gh-123018: Keep the libedit history file header when truncating - #157165
Merged
Conversation
gpshead
added
needs backport to 3.13
gpshead
commented
Sep 8, 2026
| static int | ||
| _py_libedit_history_truncate_file(const char *filename, int nlines) | ||
| { | ||
| static const char cookie[] = "_HiStOrY_V2_\n"; |
Member
Author
There was a problem hiding this comment.
over in #121160 the earlier choice was not to do a workaround because it seemed fragile. yes this PR intentionally decides the other way. libedit is not likely to change or a fix to it become widely distributed any time soon. apple patched theirs rather than push on upstream. if netbsd libedit does adopt a new history format version, this marker won't match and this function basically becomes a no-op that does nothing.
Member
Author
There was a problem hiding this comment.
It looks like someone did at least file a NetBSD bug this year https://gnats.netbsd.org/60322
gpshead
force-pushed
the
fix-editline-tests
branch
from
September 8, 2026 05:25
9ac2d9c to
39d13be
Compare
libedit's history_truncate_file() keeps the last N lines of the file, which drops the "_HiStOrY_V2_" header line that its own write_history() emits and that its read_history() requires. So on a libedit build, readline.write_history_file() or readline.append_history_file() after readline.set_history_length() produced a file that readline.read_history_file() rejected with EINVAL. Under the libedit emulation, truncate the file ourselves and keep the header, resolving the default "~/.history" the same way libedit does. Apple's libedit fork already preserves the header, so the workaround is not compiled on macOS.
gpshead
force-pushed
the
fix-editline-tests
branch
from
September 8, 2026 05:58
39d13be to
9b6d270
Compare
gpshead
enabled auto-merge (squash)
September 8, 2026 05:58
|
Thanks @gpshead for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14, 3.15. |
|
GH-157172 is a backport of this pull request to the 3.15 branch. |
bedevere-app
Bot
removed
the
needs backport to 3.15
|
Sorry, @gpshead, I could not cleanly backport this to |
|
GH-157173 is a backport of this pull request to the 3.14 branch. |
|
Yay! Thank you. |
gpshead
added a commit
that referenced
this pull request
Sep 9, 2026
GH-157165) (#157173) gh-123018: Keep the libedit history file header when truncating (GH-157165) libedit's history_truncate_file() keeps the last N lines of the file, which drops the "_HiStOrY_V2_" header line that its own write_history() emits and that its read_history() requires. So on a libedit build, readline.write_history_file() or readline.append_history_file() after readline.set_history_length() produced a file that readline.read_history_file() rejected with EINVAL. Under the libedit emulation, truncate the file ourselves and keep the header, resolving the default "~/.history" the same way libedit does. Apple's libedit fork already preserves the header, so the workaround is not compiled on macOS. (cherry picked from commit 2638785) Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com>
maurycy
added a commit
to maurycy/cpython
that referenced
this pull request
Sep 10, 2026
* main: (158 commits) pythongh-156924: Try reifying lazy imports in `ForwarRef.evaluate()` (python#156940) pythongh-156233: Fix typos and code snippet errors in the docs (python#156475) pythongh-156837: Refer to yield expressions in generator function definitions (pythonGH-156863) pythongh-155292: Skip updating unicodedata with mismatched interpreter (pythonGH-157066) pythongh-157170: Document the scope of global curses settings (pythonGH-157207) pythongh-155966: Correct handling of `math.tanpi` poles (python#155980) pythongh-157170: Restore use_env() after test_use_prescr_screen in test_curses (pythonGH-157171) pythongh-156910: fix deadlock in type_set_abstractmethods under free-threading (python#156948) pythongh-155648: Write the empty and placeholder IDLE tests (python#156260) pythongh-153569: centralize formatted-string state and source spans (python#156484) pythongh-157137: Mark the PEP 820 soft deprecations as 3.15, not `next` (python#157138) pythongh-152433: Use regular LoadLibrary in UWP for Windows system libs (pythonGH-156972) pythongh-121617: Fix Py_CLEAR() memcpy in C++: replace NULL with _Py_NULL (python#157188) pythongh-157135: Fix documentation errors in the `math.atan{2}pi` functions (python#157136) pythongh-121617: Fix Py_CLEAR() in C++: replace NULL with _Py_NULL (python#157067) pythongh-156774: Speed up pdb startup with asyncio guard (python#156775) pythongh-156109: Allow static, non-framework iOS builds (python#156110) pythongh-156780: Emscripten: add missing EM_JS_DEPS (python#156798) pythongh-152936: Make privileged functions available on Android (python#152977) pythongh-123018: Keep the libedit history file header when truncating (pythonGH-157165) ...
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
libedit's history_truncate_file() keeps the last N lines of the file, which drops the
"_HiStOrY_V2_"header line that its own write_history() emits and that its read_history() requires. So on a libedit build, readline.write_history_file() or readline.append_history_file() after readline.set_history_length() produced a file that readline.read_history_file() rejected with EINVAL.Under the libedit emulation, truncate the file ourselves and keep the header, resolving the default "~/.history" the same way libedit does. Apple's libedit fork already preserves the header, so the workaround is not compiled on macOS.