Add NU1017 (#3472)

Author: Nigusu-Allehu

docs/reference/Errors-and-Warnings.md

@@ -27,7 +27,7 @@ NuGet supports the following configuration properties.
 
 | Group | Error Numbers |
 | --- | --- |
-| Invalid input errors | [NU1001](./errors-and-warnings/NU1001.md), [NU1002](./errors-and-warnings/NU1002.md), [NU1003](./errors-and-warnings/NU1003.md), [NU1004](./errors-and-warnings/NU1004.md), [NU1005](./errors-and-warnings/NU1005.md), [NU1006](./errors-and-warnings/NU1006.md), [NU1007](./errors-and-warnings/NU1007.md), [NU1008](./errors-and-warnings/NU1008.md), [NU1009](./errors-and-warnings/NU1009.md), [NU1010](./errors-and-warnings/NU1010.md), [NU1011](./errors-and-warnings/NU1011.md), [NU1012](./errors-and-warnings/NU1012.md), [NU1013](./errors-and-warnings/NU1013.md), [NU1014](./errors-and-warnings/NU1014.md), [NU1015](./errors-and-warnings/NU1015.md), [NU1016](./errors-and-warnings/NU1016.md) |
+| Invalid input errors | [NU1001](./errors-and-warnings/NU1001.md), [NU1002](./errors-and-warnings/NU1002.md), [NU1003](./errors-and-warnings/NU1003.md), [NU1004](./errors-and-warnings/NU1004.md), [NU1005](./errors-and-warnings/NU1005.md), [NU1006](./errors-and-warnings/NU1006.md), [NU1007](./errors-and-warnings/NU1007.md), [NU1008](./errors-and-warnings/NU1008.md), [NU1009](./errors-and-warnings/NU1009.md), [NU1010](./errors-and-warnings/NU1010.md), [NU1011](./errors-and-warnings/NU1011.md), [NU1012](./errors-and-warnings/NU1012.md), [NU1013](./errors-and-warnings/NU1013.md), [NU1014](./errors-and-warnings/NU1014.md), [NU1015](./errors-and-warnings/NU1015.md), [NU1016](./errors-and-warnings/NU1016.md), [NU1017](./errors-and-warnings/NU1017.md) |
 | Missing package and project errors | [NU1100](./errors-and-warnings/NU1100.md), [NU1101](./errors-and-warnings/NU1101.md), [NU1102](./errors-and-warnings/NU1102.md), [NU1103](./errors-and-warnings/NU1103.md), [NU1104](./errors-and-warnings/NU1104.md), [NU1105](./errors-and-warnings/NU1105.md), [NU1106](./errors-and-warnings/NU1106.md), [NU1107](./errors-and-warnings/NU1107.md), [NU1108](./errors-and-warnings/NU1108.md), [NU1109](./errors-and-warnings/NU1109.md) |
 | Package source mapping errors | [NU1110](./errors-and-warnings/NU1110.md) |
 | Compatibility errors | [NU1201](./errors-and-warnings/NU1201.md), [NU1202](./errors-and-warnings/NU1202.md), [NU1203](./errors-and-warnings/NU1203.md), [NU1204](./errors-and-warnings/NU1204.md), [NU1401](./errors-and-warnings/NU1401.md), [NU1402](./errors-and-warnings/NU1402.md), [NU1403](./errors-and-warnings/NU1403.md) |

docs/reference/errors-and-warnings/NU1017.md

@@ -0,0 +1,51 @@
+---
+title: NuGet Error NU1017
+description: NU1017 error code
+author: Nigusu-Allehu
+ms.author: Nigusu-Allehu
+ms.date: 09/23/2025
+ms.topic: reference
+f1_keywords: 
+  - "NU1017"
+---
+
+# NuGet Error NU1017
+
+## Scenario
+
+> Invalid package id : `contoso../id`.
+
+### Issue
+
+The package ID is invalid because it does not match the required format.
+NuGet validates package IDs using this regex:
+
+```regex
+^\w+([.-]\w+)*$
+```
+
+* The ID must **start with a letter or number**.
+* It can only contain **letters, numbers, dots (`.`), and dashes (`-`)**.
+* Dots or dashes must be followed by more letters or numbers.
+* You can have multiple parts separated by `.` or `-`, like `Contoso.App.Service`.
+
+### Solution
+
+To fix this error:
+
+* Replace or remove any invalid characters from the package ID. Only letters, numbers, dots (`.`), and dashes (`-`) are allowed.
+* Ensure the package ID starts with a letter or number.
+* Dots (`.`) or dashes (`-`) must always be followed by another letter or number (no consecutive dots/dashes, and none at the end).
+* For example, change `contoso../id` to `Contoso.Id`.
+
+Valid:
+
+```xml
+<PackageReference Include="Contoso.Id" Version="1.0.0" />
+```
+
+Invalid:
+
+```xml
+<PackageReference Include="contoso../id" Version="1.0.0" />
+```