cq: improve derivation printing configuration

Change-Id: I7f16afa921cf2a33f750cb0f5cc53fa36a6a6964

lix/libcmd/repl.cc

@@ -210,13 +210,12 @@ struct NixRepl
     void printValue(std::ostream & str,
                               Value & v,
                               unsigned int maxDepth = std::numeric_limits<unsigned int>::max(),
-                              bool replDerivation = false)
+                              unsigned int derivationPathDepth = 0)
     {
         ::nix::printValue(state, str, v, PrintOptions {
             .ansiColors = true,
             .force = true,
-            .derivationPaths = !replDerivation,
-            .replDerivation = replDerivation,
+            .derivationPathDepth = derivationPathDepth,
             .maxDepth = maxDepth,
             .prettyIndent = 2,
             .errors = ErrorPrintBehavior::ThrowTopLevel,
@@ -796,9 +795,9 @@ ProcessLineResult NixRepl::processLine(std::string line)
         if (v.type() == nString) {
             std::cout << v.str();
         } else if (v.type() == nAttrs && state.isDerivation(v)) {
-            printValue(std::cout, v, 2, true);
+            printValue(std::cout, v, 2, 1);
         } else {
-            printValue(std::cout, v, std::numeric_limits<unsigned int>::max());
+            printValue(std::cout, v, std::numeric_limits<unsigned int>::max(), 0);
         }
         std::cout << std::endl;
     }

lix/libexpr/print-options.hh

@@ -48,16 +48,12 @@ struct PrintOptions
     bool force = false;
 
     /**
-     * If true and `force` is set, print derivations as
-     * `«derivation /nix/store/...»` instead of as attribute sets.
+     * Determines at what depth derivations start getting printed as paths.
+     * When `force` is true and our print depth is greater than or equal to
+     * this value, print derivations as `«derivation /nix/store/...»`
+     * instead of as attribute sets.
      */
-    bool derivationPaths = false;
-
-    /**
-     * If true, we are interactively printing a full derivation and should
-     * switch back to printing paths as desired normally after the first entry.
-     */
-    bool replDerivation = false;
+    size_t derivationPathDepth = std::numeric_limits<size_t>::max();
 
     /**
      * If true, track which values have been printed and skip them on

lix/libexpr/print.cc

@@ -281,16 +281,13 @@ private:
 
     void printAttrs(Value & v, size_t depth)
     {
-        if (options.force && options.derivationPaths && state.isDerivation(v)) {
+        bool shouldSimplifyDerivations = options.force && depth >= options.derivationPathDepth;
+        bool isDerivation = state.isDerivation(v);
+        if (shouldSimplifyDerivations && isDerivation) {
             printDerivation(v);
         } else if (seen && !v.attrs()->empty() && !seen->insert(v.attrs()).second) {
             printRepeated();
         } else if (depth < options.maxDepth || v.attrs()->empty()) {
-            bool isPrintingReplDerivation = depth == 0 && options.replDerivation && state.isDerivation(v);
-            if (isPrintingReplDerivation) {
-                // Switch back to eliding paths if it was initially off.
-                options.derivationPaths = true;
-            }
             increaseIndent();
             output << "{";
 
@@ -331,7 +328,7 @@ private:
                 output << " = ";
 
                 // Elide repeated drvAttrs attribute.
-                if (isPrintingReplDerivation && i.first == "drvAttrs") {
+                if (!shouldSimplifyDerivations && isDerivation && i.first == "drvAttrs") {
                     state.forceValue(i.second->value, noPos);
                     if (i.second->value.type() == ValueType::nAttrs) {
                         printElided(i.second->value.attrs()->size(), "attribute", "attributes");

lix/nix/eval.cc

@@ -110,7 +110,7 @@ struct CmdEval : MixJSON, InstallableCommand, MixReadOnlyOption
                     v,
                     PrintOptions{
                         .force = true,
-                        .derivationPaths = true,
+                        .derivationPathDepth = 0,
                         .errors = ErrorPrintBehavior::ThrowTopLevel,
                     }
                 )

tests/unit/libexpr/value/print.cc

@@ -450,7 +450,7 @@ TEST_F(ValuePrintingTests, ansiColorsDerivation)
          PrintOptions {
              .ansiColors = true,
              .force = true,
-             .derivationPaths = true
+             .derivationPathDepth = 0
          });
 
     test(vAttrs,
@@ -507,7 +507,7 @@ TEST_F(ValuePrintingTests, ansiColorsDerivationError)
          PrintOptions {
              .ansiColors = true,
              .force = true,
-             .derivationPaths = true,
+             .derivationPathDepth = 0,
          });
 }