procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
$ cat >> $HGRCPATH << EOF
> [diff]
> git=1
> [extensions]
> absorb=
> EOF
$ sedi() { # workaround check-code
> pattern="$1"
> shift
> for i in "$@"; do
> sed "$pattern" "$i" > "$i".tmp
> mv "$i".tmp "$i"
> done
> }
rename a to b, then b to a
$ hg init repo1
$ cd repo1
$ echo 1 > a
$ hg ci -A a -m 1
$ hg mv a b
$ echo 2 >> b
$ hg ci -m 2
$ hg mv b a
$ echo 3 >> a
$ hg ci -m 3
$ hg annotate -ncf a
0 eff892de26ec a: 1
1 bf56e1f4f857 b: 2
2 0b888b00216c a: 3
$ sedi 's/$/a/' a
$ hg absorb -apq
showing changes for a
@@ -0,3 +0,3 @@
eff892d -1
bf56e1f -2
0b888b0 -3
eff892d +1a
bf56e1f +2a
0b888b0 +3a
3 changesets affected
0b888b0 3
bf56e1f 2
eff892d 1
$ hg status
$ hg annotate -ncf a
0 5d1c5620e6f2 a: 1a
1 9a14ffe67ae9 b: 2a
2 9191d121a268 a: 3a
when the first changeset is public
$ hg phase --public -r 0
$ sedi 's/a/A/' a
$ hg absorb -apq
showing changes for a
@@ -0,3 +0,3 @@
-1a
9a14ffe -2a
9191d12 -3a
+1A
9a14ffe +2A
9191d12 +3A
2 changesets affected
9191d12 3
9a14ffe 2
$ hg diff
diff --git a/a b/a
--- a/a
+++ b/a
@@ -1,3 +1,3 @@
-1a
+1A
2A
3A
copy a to b
$ cd ..
$ hg init repo2
$ cd repo2
$ echo 1 > a
$ hg ci -A a -m 1
$ hg cp a b
$ echo 2 >> b
$ hg ci -m 2
$ hg log -T '{rev}:{node|short} {desc}\n'
1:17b72129ab68 2
0:eff892de26ec 1
$ sedi 's/$/a/' a
$ sedi 's/$/b/' b
$ hg absorb -apq
showing changes for a
@@ -0,1 +0,1 @@
eff892d -1
eff892d +1a
showing changes for b
@@ -0,2 +0,2 @@
-1
17b7212 -2
+1b
17b7212 +2b
2 changesets affected
17b7212 2
eff892d 1
$ hg diff
diff --git a/b b/b
--- a/b
+++ b/b
@@ -1,2 +1,2 @@
-1
+1b
2b
copy b to a
$ cd ..
$ hg init repo3
$ cd repo3
$ echo 1 > b
$ hg ci -A b -m 1
$ hg cp b a
$ echo 2 >> a
$ hg ci -m 2
$ hg log -T '{rev}:{node|short} {desc}\n'
1:e62c256d8b24 2
0:55105f940d5c 1
$ sedi 's/$/a/' a
$ sedi 's/$/a/' b
$ hg absorb -apq
showing changes for a
@@ -0,2 +0,2 @@
-1
e62c256 -2
+1a
e62c256 +2a
showing changes for b
@@ -0,1 +0,1 @@
55105f9 -1
55105f9 +1a
2 changesets affected
e62c256 2
55105f9 1
$ hg diff
diff --git a/a b/a
--- a/a
+++ b/a
@@ -1,2 +1,2 @@
-1
+1a
2a
"move" b to both a and c, follow a - sorted alphabetically
$ cd ..
