Preserve assistant newline semantics after #584

Scripts/Fixtures/test-suite-contract-ledger.tsv

@@ -474,6 +474,11 @@ root/RepoPromptTests.AgentToolTrackingControllerTests/testStopWaitsForCapturedOb
 root/RepoPromptTests.AgentToolTrackingControllerTests/testToolObserverCallbacksReturnBeforeFIFOTranscriptDeliveryCompletes	root	Tests/RepoPromptTests/AgentMode/AgentToolTrackingControllerTests.swift	RepoPromptTests.AgentToolTrackingControllerTests	testToolObserverCallbacksReturnBeforeFIFOTranscriptDeliveryCompletes	AgentMode	unreviewed		unreviewed	root_swiftpm	routine	1		unreviewed	unreviewed	0.001000			unreviewed	retain_pending_review		0	initial census source line 8
 root/RepoPromptTests.AgentTranscriptActivationRepaintRemountPolicyTests/testDuplicateRevisionExceededLimitDetachedOrIdleActivationSuppressesRemount	root	Tests/RepoPromptTests/AgentMode/Transcript/AgentTranscriptActivationRepaintRemountPolicyTests.swift	RepoPromptTests.AgentTranscriptActivationRepaintRemountPolicyTests	testDuplicateRevisionExceededLimitDetachedOrIdleActivationSuppressesRemount	AgentMode	unreviewed		unreviewed	root_swiftpm	routine	1		unreviewed	unreviewed	0.000000			unreviewed	retain_pending_review		0	initial census source line 20
 root/RepoPromptTests.AgentTranscriptActivationRepaintRemountPolicyTests/testEnteredHydratedLiveBottomActivationProducesRemountKey	root	Tests/RepoPromptTests/AgentMode/Transcript/AgentTranscriptActivationRepaintRemountPolicyTests.swift	RepoPromptTests.AgentTranscriptActivationRepaintRemountPolicyTests	testEnteredHydratedLiveBottomActivationProducesRemountKey	AgentMode	unreviewed		unreviewed	root_swiftpm	routine	1		unreviewed	unreviewed	0.000000			unreviewed	retain_pending_review		0	initial census source line 5
+root/RepoPromptTests.AgentAssistantLineDerivationTests/testCRLFCountsAsTwoScalarSeparatorsAndMatchesPreview	root	Tests/RepoPromptTests/AgentMode/AgentAssistantLineDerivationTests.swift	RepoPromptTests.AgentAssistantLineDerivationTests	testCRLFCountsAsTwoScalarSeparatorsAndMatchesPreview	AgentMode	agent_mode.assistant_line_derivation.crlf_agreement	assistant_collapse,crlf,newline_semantics,preview_agreement	deterministic_regression	root_swiftpm	fast	2		CRLF increments the bounded scalar count twice, produces the same Foundation preview line count, and collapses consistently at the ten-line boundary.	Character iteration could coalesce CRLF and make collapse eligibility disagree with preview and remaining-line counts.	0.000000			test_case	retain		0	Corrective coverage for PR #584; explicitly preserves the established scalar-separator contract.
+root/RepoPromptTests.AgentAssistantLineDerivationTests/testCombiningAndEmojiGraphemesDoNotCreateLines	root	Tests/RepoPromptTests/AgentMode/AgentAssistantLineDerivationTests.swift	RepoPromptTests.AgentAssistantLineDerivationTests	testCombiningAndEmojiGraphemesDoNotCreateLines	AgentMode	agent_mode.assistant_line_derivation.non_newline_graphemes	combining_grapheme,emoji_zwj,newline_semantics	deterministic_regression	root_swiftpm	fast	2		Combining and emoji ZWJ graphemes remain one exact line and pass through preview derivation unchanged.	A grapheme-oriented optimization could misclassify complex non-newline text or change the owning scalar contract.	0.000000			test_case	retain		0	Corrective coverage for PR #584 without a timing-sensitive CI benchmark.
+root/RepoPromptTests.AgentAssistantLineDerivationTests/testEmptyAndTrailingSeparatorInputs	root	Tests/RepoPromptTests/AgentMode/AgentAssistantLineDerivationTests.swift	RepoPromptTests.AgentAssistantLineDerivationTests	testEmptyAndTrailingSeparatorInputs	AgentMode	agent_mode.assistant_line_derivation.empty_trailing_contract	empty_input,trailing_separator,crlf,newline_semantics	boundary_contract	root_swiftpm	fast	9		Empty text remains one line; every trailing Foundation newline scalar retains an empty final component, with CRLF contributing two components.	An optimized scanner could drop trailing empty lines or change empty-input and CRLF preview behavior.	0.000000			test_case	retain		0	Corrective coverage for PR #584 across the complete trailing-separator matrix.
