator*`, `operator->`).
+ bool IgnoreValueCalls = false;
};
using UncheckedOptionalAccessLattice = CachedConstAccessorsLattice<NoopLattice>;
diff --git a/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp b/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
index 0fa333eedcfdd..f4dacfb0bcff4 100644
--- a/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
+++ b/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
@@ -1154,6 +1154,21 @@ auto buildDiagnoseMatchSwitch(
// lot of duplicated work (e.g. string comparisons), consider providing APIs
// that avoid it through memoization.
auto IgnorableOptional = ignorableOptional(Options);
+ if (Options.IgnoreValueCalls) {
+ // Only diagnose operator-based unwraps. Value calls are ignored.
+ return CFGMatchSwitchBuilder<
+ const Environment,
+ llvm::SmallVector<UncheckedOptionalAccessDiagnostic>>()
+ // optional::operator*, optional::operator->
+ .CaseOfCFGStmt<CallExpr>(valueOperatorCall(IgnorableOptional),
+ [](const CallExpr *E,
+ const MatchFinder::MatchResult &,
+ const Environment &Env) {
+ return diagnoseUnwrapCall(E->getArg(0), Env);
+ })
+ .Build();
+ }
+
return CFGMatchSwitchBuilder<
const Environment,
llvm::SmallVector<UncheckedOptionalAccessDiagnostic>>()
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