Mercurial > hg
view tests/test-amend-subrepo.t @ 47965:f9e6f2bb721d
rhg: Don’t compare ambiguous files one byte at a time
Even though the use of `BufReader` reduces the number of syscalls to read
the file from disk, `.bytes()` yields a separate `Result` for every byte.
Creating those results and dispatching on them is most likely costly.
Instead, this commit opts for simplicity by reading the entire file into memory
and comparing a single pair of byte strings. Note that memory already needs to
contain the entire previous contents of the file, as read from the filelog.
So with an extremely large file this doubles memory use but does not make it
grow by orders of magnitude.
At first I wrote code that still avoids reading the entire file into memory
and compares one buffer at a time with `BufReader`. Find this code below for
posterity. However its correctness is subtle. I ended up preferring the
simplicity of the obviously-correct single comparison.
```rust
let mut reader = BufReader::new(fobj);
let mut expected = &contents_in_p1[..];
loop {
let buf = reader.fill_buf().when_reading_file(&fs_path)?;
if buf.is_empty() {
// Found EOF
return Ok(expected.is_empty());
} else if let Some(rest) = expected.drop_prefix(buf) {
// What we read so far matches the expected content, continue reading
let buf_len = buf.len();
reader.consume(buf_len);
expected = rest
} else {
// Found different content
return Ok(false);
}
}
```
Differential Revision: https://phab.mercurial-scm.org/D11412
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Mon, 13 Sep 2021 18:48:48 +0200 |
parents | 4b7d5d10c45d |
children | c84844cd523a |
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#testcases obsstore-off obsstore-on $ cat << EOF >> $HGRCPATH > [extensions] > amend = > EOF #if obsstore-on $ cat << EOF >> $HGRCPATH > [experimental] > evolution.createmarkers = True > EOF #endif Prepare parent repo ------------------- $ hg init r $ cd r $ echo a > a $ hg ci -Am0 adding a Link first subrepo ------------------ $ echo 's = s' >> .hgsub $ hg add .hgsub $ hg init s amend without .hgsub $ hg amend s abort: can't commit subrepos without .hgsub [255] amend with subrepo $ hg amend saved backup bundle to * (glob) (obsstore-off !) $ hg status --change . A .hgsub A .hgsubstate A a $ cat .hgsubstate 0000000000000000000000000000000000000000 s Update subrepo -------------- add new commit to be amended $ echo a >> a $ hg ci -m1 amend with dirty subrepo $ echo a >> s/a $ hg add -R s adding s/a $ hg amend abort: uncommitted changes in subrepository "s" (use --subrepos for recursive commit) [255] amend with modified subrepo $ hg ci -R s -m0 $ hg amend saved backup bundle to * (glob) (obsstore-off !) $ hg status --change . M .hgsubstate M a $ cat .hgsubstate f7b1eb17ad24730a1651fccd46c43826d1bbc2ac s revert subrepo change $ hg up -R s -q null $ hg amend saved backup bundle to * (glob) (obsstore-off !) $ hg status --change . M a Link another subrepo -------------------- add new commit to be amended $ echo b >> b $ hg ci -qAm2 also checks if non-subrepo change is included $ echo a >> a amend with another subrepo $ hg init t $ echo b >> t/b $ hg ci -R t -Am0 adding b $ echo 't = t' >> .hgsub $ hg amend saved backup bundle to * (glob) (obsstore-off !) $ hg status --change . M .hgsub M .hgsubstate M a A b $ cat .hgsubstate 0000000000000000000000000000000000000000 s bfb1a4fb358498a9533dabf4f2043d94162f1fcd t Unlink one subrepo ------------------ add new commit to be amended $ echo a >> a $ hg ci -m3 $ echo 't = t' > .hgsub --interactive won't silently ignore dirty subrepos $ echo modified > t/b $ hg amend --interactive --config ui.interactive=True abort: uncommitted changes in subrepository "t" [255] $ hg amend --interactive --config ui.interactive=True --config ui.commitsubrepos=True abort: uncommitted changes in subrepository "t" [255] $ hg -R t revert -q --all --no-backup amend with one subrepo dropped $ hg amend saved backup bundle to * (glob) (obsstore-off !) $ hg status --change . M .hgsub M .hgsubstate M a $ cat .hgsubstate bfb1a4fb358498a9533dabf4f2043d94162f1fcd t Unlink subrepos completely -------------------------- add new commit to be amended $ echo a >> a $ hg ci -m3 amend with .hgsub removed $ hg rm .hgsub $ hg amend saved backup bundle to * (glob) (obsstore-off !) $ hg status --change . M a R .hgsub R .hgsubstate broken repositories will refuse to push #if obsstore-off $ hg up -q -C 2 #else $ hg up -q -C 6 #endif $ echo c >> t/b $ hg amend -q -R t $ hg init ../dest $ hg init ../dest/t $ hg init ../dest/s $ hg push -q ../dest abort: subrepo 't' is hidden in revision 04aa62396ec6 (obsstore-on !) abort: subrepo 't' not found in revision 04aa62396ec6 (obsstore-off !) [255] ... unless forced $ hg push --force -q ../dest $ hg verify -R ../dest checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 5 changesets with 12 changes to 4 files checking subrepo links subrepo 't' not found in revision 04aa62396ec6 subrepo 't' not found in revision 6bce99600681 $ cd ..