+root/RepoPromptTests.AgentAssistantLineDerivationTests/testLimitBoundariesReportExactnessAndMatchPreviewDecision	root	Tests/RepoPromptTests/AgentMode/AgentAssistantLineDerivationTests.swift	RepoPromptTests.AgentAssistantLineDerivationTests	testLimitBoundariesReportExactnessAndMatchPreviewDecision	AgentMode	agent_mode.assistant_line_derivation.limit_exactness	limit_zero,limit_boundary,is_exact,preview_agreement	boundary_contract	root_swiftpm	fast	6		Limits 0, 9, 10, and 11 return the exact bounded sentinel and isExact state while matching the preview collapse decision at and above each boundary.	Early exit could return the wrong sentinel or exactness and suppress or spuriously trigger assistant collapse.	0.000000			test_case	retain		0	Corrective boundary coverage for PR #584.
+root/RepoPromptTests.AgentAssistantLineDerivationTests/testRecognizesEveryFoundationNewlineScalar	root	Tests/RepoPromptTests/AgentMode/AgentAssistantLineDerivationTests.swift	RepoPromptTests.AgentAssistantLineDerivationTests	testRecognizesEveryFoundationNewlineScalar	AgentMode	agent_mode.assistant_line_derivation.newline_scalar_membership	lf,cr,vt,ff,nel,line_separator,paragraph_separator	contract_matrix	root_swiftpm	fast	7		LF, CR, VT, FF, NEL, U+2028, and U+2029 each increment the exact bounded count once and normalize to LF in preview text.	A native-property substitution could narrow or otherwise change the established Foundation newline scalar membership.	0.000000			test_case	retain		0	Corrective membership coverage for PR #584.
 root/RepoPromptTests.AgentTranscriptAssistantPreviewTests/testTerminalResponseDoesNotCrossTrailingNonAssistantBoundary	root	Tests/RepoPromptTests/AgentMode/Transcript/AgentTranscriptAssistantPreviewTests.swift	RepoPromptTests.AgentTranscriptAssistantPreviewTests	testTerminalResponseDoesNotCrossTrailingNonAssistantBoundary	AgentMode	agent_mode.transcript.terminal_assistant_preview	assistant_tail,tool_boundary,response_span	lifecycle_regression	root_swiftpm	routine	1		Terminal response preview joins only the asserted trailing assistant fragments and respects non-assistant/tool boundaries.	Terminal conclusions could lose assistant tails or cross a tool boundary and misrepresent the final response.	0.000000			test_case	retain		0	Authoritative test-list reconciliation for the current integration worktree.
 root/RepoPromptTests.AgentTranscriptAssistantPreviewTests/testTerminalResponseJoinsFragmentsAcrossResponseSpans	root	Tests/RepoPromptTests/AgentMode/Transcript/AgentTranscriptAssistantPreviewTests.swift	RepoPromptTests.AgentTranscriptAssistantPreviewTests	testTerminalResponseJoinsFragmentsAcrossResponseSpans	AgentMode	agent_mode.transcript.terminal_assistant_preview	assistant_tail,tool_boundary,response_span	lifecycle_regression	root_swiftpm	routine	1		Terminal response preview joins only the asserted trailing assistant fragments and respects non-assistant/tool boundaries.	Terminal conclusions could lose assistant tails or cross a tool boundary and misrepresent the final response.	0.000000			test_case	retain		0	Authoritative test-list reconciliation for the current integration worktree.
 root/RepoPromptTests.AgentTranscriptAssistantPreviewTests/testTerminalResponseJoinsTrailingFragmentsAndPreservesFullDetailRows	root	Tests/RepoPromptTests/AgentMode/Transcript/AgentTranscriptAssistantPreviewTests.swift	RepoPromptTests.AgentTranscriptAssistantPreviewTests	testTerminalResponseJoinsTrailingFragmentsAndPreservesFullDetailRows	AgentMode	agent_mode.transcript.terminal_assistant_preview	assistant_tail,tool_boundary,response_span	lifecycle_regression	root_swiftpm	routine	1		Terminal response preview joins only the asserted trailing assistant fragments and respects non-assistant/tool boundaries.	Terminal conclusions could lose assistant tails or cross a tool boundary and misrepresent the final response.	0.000000			test_case	retain		0	Authoritative test-list reconciliation for the current integration worktree.

