Warn on suspicious caret use

This warning is shown at most once per run, and is an optional blocker during
`alr with` and `alr publish`.

A new `Alire.Warnings` package allows simple emission of warnings only once.

src/alire/alire-config.ads

@@ -95,6 +95,9 @@ package Alire.Config with Preelaborate is
       --  When set to True, distro will be reported as unknown, and in turn no
       --  native package manager will be used.
 
+      Warning_Caret : constant Config_Key := "warning.caret";
+      --  Set to false to disable warnings about caret/tilde use for ^0 deps.
+
    end Keys;
 
 private
@@ -135,7 +138,64 @@ private
 
    function Image (Val : TOML.TOML_Value) return String;
 
-   type String_Access is access String;
-   Config_Path : String_Access;
+   function "+" (Source : String) return Ada.Strings.Unbounded.Unbounded_String
+                 renames Ada.Strings.Unbounded.To_Unbounded_String;
+
+   Builtins : constant array (Natural range <>) of Builtin_Entry :=
+     (
+      (+Keys.User_Name,
+       Cfg_String,
+       +("User full name. Used for the authors and " &
+          "maintainers field of a new crate.")),
+      (+Keys.User_Email,
+       Cfg_Email,
+       +("User email address. Used for the authors and" &
+           " maintainers field of a new crate.")),
+      (+Keys.User_Github_Login,
+       Cfg_GitHub_Login,
+       +("User GitHub login/username. Used to for the maintainers-logins " &
+           "field of a new crate.")),
+
+      (+Keys.Editor_Cmd,
+       Cfg_String,
+       +("Editor command and arguments for editing crate code (alr edit)." &
+           " The executables and arguments are separated by a single space" &
+           " character. The token ${GPR_FILE} is replaced by" &
+           " a path to the project file to open.")),
+
+      (+"msys2.do_not_install",
+       Cfg_Bool,
+       +("If true, Alire will not try to automatically" &
+          " install msys2 system package manager. (Windows only)")),
+
+      (+"msys2.install_dir",
+       Cfg_Absolute_Path,
+       +("Directory where Alire will detect and/or install" &
+           " msys2 system package manager. (Windows only)")),
+
+      (+"auto-gpr-with",
+       Cfg_Bool,
+       +("If true, Alire will automatically add/edit a list of 'with' " &
+           "statements in the root GPR project file based on the " &
+           "dependencies of the crate.")),
+
+      (+Keys.Update_Manually,
+       Cfg_Bool,
+       +("If true, Alire will not attempt to update dependencies even after "
+         & "the manifest is manually edited, or when no valid solution has "
+         & "been ever computed. All updates have to be manually requested "
+         & "through `alr update`")),
+
+      (+Keys.Distribution_Disable_Detection,
+       Cfg_Bool,
+       +("If true, Alire will report an unknown distribution and will not"
+         & " attempt to use the system package manager.")),
+
+      (+Keys.Warning_Caret,
+       Cfg_Bool,
+       +("If true, Alire will warn about the use of caret (^) "
+         & "for pre-1 dependencies."))
+
+     );
 
 end Alire.Config;

src/alire/alire-properties-licenses.adb

@@ -1,4 +1,5 @@
 with Alire.Errors;
+with Alire.Warnings;
 
 package body Alire.Properties.Licenses is
 
@@ -95,7 +96,7 @@ package body Alire.Properties.Licenses is
       Value : constant TOML.TOML_Value := From.Pop;
    begin
       if Value.Kind = TOML_Array then
-         Trace.Warning
+         Warnings.Warn_Once
            (From.Message
               ("Array of license in manifest is deprecated. " &
                  "License should be a single string containing a " &

src/alire/alire-publish.adb

@@ -491,6 +491,8 @@ package body Alire.Publish is
       Recommend : Utils.String_Vector; -- Optional
       Missing   : Utils.String_Vector; -- Mandatory
 
