Improve log rendering error handling and test coverage

Refactors log rendering to print errors to stderr and continue processing on JSON parse or rendering failures, instead of returning early. Updates tests to check both stdout and stderr outputs, and adds new test cases and testdata for tolerant parsing and error scenarios.

pkg/cmd/agent-task/shared/log.go

@@ -133,15 +133,16 @@ func renderLogEntry(entry chatCompletionChunkEntry, w io.Writer, io *iostreams.I
 			case "view":
 				args := viewToolArgs{}
 				if err := json.Unmarshal([]byte(tc.Function.Arguments), &args); err != nil {
-					return false, fmt.Errorf("failed to parse 'view' tool call arguments: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to parse 'view' tool call arguments: %v\n", err)
+					continue
 				}
-				fmt.Fprintf(w, "View %s\n", cs.Bold(relativeFilePath(args.Path)))
+				renderToolCallTitle(w, cs, fmt.Sprintf("View %s", cs.Bold(relativeFilePath(args.Path))), "")
 
 				content := stripDiffFormat(choice.Delta.Content)
 
-				// TODO: Strip the diff formatting from this, but for now render as it is.
 				if err := renderFileContentAsMarkdown(args.Path, content, w, io); err != nil {
-					return false, fmt.Errorf("failed to render viewed file content: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to render viewed file content: %v\n\n", err)
+					fmt.Fprintln(io.ErrOut, content) // raw fallback
 				}
 			case "bash":
 				if v := unmarshal[bashToolArgs](args); v != nil {
@@ -156,7 +157,8 @@ func renderLogEntry(entry chatCompletionChunkEntry, w io.Writer, io *iostreams.I
 						contentWithCommand = fmt.Sprintf("$ %s\n%s", v.Command, choice.Delta.Content)
 					}
 					if err := renderFileContentAsMarkdown("commands.sh", contentWithCommand, w, io); err != nil {
-						return false, fmt.Errorf("failed to render bash command output: %w", err)
+						fmt.Fprintf(io.ErrOut, "\nfailed to render bash command output: %v\n\n", err)
+						fmt.Fprintln(io.ErrOut, contentWithCommand)
 					}
 				}
 			// TODO: consider including more details for these bash-related tool calls.
@@ -193,24 +195,26 @@ func renderLogEntry(entry chatCompletionChunkEntry, w io.Writer, io *iostreams.I
 			case "think":
 				args := thinkToolArgs{}
 				if err := json.Unmarshal([]byte(tc.Function.Arguments), &args); err != nil {
-					return false, fmt.Errorf("failed to parse 'think' tool call arguments: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to parse 'think' tool call arguments: %v\n", err)
+					continue
 				}
 
 				// NOTE: omit the delta.content since it's the same as thought
 				renderToolCallTitle(w, cs, "Thought", "")
 				if err := renderRawMarkdown(args.Thought, w, io); err != nil {
-					return false, fmt.Errorf("failed to render thought: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to render thought: %v\n", err)
 				}
 			case "report_progress":
 				args := reportProgressToolArgs{}
 				if err := json.Unmarshal([]byte(tc.Function.Arguments), &args); err != nil {
-					return false, fmt.Errorf("failed to parse 'report_progress' tool call arguments: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to parse 'report_progress' tool call arguments: %v\n", err)
+					continue
 				}
 
 				renderToolCallTitle(w, cs, "Progress update", cs.Bold(args.CommitMessage))
 				if args.PrDescription != "" {
 					if err := renderRawMarkdown(args.PrDescription, w, io); err != nil {
-						return false, fmt.Errorf("failed to render PR description: %w", err)
+						fmt.Fprintf(io.ErrOut, "\nfailed to render PR description: %v\n", err)
 					}
 				}
 
@@ -218,29 +222,33 @@ func renderLogEntry(entry chatCompletionChunkEntry, w io.Writer, io *iostreams.I
 				if choice.Delta.Content != "" {
 					// Try to treat this as JSON
 					if err := renderContentAsJSONMarkdown("", choice.Delta.Content, w, io); err != nil {
-						return false, fmt.Errorf("failed to render progress update content: %w", err)
+						fmt.Fprintf(io.ErrOut, "\nfailed to render progress update content: %v\n", err)
 					}
 				}
 
 			case "create":
 				args := createToolArgs{}
 				if err := json.Unmarshal([]byte(tc.Function.Arguments), &args); err != nil {
-					return false, fmt.Errorf("failed to parse 'create' tool call arguments: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to parse 'create' tool call arguments: %v\n", err)
+					continue
 				}
 				renderToolCallTitle(w, cs, "Create", cs.Bold(relativeFilePath(args.Path)))
 
