Fix gcc warning -Wmissing-field-initializers

The approach that was taken here was to add default values to the type
definitions rather than specify them whenever they are missing.

Now the only remaining warning is '-Wunused-parameter' which @jade said
is usually counterproductive and that we can just disable it:
https://git.lix.systems/lix-project/lix/issues/456#issuecomment-6617

So this change adds the flags '-Wall', '-Wextra' and
'-Wno-unused-parameter', so that all warnings are enabled except for
'-Wunused-parameter'.

Change-Id: Ic223a964d67ab429e8da804c0721ba5e25d53012

7 files changed, 11 insertions, 11 deletions

diff --git a/src/libstore/build-result.hh b/src/libstore/build-result.hh
index 9634fb944..846c6c9b9 100644
--- a/src/libstore/build-result.hh
+++ b/src/libstore/build-result.hh
@@ -47,7 +47,7 @@ struct BuildResult
      * @todo This should be an entire ErrorInfo object, not just a
      * string, for richer information.
      */
-    std::string errorMsg;
+    std::string errorMsg = {};
 
     std::string toString() const {
         auto strStatus = [&]() {
@@ -90,7 +90,7 @@ struct BuildResult
      * For derivations, a mapping from the names of the wanted outputs
      * to actual paths.
      */
-    SingleDrvOutputs builtOutputs;
+    SingleDrvOutputs builtOutputs = {};
 
     /**
      * The start/stop times of the build (or one of the rounds, if it
diff --git a/src/libstore/build/derivation-goal.hh b/src/libstore/build/derivation-goal.hh
index 3885afe4a..6dd58afd2 100644
--- a/src/libstore/build/derivation-goal.hh
+++ b/src/libstore/build/derivation-goal.hh
@@ -63,7 +63,7 @@ struct InitialOutputStatus {
 struct InitialOutput {
     bool wanted;
     Hash outputHash;
-    std::optional<InitialOutputStatus> known;
+    std::optional<InitialOutputStatus> known = {};
 };
 
 /**
diff --git a/src/libstore/build/goal.hh b/src/libstore/build/goal.hh
index de1c92c85..29540dcd3 100644
--- a/src/libstore/build/goal.hh
+++ b/src/libstore/build/goal.hh
@@ -88,8 +88,8 @@ protected:
 public:
     struct [[nodiscard]] WorkResult {
         ExitCode exitCode;
-        BuildResult result;
-        std::shared_ptr<Error> ex;
+        BuildResult result = {};
+        std::shared_ptr<Error> ex = {};
         bool permanentFailure = false;
         bool timedOut = false;
         bool hashMismatch = false;
diff --git a/src/libstore/nar-accessor.cc b/src/libstore/nar-accessor.cc
index 7600de6e7..f228004a9 100644
--- a/src/libstore/nar-accessor.cc
+++ b/src/libstore/nar-accessor.cc
@@ -20,10 +20,10 @@ struct NarMember
        file in the NAR. */
     uint64_t start = 0, size = 0;
 
-    std::string target;
+    std::string target = {};
 
     /* If this is a directory, all the children of the directory. */
-    std::map<std::string, NarMember> children;
+    std::map<std::string, NarMember> children = {};
 };
 
 struct NarAccessor : public FSAccessor
diff --git a/src/libstore/path-with-outputs.hh b/src/libstore/path-with-outputs.hh
index 57e03252d..8e2da1908 100644
--- a/src/libstore/path-with-outputs.hh
+++ b/src/libstore/path-with-outputs.hh
@@ -17,7 +17,7 @@ namespace nix {
 struct StorePathWithOutputs
 {
     StorePath path;
-    std::set<std::string> outputs;
+    std::set<std::string> outputs = {};
 
     std::string to_string(const Store & store) const;
 
diff --git a/src/libstore/realisation.hh b/src/libstore/realisation.hh
index f2b228fa0..baeb7a2c9 100644
--- a/src/libstore/realisation.hh
+++ b/src/libstore/realisation.hh
@@ -50,7 +50,7 @@ struct Realisation {
     DrvOutput id;
     StorePath outPath;
 
-    StringSet signatures;
+    StringSet signatures = {};
 
     /**
      * The realisations that are required for the current one to be valid.
@@ -58,7 +58,7 @@ struct Realisation {
      * When importing this realisation, the store will first check that all its
      * dependencies exist, and map to the correct output path
      */
-    std::map<DrvOutput, StorePath> dependentRealisations;
+    std::map<DrvOutput, StorePath> dependentRealisations = {};
 
     nlohmann::json toJSON() const;
     static Realisation fromJSON(const nlohmann::json& json, const std::string& whence);
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index d35a0e6a1..18f80eef8 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -829,7 +829,7 @@ StorePathSet Store::queryValidPaths(const StorePathSet & paths, SubstituteFlag m
     {
         size_t left;
         StorePathSet valid;
-        std::exception_ptr exc;
+        std::exception_ptr exc = {};
     };
 
     Sync<State> state_(State{paths.size(), StorePathSet()});