more robust user input removal

Author: hugodutka

lib/msgfmt/msgfmt.go

@@ -99,40 +99,43 @@ func findUserInputStartIdx(msg []rune, msgRuneLineLocations []int, userInput []r
 	return IndexSubslice(msgPrefix, userInputPrefix)
 }
 
+// Find the next match between the message and the user input.
+// We're assuming that user input likely won't be truncated much,
+// but it's likely some characters will be missing (e.g. OpenAI Codex strips
+// "```" and instead formats enclosed text as a code block).
+// We're going to see if any of the next 5 runes in the message
+// match any of the next 5 runes in the user input.
+func findNextMatch(knownMsgMatchIdx int, knownUserInputMatchIdx int, msg []rune, userInput []rune) (int, int) {
+	for i := range 5 {
+		for j := range 5 {
+			userInputIdx := knownUserInputMatchIdx + i + 1
+			msgIdx := knownMsgMatchIdx + j + 1
+
+			if userInputIdx >= len(userInput) || msgIdx >= len(msg) {
+				return -1, -1
+			}
+			if userInput[userInputIdx] == msg[msgIdx] {
+				return msgIdx, userInputIdx
+			}
+		}
+	}
+	return -1, -1
+}
+
 // Find where the user input ends in the message. Returns the index of the last rune
 // of the user input in the message.
 func findUserInputEndIdx(userInputStartIdx int, msg []rune, userInput []rune) int {
 	userInputIdx := 0
 	msgIdx := userInputStartIdx
-OuterLoop:
 	for {
-		if userInputIdx >= len(userInput) {
+		m, u := findNextMatch(msgIdx, userInputIdx, msg, userInput)
+		if m == -1 || u == -1 {
 			break
 		}
-		if msgIdx >= len(msg) {
-			break
-		}
-		if userInput[userInputIdx] == msg[msgIdx] {
-			userInputIdx++
-			msgIdx++
-			continue
-		}
-		// If we haven't found a match, we'll search the next 5 runes of the message.
-		// If we can't find a match, we'll assume the echoed user input was truncated.
-		// 5 is arbitrary.
-		for i := 1; i <= 5; i++ {
-			if msgIdx+i >= len(msg) {
-				break
-			}
-			if userInput[userInputIdx] == msg[msgIdx+i] {
-				userInputIdx++
-				msgIdx = msgIdx + i
-				continue OuterLoop
-			}
-		}
-		break
+		msgIdx = m
+		userInputIdx = u
 	}
-	return msgIdx - 1
+	return msgIdx
 }
 
 // RemoveUserInput removes the user input from the message.

lib/msgfmt/msgfmt_test.go

@@ -168,7 +168,8 @@ func TestFindUserInputEndIdx(t *testing.T) {
 		msg := "Hello,World!"
 		userInput := "/init"
 		userInputEndIdx := findUserInputEndIdx(len(msg), []rune(msg), []rune(userInput))
-		assert.Equal(t, len(msg)-1, userInputEndIdx)
+		// returns the same index as userInputStartIdx
+		assert.Equal(t, len(msg), userInputEndIdx)
 	})
 }
 

lib/msgfmt/testdata/format/codex/multi_line2/expected.txt

@@ -0,0 +1,45 @@
+    thinking for 10s                                                            
+                                                                                
+    command                                                                     
+                                                                                
+    $ grep -R "Process) Close" -n .                                             
+                                                                                
+    command.stdout (code: 0, duration: 6.9s)                                    
+                                                                                
+    ./lib/termexec/termexec.go:76:func (p *Process) Close(logger *slog.Logger,  
+    timeout time.Duration) error {                                              
+    ./lib/msgfmt/testdata/format/codex/multi_line2/msg.txt:9:│ func (p *Process)
+     Close(logger *slog.Logger, timeout time.Duration) error {  │               
+    ./lib/msgfmt/testdata/format/codex/multi_line2/msg.txt:37:    func (p       
+    *Process) Close(logger *slog.Logger, timeout time.Duration) error {         
+    ./lib/msgfmt/testdata/format/codex/multi_line/user.txt:6:func (p *Process)  
+    Close(logger *slog.Logger, timeout time.Duration) error {                   
+    ... (2 more lines)                                                          
+                                                                                
+    thinking for 20s                                                            
+                                                                                
+    command                                                                     
+                                                                                
+    $ sed -n '1,150p' lib/termexec/termexec.go                                  
+                                                                                
+    command.stdout (code: 0, duration: 0s)                                      
+                                                                                
+    package termexec                                                            
+                                                                                
+    import (                                                                    
+        "context"                                                               
+    ... (113 more lines)                                                        
+                                                                                
+    thinking for 26s                                                            
+                                                                                
+    codex                                                                       
+    That’s the Close method on the Process type in the termexec package. You can
+     find it here:                                                              
+                                                                                
+      lib/termexec/termexec.go, starting at line 76:                            
+                                                                                
+        // Closecloses the process using a SIGINT signal …                      
+        func (p *Process) Close(logger *slog.Logger, timeout time.Duration)     
+    error {                                                                     
+            …                                                                   
+        }