dirstate-tree: Add tree traversal/iteration
Like Python’s, Rust’s iterators are "external" in that they are driven
by a caller who calls a `next` method. This is as opposed to "internal"
iterators who drive themselves and call a callback for each item.
Writing an internal iterator traversing a tree is easy with recursion,
but internal iterators cannot rely on the call stack in that way,
they must save in an explicit object all state that they need to be
preserved across two `next` calls.
This algorithm uses a `Vec` as a stack that contains what would be
local variables on the call stack if we could use recursion.
Differential Revision: https://phab.mercurial-scm.org/D10370
$ 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 ..