List the built-in Homebrew sources and use tap names to add and remove sources

src/UniGetUI.PackageEngine.Managers.Homebrew/Helpers/HomebrewSourceHelper.cs

@@ -19,7 +19,7 @@ public HomebrewSourceHelper(Homebrew manager)
 
     protected override IReadOnlyList<IManagerSource> GetSources_UnSafe()
     {
-        var sources = new List<ManagerSource>();
+        var tapLines = new List<string>();
 
         using var p = new Process
         {
@@ -32,8 +32,31 @@ protected override IReadOnlyList<IManagerSource> GetSources_UnSafe()
         while ((line = p.StandardOutput.ReadLine()) is not null)
         {
             logger.AddToStdOut(line);
-            var name = line.Trim();
+            tapLines.Add(line);
+        }
+
+        logger.AddToStdErr(p.StandardError.ReadToEnd());
+        p.WaitForExit();
+        logger.Close(p.ExitCode);
+        return BuildSourceList(tapLines);
+    }
+
+    /// <summary>
+    /// Homebrew 4 and later serve homebrew/core and homebrew/cask from the API, so `brew tap` does not
+    /// print them and `brew tap homebrew/core` is refused. The built-in sources are therefore always
+    /// listed, followed by every other tap.
+    /// </summary>
+    internal IReadOnlyList<IManagerSource> BuildSourceList(IEnumerable<string> tapLines)
+    {
+        var sources = new List<IManagerSource>(Manager.Properties.KnownSources);
+
+        foreach (string rawLine in tapLines)
+        {
+            var name = rawLine.Trim();
             if (name.Length == 0) continue;
+            if (name.Equals(CoreTap, StringComparison.OrdinalIgnoreCase)
+                || name.Equals(CaskTap, StringComparison.OrdinalIgnoreCase))
+                continue;
 
             // Build a best-effort URL: "org/repo" → "https://github.com/org/homebrew-repo"
             Uri url;
@@ -60,19 +83,33 @@ protected override IReadOnlyList<IManagerSource> GetSources_UnSafe()
             }
         }
 
-        logger.AddToStdErr(p.StandardError.ReadToEnd());
-        p.WaitForExit();
-        logger.Close(p.ExitCode);
         return sources;
     }
 
     // ── Add / remove ───────────────────────────────────────────────────────
 
+    internal const string CoreTap = "homebrew/core";
+    internal const string CaskTap = "homebrew/cask";
+
+    /// <summary>
+    /// The tap name brew expects for a source: the built-in "Homebrew" and "Homebrew Cask" sources map to
+    /// homebrew/core and homebrew/cask; any other source is named after its tap already.
+    /// </summary>
+    internal static string GetTapName(IManagerSource source) => source.Name switch
+    {
+        "Homebrew" => CoreTap,
+        "Homebrew Cask" => CaskTap,
+        _ => source.Name,
+    };
+
     public override string[] GetAddSourceParameters(IManagerSource source)
-        => ["tap", source.Name, source.Url.ToString()];
+    {
+        string tap = GetTapName(source);
+        return tap == source.Name ? ["tap", tap, source.Url.ToString()] : ["tap", tap];
+    }
 
     public override string[] GetRemoveSourceParameters(IManagerSource source)
-        => ["untap", source.Name];
+        => ["untap", GetTapName(source)];
 
     protected override OperationVeredict _getAddSourceOperationVeredict(
         IManagerSource source, int ReturnCode, string[] Output)

src/UniGetUI.PackageEngine.Managers.Homebrew/Homebrew.cs

@@ -69,11 +69,7 @@ public Homebrew()
             InstallVerb = "install",
             UpdateVerb = "upgrade",
             UninstallVerb = "uninstall",
-            KnownSources =
-            [
-                new HomebrewSource(this, "Homebrew", new Uri("https://github.com/Homebrew/homebrew-core")),
-                new HomebrewSource(this, "Homebrew Cask", new Uri("https://github.com/Homebrew/homebrew-cask")),
-            ],
+            KnownSources = CreateBuiltInSources(this, OperatingSystem.IsMacOS()),
             DefaultSource = new HomebrewSource(this, "Homebrew", new Uri("https://github.com/Homebrew/homebrew-core")),
         };
 
@@ -82,6 +78,19 @@ public Homebrew()
         OperationHelper = new HomebrewPkgOperationHelper(this);
     }
 
