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.
GNU diff is the reference for all of these results.
Prepare tests:
$ echo '[alias]' >> $HGRCPATH
$ echo 'ndiff = diff --nodates' >> $HGRCPATH
$ hg init
$ printf 'hello world\ngoodbye world\n' >foo
$ hg ci -Amfoo -ufoo
adding foo
Test added blank lines:
$ printf '\nhello world\n\ngoodbye world\n\n' >foo
>>> two diffs showing three added lines <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
+
hello world
+
goodbye world
+
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
+
hello world
+
goodbye world
+
>>> no diffs <<<
$ hg ndiff -B
$ hg ndiff -Bb
Test added horizontal space first on a line():
$ printf '\t hello world\ngoodbye world\n' >foo
>>> four diffs showing added space first on the first line <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+ hello world
goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+ hello world
goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+ hello world
goodbye world
$ hg ndiff -Bb
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+ hello world
goodbye world
Test added horizontal space last on a line:
$ printf 'hello world\t \ngoodbye world\n' >foo
>>> two diffs showing space appended to the first line <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+hello world
goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+hello world
goodbye world
>>> no diffs <<<
$ hg ndiff -b
$ hg ndiff -Bb
Test added horizontal space in the middle of a word:
$ printf 'hello world\ngood bye world\n' >foo
>>> four diffs showing space inserted into "goodbye" <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+good bye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+good bye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+good bye world
$ hg ndiff -Bb
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+good bye world
Test increased horizontal whitespace amount:
$ printf 'hello world\ngoodbye\t\t \tworld\n' >foo
>>> two diffs showing changed whitespace amount in the last line <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+goodbye world
>>> no diffs <<<
$ hg ndiff -b
$ hg ndiff -Bb
Test added blank line with horizontal whitespace:
$ printf 'hello world\n \t\ngoodbye world\n' >foo
>>> three diffs showing added blank line with horizontal space <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+
goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+
goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+
goodbye world
>>> no diffs <<<
$ hg ndiff -Bb
Test added blank line with other whitespace:
$ printf 'hello world\n \t\ngoodbye world \n' >foo
>>> three diffs showing added blank line with other space <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
-goodbye world
+hello world
+
+goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
-goodbye world
+hello world
+
+goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+
goodbye world
>>> no diffs <<<
$ hg ndiff -Bb
Test whitespace changes:
$ printf 'helloworld\ngoodbye\tworld \n' >foo
>>> four diffs showing changed whitespace <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
-goodbye world
+helloworld
+goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
-goodbye world
+helloworld
+goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+helloworld
goodbye world
$ hg ndiff -Bb
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+helloworld
goodbye world
>>> no diffs <<<
$ hg ndiff -w
Test whitespace changes and blank lines:
$ printf 'helloworld\n\n\n\ngoodbye\tworld \n' >foo
>>> five diffs showing changed whitespace <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
-hello world
-goodbye world
+helloworld
+
+
+
+goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
-hello world
-goodbye world
+helloworld
+
+
+
+goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
-hello world
+helloworld
+
+
+
goodbye world
$ hg ndiff -Bb
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
-hello world
+helloworld
+
+
+
goodbye world
$ hg ndiff -w
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
hello world
+
+
+
goodbye world
>>> no diffs <<<
$ hg ndiff -wB
Test \r (carriage return) as used in "DOS" line endings:
$ printf 'hello world\r\n\r\ngoodbye\rworld\n' >foo
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
-goodbye world
+hello world\r (esc)
+\r (esc)
+goodbye\r (no-eol) (esc)
world
Test \r (carriage return) as used in "DOS" line endings:
$ printf 'hello world \r\n\t\ngoodbye world\n' >foo
$ hg ndiff --ignore-space-at-eol
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+\t (esc)
goodbye world
No completely blank lines to ignore:
$ printf 'hello world\r\n\r\ngoodbye\rworld\n' >foo
$ hg ndiff --ignore-blank-lines
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
-goodbye world
+hello world\r (esc)
+\r (esc)
+goodbye\r (no-eol) (esc)
world
Only new line noticed:
$ hg ndiff --ignore-space-change
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+\r (esc)
goodbye world
$ hg ndiff --ignore-all-space
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+\r (esc)
goodbye world
New line not noticed when space change ignored:
$ hg ndiff --ignore-blank-lines --ignore-all-space
Do not ignore all newlines, only blank lines
$ printf 'hello \nworld\ngoodbye world\n' > foo
$ hg ndiff --ignore-blank-lines
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
+hello
+world
goodbye world
Test hunk offsets adjustments with --ignore-blank-lines
$ hg revert -aC
reverting foo
$ printf '\nb\nx\nd\n' > a
$ printf 'b\ny\nd\n' > b
$ hg add a b
$ hg ci -m add
$ hg cat -r . a > b
$ hg cat -r . b > a
$ hg diff -B --nodates a > ../diffa
$ cat ../diffa
diff -r 0e66aa54f318 a
--- a/a
+++ b/a
@@ -1,4 +1,4 @@
b
-x
+y
d
$ hg diff -B --nodates b > ../diffb
$ cat ../diffb
diff -r 0e66aa54f318 b
--- a/b
+++ b/b
@@ -1,3 +1,3 @@
b
-y
+x
d
$ hg revert -aC
reverting a
reverting b
$ hg import --no-commit ../diffa
applying ../diffa
$ hg revert -aC
reverting a
$ hg import --no-commit ../diffb
applying ../diffb
$ hg revert -aC
reverting b