 				if err := renderFileContentAsMarkdown(args.Path, args.FileText, w, io); err != nil {
-					return false, fmt.Errorf("failed to render created file content: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to render created file content: %v\n\n", err)
+					fmt.Fprintln(io.ErrOut, args.FileText)
 				}
 			case "str_replace":
 				args := strReplaceToolArgs{}
 				if err := json.Unmarshal([]byte(tc.Function.Arguments), &args); err != nil {
-					return false, fmt.Errorf("failed to parse 'str_replace' tool call arguments: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to parse 'str_replace' tool call arguments: %v\n", err)
+					continue
 				}
 
 				renderToolCallTitle(w, cs, "Edit", cs.Bold(relativeFilePath(args.Path)))
 				if err := renderFileContentAsMarkdown("output.diff", choice.Delta.Content, w, io); err != nil {
-					return false, fmt.Errorf("failed to render str_replace diff: %w", err)
+					fmt.Fprintf(io.ErrOut, "\nfailed to render str_replace diff: %v\n\n", err)
+					fmt.Fprintln(io.ErrOut, choice.Delta.Content)
 				}
 			default:
 				// Unknown tool call. For example for "codeql_checker":

pkg/cmd/agent-task/shared/log_test.go

@@ -13,19 +13,26 @@ import (
 
 func TestFollow(t *testing.T) {
 	tests := []struct {
-		name string
-		log  string
-		want string
+		name           string
+		log            string
+		wantStdoutFile string
+		wantStderrFile string
 	}{
 		{
-			name: "sample log 1",
-			log:  "testdata/log-1-input.txt",
-			want: "testdata/log-1-want.txt",
+			name:           "sample log 1",
+			log:            "testdata/log-1-input.txt",
+			wantStdoutFile: "testdata/log-1-want.txt",
 		},
 		{
-			name: "sample log 2",
-			log:  "testdata/log-2-input.txt",
-			want: "testdata/log-2-want.txt",
+			name:           "sample log 2",
+			log:            "testdata/log-2-input.txt",
+			wantStdoutFile: "testdata/log-2-want.txt",
+		},
+		{
+			name:           "sample log 3 (tolerant parse failures)",
+			log:            "testdata/log-3-synthetic-failures-input.txt",
+			wantStdoutFile: "testdata/log-3-synthetic-failures-want.txt",
+			wantStderrFile: "testdata/log-3-synthetic-failures-want-stderr.txt",
 		},
 	}
 
@@ -50,7 +57,7 @@ func TestFollow(t *testing.T) {
 				return []byte(strings.Join(lines[0:hits], "\n\n")), nil
 			}
 
-			ios, _, stdout, _ := iostreams.Test()
+			ios, _, stdout, stderr := iostreams.Test()
 
 			err = NewLogRenderer().Follow(fetcher, stdout, ios)
 			require.NoError(t, err)
@@ -60,14 +67,29 @@ func TestFollow(t *testing.T) {
 			// stripped := strings.TrimSuffix(tt.log, ext)
 			// stripped = strings.TrimSuffix(stripped, "-input")
 			// os.WriteFile(stripped+"-want"+ext, stdout.Bytes(), 0644)
+			// if tt.wantStderrFile != "" {
+			// 	os.WriteFile(stripped+"-want-stderr"+ext, stderr.Bytes(), 0644)
+			// }
 
-			want, err := os.ReadFile(tt.want)
+			wantStdout, err := os.ReadFile(tt.wantStdoutFile)
 			require.NoError(t, err)
 
 			// Normalize CRLF to LF to make the tests OS-agnostic.
-			want = []byte(strings.ReplaceAll(string(want), "\r\n", "\n"))
+			wantStdout = []byte(strings.ReplaceAll(string(wantStdout), "\r\n", "\n"))
 
-			assert.Equal(t, string(want), stdout.String())
+			assert.Equal(t, string(wantStdout), stdout.String())
+
+			if tt.wantStderrFile != "" {
+				wantStderr, err := os.ReadFile(tt.wantStderrFile)
+				require.NoError(t, err)
+
+				// Normalize CRLF to LF to make the tests OS-agnostic.
+				wantStderr = []byte(strings.ReplaceAll(string(wantStderr), "\r\n", "\n"))
+
+				assert.Equal(t, string(wantStderr), stderr.String())
+			} else {
+				require.Empty(t, stderr, "expected no stderr output")
+			}
 		})
 	}
 }