+    /// <summary>
+    /// The sources Homebrew serves from its API without a tap: formulae everywhere, casks on macOS
+    /// only (Homebrew on Linux has no casks).
+    /// </summary>
+    internal static IManagerSource[] CreateBuiltInSources(Homebrew manager, bool isMacOS)
+    {
+        var formulae = new HomebrewSource(manager, "Homebrew", new Uri("https://github.com/Homebrew/homebrew-core"));
+        if (!isMacOS)
+            return [formulae];
+
+        return [formulae, new HomebrewSource(manager, "Homebrew Cask", new Uri("https://github.com/Homebrew/homebrew-cask"))];
+    }
+
     // ── Executable discovery ───────────────────────────────────────────────
 
     public override IReadOnlyList<string> FindCandidateExecutableFiles()

src/UniGetUI.PackageEngine.Tests/HomebrewManagerTests.cs

@@ -1,5 +1,6 @@
 using UniGetUI.Core.Data;
 using UniGetUI.Core.SettingsEngine;
+using UniGetUI.PackageEngine.Classes.Manager;
 using UniGetUI.PackageEngine.Interfaces;
 using UniGetUI.PackageEngine.Managers.HomebrewManager;
 using UniGetUI.PackageEngine.PackageClasses;
@@ -103,6 +104,73 @@ public void ParseAvailableUpdatesDetectsBothFormulaAndCaskUpdates()
         );
     }
 
+    // Issue #5219: on Homebrew 4 and later `brew tap` prints nothing for homebrew/core, so the
+    // sources page was empty and the default "Homebrew" source was reported as not configured.
+    [Fact]
+    public void SourcesListTheBuiltInSourcesWhenBrewTapPrintsNothing()
+    {
+        var manager = new Homebrew();
+        var helper = (HomebrewSourceHelper)manager.SourcesHelper;
+
+        IReadOnlyList<IManagerSource> sources = helper.BuildSourceList([]);
+
+        Assert.Equal(manager.Properties.KnownSources, sources);
+        Assert.Contains(sources, source => source.Name == "Homebrew");
+    }
+
+    [Fact]
+    public void SourcesListOtherTapsOnceAndSkipTheBuiltInTaps()
+    {
+        var manager = new Homebrew();
+        var helper = (HomebrewSourceHelper)manager.SourcesHelper;
+
+        IReadOnlyList<IManagerSource> sources = helper.BuildSourceList(
+            ["homebrew/core", "hashicorp/tap", "", "  ", "Homebrew/cask"]
+        );
+
+        Assert.Equal(manager.Properties.KnownSources.Length + 1, sources.Count);
+        Assert.Equal(manager.Properties.KnownSources, sources.Take(manager.Properties.KnownSources.Length));
+        IManagerSource tap = sources[^1];
+        Assert.Equal("hashicorp/tap", tap.Name);
+        Assert.Equal(new Uri("https://github.com/hashicorp/homebrew-tap"), tap.Url);
+    }
+
+    [Fact]
+    public void CasksAreABuiltInSourceOnMacOsOnly()
+    {
+        var manager = new Homebrew();
+
+        Assert.Equal(["Homebrew"], Homebrew.CreateBuiltInSources(manager, isMacOS: false).Select(s => s.Name));
+        Assert.Equal(
+            ["Homebrew", "Homebrew Cask"],
+            Homebrew.CreateBuiltInSources(manager, isMacOS: true).Select(s => s.Name)
+        );
+        Assert.Equal(
+            OperatingSystem.IsMacOS() ? 2 : 1,
+            manager.Properties.KnownSources.Length
+        );
+    }
+
+    // brew rejects "Homebrew" and "Homebrew Cask" ("Error: Invalid tap name: 'Homebrew'"); the
+    // parameters must name the tap.
+    [Theory]
+    [InlineData("Homebrew", "https://github.com/Homebrew/homebrew-core", "tap homebrew/core", "untap homebrew/core")]
+    [InlineData("Homebrew Cask", "https://github.com/Homebrew/homebrew-cask", "tap homebrew/cask", "untap homebrew/cask")]
+    [InlineData(
+        "hashicorp/tap",
+        "https://github.com/hashicorp/homebrew-tap",
+        "tap hashicorp/tap https://github.com/hashicorp/homebrew-tap",
+        "untap hashicorp/tap"
+    )]
+    public void AddAndRemoveParametersUseTheTapName(string name, string url, string add, string remove)
+    {
+        var manager = new Homebrew();
+        var source = new ManagerSource(manager, name, new Uri(url));
+
+        Assert.Equal(add, string.Join(' ', manager.SourcesHelper.GetAddSourceParameters(source)));
+        Assert.Equal(remove, string.Join(' ', manager.SourcesHelper.GetRemoveSourceParameters(source)));
+    }
+
     private static string[] ReadFixtureLines(string relativePath)
     {
         return PackageEngineFixtureFiles.ReadAllText(relativePath).Replace("\r\n", "\n").Split('\n');