Merge changes I6358a393,I2d9f276b,Idd096dc9 into main

* changes:
  clang-tidy: write a lint for charptr_cast
  tree-wide: automated migration to charptr_cast
  clang-tidy: enforce the new rules

7 files changed, 20 insertions, 13 deletions

diff --git a/src/libstore/build/worker.cc b/src/libstore/build/worker.cc
index aaa4e8907..a27cb0076 100644
--- a/src/libstore/build/worker.cc
+++ b/src/libstore/build/worker.cc
@@ -1,3 +1,4 @@
+#include "charptr-cast.hh"
 #include "machines.hh"
 #include "worker.hh"
 #include "substitution-goal.hh"
@@ -539,7 +540,7 @@ void Worker::waitForInput()
                 } else {
                     printMsg(lvlVomit, "%1%: read %2% bytes",
                         goal->getName(), rd);
-                    std::string_view data(reinterpret_cast<char *>(buffer.data()), rd);
+                    std::string_view data(charptr_cast<char *>(buffer.data()), rd);
                     j->lastOutput = after;
                     handleWorkResult(goal, goal->handleChildOutput(k, data));
                 }
diff --git a/src/libstore/crypto.cc b/src/libstore/crypto.cc
index e8ab15537..6f4a36735 100644
--- a/src/libstore/crypto.cc
+++ b/src/libstore/crypto.cc
@@ -1,3 +1,4 @@
+#include "charptr-cast.hh"
 #include "crypto.hh"
 #include "file-system.hh"
 #include "globals.hh"
@@ -44,15 +45,15 @@ std::string SecretKey::signDetached(std::string_view data) const
 {
     unsigned char sig[crypto_sign_BYTES];
     unsigned long long sigLen;
-    crypto_sign_detached(sig, &sigLen, reinterpret_cast<const unsigned char *>(data.data()), data.size(),
-        reinterpret_cast<const unsigned char *>(key.data()));
+    crypto_sign_detached(sig, &sigLen, charptr_cast<const unsigned char *>(data.data()), data.size(),
+        charptr_cast<const unsigned char *>(key.data()));
     return name + ":" + base64Encode(std::string(reinterpret_cast<char *>(sig), sigLen));
 }
 
 PublicKey SecretKey::toPublicKey() const
 {
     unsigned char pk[crypto_sign_PUBLICKEYBYTES];
-    crypto_sign_ed25519_sk_to_pk(pk, reinterpret_cast<const unsigned char *>(key.data()));
+    crypto_sign_ed25519_sk_to_pk(pk, charptr_cast<const unsigned char *>(key.data()));
     return PublicKey(name, std::string(reinterpret_cast<char *>(pk), crypto_sign_PUBLICKEYBYTES));
 }
 
@@ -85,9 +86,9 @@ bool verifyDetached(const std::string & data, const std::string & sig,
     if (sig2.size() != crypto_sign_BYTES)
         throw Error("signature is not valid");
 
-    return crypto_sign_verify_detached(reinterpret_cast<unsigned char *>(sig2.data()),
-        reinterpret_cast<const unsigned char *>(data.data()), data.size(),
-        reinterpret_cast<const unsigned char *>(key->second.key.data())) == 0;
+    return crypto_sign_verify_detached(charptr_cast<unsigned char *>(sig2.data()),
+        charptr_cast<const unsigned char *>(data.data()), data.size(),
+        charptr_cast<const unsigned char *>(key->second.key.data())) == 0;
 }
 
 PublicKeys getDefaultPublicKeys()
diff --git a/src/libstore/sqlite.cc b/src/libstore/sqlite.cc
index 3114aad48..8d0bfcb11 100644
--- a/src/libstore/sqlite.cc
+++ b/src/libstore/sqlite.cc
@@ -1,3 +1,4 @@
+#include "charptr-cast.hh"
 #include "sqlite.hh"
 #include "globals.hh"
 #include "logging.hh"
@@ -201,7 +202,7 @@ bool SQLiteStmt::Use::next()
 