Sources/RepoPrompt/Features/AgentMode/Views/AgentMessageBubble.swift

@@ -1408,7 +1408,8 @@ enum AgentAssistantLineDerivation {
             return (count, false)
         }
 
-        for char in text where char.isNewline {
+        let newlineScalars = CharacterSet.newlines
+        for scalar in text.unicodeScalars where newlineScalars.contains(scalar) {
             count += 1
             if count > limit {
                 return (count, false)

Tests/RepoPromptTests/AgentMode/AgentAssistantLineDerivationTests.swift

@@ -0,0 +1,135 @@
+import Foundation
+@testable import RepoPromptApp
+import XCTest
+
+final class AgentAssistantLineDerivationTests: XCTestCase {
+    func testRecognizesEveryFoundationNewlineScalar() {
+        let separators: [(name: String, scalar: Unicode.Scalar)] = [
+            ("LF", "\n"),
+            ("CR", "\r"),
+            ("VT", "\u{000B}"),
+            ("FF", "\u{000C}"),
+            ("NEL", "\u{0085}"),
+            ("line separator", "\u{2028}"),
+            ("paragraph separator", "\u{2029}")
+        ]
+
+        for separator in separators {
+            let text = "before\(String(separator.scalar))after"
+            let bounded = AgentAssistantLineDerivation.lineCount(upTo: 10, in: text)
+            let preview = AgentAssistantLineDerivation.previewSummary(
+                for: text,
+                previewLineCount: 10
+            )
+
+            XCTAssertEqual(bounded.count, 2, separator.name)
+            XCTAssertTrue(bounded.isExact, separator.name)
+            XCTAssertEqual(preview.lineCount, 2, separator.name)
+            XCTAssertEqual(preview.previewText, "before\nafter", separator.name)
+            XCTAssertFalse(preview.needsCollapse, separator.name)
+        }
+    }
+
+    func testCRLFCountsAsTwoScalarSeparatorsAndMatchesPreview() {
+        let shortText = "before\r\nafter"
+        let shortCount = AgentAssistantLineDerivation.lineCount(upTo: 10, in: shortText)
+        let shortPreview = AgentAssistantLineDerivation.previewSummary(
+            for: shortText,
+            previewLineCount: 10
+        )
+
+        XCTAssertEqual(shortCount.count, 3, "CRLF must increment once for CR and once for LF")
+        XCTAssertTrue(shortCount.isExact)
+        XCTAssertEqual(shortPreview.lineCount, shortCount.count)
+        XCTAssertEqual(shortPreview.previewText, "before\n\nafter")
+        XCTAssertFalse(shortPreview.needsCollapse)
+
+        let lineLimit = 10
+        let boundaryText = String(repeating: "line\n", count: 8) + "line\r\nfinal"
+        let boundaryCount = AgentAssistantLineDerivation.lineCount(upTo: lineLimit, in: boundaryText)
+        let boundaryPreview = AgentAssistantLineDerivation.previewSummary(
+            for: boundaryText,
+            previewLineCount: lineLimit
+        )
+
+        XCTAssertEqual(boundaryCount.count, 11)
+        XCTAssertFalse(boundaryCount.isExact)
+        XCTAssertEqual(boundaryPreview.lineCount, boundaryCount.count)
+        XCTAssertTrue(boundaryPreview.needsCollapse)
+        XCTAssertEqual(!boundaryCount.isExact || boundaryCount.count > lineLimit, boundaryPreview.needsCollapse)
+    }
+
+    func testEmptyAndTrailingSeparatorInputs() {
+        let cases: [(name: String, text: String, count: Int, preview: String)] = [