+      Caret_Pre_1 : Boolean := False; -- To warn about this
+
       function Tomify (S : String) return String renames TOML_Adapters.Tomify;
    begin
 
@@ -538,6 +540,8 @@ package body Alire.Publish is
          end if;
       end loop;
 
+      Caret_Pre_1 := Release.Check_Caret_Warning;
+
       if not Missing.Is_Empty then
          Ada.Text_IO.New_Line;
          Raise_Checked_Error ("Missing required properties: "
@@ -551,7 +555,8 @@ package body Alire.Publish is
       if Utils.User_Input.Query
         ("Do you want to proceed with this information?",
          Valid   => (Yes | No => True, others => False),
-         Default => (if Force or else Recommend.Is_Empty
+         Default => (if Force or else
+                         (Recommend.Is_Empty and then not Caret_Pre_1)
                      then Yes
                      else No)) /= Yes
       then

src/alire/alire-releases.adb

@@ -2,6 +2,7 @@ with Ada.Directories;
 with Ada.Strings.Fixed;
 with Ada.Text_IO;
 
+with Alire.Config;
 with Alire.Crates;
 with Alire.Defaults;
 with Alire.Errors;
@@ -10,6 +11,7 @@ with Alire.Requisites.Booleans;
 with Alire.TOML_Expressions;
 with Alire.TOML_Load;
 with Alire.Utils.YAML;
+with Alire.Warnings;
 
 with GNAT.IO; -- To keep preelaborable
 
@@ -58,6 +60,37 @@ package body Alire.Releases is
       return Enumerate (R.Dependencies.Evaluate (P));
    end Flat_Dependencies;
 
+   -------------------------
+   -- Check_Caret_Warning --
+   -------------------------
+   --  Warn of ^0.x dependencies that probably should be ~0.x
+   function Check_Caret_Warning (This : Release) return Boolean is
+      use Alire.Utils;
+      Warning_Id : constant String := "caret or tilde";
+      Newline    : constant String := ASCII.LF & "   ";
+   begin
+      for Dep of This.Flat_Dependencies loop
+         if Config.Get (Config.Keys.Warning_Caret, Default => True) and then
+           Utils.Contains (Dep.Versions.Image, "^0")
+         then
+            Warnings.Warn_Once
+              ("Possible tilde intended instead of caret for a 0.x version."
+               & Newline
+               & "Alire does not change the meaning of caret and tilde"
+               & " for pre/post-1.0 versions."
+               & Newline
+               & "The suspicious dependency is: " & TTY.Version (Dep.Image)
+               & Newline
+               & "You can disable this warning by setting the option "
+               & TTY.Emph (Config.Keys.Warning_Caret) & " to false.",
+               Warning_Id);
+            return True;
+         end if;
+      end loop;
+
+      return False;
+   end Check_Caret_Warning;
+
    ---------------
    -- Extending --
    ---------------

src/alire/alire-releases.ads

@@ -309,6 +309,10 @@ package Alire.Releases is
    --  Say if the property exists in any branch of the property tree. Key is
    --  case-insensitive.
 
+   function Check_Caret_Warning (This : Release) return Boolean;
+   --  Check if this release contains a ^0.x dependency, and warn about it.
+   --  Returns whether a warning was emitted.
+
 private
 
    use Semantic_Versioning;

src/alire/alire-warnings.adb

@@ -21,4 +21,11 @@ package body Alire.Warnings is
       end if;
    end Warn_Once;
 
+   --------------------
+   -- Already_Warned --
+   --------------------
+
+   function Already_Warned (ID : String) return Boolean
+   is (Already_Emitted.Contains (ID));
+
 end Alire.Warnings;

src/alire/alire-warnings.ads

@@ -1,10 +1,15 @@
 package Alire.Warnings with Preelaborate is
 
+   --  TODO: thread-unsafe
+
    procedure Warn_Once (Text : String;
                         ID   : String := "";
                         Level : Trace.Levels := Trace.Warning);
    --  Emit a warning just once. If it has been already seen, do not warn
    --  again. ID is used to determine if a warning has already been emitted
    --  or, when not given, the actual warning text.
 
