[Repo Assist] Fix #1439: InferRows counts CSV rows, not text lines (multiline quoted fields) (#1625)

* Update test/build dependencies: FAKE 6.1.4, NUnit 3.13.3, FsUnit 4.2.0, FsCheck 2.16.6

- FAKE packages: 6.1.3 → 6.1.4 (patch)
- NUnit: 3.13.1 → 3.13.3 (patch)
- FsUnit: 4.0.4 → 4.2.0 (minor)
- FsCheck: 2.15.1 → 2.16.6 (minor)

Build: passes (0 errors)
Tests: all offline tests pass; network tests skip due to sandbox

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix #1439: InferRows now counts CSV rows not text lines for multiline quoted fields

The maxNumberOfRows text-truncation in parseTextAtDesignTime counted text
lines using reader.ReadLine(), which broke CSV files where a single data row
spans multiple text lines due to quoted fields (e.g. "multi-\nline",2).

Fix: pass None as maxNumberOfRows so the raw text is never pre-truncated.
Row-count limiting is already handled correctly by InferColumnTypes via
Seq.truncate inferRows - this has always been the authoritative row limit.
The performance cost is reading the full sample file as a string; this is
the same cost as all other providers (XmlProvider, JsonProvider) which also
pass None here.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Repo Assist <repo-assist@github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Don Syme <dsyme@users.noreply.github.com>
Co-authored-by: Don Syme <dsyme@github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: 4 people

src/FSharp.Data.DesignTime/Csv/CsvProvider.fs

@@ -202,10 +202,12 @@ type public CsvProvider(cfg: TypeProviderConfig) as this =
               CreateFromTextReaderForSampleList = fun _ -> failwith "Not Applicable"
               CreateFromValue = None }
 
-        let maxNumberOfRows = if inferRows > 0 then Some inferRows else None
-
         // On the CsvProvider the schema might be partial and we will still infer from the sample
-        // So we handle it in a custom way
+        // So we handle it in a custom way.
+        // Note: we pass None for maxNumberOfRows so that the raw text is never truncated by
+        // line count. Truncating by line is incorrect for CSV because a single data row can span
+        // multiple text lines when fields are quoted (see issue #1439). Row limiting during
+        // inference is handled correctly by InferColumnTypes via its own inferRows parameter.
         generateType
             "CSV"
             (if sample <> "" then Sample sample else Schema schema)
@@ -216,7 +218,7 @@ type public CsvProvider(cfg: TypeProviderConfig) as this =
             resolutionFolder
             resource
             typeName
-            maxNumberOfRows
+            None
 
     // Add static parameter that specifies the API we want to get (compile-time)
     let parameters =

tests/FSharp.Data.Tests/CsvProvider.fs

@@ -705,3 +705,18 @@ let ``Can infer from a multiline schema`` () =
     csv.NumberOfColumns |> should equal 16
     firstRow.OrderCreated |> should equal "2022-01-01 10:00:00"
     firstRow.FioFull |> should equal "John Smith"
+
+// Regression test for issue #1439: InferRows must count CSV rows, not text lines.
+// A multiline quoted field occupies 2 text lines but is only 1 data row.
+// With InferRows=2, both data rows should be accessible (the first spans 2 lines).
+type MultilineFieldsCsv = CsvProvider<"Data/MultilineFields.csv", InferRows=2>
+
+[<Test>]
+let ``InferRows counts CSV rows not text lines for multiline quoted fields`` () =
+    let csv = MultilineFieldsCsv.GetSample()
+    let rows = csv.Rows |> Seq.toArray
+    rows.Length |> should equal 2
+    rows.[0].F1 |> should equal "multi-\nline field"
+    rows.[0].F2 |> should equal 2
+    rows.[1].F1 |> should equal "normal"
+    rows.[1].F2 |> should equal 3

tests/FSharp.Data.Tests/Data/MultilineFields.csv

@@ -0,0 +1,4 @@
+f1,f2
+"multi-
+line field",2
+normal,3