From d8b067b549f90fc57f295debe40eccb4145e795c Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Fri, 6 Jun 2025 14:04:44 +0200
Subject: [PATCH] repl: Don't wait on incomplete parses from imported file

Fixes #13332.
---
 src/libcmd/repl.cc       | 24 +++++++++++++-----------
 tests/functional/repl.sh |  6 ++++++
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc
index 07968fa43..75a0baebc 100644
--- a/src/libcmd/repl.cc
+++ b/src/libcmd/repl.cc
@@ -158,6 +158,8 @@ static std::ostream & showDebugTrace(std::ostream & out, const PosTable & positi
     return out;
 }
 
+MakeError(IncompleteReplExpr, ParseError);
+
 static bool isFirstRepl = true;
 
 ReplExitStatus NixRepl::mainLoop()
@@ -205,16 +207,8 @@ ReplExitStatus NixRepl::mainLoop()
                 default:
                     unreachable();
             }
-        } catch (ParseError & e) {
-            if (e.msg().find("unexpected end of file") != std::string::npos) {
-                // For parse errors on incomplete input, we continue waiting for the next line of
-                // input without clearing the input so far.
-                continue;
-            } else {
-              printMsg(lvlError, e.msg());
-            }
-        } catch (EvalError & e) {
-            printMsg(lvlError, e.msg());
+        } catch (IncompleteReplExpr &) {
+            continue;
         } catch (Error & e) {
             printMsg(lvlError, e.msg());
         } catch (Interrupted & e) {
@@ -837,7 +831,15 @@ Expr * NixRepl::parseString(std::string s)
 
 void NixRepl::evalString(std::string s, Value & v)
 {
-    Expr * e = parseString(s);
+    Expr * e;
+    try {
+        e = parseString(s);
+    } catch (ParseError & e) {
+        if (e.msg().find("unexpected end of file") != std::string::npos)
+            // For parse errors on incomplete input, we continue waiting for the next line of
+            // input without clearing the input so far.
+            throw IncompleteReplExpr(e.msg());
+    }
     e->eval(*state, *env, v);
     state->forceValue(v, v.determinePos(noPos));
 }
diff --git a/tests/functional/repl.sh b/tests/functional/repl.sh
index 762636e44..015d296d5 100755
--- a/tests/functional/repl.sh
+++ b/tests/functional/repl.sh
@@ -277,6 +277,12 @@ testReplResponseNoRegex '
 }
 '
 
+# Don't prompt for more input when getting unexpected EOF in imported files.
+testReplResponse "
+import $testDir/lang/parse-fail-eof-pos.nix
+" \
+'.*error: syntax error, unexpected end of file.*'
+
 # TODO: move init to characterisation/framework.sh
 badDiff=0
 badExitCode=0