+   function Already_Warned (ID : String) return Boolean;
+   --  Says if a warning has been already emitted in the current run
+
 end Alire.Warnings;

src/alire/alire-workspace.adb

@@ -12,37 +12,11 @@ with Alire.Paths;
 with Alire.Properties.Actions.Executor;
 with Alire.Roots;
 with Alire.Solutions.Diffs;
-with Alire.Utils.TTY;
-with Alire.Warnings;
 
 package body Alire.Workspace is
 
    use type Conditional.Dependencies;
 
-   -------------------------
-   -- Check_Caret_Warning --
-   -------------------------
-   --  Warn of ^0.x dependencies that probably should be ~0.x
-   procedure Check_Caret_Warning (Root : Roots.Root) is
-      use Alire.Utils;
-      Warning_Id : constant String := "caret or tilde";
-   begin
-      for Dep of Root.Release.Flat_Dependencies loop
-         if Utils.Contains (Dep.Versions.Image, "^0") then
-            Warnings.Warn_Once
-              ("Possible tilde instead of caret intended for a 0.x version.",
-               Warning_Id & "1");
-            Warnings.Warn_Once
-              ("Alire interprets caret and tilde the same way "
-               & "for both pre/post-1 versions.",
-               Warning_Id & "2");
-            Warnings.Warn_Once
-              ("The suspicious dependency is: " & TTY.Version (Dep.Image),
-               Warning_Id & "3");
-         end if;
-      end loop;
-   end Check_Caret_Warning;
-
    -------------------------
    -- Deploy_Dependencies --
    -------------------------
@@ -154,7 +128,8 @@ package body Alire.Workspace is
       --  taking advantage that this procedure is called whenever a change
       --  to dependencies is happening.
 
-      Check_Caret_Warning (Root);
+      pragma Assert (Root.Release.Check_Caret_Warning or else True);
+      --  We don't care about the return value here
 
    end Deploy_Dependencies;
 

src/alr/alr-commands-withing.adb

@@ -26,6 +26,8 @@ with Semantic_Versioning.Extended;
 
 package body Alr.Commands.Withing is
 
+   package Semver renames Semantic_Versioning;
+
    Switch_URL : constant String := "--use";
 
    procedure Replace_Current
@@ -145,14 +147,18 @@ package body Alr.Commands.Withing is
    procedure Detect_Softlink (Path : String) is
       Root : constant Alire.Roots.Optional.Root :=
                Alire.Roots.Optional.Detect_Root (Path);
+      use all type Semver.Point;
    begin
       if Root.Is_Valid then
          if Root.Value.Is_Stored then
             --  Add a dependency on ^(detected version) (i.e., safely
-            --  upgradable)
+            --  upgradable) or ~(detected version) (if pre-1.0).
             Add_Softlink
               (Dep_Spec => Root.Value.Release.Name_Str
-               & "^" & Root.Value.Release.Version.Image,
+               & (if Semver.Major (Root.Value.Release.Version) = 0
+                  then "~"
+                  else "^")
+               & Root.Value.Release.Version.Image,
                Path     => Path);
          else
             Reportaise_Command_Failed
@@ -247,8 +253,21 @@ package body Alr.Commands.Withing is
 
          Deps_Diff : constant Alire.Dependencies.Diffs.Diff :=
                        Alire.Dependencies.Diffs.Between (Old_Deps, New_Deps);
+
+         use Alire.Utils.User_Input;
       begin
 
+         --  First of all, warn about dubious caret
+
+         if New_Root.Release.Check_Caret_Warning and then
+           Query
+             (Question => "Do you want to continue with that dependency?",
+              Valid    => (Yes | No => True, others => False),
+              Default  => No) = No
+         then
+            Reportaise_Command_Failed ("Abandoned by user");
+         end if;
+
          --  Show changes to apply
 
          Trace.Info ("Requested changes:");