absorb: preserve changesets which were already empty
Most commands in Mercurial (commit, rebase, absorb itself) don’t create empty
changesets or drop them if they become empty. If there’s a changeset that’s
empty, it must be a deliberate choice of the user. At least it shouldn’t be
absorb’s responsibility to prune them. The fact that changesets that became
empty during absorb are pruned, is unaffected by this.
This case was found while writing patches which make it possible to configure
absorb and rebase to not drop empty changesets. Even without having such config
set, I think it’s valuable to preserve changesets which were already empty.
$ cat > makepatch.py <<EOF
> import sys
> f = open(sys.argv[2], 'wb')
> w = f.write
> w(b'test message\n')
> w(b'diff --git a/a b/a\n')
> w(b'--- a/a\n')
> w(b'+++ b/a\n')
> w(b'@@ -1,5 +1,5 @@\n')
> w(b' a\n')
> w(b'-bbb\r\n')
> w(b'+yyyy\r\n')
> w(b' cc\r\n')
> w({'empty:lf': b' \n',
> 'empty:crlf': b' \r\n',
> 'empty:stripped-lf': b'\n',
> 'empty:stripped-crlf': b'\r\n'}[sys.argv[1]])
> w(b' d\n')
> w(b'-e\n')
> w(b'\\\\ No newline at end of file\n')
> w(b'+z\r\n')
> w(b'\\\\ No newline at end of file\r\n')
> EOF
$ hg init repo
$ cd repo
$ echo '\.diff' > .hgignore
Test different --eol values
$ "$PYTHON" -c 'open("a", "wb").write(b"a\nbbb\ncc\n\nd\ne")'
$ hg ci -Am adda
adding .hgignore
adding a
$ "$PYTHON" ../makepatch.py empty:lf eol.diff
$ "$PYTHON" ../makepatch.py empty:crlf eol-empty-crlf.diff
$ "$PYTHON" ../makepatch.py empty:stripped-lf eol-empty-stripped-lf.diff
$ "$PYTHON" ../makepatch.py empty:stripped-crlf eol-empty-stripped-crlf.diff
invalid eol
$ hg --config patch.eol='LFCR' import eol.diff
applying eol.diff
abort: unsupported line endings type: LFCR
[255]
$ hg revert -a
force LF
$ hg --traceback --config patch.eol='LF' import eol.diff
applying eol.diff
$ hg id
9e4ef7b3d4af tip
$ cat a
a
yyyy
cc
d
e (no-eol)
$ hg st
(test empty-line variants: all of them should generate the same revision)
$ hg up -qC 0
$ hg --config patch.eol='LF' import eol-empty-crlf.diff
applying eol-empty-crlf.diff
$ hg id
9e4ef7b3d4af tip
$ hg up -qC 0
$ hg --config patch.eol='LF' import eol-empty-stripped-lf.diff
applying eol-empty-stripped-lf.diff
$ hg id
9e4ef7b3d4af tip
$ hg up -qC 0
$ hg --config patch.eol='LF' import eol-empty-stripped-crlf.diff
applying eol-empty-stripped-crlf.diff
$ hg id
9e4ef7b3d4af tip
force CRLF
$ hg up -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg --traceback --config patch.eol='CRLF' import eol.diff
applying eol.diff
$ cat a
a\r (esc)
yyyy\r (esc)
cc\r (esc)
\r (esc)
d\r (esc)
e (no-eol)
$ hg st
auto EOL on LF file
$ hg up -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg --traceback --config patch.eol='auto' import eol.diff
applying eol.diff
$ cat a
a
yyyy
cc
d
e (no-eol)
$ hg st
auto EOL on CRLF file
$ "$PYTHON" -c 'open("a", "wb").write(b"a\r\nbbb\r\ncc\r\n\r\nd\r\ne")'
$ hg commit -m 'switch EOLs in a'
$ hg --traceback --config patch.eol='auto' import eol.diff
applying eol.diff
$ cat a
a\r (esc)
yyyy\r (esc)
cc\r (esc)
\r (esc)
d\r (esc)
e (no-eol)
$ hg st
auto EOL on new file or source without any EOL
$ "$PYTHON" -c 'open("noeol", "wb").write(b"noeol")'
$ hg add noeol
$ hg commit -m 'add noeol'
$ "$PYTHON" -c 'open("noeol", "wb").write(b"noeol\r\nnoeol\n")'
$ "$PYTHON" -c 'open("neweol", "wb").write(b"neweol\nneweol\r\n")'
$ hg add neweol
$ hg diff --git > noeol.diff
$ hg revert --no-backup noeol neweol
$ rm neweol
$ hg --traceback --config patch.eol='auto' import -m noeol noeol.diff
applying noeol.diff
$ cat noeol
noeol\r (esc)
noeol
$ cat neweol
neweol
neweol\r (esc)
$ hg st
Test --eol and binary patches
$ "$PYTHON" -c 'open("b", "wb").write(b"a\x00\nb\r\nd")'
$ hg ci -Am addb
adding b
$ "$PYTHON" -c 'open("b", "wb").write(b"a\x00\nc\r\nd")'
$ hg diff --git > bin.diff
$ hg revert --no-backup b
binary patch with --eol
$ hg import --config patch.eol='CRLF' -m changeb bin.diff
applying bin.diff
$ cat b
a\x00 (esc)
c\r (esc)
d (no-eol)
$ hg st
$ cd ..