From bf19eebb9b905c1366fa96ae9b1b9f06aa1fe672 Mon Sep 17 00:00:00 2001
From: eldritch horrors <pennae@lix.systems>
Date: Fri, 8 Mar 2024 09:51:51 +0100
Subject: [PATCH] use the same bindings print for ExprAttrs and ExprLet

this also has the effect of sorting let bindings lexicographically
rather than by symbol creation order as was previously done, giving a
better canonicalization in the process.

(cherry picked from commit 6c08fba533ef31cad2bdc03ba72ecf58dc8ee5a0)
Change-Id: Ia887f629305645bb8a165fbbc0d32e620912595a
---
 src/libexpr/nixexpr.cc                        | 21 ++++++++-----------
 src/libexpr/nixexpr.hh                        |  2 ++
 tests/functional/lang/parse-okay-inherits.exp |  2 +-
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index 531d5027c..525b2440b 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -68,10 +68,8 @@ void ExprOpHasAttr::show(const SymbolTable & symbols, std::ostream & str) const
     str << ") ? " << showAttrPath(symbols, attrPath) << ")";
 }
 
-void ExprAttrs::show(const SymbolTable & symbols, std::ostream & str) const
+void ExprAttrs::showBindings(const SymbolTable & symbols, std::ostream & str) const
 {
-    if (recursive) str << "rec ";
-    str << "{ ";
     typedef const decltype(attrs)::value_type * Attr;
     std::vector<Attr> sorted;
     for (auto & i : attrs) sorted.push_back(&i);
@@ -95,6 +93,13 @@ void ExprAttrs::show(const SymbolTable & symbols, std::ostream & str) const
         i.valueExpr->show(symbols, str);
         str << "; ";
     }
+}
+
+void ExprAttrs::show(const SymbolTable & symbols, std::ostream & str) const
+{
+    if (recursive) str << "rec ";
+    str << "{ ";
+    showBindings(symbols, str);
     str << "}";
 }
 
@@ -150,15 +155,7 @@ void ExprCall::show(const SymbolTable & symbols, std::ostream & str) const
 void ExprLet::show(const SymbolTable & symbols, std::ostream & str) const
 {
     str << "(let ";
-    for (auto & i : attrs->attrs)
-        if (i.second.inherited()) {
-            str << "inherit " << symbols[i.first] << "; ";
-        }
-        else {
-            str << symbols[i.first] << " = ";
-            i.second.e->show(symbols, str);
-            str << "; ";
-        }
+    attrs->showBindings(symbols, str);
     str << "in ";
     body->show(symbols, str);
     str << ")";
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
index 246221c0f..793e1a707 100644
--- a/src/libexpr/nixexpr.hh
+++ b/src/libexpr/nixexpr.hh
@@ -201,6 +201,8 @@ struct ExprAttrs : Expr
     ExprAttrs() : recursive(false) { };
     PosIdx getPos() const override { return pos; }
     COMMON_METHODS
+
+    void showBindings(const SymbolTable & symbols, std::ostream & str) const;
 };
 
 struct ExprList : Expr
diff --git a/tests/functional/lang/parse-okay-inherits.exp b/tests/functional/lang/parse-okay-inherits.exp
index 050b54afd..722101ceb 100644
--- a/tests/functional/lang/parse-okay-inherits.exp
+++ b/tests/functional/lang/parse-okay-inherits.exp
@@ -1 +1 @@
-(let c = { }; b = 2; in { a = 1; inherit b ; d = (c).d; e = (c).e; f = 3; })
+(let b = 2; c = { }; in { a = 1; inherit b ; d = (c).d; e = (c).e; f = 3; })