From 61e3d598b67290ca66f34fcac7b7373f506240da Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 4 Jun 2020 10:57:40 +0200
Subject: [PATCH 1/2] Rename 'nix dev-shell' to 'nix develop'

Fixes #3648.
---
 src/nix/{dev-shell.cc => develop.cc} | 14 +++++++-------
 src/nix/local.mk                     |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)
 rename src/nix/{dev-shell.cc => develop.cc} (96%)

diff --git a/src/nix/dev-shell.cc b/src/nix/develop.cc
similarity index 96%
rename from src/nix/dev-shell.cc
rename to src/nix/develop.cc
index d300f6a23..3045d7dc3 100644
--- a/src/nix/dev-shell.cc
+++ b/src/nix/develop.cc
@@ -110,7 +110,7 @@ StorePath getDerivationEnvironment(ref<Store> store, const StorePath & drvPath)
 
     auto builder = baseNameOf(drv.builder);
     if (builder != "bash")
-        throw Error("'nix dev-shell' only works on derivations that use 'bash' as their builder");
+        throw Error("'nix develop' only works on derivations that use 'bash' as their builder");
 
     auto getEnvShPath = store->addTextToStore("get-env.sh", getEnvSh, {});
 
@@ -231,11 +231,11 @@ struct Common : InstallableCommand, MixProfile
     }
 };
 
-struct CmdDevShell : Common, MixEnvironment
+struct CmdDevelop : Common, MixEnvironment
 {
     std::vector<std::string> command;
 
-    CmdDevShell()
+    CmdDevelop()
     {
         addFlag({
             .longName = "command",
@@ -259,15 +259,15 @@ struct CmdDevShell : Common, MixEnvironment
         return {
             Example{
                 "To get the build environment of GNU hello:",
-                "nix dev-shell nixpkgs.hello"
+                "nix develop nixpkgs.hello"
             },
             Example{
                 "To store the build environment in a profile:",
-                "nix dev-shell --profile /tmp/my-shell nixpkgs.hello"
+                "nix develop --profile /tmp/my-shell nixpkgs.hello"
             },
             Example{
                 "To use a build environment previously recorded in a profile:",
-                "nix dev-shell /tmp/my-shell"
+                "nix develop /tmp/my-shell"
             },
         };
     }
@@ -341,4 +341,4 @@ struct CmdPrintDevEnv : Common
 };
 
 static auto r1 = registerCommand<CmdPrintDevEnv>("print-dev-env");
-static auto r2 = registerCommand<CmdDevShell>("dev-shell");
+static auto r2 = registerCommand<CmdDevelop>("develop");
diff --git a/src/nix/local.mk b/src/nix/local.mk
index 8c0eed19e..43b7754e3 100644
--- a/src/nix/local.mk
+++ b/src/nix/local.mk
@@ -28,4 +28,4 @@ $(eval $(call install-symlink, $(bindir)/nix, $(libexecdir)/nix/build-remote))
 
 src/nix-env/user-env.cc: src/nix-env/buildenv.nix.gen.hh
 
-src/nix/dev-shell.cc: src/nix/get-env.sh.gen.hh
+src/nix/develop.cc: src/nix/get-env.sh.gen.hh

From 0f44b60e6dc999697bf9f2a4b3652a0551016598 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 4 Jun 2020 11:14:19 +0200
Subject: [PATCH 2/2] Make 'nix dev-shell' a deprecated alias for 'nix develop'

---
 src/libutil/args.cc | 11 ++++++++---
 src/libutil/args.hh |  2 ++
 src/libutil/util.hh |  3 +--
 src/nix/main.cc     |  2 ++
 4 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/libutil/args.cc b/src/libutil/args.cc
index f829415d1..afeaf4cea 100644
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@@ -217,10 +217,15 @@ MultiCommand::MultiCommand(const Commands & commands)
 {
     expectedArgs.push_back(ExpectedArg{"command", 1, true, [=](std::vector<std::string> ss) {
         assert(!command);
-        auto i = commands.find(ss[0]);
+        auto cmd = ss[0];
+        if (auto alias = get(deprecatedAliases, cmd)) {
+            warn("'%s' is a deprecated alias for '%s'", cmd, *alias);
+            cmd = *alias;
+        }
+        auto i = commands.find(cmd);
         if (i == commands.end())
-            throw UsageError("'%s' is not a recognised command", ss[0]);
-        command = {ss[0], i->second()};
+            throw UsageError("'%s' is not a recognised command", cmd);
+        command = {cmd, i->second()};
     }});
 
     categories[Command::catDefault] = "Available commands";
diff --git a/src/libutil/args.hh b/src/libutil/args.hh
index 1932e6a8a..154d1e6aa 100644
--- a/src/libutil/args.hh
+++ b/src/libutil/args.hh
@@ -234,6 +234,8 @@ public:
 
     std::map<Command::Category, std::string> categories;
 
+    std::map<std::string, std::string> deprecatedAliases;
+
     // Selected command, if any.
     std::optional<std::pair<std::string, ref<Command>>> command;
 
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index a63ee05b3..4b117f9bc 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -459,8 +459,7 @@ string base64Encode(const string & s);
 string base64Decode(const string & s);
 
 
-/* Get a value for the specified key from an associate container, or a
-   default value if the key doesn't exist. */
+/* Get a value for the specified key from an associate container. */
 template <class T>
 std::optional<typename T::mapped_type> get(const T & map, const typename T::key_type & key)
 {
diff --git a/src/nix/main.cc b/src/nix/main.cc
index ef301580a..1120ba5ef 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -110,6 +110,8 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
             .description = "consider all previously downloaded files out-of-date",
             .handler = {[&]() { refresh = true; }},
         });
+
+        deprecatedAliases.insert({"dev-shell", "develop"});
     }
 
     void printFlags(std::ostream & out) override