[chromium-dev] 'runtime/string' cpplint; returning a const std::string&

[Nigel Tao]

I have a static string constant:

class Foo {
// Etc.

// An empty string that some methods return a reference to.
static const std::string empty_string_;
}

https://chromium-review.googlesource.com/c/chromium/src/+/1335071/1/chrome/services/app_service/public/cpp/app_update.h#59

that I use because a method wants to return a "const std::string&":

const std::string& AppUpdate::Name() const {
// Etc.
return empty_string_;
}

https://chromium-review.googlesource.com/c/chromium/src/+/1335071/1/chrome/services/app_service/public/cpp/app_update.cc#66

cpplint complains with "For a static/global string constant, use a C
style string instead: "const char AppUpdate::empty_string_[]".
[runtime/string] [4]"

but a C style string doesn't work here. I don't want a particular
sequence of characters. I want a fallback *value* (specifically of
type std::string) that I can return a const reference to, that the
caller can use *after the function returns*, but the caller also
shouldn't destroy that std::string.

What should I do instead, to please cpplint?

[Lei Zhang]

return base::EmptyString() instead?

Post by Nigel Tao
class Foo {
// Etc.
// An empty string that some methods return a reference to.
static const std::string empty_string_;
}
https://chromium-review.googlesource.com/c/chromium/src/+/1335071/1/chrome/services/app_service/public/cpp/app_update.h#59
const std::string& AppUpdate::Name() const {
// Etc.
return empty_string_;
}
https://chromium-review.googlesource.com/c/chromium/src/+/1335071/1/chrome/services/app_service/public/cpp/app_update.cc#66
cpplint complains with "For a static/global string constant, use a C
style string instead: "const char AppUpdate::empty_string_[]".
[runtime/string] [4]"
but a C style string doesn't work here. I don't want a particular
sequence of characters. I want a fallback *value* (specifically of
type std::string) that I can return a const reference to, that the
caller can use *after the function returns*, but the caller also
shouldn't destroy that std::string.
What should I do instead, to please cpplint?
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[Sam McNally]

Use base::EmptyString():
https://cs.chromium.org/chromium/src/base/strings/string_util.h?l=159&rcl=78e17bee9c2e5139fb675d08e3527a6e138f3fe4
.

Post by Nigel Tao
class Foo {
// Etc.
// An empty string that some methods return a reference to.
static const std::string empty_string_;
}
https://chromium-review.googlesource.com/c/chromium/src/+/1335071/1/chrome/services/app_service/public/cpp/app_update.h#59
const std::string& AppUpdate::Name() const {
// Etc.
return empty_string_;
}
https://chromium-review.googlesource.com/c/chromium/src/+/1335071/1/chrome/services/app_service/public/cpp/app_update.cc#66
cpplint complains with "For a static/global string constant, use a C
style string instead: "const char AppUpdate::empty_string_[]".
[runtime/string] [4]"
but a C style string doesn't work here. I don't want a particular
sequence of characters. I want a fallback *value* (specifically of
type std::string) that I can return a const reference to, that the
caller can use *after the function returns*, but the caller also
shouldn't destroy that std::string.
What should I do instead, to please cpplint?
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.

[Nigel Tao]

base::EmptyString is perfect. Thanks.