Remove some trim/AOT warnings: easy cases

[charlesroddie]

Description

Removes four trim/Native AOT warnings with local changes:

• IpAddressPreferenceUtilities: lists the preference names in the lookup's initializer instead of building it with Enum.GetValues(Type) (IL3050). Enum.GetValues<T> isn't available on net462. A unit test checks that every enum value's name converts.
• LocalDB: uses the generic Marshal.GetDelegateForFunctionPointer<T> (IL3050).
• SqlDataSourceEnumeratorNativeHelper: replaces DataTable.Select with a row scan (IL2026). The comparison matches DataTable's string equality: options follow DataTable.CaseSensitive (this table is case-insensitive, so case, kana type and width are ignored) and trailing spaces are trimmed. ParseServerEnumString is now internal and has unit tests.
• SqlMetaDataFactory: suppresses IL2072 on a small AddColumn helper around DataColumnCollection.Add(string, Type). DataColumn needs the annotation only to find a static Null member on INullable column types, which schema collection queries don't return. ConnectionSchemaTest now asserts this for every schema collection.

Trim/AOT warnings with -p:IsAotCompatible=true (unique by location and code):

TFM	Before	After
net8.0	50	46
net9.0	52	48

No public API or behavioral changes for valid server and instance names.

Issues

Part of #1947.

Testing

• Built net462, net8.0 and net9.0 with -p:IsAotCompatible=true; no warnings in the touched files.
• Existing connection string, enumerator and metadata unit tests pass on net462, net8.0 and net10.0.
• ConnectionSchemaTest (16 tests), including the new INullable check, passes on net8.0 against SQL Server 2019 LocalDB.
• New SqlDataSourceEnumeratorNativeHelperTest (parsing; de-duplication across case, trailing ASCII and ideographic spaces, and full-width names; instance matching) passes on net462, net8.0 and net10.0.
• The LocalDB delegate path has no unit test; it needs LocalDB on Windows and was not run locally.

🤖 Generated with Claude Code

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🔵 Needs a closer look

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Pull request overview

Removes four trim/Native AOT warnings without changing the public API.

Changes:

• Replaces reflection-based enum and delegate APIs.
• Replaces DataTable.Select duplicate filtering with row scanning.
• Suppresses the schema metadata reflection warning.

File summaries

File	Description
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlMetaDataFactory.cs	Updated as part of this pull request.
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ManagedSni/LocalDB.netcore.cs	Updated as part of this pull request.
src/Microsoft.Data.SqlClient/src/Microsoft/Data/Sql/SqlDataSourceEnumeratorNativeHelper.cs	Updated as part of this pull request.
src/Microsoft.Data.SqlClient/src/Microsoft/Data/Common/ConnectionString/IpAddressPreferenceUtilities.cs	Updated as part of this pull request.

Review details

Suppressed comments (2)

src/Microsoft.Data.SqlClient/src/Microsoft/Data/Sql/SqlDataSourceEnumeratorNativeHelper.cs:173

• ContainsInstance now reimplements DataTable.Select's duplicate semantics, including culture-sensitive case/kana/width and trailing-space handling, but this path has no automated regression coverage: the existing manual tests only assert a row-count bound and require SQL Browser. Add focused tests around parsing/deduplication, including apostrophes, empty instance names, and the stated comparison rules, so this replacement cannot silently diverge from DataTable.Select.

        private static bool ContainsInstance(DataTable dataTable, string serverName, string instanceName)
        {
            CompareInfo compareInfo = dataTable.Locale.CompareInfo;

            foreach (DataRow row in dataTable.Rows)

src/Microsoft.Data.SqlClient/src/Microsoft/Data/Sql/SqlDataSourceEnumeratorNativeHelper.cs:189

• This trims the values before comparing, which changes the old DataTable.Select semantics: string equality treats trailing spaces as significant, so rows such as HOST and HOST were distinct before but are now treated as duplicates and one is dropped. Please compare the raw values here (or add an explicit regression test if trimming is intentional).

                s1?.TrimEnd(' ', '\u3000'),
                s2?.TrimEnd(' ', '\u3000'),

• Files reviewed: 4/4 changed files
• Comments generated: 0
• Review effort level: Lite (auto)

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🟡 Changes recommended

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Review details

Suppressed comments (1)

Previously missed (1) — in code that hasn't changed since the last review.

src/Microsoft.Data.SqlClient/src/Microsoft/Data/Sql/SqlDataSourceEnumeratorNativeHelper.cs:152

• Please add a focused regression test for this replacement, covering duplicate server/instance names that differ only by case, kana/width, trailing spaces, and embedded apostrophes. The existing enumerator tests only assert a broad row-count range against a live SQL Browser, so they would not detect a mismatch between this comparator and the former DataTable.Select behavior.

• Files reviewed: 5/5 changed files
• Comments generated: 1
• Review effort level: Lite (auto)

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

[Copilot]

🟡 Changes recommended

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Review details

Suppressed comments (2)

Previously missed (1) — in code that hasn't changed since the last review.

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/DataBaseSchemaTest/ConnectionSchemaTest.cs:180

• The new helper is documented only with an inline comment, but the repository's test guidance requires XML summaries for helper methods and parameter documentation where applicable. Replace this comment with XML documentation describing the assertion and the schemaTable parameter.

src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/Sql/SqlDataSourceEnumeratorNativeHelperTest.cs:34

• Because this refactor replaces DataTable.Select's comparison, these tests should cover the remaining comparison semantics encoded in EqualsInTable: IgnoreKanaType, IgnoreWidth, and U+3000 trailing-space trimming. Without representative kana/full-/half-width and ideographic-space cases, a regression in any of those flags would still pass; add those cases to this theory.

    [Theory]
    [InlineData("server", "inst")]
    [InlineData("SERVER", "INST")]
    [InlineData("server  ", "inst ")]
    public void EquivalentEntry_IsDropped(string serverName, string instanceName)

• Files reviewed: 7/7 changed files
• Comments generated: 1
• Review effort level: Lite (auto)

Note

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[Copilot]

🟢 Approval recommended

No unresolved issues were identified that would block approval.

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 0 new
• Review effort level: Lite (auto)

Note

Copilot is running an experiment and ran this review at Lite.

[Copilot]

🟢 Approval recommended

Reviewed changes have no unresolved blocking issues.

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 0 new
• Review effort level: Lite (auto)

Note

Copilot is running an experiment and ran this review at Lite.

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🟢 Approval recommended

Reviewed changes have no unresolved blocking issues.

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 0 new
• Review effort level: Lite (auto)

Note

Copilot is running an experiment and ran this review at Lite.

[cheenamalhotra]

/azp run

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