debugignore: find out why a file is being ignored (issue4856)

This patch adds a capability to hg debugignore: to explain why a given file is
being ignores by mercurial. We display the filename, line and linenumber of the
rule that lead us to ignore the file.

tests/test-hgignore.t

@@ -1,285 +1,288 b''
   $ hg init ignorerepo
   $ cd ignorerepo
 
 Issue562: .hgignore requires newline at end:
 
   $ touch foo
   $ touch bar
   $ touch baz
   $ cat > makeignore.py <<EOF
   > f = open(".hgignore", "w")
   > f.write("ignore\n")
   > f.write("foo\n")
   > # No EOL here
   > f.write("bar")
   > f.close()
   > EOF
 
   $ python makeignore.py
 
 Should display baz only:
 
   $ hg status
   ? baz
 
   $ rm foo bar baz .hgignore makeignore.py
 
   $ touch a.o
   $ touch a.c
   $ touch syntax
   $ mkdir dir
   $ touch dir/a.o
   $ touch dir/b.o
   $ touch dir/c.o
 
   $ hg add dir/a.o
   $ hg commit -m 0
   $ hg add dir/b.o
 
   $ hg status
   A dir/b.o
   ? a.c
   ? a.o
   ? dir/c.o
   ? syntax
 
   $ echo "*.o" > .hgignore
   $ hg status
   abort: $TESTTMP/ignorerepo/.hgignore: invalid pattern (relre): *.o (glob)
   [255]
 
   $ echo ".*\.o" > .hgignore
   $ hg status
   A dir/b.o
   ? .hgignore
   ? a.c
   ? syntax
 
 Ensure that comments work:
 
   $ touch 'foo#bar' 'quux#'
 #if no-windows
   $ touch 'baz\#wat'
 #endif
   $ cat <<'EOF' >> .hgignore
   > # full-line comment
   >   # whitespace-only comment line
   > syntax# pattern, no whitespace, then comment
   > a.c  # pattern, then whitespace, then comment
   > baz\\# # escaped comment character
   > foo\#b # escaped comment character
   > quux\## escaped comment character at end of name
   > EOF
   $ hg status
   A dir/b.o
   ? .hgignore
   $ rm 'foo#bar' 'quux#'
 #if no-windows
   $ rm 'baz\#wat'
 #endif
 
 Check it does not ignore the current directory '.':
 
   $ echo "^\." > .hgignore
   $ hg status
   A dir/b.o
   ? a.c
   ? a.o
   ? dir/c.o
   ? syntax
 
 Test that patterns from ui.ignore options are read:
 
   $ echo > .hgignore
   $ cat >> $HGRCPATH << EOF
   > [ui]
   > ignore.other = $TESTTMP/ignorerepo/.hg/testhgignore
   > EOF
   $ echo "glob:**.o" > .hg/testhgignore
   $ hg status
   A dir/b.o
   ? .hgignore
   ? a.c
   ? syntax
 
 empty out testhgignore
   $ echo > .hg/testhgignore
 
 Test relative ignore path (issue4473):
 
   $ cat >> $HGRCPATH << EOF
   > [ui]
   > ignore.relative = .hg/testhgignorerel
   > EOF
   $ echo "glob:*.o" > .hg/testhgignorerel
   $ cd dir
   $ hg status
   A dir/b.o
   ? .hgignore
   ? a.c
   ? syntax
 
   $ cd ..
   $ echo > .hg/testhgignorerel
   $ echo "syntax: glob" > .hgignore
   $ echo "re:.*\.o" >> .hgignore
   $ hg status
   A dir/b.o
   ? .hgignore
   ? a.c
   ? syntax
 
   $ echo "syntax: invalid" > .hgignore
   $ hg status
   $TESTTMP/ignorerepo/.hgignore: ignoring invalid syntax 'invalid' (glob)
   A dir/b.o
   ? .hgignore
   ? a.c
   ? a.o
   ? dir/c.o
   ? syntax
 
   $ echo "syntax: glob" > .hgignore
   $ echo "*.o" >> .hgignore
   $ hg status
   A dir/b.o
   ? .hgignore
   ? a.c
   ? syntax
 
   $ echo "relglob:syntax*" > .hgignore
   $ hg status
   A dir/b.o
   ? .hgignore
   ? a.c
   ? a.o
   ? dir/c.o
 
   $ echo "relglob:*" > .hgignore
   $ hg status
   A dir/b.o
 
   $ cd dir
   $ hg status .
   A b.o
 
   $ hg debugignore
   (?:(?:|.*/)[^/]*(?:/|$))
 
   $ hg debugignore b.o
   b.o is ignored
+  (ignore rule in $TESTTMP/ignorerepo/.hgignore, line 1: '*')
 
   $ cd ..
 
