Re: [gentoo-portage-dev] [PATCH v2] emerge --search: auto-detect regular expressions (bug 737480)

[Michał Górny]

On Tue, 2020-09-01 at 19:59 -0700, Zac Medico wrote:
> Automatically detect regular expressions when the search string
> contains any of these regular expression characters or character
> sequences:
>
>   ^ $ * [ ] { } | ? .+

Isn't this going to break search for gtk+?

>
> This simplifies usage, so that users no longer have to remember
> to prefix regular expressions with the % character. The new
> behavior can be disabled by --regex-search-auto=n, in case the
> regular expressions interpretation causes some kind of problem.
>
> Note that fuzzy search and regular expression search are
> mutually exclusive, and fuzzy search remains the default for
> search strings that do not contain any regular expression
> characters.
>
> Bug: https://bugs.gentoo.org/737480
> Signed-off-by: Zac Medico <zmedico@g.o>
> ---
> [PATCH v2] Recognize .+ as suggested by Arfrever.
>
>  lib/_emerge/actions.py |  1 +
>  lib/_emerge/main.py    |  6 ++++++
>  lib/_emerge/search.py  | 12 +++++++++++-
>  man/emerge.1           | 12 +++++++++++-
>  4 files changed, 29 insertions(+), 2 deletions(-)
>
> diff --git a/lib/_emerge/actions.py b/lib/_emerge/actions.py
> index a4ecfe43d..f57269817 100644
> --- a/lib/_emerge/actions.py
> +++ b/lib/_emerge/actions.py
> @@ -2036,6 +2036,7 @@ def action_search(root_config, myopts, myfiles, spinner):
>  			search_index=myopts.get("--search-index", "y") != "n",
>  			search_similarity=myopts.get("--search-similarity"),
>  			fuzzy=myopts.get("--fuzzy-search") != "n",
> +			regex_auto=myopts.get("--regex-search-auto") != "n",
>  			)
>  		for mysearch in myfiles:
>  			try:
> diff --git a/lib/_emerge/main.py b/lib/_emerge/main.py
> index 975738762..5075f7f57 100644
> --- a/lib/_emerge/main.py
> +++ b/lib/_emerge/main.py
> @@ -709,6 +709,12 @@ def parse_opts(tmpcmdline, silent=False):
>  			"action" : "store"
>  		},
>
> +		"--regex-search-auto": {
> +			"help"   : "Enable or disable automatic regular expression detection for search actions",
> +			"choices": y_or_n,
> +			"default": "y",
> +		},
> +
>  		"--root": {
>  		 "help"   : "specify the target root filesystem for merging packages",
>  		 "action" : "store"
> diff --git a/lib/_emerge/search.py b/lib/_emerge/search.py
> index a59191c1a..61eed0827 100644
> --- a/lib/_emerge/search.py
> +++ b/lib/_emerge/search.py
> @@ -28,7 +28,7 @@ class search:
>  	#
>  	def __init__(self, root_config, spinner, searchdesc,
>  		verbose, usepkg, usepkgonly, search_index=True,
> -		search_similarity=None, fuzzy=True):
> +		search_similarity=None, fuzzy=True, regex_auto=False):
>  		"""Searches the available and installed packages for the supplied search key.
>  		The list of available and installed packages is created at object instantiation.
>  		This makes successive searches faster."""
> @@ -42,6 +42,7 @@ class search:
>  		self.spinner = None
>  		self.root_config = root_config
>  		self.setconfig = root_config.setconfig
> +		self.regex_auto = regex_auto
>  		self.fuzzy = fuzzy
>  		self.search_similarity = (80 if search_similarity is None
>  			else search_similarity)
> @@ -259,6 +260,15 @@ class search:
>  		if '/' in self.searchkey:
>  			match_category = 1
>  		fuzzy = False
> +
> +		if self.regex_auto and not regexsearch and re.search(r'[\^\$\*\[\]\{\}\|\?]|\.\+', self.searchkey) is not None:
> +			try:
> +				re.compile(self.searchkey, re.I)
> +			except Exception:
> +				pass
> +			else:
> +				regexsearch = True
> +
>  		if regexsearch:
>  			self.searchre=re.compile(self.searchkey,re.I)
>  		else:
> diff --git a/man/emerge.1 b/man/emerge.1
> index fe7d05a21..c1bcd0220 100644
> --- a/man/emerge.1
> +++ b/man/emerge.1
> @@ -229,7 +229,9 @@ explicitly discarded by running `emaint \-\-fix cleanresume` (see
>  .BR \-\-search ", " \-s
>  Searches for matches of the supplied string in the ebuild repository.
>  By default emerge uses a case-insensitive simple search, but you can
> -enable a regular expression search by prefixing the search string with %.
> +enable a regular expression search by prefixing the search string with %
> +(the % prefix can often be omitted if the
> +\fB\-\-regex\-search\-auto\fR option is enabled).
>  For example, \fBemerge \-\-search "%^kde"\fR searches for any package whose
>  name starts with "kde"; \fBemerge \-\-search "%gcc$"\fR searches for any
>  package that ends with "gcc"; \fBemerge \-\-search "office"\fR searches for
> @@ -764,6 +766,14 @@ matching packages due to \fB\-\-rebuild\fR.
>  A space separated list of package names or slot atoms. Emerge will not rebuild
>  packages that depend on matching packages due to \fB\-\-rebuild\fR.
>  .TP
> +.BR "\-\-regex\-search\-auto < y | n >"
> +Enable or disable automatic regular expression detection for search actions.
> +If this option is enabled (the default), then regular expression search
> +is automatically enabled when the search string is a valid regular expression
> +which contains any of these commonly used regular expression characters or
> +character sequences:
> +^ $ * [ ] { } | ? .+
> +.TP
>  .BR \-\-oneshot ", " \-1
>  Emerge as normal, but do not add the packages to the world file
>  for later updating.

-- 
Best regards,
Michał Górny