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nixpkgs/lib/sources.nix
Franz Pletz 46773a15b3
nixos/version: fix case where .git is a symlink
Before c9214c394b and
9d396d2e42 if .git is symlink the version
would gracefully default to no git revision. With those changes an
exception is thrown instead.

This introduces a new function `pathIsGitRepo` that checks if
`commitIdFromGitRepo` fails without error so we don't have to
reimplement this logic again and can fail gracefully.
2020-01-20 00:53:44 +01:00

163 lines
6.8 KiB
Nix

# Functions for copying sources to the Nix store.
{ lib }:
rec {
# Returns the type of a path: regular (for file), symlink, or directory
pathType = p: with builtins; getAttr (baseNameOf p) (readDir (dirOf p));
# Returns true if the path exists and is a directory, false otherwise
pathIsDirectory = p: if builtins.pathExists p then (pathType p) == "directory" else false;
# Returns true if the path exists and is a regular file, false otherwise
pathIsRegularFile = p: if builtins.pathExists p then (pathType p) == "regular" else false;
# Bring in a path as a source, filtering out all Subversion and CVS
# directories, as well as backup files (*~).
cleanSourceFilter = name: type: let baseName = baseNameOf (toString name); in ! (
# Filter out version control software files/directories
(baseName == ".git" || type == "directory" && (baseName == ".svn" || baseName == "CVS" || baseName == ".hg")) ||
# Filter out editor backup / swap files.
lib.hasSuffix "~" baseName ||
builtins.match "^\\.sw[a-z]$" baseName != null ||
builtins.match "^\\..*\\.sw[a-z]$" baseName != null ||
# Filter out generates files.
lib.hasSuffix ".o" baseName ||
lib.hasSuffix ".so" baseName ||
# Filter out nix-build result symlinks
(type == "symlink" && lib.hasPrefix "result" baseName)
);
# Filters a source tree removing version control files and directories using cleanSourceWith
#
# Example:
# cleanSource ./.
cleanSource = src: cleanSourceWith { filter = cleanSourceFilter; inherit src; };
# Like `builtins.filterSource`, except it will compose with itself,
# allowing you to chain multiple calls together without any
# intermediate copies being put in the nix store.
#
# lib.cleanSourceWith {
# filter = f;
# src = lib.cleanSourceWith {
# filter = g;
# src = ./.;
# };
# }
# # Succeeds!
#
# builtins.filterSource f (builtins.filterSource g ./.)
# # Fails!
#
# Parameters:
#
# src: A path or cleanSourceWith result to filter and/or rename.
#
# filter: A function (path -> type -> bool)
# Optional with default value: constant true (include everything)
# The function will be combined with the && operator such
# that src.filter is called lazily.
# For implementing a filter, see
# https://nixos.org/nix/manual/#builtin-filterSource
#
# name: Optional name to use as part of the store path.
# This defaults `src.name` or otherwise `baseNameOf src`.
# We recommend setting `name` whenever `src` is syntactically `./.`.
# Otherwise, you depend on `./.`'s name in the parent directory,
# which can cause inconsistent names, defeating caching.
#
cleanSourceWith = { filter ? _path: _type: true, src, name ? null }:
let
isFiltered = src ? _isLibCleanSourceWith;
origSrc = if isFiltered then src.origSrc else src;
filter' = if isFiltered then name: type: filter name type && src.filter name type else filter;
name' = if name != null then name else if isFiltered then src.name else baseNameOf src;
in {
inherit origSrc;
filter = filter';
outPath = builtins.path { filter = filter'; path = origSrc; name = name'; };
_isLibCleanSourceWith = true;
name = name';
};
# Filter sources by a list of regular expressions.
#
# E.g. `src = sourceByRegex ./my-subproject [".*\.py$" "^database.sql$"]`
sourceByRegex = src: regexes:
let
isFiltered = src ? _isLibCleanSourceWith;
origSrc = if isFiltered then src.origSrc else src;
in lib.cleanSourceWith {
filter = (path: type:
let relPath = lib.removePrefix (toString origSrc + "/") (toString path);
in lib.any (re: builtins.match re relPath != null) regexes);
inherit src;
};
# Get all files ending with the specified suffices from the given
# directory or its descendants. E.g. `sourceFilesBySuffices ./dir
# [".xml" ".c"]'.
sourceFilesBySuffices = path: exts:
let filter = name: type:
let base = baseNameOf (toString name);
in type == "directory" || lib.any (ext: lib.hasSuffix ext base) exts;
in cleanSourceWith { inherit filter; src = path; };
pathIsGitRepo = path: (builtins.tryEval (commitIdFromGitRepo path)).success;
# Get the commit id of a git repo
# Example: commitIdFromGitRepo <nixpkgs/.git>
commitIdFromGitRepo =
let readCommitFromFile = file: path:
with builtins;
let fileName = toString path + "/" + file;
packedRefsName = toString path + "/packed-refs";
absolutePath = base: path:
if lib.hasPrefix "/" path
then path
else toString (/. + "${base}/${path}");
in if pathIsRegularFile path
# Resolve git worktrees. See gitrepository-layout(5)
then
let m = match "^gitdir: (.*)$" (lib.fileContents path);
in if m == null
then throw ("File contains no gitdir reference: " + path)
else
let gitDir = absolutePath (dirOf path) (lib.head m);
commonDir' = if pathIsRegularFile "${gitDir}/commondir"
then lib.fileContents "${gitDir}/commondir"
else gitDir;
commonDir = absolutePath gitDir commonDir';
refFile = lib.removePrefix "${commonDir}/" "${gitDir}/${file}";
in readCommitFromFile refFile commonDir
else if pathIsRegularFile fileName
# Sometimes git stores the commitId directly in the file but
# sometimes it stores something like: «ref: refs/heads/branch-name»
then
let fileContent = lib.fileContents fileName;
matchRef = match "^ref: (.*)$" fileContent;
in if matchRef == null
then fileContent
else readCommitFromFile (lib.head matchRef) path
else if pathIsRegularFile packedRefsName
# Sometimes, the file isn't there at all and has been packed away in the
# packed-refs file, so we have to grep through it:
then
let fileContent = readFile packedRefsName;
matchRef = match (".*\n([^\n ]*) " + file + "\n.*") fileContent;
in if matchRef == null
then throw ("Could not find " + file + " in " + packedRefsName)
else lib.head matchRef
else throw ("Not a .git directory: " + path);
in readCommitFromFile "HEAD";
pathHasContext = builtins.hasContext or (lib.hasPrefix builtins.storeDir);
canCleanSource = src: src ? _isLibCleanSourceWith || !(pathHasContext (toString src));
}