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.
===================================
Test repository filtering avoidance
===================================
This test file is a bit special as he does not check feature, but performance related internal code path.
Right now, filtering a repository comes with a cost that might be significant.
Until this get better, ther are various operation that try hard not to trigger
a filtering computation. This test file make sure we don't reintroduce code that trigger the filtering for these operation:
Setup
-----
$ hg init test-repo
$ cd test-repo
$ echo "some line" > z
$ echo a > a
$ hg commit -Am a
adding a
adding z
$ echo "in a" >> z
$ echo b > b
$ hg commit -Am b
adding b
$ echo "file" >> z
$ echo c > c
$ hg commit -Am c
adding c
$ hg rm a
$ echo c1 > c
$ hg add c
c already tracked!
$ echo d > d
$ hg add d
$ rm b
$ cat << EOF >> $HGRCPATH
> [devel]
> debug.repo-filters = yes
> [ui]
> debug = yes
> EOF
tests
-----
Getting the node of `null`
$ hg log -r null -T "{node}\n"
0000000000000000000000000000000000000000
Getting basic changeset inforation about `null`
$ hg log -r null -T "{node}\n{date}\n"
0000000000000000000000000000000000000000
0.00
Getting status of null
$ hg status --change null
Getting status of working copy
$ hg status
M c
A d
R a
! b
$ hg status --copies
M c
A d
R a
! b
Getting data about the working copy parent
$ hg log -r '.' -T "{node}\n{date}\n"
c2932ca7786be30b67154d541a8764fae5532261
0.00
Getting working copy diff
$ hg diff
diff -r c2932ca7786be30b67154d541a8764fae5532261 a
--- a/a Thu Jan 01 00:00:00 1970 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +0,0 @@
-a
diff -r c2932ca7786be30b67154d541a8764fae5532261 c
--- a/c Thu Jan 01 00:00:00 1970 +0000
+++ b/c Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +1,1 @@
-c
+c1
diff -r c2932ca7786be30b67154d541a8764fae5532261 d
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/d Thu Jan 01 00:00:00 1970 +0000
@@ -0,0 +1,1 @@
+d
$ hg diff --change .
diff -r 05293e5dd8d1ae4f84a8520a11c6f97cad26deca -r c2932ca7786be30b67154d541a8764fae5532261 c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/c Thu Jan 01 00:00:00 1970 +0000
@@ -0,0 +1,1 @@
+c
diff -r 05293e5dd8d1ae4f84a8520a11c6f97cad26deca -r c2932ca7786be30b67154d541a8764fae5532261 z
--- a/z Thu Jan 01 00:00:00 1970 +0000
+++ b/z Thu Jan 01 00:00:00 1970 +0000
@@ -1,2 +1,3 @@
some line
in a
+file
exporting the current changeset
$ hg export
exporting patch:
# HG changeset patch
# User test
# Date 0 0
# Thu Jan 01 00:00:00 1970 +0000
# Node ID c2932ca7786be30b67154d541a8764fae5532261
# Parent 05293e5dd8d1ae4f84a8520a11c6f97cad26deca
c
diff -r 05293e5dd8d1ae4f84a8520a11c6f97cad26deca -r c2932ca7786be30b67154d541a8764fae5532261 c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/c Thu Jan 01 00:00:00 1970 +0000
@@ -0,0 +1,1 @@
+c
diff -r 05293e5dd8d1ae4f84a8520a11c6f97cad26deca -r c2932ca7786be30b67154d541a8764fae5532261 z
--- a/z Thu Jan 01 00:00:00 1970 +0000
+++ b/z Thu Jan 01 00:00:00 1970 +0000
@@ -1,2 +1,3 @@
some line
in a
+file
using annotate
- file with a single change
$ hg annotate a
0: a
- file with multiple change
$ hg annotate z
0: some line
1: in a
2: file