 Check patterns that match only the directory
 
   $ echo "^dir\$" > .hgignore
   $ hg status
   A dir/b.o
   ? .hgignore
   ? a.c
   ? a.o
   ? syntax
 
 Check recursive glob pattern matches no directories (dir/**/c.o matches dir/c.o)
 
   $ echo "syntax: glob" > .hgignore
   $ echo "dir/**/c.o" >> .hgignore
   $ touch dir/c.o
   $ mkdir dir/subdir
   $ touch dir/subdir/c.o
   $ hg status
   A dir/b.o
   ? .hgignore
   ? a.c
   ? a.o
   ? syntax
   $ hg debugignore a.c
   a.c is not ignored
   $ hg debugignore dir/c.o
   dir/c.o is ignored
+  (ignore rule in $TESTTMP/ignorerepo/.hgignore, line 2: 'dir/**/c.o')
 
 Check using 'include:' in ignore file
 
   $ hg purge --all --config extensions.purge=
   $ touch foo.included
 
   $ echo ".*.included" > otherignore
   $ hg status -I "include:otherignore"
   ? foo.included
 
   $ echo "include:otherignore" >> .hgignore
   $ hg status
   A dir/b.o
   ? .hgignore
   ? otherignore
 
 Check recursive uses of 'include:'
 
   $ echo "include:nested/ignore" >> otherignore
   $ mkdir nested
   $ echo "glob:*ignore" > nested/ignore
   $ hg status
   A dir/b.o
 
   $ cp otherignore goodignore
   $ echo "include:badignore" >> otherignore
   $ hg status
   skipping unreadable pattern file 'badignore': No such file or directory
   A dir/b.o
 
   $ mv goodignore otherignore
 
 Check using 'include:' while in a non-root directory
 
   $ cd ..
   $ hg -R ignorerepo status
   A dir/b.o
   $ cd ignorerepo
 
 Check including subincludes
 
   $ hg revert -q --all
   $ hg purge --all --config extensions.purge=
   $ echo ".hgignore" > .hgignore
   $ mkdir dir1 dir2
   $ touch dir1/file1 dir1/file2 dir2/file1 dir2/file2
   $ echo "subinclude:dir2/.hgignore" >> .hgignore
   $ echo "glob:file*2" > dir2/.hgignore
   $ hg status
   ? dir1/file1
   ? dir1/file2
   ? dir2/file1
 
 Check including subincludes with regexs
 
   $ echo "subinclude:dir1/.hgignore" >> .hgignore
   $ echo "regexp:f.le1" > dir1/.hgignore
 
   $ hg status
   ? dir1/file2
   ? dir2/file1
 
 Check multiple levels of sub-ignores
 
   $ mkdir dir1/subdir
   $ touch dir1/subdir/subfile1 dir1/subdir/subfile3 dir1/subdir/subfile4
   $ echo "subinclude:subdir/.hgignore" >> dir1/.hgignore
   $ echo "glob:subfil*3" >> dir1/subdir/.hgignore
 
   $ hg status
   ? dir1/file2
   ? dir1/subdir/subfile4
   ? dir2/file1
 
 Check include subignore at the same level
 
   $ mv dir1/subdir/.hgignore dir1/.hgignoretwo
   $ echo "regexp:f.le1" > dir1/.hgignore
   $ echo "subinclude:.hgignoretwo" >> dir1/.hgignore
   $ echo "glob:file*2" > dir1/.hgignoretwo
 
   $ hg status | grep file2
   [1]
   $ hg debugignore dir1/file2
   dir1/file2 is ignored
+  (ignore rule in dir2/.hgignore, line 1: 'file*2')