test(trace): check the generated line counts in the e2e suite

Also note that the session line totals are raw diff totals when a
commit cannot be read.

Assisted-by: Claude Code
Signed-off-by: Jose I. Paris <jiparis@chainloop.dev>

Chainloop-Trace-Sessions: d13fc871-d294-4c08-b1d4-e7bdcaef6969

Author: jiparis

app/cli/internal/trace/e2e/checks.go

@@ -99,9 +99,7 @@ var features = map[string]Feature{
 	"Shell changes attribution": {Checks: []Check{{scenarioEditAndCommit, checkFileAttributedToAI("shell.txt")}}},
 	"Partial commits":           {Checks: []Check{{scenarioPartial, checkBothCommitsCredited}}},
 	"Line ranges":               {Checks: []Check{{scenarioEditAndCommit, checkLineRanges("greeting.txt", 3)}}},
-	"Generated line counts": {
-		NotCovered: "neither the user nor the evidence can see the generated line counts yet",
-	},
+	"Generated line counts":     {Checks: []Check{{scenarioEditAndCommit, checkGeneratedLineCounts}}},
 
 	// User experience
 	"Welcome message":         {Checks: []Check{{scenarioEditAndCommit, checkWelcomeMessage}}},
@@ -196,6 +194,23 @@ func checkFileAttributedToAI(path string) func(s *Session) error {
 	}
 }
 
+// checkGeneratedLineCounts verifies that the evidence reports the lines of
+// all the agent edits. Each net AI line came from an agent edit, so the
+// generated lines are at least the net AI lines.
+func checkGeneratedLineCounts(s *Session) error {
+	cc := evidence(s).CodeChanges
+	if cc == nil {
+		return errors.New("the evidence has no code changes")
+	}
+	if cc.AIGeneratedLinesAdded == 0 {
+		return errors.New("the evidence has no generated lines added")
+	}
+	if cc.AIGeneratedLinesAdded < cc.AILinesAdded {
+		return fmt.Errorf("%d generated lines added, fewer than the %d net AI lines added", cc.AIGeneratedLinesAdded, cc.AILinesAdded)
+	}
+	return nil
+}
+
 // hookMessage returns the first hook message of an event, or errNotCovered
 // when the harness does not report hook messages.
 func hookMessage(s *Session, event string) (*HookMessage, error) {

internal/schemavalidators/internal_schemas/aicodingsession/ai-coding-session-0.1.schema.json

@@ -170,11 +170,11 @@
         },
         "lines_added": {
           "type": "integer",
-          "description": "Net lines added by the session's commits: AI plus human lines"
+          "description": "Net lines added by the session's commits (AI plus human); raw diff totals if a commit is unreadable"
         },
         "lines_removed": {
           "type": "integer",
-          "description": "Net lines removed by the session's commits: AI plus human lines"
+          "description": "Net lines removed by the session's commits (AI plus human); raw diff totals if a commit is unreadable"
         },
         "ai_lines_added": {
           "type": "integer",

pkg/attestation/crafter/materials/aicodingsession/aicodingsession.go

@@ -255,7 +255,7 @@ type CodeChanges struct {
 	FilesModified int `json:"files_modified,omitempty"`
 	FilesCreated  int `json:"files_created,omitempty"`
 	FilesDeleted  int `json:"files_deleted,omitempty"`
-	// Net lines of the session's commits: the AI lines plus the human lines.
+	// Net lines of the session's commits (AI plus human); raw diff totals if a commit is unreadable.
 	LinesAdded   int `json:"lines_added,omitempty"`
 	LinesRemoved int `json:"lines_removed,omitempty"`
 	// Net committed lines attributed to the AI.