feat: abbreviated dependency tree printing

doc/user-changes.md

@@ -6,6 +6,38 @@ stay on top of `alr` new features.
 
 ## Release `2.1`
 
+### Abbreviated `--tree` output for repeating dependencies
+
+PR [1814](https://github.com/alire-project/alire/pull/1814)
+
+By default, repeated dependencies are now omitted by `--tree` output, e.g.:
+
+```
+$ alr show --tree libgpr2
+...
+Dependencies (tree):
+   gnat=14.1.3 (gnat_native) (>=14)
+   gnatcoll=25.0.0 (~25.0.0)
+   ├── gnat=14.1.3 (gnat_native) (>=13)
+   └── libgpr=25.0.0 (~25.0.0)
+       ├── gnat=14.1.3 (gnat_native) (/=2020)
+       └── xmlada=25.0.0 (~25.0.0)
+           └── gnat=14.1.3 (gnat_native) (>=11)
+   gnatcoll_gmp=25.0.0 (~25.0.0)
+   ├── gnatcoll=25.0.0 (~25.0.0) ···
+   └── libgmp=6.3.0 (*)
+   gnatcoll_iconv=25.0.0 (~25.0.0)
+   └── gnatcoll=25.0.0 (~25.0.0) ···
+```
+
+Whenever '...' appears, it means that the preceding release has its
+dependencies already printed somewhere in the preceding tree lines.
+
+The old behavior can be obtained by increasing verbosity with the global `-v`
+switch.
+
+### Faster `alr search` without resolving dependencies
+
 PR [1799](https://github.com/alire-project/alire/pull/1799)
 
 `alr search` no longer solves dependencies of releases by default, in order to

src/alire/alire-solutions.adb

@@ -916,7 +916,8 @@ package body Alire.Solutions is
    procedure Print_Tree (This       : Solution;
                          Root       : Alire.Releases.Release;
                          Prefix     : String := "";
-                         Print_Root : Boolean := True)
+                         Print_Root : Boolean := True;
+                         Concise    : Boolean := not Detailed)
    is
 
       Mid_Node  : constant String :=
@@ -925,14 +926,52 @@ package body Alire.Solutions is
                     (if TTY.Color_Enabled then U ("└── ") else "+-- ");
       Branch    : constant String :=
                     (if TTY.Color_Enabled then U ("│   ") else "|   ");
+      More_Deps : constant String :=
+                    (if TTY.Color_Enabled then U (" ···") else " ...");
       No_Branch : constant String := "    ";
 
+      Printed   : AAA.Strings.Sets.Set;
+      --  Dependencies already printed, to avoid reprinting in Concise mode
+
+      -----------
+      -- Label --
+      -----------
+      --  The dependency Milestone or State
+      function Label (Dep : Dependencies.Dependency) return String
+      is (if This.State (Dep.Crate).Has_Release
+          then This.State (Dep.Crate).Milestone_Image
+          else This.State (Dep.Crate).TTY_Image);
+
+      -----------
+      -- Print --
+      -----------
+
       procedure Print (Deps   : Dependencies.Containers.Set;
                        Prefix : String := "";
                        Omit   : Boolean := False)
         --  Omit is used to remove the top-level connectors, for when the tree
         --  is printed without the root release.
       is
+
+         -------------------------------------
+         -- Inline_Concise_Marker_If_Needed --
+         -------------------------------------
+
+         function Inline_Concise_Marker_If_Needed
+           (Dep : Dependencies.Dependency) return String is
+         begin
+            if Concise
+              and then Printed.Contains (Label (Dep))
+              and then This.State (Dep.Crate).Has_Release
+              and then not Conditional.Enumerate
+                (This.State (Dep.Crate).Release.Dependencies).Is_Empty
+            then
+               return More_Deps;
+            else
+               return "";
+            end if;
+         end Inline_Concise_Marker_If_Needed;
+
          Last : UString;
          --  Used to store the last dependency name in a subtree, to be able to
          --  use the proper ASCII connector. See just below.
@@ -966,27 +1005,36 @@ package body Alire.Solutions is
 