 std::optional<std::string> SQLiteStmt::Use::getStrNullable(int col)
 {
-    auto s = reinterpret_cast<const char *>(sqlite3_column_text(stmt, col));
+    auto s = charptr_cast<const char *>(sqlite3_column_text(stmt, col));
     return s != nullptr ? std::make_optional<std::string>((s)) : std::nullopt;
 }
 
diff --git a/src/libutil/charptr-cast.hh b/src/libutil/charptr-cast.hh
index 990f2ec55..ec53d8924 100644
--- a/src/libutil/charptr-cast.hh
+++ b/src/libutil/charptr-cast.hh
@@ -134,6 +134,7 @@ template<typename To, typename From>
     requires charptr_cast_detail::IsCharCastable<From, To>
 inline To charptr_cast(From p)
 {
+    // NOLINTNEXTLINE(lix-charptrcast): stop the linter ever getting too clever and causing funny recursion
     return reinterpret_cast<To>(p);
 }
 
diff --git a/src/libutil/compression.cc b/src/libutil/compression.cc
index 6b0fa9d15..5152a2146 100644
--- a/src/libutil/compression.cc
+++ b/src/libutil/compression.cc
@@ -1,3 +1,4 @@
+#include "charptr-cast.hh"
 #include "compression.hh"
 #include "tarfile.hh"
 #include "signals.hh"
@@ -160,7 +161,7 @@ struct BrotliDecompressionSource : Source
 
     size_t read(char * data, size_t len) override
     {
-        uint8_t * out = reinterpret_cast<uint8_t *>(data);
+        uint8_t * out = charptr_cast<uint8_t *>(data);
         const auto * begin = out;
 
         while (len && !BrotliDecoderIsFinished(state.get())) {
@@ -172,7 +173,7 @@ struct BrotliDecompressionSource : Source
                 } catch (EndOfFile &) {
                     break;
                 }
-                next_in = reinterpret_cast<const uint8_t *>(buf.get());
+                next_in = charptr_cast<const uint8_t *>(buf.get());
             }
 
             if (!BrotliDecoderDecompressStream(
@@ -238,7 +239,7 @@ struct BrotliCompressionSink : ChunkedCompressionSink
 
     void writeInternal(std::string_view data) override
     {
-        auto next_in = reinterpret_cast<const uint8_t *>(data.data());
+        auto next_in = charptr_cast<const uint8_t *>(data.data());
         size_t avail_in = data.size();
         uint8_t * next_out = outbuf;
         size_t avail_out = sizeof(outbuf);
diff --git a/src/libutil/file-descriptor.cc b/src/libutil/file-descriptor.cc
index 7c82988b3..be9f8c889 100644
--- a/src/libutil/file-descriptor.cc
+++ b/src/libutil/file-descriptor.cc
@@ -1,3 +1,4 @@
+#include "charptr-cast.hh"
 #include "file-system.hh"
 #include "finally.hh"
 #include "logging.hh"
@@ -115,7 +116,7 @@ Generator<Bytes> drainFDSource(int fd, bool block)
                 throw SysError("reading from file");
         }
         else if (rd == 0) break;
-        else co_yield std::span{reinterpret_cast<char *>(buf.data()), (size_t) rd};
+        else co_yield std::span{charptr_cast<char *>(buf.data()), (size_t) rd};
     }
 }
 
diff --git a/src/libutil/tarfile.cc b/src/libutil/tarfile.cc
index f024149ec..316751533 100644
--- a/src/libutil/tarfile.cc
+++ b/src/libutil/tarfile.cc
@@ -1,6 +1,7 @@
 #include <archive.h>
 #include <archive_entry.h>
 
+#include "charptr-cast.hh"
 #include "file-system.hh"
 #include "logging.hh"
 #include "serialise.hh"
@@ -19,7 +20,7 @@ static ssize_t callback_read(struct archive * archive, void * _self, const void
     *buffer = self->buffer.data();
 
     try {
-        return self->source->read(reinterpret_cast<char *>(self->buffer.data()), self->buffer.size());
+        return self->source->read(charptr_cast<char *>(self->buffer.data()), self->buffer.size());
     } catch (EndOfFile &) {
         return 0;
     } catch (std::exception & err) {