refactor(tvix/libutil): Mark single-argument constructors explicit r/1704

This is the clang-tidy lint 'google-explicit-constructor'.

There's a whole bunch of breakage that was introduced by this, and we
had to opt out a few types of this (esp. the string formatting crap).

In some cases minor other changes have been done to keep the code
working, instead of converting between types (e.g. an explicit
comparison operator implementation for nix::Pid).

Change-Id: I12e1ca51a6bc2c882dba81a2526b9729d26988e7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1832
Tested-by: BuildkiteCI
Reviewed-by: kanepyork <rikingcoding@gmail.com>
Reviewed-by: glittershark <grfn@gws.fyi>

1 files changed, 4 insertions, 4 deletions

diff --git a/third_party/nix/src/libutil/types.hh b/third_party/nix/src/libutil/types.hh
index b8e7a3c9d5..bf95206d08 100644
--- a/third_party/nix/src/libutil/types.hh
+++ b/third_party/nix/src/libutil/types.hh
@@ -27,7 +27,7 @@ using boost::format;
    for all variadic arguments but ignoring the result. */
 struct nop {
   template <typename... T>
-  nop(T...) {}
+  explicit nop(T...) {}
 };
 
 struct FormatOrString {
@@ -69,11 +69,11 @@ class BaseError : public std::exception {
   unsigned int status = 1;  // exit status
 
   template <typename... Args>
-  BaseError(unsigned int status, Args... args)
+  explicit BaseError(unsigned int status, Args... args)
       : err(fmt(args...)), status(status) {}
 
   template <typename... Args>
-  BaseError(Args... args) : err(fmt(args...)) {}
+  explicit BaseError(Args... args) : err(fmt(args...)) {}
 
 #ifdef EXCEPTION_NEEDS_THROW_SPEC
   ~BaseError() noexcept {};
@@ -100,7 +100,7 @@ class SysError : public Error {
   int errNo;
 
   template <typename... Args>
-  SysError(Args... args) : Error(addErrno(fmt(args...))) {}
+  explicit SysError(Args... args) : Error(addErrno(fmt(args...))) {}
 
  private:
   std::string addErrno(const std::string& s);