$ hg init repo4
$ cd repo4
$ echo 1 > b
$ hg ci -A b -m 1
$ hg cp b a
$ hg cp b c
$ hg rm b
$ echo 2 >> a
$ echo 3 >> c
$ hg commit -m cp
$ hg log -T '{rev}:{node|short} {desc}\n'
1:366daad8e679 cp
0:55105f940d5c 1
$ sedi 's/$/a/' a
$ sedi 's/$/c/' c
$ hg absorb -apq
showing changes for a
@@ -0,2 +0,2 @@
55105f9 -1
366daad -2
55105f9 +1a
366daad +2a
showing changes for c
@@ -0,2 +0,2 @@
-1
366daad -3
+1c
366daad +3c
2 changesets affected
366daad cp
55105f9 1
$ hg log -G -p -T '{rev}:{node|short} {desc}\n'
@ 1:70606019f91b cp
| diff --git a/b b/a
| rename from b
| rename to a
| --- a/b
| +++ b/a
| @@ -1,1 +1,2 @@
| 1a
| +2a
| diff --git a/b b/c
| copy from b
| copy to c
| --- a/b
| +++ b/c
| @@ -1,1 +1,2 @@
| -1a
| +1
| +3c
|
o 0:bfb67c3539c1 1
diff --git a/b b/b
new file mode 100644
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+1a
run absorb again would apply the change to c
$ hg absorb -apq
showing changes for c
@@ -0,1 +0,1 @@
7060601 -1
7060601 +1c
1 changesets affected
7060601 cp
$ hg log -G -p -T '{rev}:{node|short} {desc}\n'
@ 1:8bd536cce368 cp
| diff --git a/b b/a
| rename from b
| rename to a
| --- a/b
| +++ b/a
| @@ -1,1 +1,2 @@
| 1a
| +2a
| diff --git a/b b/c
| copy from b
| copy to c
| --- a/b
| +++ b/c
| @@ -1,1 +1,2 @@
| -1a
| +1c
| +3c
|
o 0:bfb67c3539c1 1
diff --git a/b b/b
new file mode 100644
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+1a
"move" b to a, c and d, follow d if a gets renamed to e, and c is deleted
$ cd ..
$ hg init repo5
$ cd repo5
$ echo 1 > b
$ hg ci -A b -m 1
$ hg cp b a
$ hg cp b c
$ hg cp b d
$ hg rm b
$ echo 2 >> a
$ echo 3 >> c
$ echo 4 >> d
$ hg commit -m cp
$ hg mv a e
$ hg rm c
$ hg commit -m mv
$ hg log -T '{rev}:{node|short} {desc}\n'
2:49911557c471 mv
1:7bc3d43ede83 cp
0:55105f940d5c 1
$ sedi 's/$/e/' e
$ sedi 's/$/d/' d
$ hg absorb -apq
showing changes for d
@@ -0,2 +0,2 @@
55105f9 -1
7bc3d43 -4
55105f9 +1d
7bc3d43 +4d
showing changes for e
@@ -0,2 +0,2 @@
-1
7bc3d43 -2
+1e
7bc3d43 +2e
2 changesets affected
7bc3d43 cp
55105f9 1
$ hg diff
diff --git a/e b/e
--- a/e
+++ b/e
@@ -1,2 +1,2 @@
-1
+1e
2e
$ hg log -G -p -T '{rev}:{node|short} {desc}\n'
@ 2:34be9b0c786e mv
| diff --git a/c b/c
| deleted file mode 100644
| --- a/c
| +++ /dev/null
| @@ -1,2 +0,0 @@
| -1
| -3
| diff --git a/a b/e
| rename from a
| rename to e
|
o 1:13e56db5948d cp
| diff --git a/b b/a
| rename from b
| rename to a
| --- a/b
| +++ b/a
| @@ -1,1 +1,2 @@
| -1d
| +1
| +2e
| diff --git a/b b/c
| copy from b
| copy to c
| --- a/b
| +++ b/c
| @@ -1,1 +1,2 @@
| -1d
| +1
| +3
| diff --git a/b b/d
| copy from b
| copy to d
| --- a/b
| +++ b/d
| @@ -1,1 +1,2 @@
| 1d
| +4d
|
o 0:0037613a5dc6 1
diff --git a/b b/b
new file mode 100644
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+1d