                   --  For a dependency solved by a release, print exact
                   --  version. Otherwise print the state of the dependency.
-                  & (if This.State (Dep.Crate).Has_Release
-                    then This.State (Dep.Crate).Milestone_Image
-                    else This.State (Dep.Crate).TTY_Image)
+                  & Label (Dep)
 
                   --  And dependency that introduces the crate in the solution
-                  & " (" & TTY.Emph (Dep.Versions.Image) & ")");
-
-               --  Recurse for further releases
-
-               if This.State (Dep.Crate).Has_Release then
-                  Print (Conditional.Enumerate
-                          (This.State (Dep.Crate).Release.Dependencies).To_Set,
-                         Prefix =>
-                           Prefix
-                           --  Indent adding the proper running connector
-                           & (if Omit
-                              then ""
-                              else (if +Dep.Crate = +Last
-                                    then No_Branch  -- End of this connector
-                                    else Branch))); -- "│" over the subtree
+                  & " (" & TTY.Emph (Dep.Versions.Image) & ")"
+
+                  --  If concise and this has dependencies, print the marker
+                  & Inline_Concise_Marker_If_Needed (Dep)
+                 );
+
+               --  Recurse for further releases if not conise and printed
+
+               if (not Concise or else not Printed.Contains (Label (Dep)))
+                 and then This.State (Dep.Crate).Has_Release
+                 and then not Conditional.Enumerate
+                   (This.State (Dep.Crate).Release.Dependencies).Is_Empty
+               then
+                  Print
+                    (Conditional.Enumerate
+                       (This.State (Dep.Crate).Release.Dependencies).To_Set,
+                     Prefix =>
+                       Prefix
+                       --  Indent adding the proper running connector
+                     & (if Omit
+                       then ""
+                       else (if +Dep.Crate = +Last
+                         then No_Branch  -- End of this connector
+                         else Branch))); -- "│" over the subtree
                end if;
+
+               Printed.Include (Label (Dep));
             end if;
          end loop;
       end Print;

src/alire/alire-solutions.ads

@@ -412,9 +412,11 @@ package Alire.Solutions is
    procedure Print_Tree (This       : Solution;
                          Root       : Alire.Releases.Release;
                          Prefix     : String := "";
-                         Print_Root : Boolean := True);
+                         Print_Root : Boolean := True;
+                         Concise    : Boolean := not Detailed);
    --  Print the solution in tree form. If Print_Root, Root is printed too;
    --  otherwise the tree is a forest starting at Root direct dependencies.
+   --  If Concise, print each unique dependency only once.
 
    procedure Print_Versions (This : Solution;
                              Root : Roots.Root);

testsuite/tests/with/tree-concise/test.py

@@ -0,0 +1,42 @@
+"""
+Test the concise mode of the --tree switch. Repeating dependencies are
+substituted by a "..." ellipsis.
+"""
+
+import os
+import re
+from drivers.alr import run_alr, alr_with, init_local_crate
+from drivers.asserts import assert_eq, assert_match
+
+# Prepare a crate in which dependencies appear twice, so their dependencies in
+# turn can be elided.
+
+init_local_crate("yyy")
+alr_with("hello")
+os.chdir("..")
+init_local_crate("xxx")
+alr_with("hello")
+alr_with("yyy", path="../yyy")
+
+# Check the concise tree
+assert_eq("""\
+xxx=0.1.0-dev
++-- hello=1.0.1 (*)
+|   +-- libhello=1.0.0 (^1.0)
++-- yyy=0.1.0-dev (*)
+    +-- hello=1.0.1 (*) ...\
+""",
+           run_alr("with", "--tree").out.strip())
+
+# Check the regular tree
+assert_match(".*" + re.escape("""\
+xxx=0.1.0-dev
++-- hello=1.0.1 (*)
+|   +-- libhello=1.0.0 (^1.0)
++-- yyy=0.1.0-dev (*)
+    +-- hello=1.0.1 (*)
+        +-- libhello=1.0.0 (^1.0)\
+"""),
+           run_alr("-v", "with", "--tree", quiet=False).out.strip())
+
+print("SUCCESS")

testsuite/tests/with/tree-concise/test.yaml

@@ -0,0 +1,5 @@
+driver: python-script
+build_mode: both
+indexes:
+    basic_index:
+        in_fixtures: true