+            ("empty", "", 1, ""),
+            ("trailing LF", "value\n", 2, "value\n"),
+            ("trailing CR", "value\r", 2, "value\n"),
+            ("trailing VT", "value\u{000B}", 2, "value\n"),
+            ("trailing FF", "value\u{000C}", 2, "value\n"),
+            ("trailing NEL", "value\u{0085}", 2, "value\n"),
+            ("trailing line separator", "value\u{2028}", 2, "value\n"),
+            ("trailing paragraph separator", "value\u{2029}", 2, "value\n"),
+            ("trailing CRLF", "value\r\n", 3, "value\n\n")
+        ]
+
+        for testCase in cases {
+            let bounded = AgentAssistantLineDerivation.lineCount(upTo: 10, in: testCase.text)
+            let preview = AgentAssistantLineDerivation.previewSummary(
+                for: testCase.text,
+                previewLineCount: 10
+            )
+
+            XCTAssertEqual(bounded.count, testCase.count, testCase.name)
+            XCTAssertTrue(bounded.isExact, testCase.name)
+            XCTAssertEqual(preview.lineCount, testCase.count, testCase.name)
+            XCTAssertEqual(preview.previewText, testCase.preview, testCase.name)
+            XCTAssertFalse(preview.needsCollapse, testCase.name)
+        }
+    }
+
+    func testCombiningAndEmojiGraphemesDoNotCreateLines() {
+        let cases: [(name: String, text: String)] = [
+            ("combining grapheme", "e\u{0301}"),
+            ("emoji ZWJ grapheme", "👩🏽‍💻")
+        ]
+
+        for testCase in cases {
+            let bounded = AgentAssistantLineDerivation.lineCount(upTo: 10, in: testCase.text)
+            let preview = AgentAssistantLineDerivation.previewSummary(
+                for: testCase.text,
+                previewLineCount: 10
+            )
+
+            XCTAssertEqual(bounded.count, 1, testCase.name)
+            XCTAssertTrue(bounded.isExact, testCase.name)
+            XCTAssertEqual(preview.lineCount, 1, testCase.name)
+            XCTAssertEqual(preview.previewText, testCase.text, testCase.name)
+            XCTAssertFalse(preview.needsCollapse, testCase.name)
+        }
+    }
+
+    func testLimitBoundariesReportExactnessAndMatchPreviewDecision() {
+        let cases: [(limit: Int, lineCount: Int, expectedCount: Int, isExact: Bool)] = [
+            (0, 11, 1, false),
+            (9, 9, 9, true),
+            (9, 10, 10, false),
+            (10, 10, 10, true),
+            (10, 11, 11, false),
+            (11, 11, 11, true)
+        ]
+
+        for testCase in cases {
+            let text = Array(repeating: "line", count: testCase.lineCount).joined(separator: "\n")
+            let bounded = AgentAssistantLineDerivation.lineCount(upTo: testCase.limit, in: text)
+            let preview = AgentAssistantLineDerivation.previewSummary(
+                for: text,
+                previewLineCount: testCase.limit
+            )
+            let message = "limit=\(testCase.limit), lines=\(testCase.lineCount)"
+
+            XCTAssertEqual(bounded.count, testCase.expectedCount, message)
+            XCTAssertEqual(bounded.isExact, testCase.isExact, message)
+            XCTAssertEqual(!bounded.isExact || bounded.count > testCase.limit, preview.needsCollapse, message)
+        }
+    }
+}