Fix CopilotCliRunner version parsing for 'GitHub Copilot CLI X.X.X' format

src/Aspire.Cli/Agents/CopilotCli/CopilotCliRunner.cs

@@ -52,28 +52,8 @@ internal sealed class CopilotCliRunner(ILogger<CopilotCliRunner> logger) : ICopi
             }
 
             var output = await outputTask.ConfigureAwait(false);
-            var versionString = output.Trim();
 
-            if (string.IsNullOrEmpty(versionString))
-            {
-                logger.LogDebug("GitHub Copilot CLI returned empty version output");
-                return null;
-            }
-
-            // Version output may be on the first line if multi-line
-            var lines = versionString.Split(['\n', '\r'], StringSplitOptions.RemoveEmptyEntries);
-            if (lines.Length > 0)
-            {
-                versionString = lines[0].Trim();
-            }
-
-            // Try to parse the version string (may have a 'v' prefix like "v1.2.3")
-            if (versionString.StartsWith('v') || versionString.StartsWith('V'))
-            {
-                versionString = versionString[1..];
-            }
-
-            if (SemVersion.TryParse(versionString, SemVersionStyles.Any, out var version))
+            if (TryParseVersionOutput(output, out var version))
             {
                 logger.LogDebug("Found GitHub Copilot CLI version: {Version}", version);
                 return version;
@@ -88,4 +68,40 @@ internal sealed class CopilotCliRunner(ILogger<CopilotCliRunner> logger) : ICopi
             return null;
         }
     }
+
+    internal static bool TryParseVersionOutput(string output, out SemVersion? version)
+    {
+        version = null;
+        var versionString = output.Trim();
+
+        if (string.IsNullOrEmpty(versionString))
+        {
+            return false;
+        }
+
+        // Version output may be on the first line if multi-line
+        var lines = versionString.Split(['\n', '\r'], StringSplitOptions.RemoveEmptyEntries);
+        if (lines.Length > 0)
+        {
+            versionString = lines[0].Trim();
+        }
+
+        // Try to extract the version from known formats like "GitHub Copilot CLI 0.0.397"
+        var lastSpaceIndex = versionString.LastIndexOf(' ');
+        if (lastSpaceIndex >= 0)
+        {
+            versionString = versionString[(lastSpaceIndex + 1)..];
+        }
+
+        // Trim common trailing punctuation that may follow the version (for example, "0.0.397.")
+        versionString = versionString.TrimEnd('.', ',', ')');
+
+        // Try to parse the version string (may have a 'v' prefix like "v1.2.3")
+        if (versionString.StartsWith('v') || versionString.StartsWith('V'))
+        {
+            versionString = versionString[1..];
+        }
+
+        return SemVersion.TryParse(versionString, SemVersionStyles.Any, out version);
+    }
 }

tests/Aspire.Cli.Tests/Agents/CopilotCliRunnerTests.cs

@@ -24,4 +24,37 @@ public async Task GetVersionAsync_ChecksForCopilot()
         // we just verify the method completes without throwing
         // Version can be null (not installed) or a real version
     }
+
+    [Theory]
+    [InlineData("GitHub Copilot CLI 0.0.397", 0, 0, 397)]
+    [InlineData("GitHub Copilot CLI 1.2.3", 1, 2, 3)]
+    [InlineData("0.0.397", 0, 0, 397)]
+    [InlineData("1.2.3", 1, 2, 3)]
+    [InlineData("v1.2.3", 1, 2, 3)]
+    [InlineData("V1.2.3", 1, 2, 3)]
+    [InlineData("GitHub Copilot CLI 0.0.397\nsome other output", 0, 0, 397)]
+    [InlineData("  GitHub Copilot CLI 0.0.397  ", 0, 0, 397)]
+    [InlineData("GitHub Copilot CLI 0.0.397.", 0, 0, 397)]
+    public void TryParseVersionOutput_ValidVersionStrings_ReturnsTrue(string input, int major, int minor, int patch)
+    {
+        var result = CopilotCliRunner.TryParseVersionOutput(input, out var version);
+
+        Assert.True(result);
+        Assert.NotNull(version);
+        Assert.Equal(major, version.Major);
+        Assert.Equal(minor, version.Minor);
+        Assert.Equal(patch, version.Patch);
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData("not a version")]
+    public void TryParseVersionOutput_InvalidVersionStrings_ReturnsFalse(string input)
+    {
+        var result = CopilotCliRunner.TryParseVersionOutput(input, out var version);
+
+        Assert.False(result);
+        Assert.Null(version);
+    }
 }