pkg/cmd/agent-task/shared/testdata/log-3-input.txt

@@ -0,0 +1,27 @@
+data: {"id": "bad1", "object": "chat.completion.chunk", "choices": [ { "delta": { "tool_calls": [ { "function": { "name": "view", "arguments": "{bad json" } } ] } } ] }
+
+data: {"id":"v1","object":"chat.completion.chunk","choices":[{"delta":{"content":"@@ -1,2 +1,2 @@\n-old line\n+new line\nunchanged line\nINSIDE A VIEW CALL","tool_calls":[{"function":{"name":"view","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/README.md\"}"},"id":"tc1","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"v1b","object":"chat.completion.chunk","choices":[{"delta":{"content":"@@ -1,2 +1,2 @@\n-old line\n+new line\nunchanged line","tool_calls":[{"function":{"name":"view","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/README.md\"}"},"id":"tc1b","index":0}]}],"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"v1","object":"chat.completion.chunk","choices":[{"delta":{"content":"@@ -1,2 +1,2 @@\n-old line\n+new line\nunchanged line\nINSIDE A VIEW CALL","tool_calls":[{"function":{"name":"view","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/README.md"},"id":"tc1","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"t1","object":"chat.completion.chunk","choices":[{"delta":{"content":"THINK","tool_calls":[{"function":{"name":"think","arguments":"{\"thought\":123"},"id":"tc2","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"t2","object":"chat.completion.chunk","choices":[{"delta":{"content":"A valid thought to render.","reasoning_text":"Interim reasoning that should show as raw markdown.","tool_calls":[{"function":{"name":"think","arguments":"{\"thought\":\"A valid thought to render.\"}"},"id":"tc3","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"rp1","object":"chat.completion.chunk","choices":[{"delta":{"content":"RP","tool_calls":[{"function":{"name":"report_progress","arguments":"{\"commitMessage\": 5"},"id":"tc4","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"rp2","object":"chat.completion.chunk","choices":[{"delta":{"content":"not-json","tool_calls":[{"function":{"name":"report_progress","arguments":"{\"commitMessage\":\"Valid commit msg\"}"},"id":"tc5","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"c1","object":"chat.completion.chunk","choices":[{"delta":{"content":"CREATE","tool_calls":[{"function":{"name":"create","arguments":"{\"path\":\"/abs/path/file.txt\""},"id":"tc6","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"c2","object":"chat.completion.chunk","choices":[{"delta":{"content":"CREATE2","tool_calls":[{"function":{"name":"create","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/new.txt\",\"file_text\":\"hello world\"}"},"id":"tc7","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"sr1","object":"chat.completion.chunk","choices":[{"delta":{"content":"SR","tool_calls":[{"function":{"name":"str_replace","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/file.diff"},"id":"tc8","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"sr2","object":"chat.completion.chunk","choices":[{"delta":{"content":"@@ -1,2 +1,2 @@\n-old line\n+new line\nunchanged line","tool_calls":[{"function":{"name":"str_replace","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/file.diff\"}"},"id":"tc9","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"u1","object":"chat.completion.chunk","choices":[{"delta":{"content":"{\"foo\":1}","tool_calls":[{"function":{"name":"mystery_tool","arguments":"{\"bar\":2}"},"id":"tc10","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"end","object":"chat.completion.chunk","choices":[{"delta":{"content":"","tool_calls":[],"role":"assistant"},"finish_reason":"stop","index":0}]}

