graft: moved abortgraft and readgraft to cmdutil This patch moves `abortgraft` and `readgraft` to `cmdutil`. Various callers are updated accordingly. This is done because these serve as ulitlity functions for command `graft` and so that new functions regarding graft can be built from them. Differential Revision: https://phab.mercurial-scm.org/D6608

cleanup: use named constants for second arg to .seek() Differential Revision: https://phab.mercurial-scm.org/D6556

patch: use a short, fixed-size message for last line of prompt (issue6158) See issue6158 and the previous commit for examples of what might go wrong if we have some combinations of readline version and terminal and need to wrap the line. Briefly: readline may not display the beginning of the last line of the prompt, or it may print over it with the end of the prompt, making it difficult for users to know what's going on. Differential Revision: https://phab.mercurial-scm.org/D6563

filemerge: make last line of prompts <40 english chars (issue6158) I've chosen <40 as the target so that other languages that may have a 2x blowup in character count can still have a chance to fit into an 80 column screen. Previously, we would show a prompt like: ``` keep (l)ocal [dest], take (o)ther [source], or leave (u)nresolved for some/potentially/really/long/path? ``` On at least some systems, if readline was in use then the last line of the prompt would be wrapped strangely if it couldn't fit entirely on one line. This strange wrapping may be just a carriage return without a line feed, overwriting the beginning of the line; example (100 columns wide, 65 character filename, and yes there's 10 spaces on the end, I assume this is to handle the user inputting longest word we provide as an option, "unresolved"): ``` ng/dir/name/that/does/not/work/well/with/readline/file.txt? ave (u)nresolved for some/lon ``` In some cases it may partially wrap onto the next line, but still be missing earlier parts in the line, such as below (60 columns wide, 65 character filename): ``` rev], or leave (u)nresolved for some/long/dir/name/that/do s/not/work/well/with/readline/file.txt? ``` With this fix, this looks like this on a 60 column screen: ``` tool vim_with_markers (for pattern some/long/dir/name/that/d oes/not/work/well/with/readline/file.txt) can't handle binar y tool meld can't handle binary tool vim_with_markers can't handle binary tool internal:merge3 can't handle binary tool merge can't handle binary no tool found to merge some/long/dir/name/that/does/not/work /well/with/readline/file.txt file 'some/long/dir/name/that/does/not/work/well/with/readli ne/file.txt' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev ], or leave (u)nresolved. What do you want to do? ``` Differential Revision: https://phab.mercurial-scm.org/D6562

Added signature for changeset 97ada9b8d51b

Added tag 5.0.2 for changeset 97ada9b8d51b

posix: always seek to EOF when opening a file in append mode Python 3 already does this, so skip it there. Consider the program: #include <stdio.h> int main() { FILE *f = fopen("narf", "w"); fprintf(f, "narf\n"); fclose(f); f = fopen("narf", "a"); printf("%ld\n", ftell(f)); fprintf(f, "troz\n"); printf("%ld\n", ftell(f)); return 0; } on macOS, FreeBSD, and Linux with glibc, this program prints 5 10 but on musl libc (Alpine Linux and probably others) this prints 0 10 By my reading of https://pubs.opengroup.org/onlinepubs/009695399/functions/fopen.html this is technically correct, specifically: > Opening a file with append mode (a as the first character in the > mode argument) shall cause all subsequent writes to the file to be > forced to the then current end-of-file, regardless of intervening > calls to fseek(). in other words, the file position doesn't really matter in append-mode files, and we can't depend on it being at all meaningful unless we perform a seek() before tell() after open(..., 'a'). Experimentally after a .write() we can do a .tell() and it'll always be reasonable, but I'm unclear from reading the specification if that's a smart thing to rely on. This matches what we do on Windows and what Python 3 does for free, so let's just be consistent. Thanks to Yuya for the idea.