thread 'main' panicked at 'Hunk lines should be present in matched lines', src/display/hunks.rs:663:23

[Adamkadaban]

Panic in display/hunks.rs

Files: 1.txt 2.txt

thread 'main' panicked at 'Hunk lines should be present in matched lines', src/display/hunks.rs:663:23
stack backtrace:
   0:     0x56481b1cb5b5 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hb070b7fa7e3175df
   1:     0x56481b01c23e - core::fmt::write::hd5207aebbb9a86e9
   2:     0x56481b1c7b05 - std::io::Write::write_fmt::h3bd699bbd129ab8a
   3:     0x56481b1ccd23 - std::panicking::default_hook::{{closure}}::h04cca40023d0eeca
   4:     0x56481b1cca2f - std::panicking::default_hook::haa3ca8c310ed5402
   5:     0x56481b1cd34c - std::panicking::rust_panic_with_hook::h7b190ce1a948faac
   6:     0x56481b1cd254 - std::panicking::begin_panic_handler::{{closure}}::hbafbfdc3e1b97f68
   7:     0x56481b1cbabc - std::sys_common::backtrace::__rust_end_short_backtrace::hda93e5fef243b4c0
   8:     0x56481b1ccfa2 - rust_begin_unwind
   9:     0x56481af7c793 - core::panicking::panic_fmt::h8d17ca1073d9a733
  10:     0x56481b01ace1 - core::panicking::panic_display::he956d1fbfe1d4c76
  11:     0x56481b01ac8b - core::panicking::panic_str::h7d5968eea59d06d2
  12:     0x56481af7c606 - core::option::expect_failed::h03d502d0855ade10
  13:     0x56481b089b96 - difft::display::hunks::matched_lines_indexes_for_hunk::h4b77df964d62e4c9
  14:     0x56481b07a891 - difft::display::side_by_side::print::h5d49acdfd78f8219
  15:     0x56481b03e06b - difft::print_diff_result::hbab8ebae5e039c47
  16:     0x56481b039f54 - difft::main::h829b432de9803b7e
  17:     0x56481b046203 - std::sys_common::backtrace::__rust_begin_short_backtrace::h1cf47cf43a9e9613
  18:     0x56481b08cdb9 - std::rt::lang_start::{{closure}}::hfa91847e2be1747f
  19:     0x56481b1c180a - std::rt::lang_start_internal::h6ba1bb743c1e9df9
  20:     0x56481b03e728 - main
  21:     0x7fcd62d4724a - __libc_start_call_main
                               at ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
  22:     0x7fcd62d47305 - __libc_start_main_impl
                               at ./csu/../csu/libc-start.c:360:3
  23:     0x56481af9781e - _start
  24:                0x0 - <unknown>

Version: Difftastic 0.60.0 (1ac9553 2024-07-30, built with rustc 1.65.0) Downloaded from releases

[Adamkadaban]

I'm unsure if this was the case when I first submitted the issue, but it seems this now only happens with one order of the files

thread 'main' panicked at 'Hunk lines should be present in matched lines', src/display/hunks.rs:663:23
stack backtrace:
   0:     0x55bb9f96fd15 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h3155a8c966b4beb5
   1:     0x55bb9f7bf23e - core::fmt::write::h062c617411b691df
   2:     0x55bb9f96c8d5 - std::io::Write::write_fmt::hb61fdf1275c61e1c
   3:     0x55bb9f96fae5 - std::sys_common::backtrace::print::hca896ae22beb06cb
   4:     0x55bb9f9712bf - std::panicking::default_hook::{{closure}}::h0b5eeed5cf36ab5f
   5:     0x55bb9f97102a - std::panicking::default_hook::h8932b573145a321b
   6:     0x55bb9f97192f - std::panicking::rust_panic_with_hook::h4b1447a24e3e94f8
   7:     0x55bb9f9716e4 - std::panicking::begin_panic_handler::{{closure}}::h8701da9995a3820c
   8:     0x55bb9f97021c - std::sys_common::backtrace::__rust_end_short_backtrace::hb696c5ed02a01598
   9:     0x55bb9f971432 - rust_begin_unwind
  10:     0x55bb9f71c5c3 - core::panicking::panic_fmt::h8aa706a976963c88
  11:     0x55bb9f7bdce1 - core::panicking::panic_display::h145080b539a57164
  12:     0x55bb9f7bdc8b - core::panicking::panic_str::hb7f52c873200464f
  13:     0x55bb9f71c586 - core::option::expect_failed::hf416ac71eef81151
  14:     0x55bb9f82f3c6 - difft::display::hunks::matched_lines_indexes_for_hunk::h9f9e2aa738126b7f
  15:     0x55bb9f820044 - difft::display::side_by_side::print::h9b8d9ae36adfd23d
  16:     0x55bb9f7e109b - difft::print_diff_result::h8899cf4ba00640da
  17:     0x55bb9f7dd01e - difft::main::h2b7829dd9e2a2a59
  18:     0x55bb9f7e94f3 - std::sys_common::backtrace::__rust_begin_short_backtrace::he7f7716f7442975a
  19:     0x55bb9f840d39 - std::rt::lang_start::{{closure}}::hfde1be8a0e006cca
  20:     0x55bb9f965fd8 - std::rt::lang_start_internal::hcd7e45acd25ab5ab
  21:     0x55bb9f7e1755 - main
  22:     0x7fdf7104624a - __libc_start_call_main
                               at ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
  23:     0x7fdf71046305 - __libc_start_main_impl
                               at ./csu/../csu/libc-start.c:360:3
  24:     0x55bb9f73a18e - _start
  25:                0x0 - <unknown>

[jarjk]

same

[Adamkadaban]

Haven't fully tested, but these changes work for my usecase (and seem to past all the testcases in the repo)

diff --git a/src/display/hunks.rs b/src/display/hunks.rs
index 06187393a..19cb82ff4 100644
--- a/src/display/hunks.rs
+++ b/src/display/hunks.rs
@@ -660,8 +660,11 @@ pub(crate) fn matched_lines_indexes_for_hunk(
         }
     }
 
-    let mut start_i = start_i.expect("Hunk lines should be present in matched lines");
-    let mut end_i = end_i.expect("Hunk lines should be present in matched lines");
+    // If start_i or end_i is None, it means the hunk lines weren't found in matched_lines.
+    // This can happen when one side of the diff has no novel content.
+    // In that case, use the start or end of matched_lines
+    let mut start_i = start_i.unwrap_or(0);
+    let mut end_i = end_i.unwrap_or(matched_lines.len());
     if start_i >= num_context_lines {
         start_i -= num_context_lines;
     } else {