pkg/cmd/agent-task/shared/testdata/log-3-synthetic-failures-input.txt

@@ -0,0 +1,27 @@
+data: {"id": "bad1", "object": "chat.completion.chunk", "choices": [ { "delta": { "tool_calls": [ { "function": { "name": "view", "arguments": "{bad json" } } ] } } ] }
+
+data: {"id":"v1","object":"chat.completion.chunk","choices":[{"delta":{"content":"@@ -1,2 +1,2 @@\n-old line\n+new line\nunchanged line\nINSIDE A VIEW CALL","tool_calls":[{"function":{"name":"view","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/README.md\"}"},"id":"tc1","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"v1b","object":"chat.completion.chunk","choices":[{"delta":{"content":"@@ -1,2 +1,2 @@\n-old line\n+new line\nunchanged line","tool_calls":[{"function":{"name":"view","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/README.md\"}"},"id":"tc1b","index":0}]}],"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"v1","object":"chat.completion.chunk","choices":[{"delta":{"content":"@@ -1,2 +1,2 @@\n-old line\n+new line\nunchanged line\nINSIDE A VIEW CALL","tool_calls":[{"function":{"name":"view","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/README.md"},"id":"tc1","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"t1","object":"chat.completion.chunk","choices":[{"delta":{"content":"THINK","tool_calls":[{"function":{"name":"think","arguments":"{\"thought\":123"},"id":"tc2","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"t2","object":"chat.completion.chunk","choices":[{"delta":{"content":"A valid thought to render.","reasoning_text":"Interim reasoning that should show as raw markdown.","tool_calls":[{"function":{"name":"think","arguments":"{\"thought\":\"A valid thought to render.\"}"},"id":"tc3","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"rp1","object":"chat.completion.chunk","choices":[{"delta":{"content":"RP","tool_calls":[{"function":{"name":"report_progress","arguments":"{\"commitMessage\": 5"},"id":"tc4","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"rp2","object":"chat.completion.chunk","choices":[{"delta":{"content":"not-json","tool_calls":[{"function":{"name":"report_progress","arguments":"{\"commitMessage\":\"Valid commit msg\"}"},"id":"tc5","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"c1","object":"chat.completion.chunk","choices":[{"delta":{"content":"CREATE","tool_calls":[{"function":{"name":"create","arguments":"{\"path\":\"/abs/path/file.txt\""},"id":"tc6","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"c2","object":"chat.completion.chunk","choices":[{"delta":{"content":"CREATE2","tool_calls":[{"function":{"name":"create","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/new.txt\",\"file_text\":\"hello world\"}"},"id":"tc7","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"sr1","object":"chat.completion.chunk","choices":[{"delta":{"content":"SR","tool_calls":[{"function":{"name":"str_replace","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/file.diff"},"id":"tc8","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"sr2","object":"chat.completion.chunk","choices":[{"delta":{"content":"@@ -1,2 +1,2 @@\n-old line\n+new line\nunchanged line","tool_calls":[{"function":{"name":"str_replace","arguments":"{\"path\":\"/home/runner/work/repo/owner/repo/file.diff\"}"},"id":"tc9","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"u1","object":"chat.completion.chunk","choices":[{"delta":{"content":"{\"foo\":1}","tool_calls":[{"function":{"name":"mystery_tool","arguments":"{\"bar\":2}"},"id":"tc10","index":0}]},"finish_reason":"tool_calls","index":0}]}
+
+data: {"id":"end","object":"chat.completion.chunk","choices":[{"delta":{"content":"","tool_calls":[],"role":"assistant"},"finish_reason":"stop","index":0}]}

pkg/cmd/agent-task/shared/testdata/log-3-synthetic-failures-want-stderr.txt

@@ -0,0 +1,10 @@
+
+failed to parse 'view' tool call arguments: unexpected end of JSON input
+
+failed to parse 'think' tool call arguments: unexpected end of JSON input
+
+failed to parse 'report_progress' tool call arguments: unexpected end of JSON input
+
+failed to parse 'create' tool call arguments: unexpected end of JSON input
+
+failed to parse 'str_replace' tool call arguments: unexpected end of JSON input

pkg/cmd/agent-task/shared/testdata/log-3-synthetic-failures-want.txt

@@ -0,0 +1,39 @@
+View repo/README.md
+
+old line                                                                    
+  new line                                                                    
+  unchanged line                                                              
+  INSIDE A VIEW CALL
+
+
+Interim reasoning that should show as raw markdown.
+
+Thought
+
+A valid thought to render.
+
+Progress update: Valid commit msg
+Create: repo/new.txt
+hello world
+
+Edit: repo/file.diff
+@@ -1,2 +1,2 @@                                                           
+    -old line                                                                 
+    +new line                                                                 
+    unchanged line
+
+Call to mystery_tool
+
+Output:
+
+{                                                                         
+      "foo": 1                                                                
+    }
+
+
+Input:
+
+{                                                                         
+      "bar": 2                                                                
+    }
+

pkg/cmd/agent-task/shared/testdata/log-3-want.txt

@@ -0,0 +1,39 @@
+View repo/README.md
+
+old line                                                                    
+  new line                                                                    
+  unchanged line                                                              
+  INSIDE A VIEW CALL
+
+
+Interim reasoning that should show as raw markdown.
+
+Thought
+
+A valid thought to render.
+
+Progress update: Valid commit msg
+Create: repo/new.txt
+hello world
+
+Edit: repo/file.diff
+@@ -1,2 +1,2 @@                                                           
+    -old line                                                                 
+    +new line                                                                 
+    unchanged line
+
+Call to mystery_tool
+
+Output:
+
+{                                                                         
+      "foo": 1                                                                
+    }
+
+
+Input:
+
+{                                                                         
+      "bar": 2                                                                
+    }
+