[oe-core][PATCHv3] reproducible: fix git SOURCE_DATE_EPOCH randomness

[<rs@ti.com>]

From: Randolph Sapp <rs@ti.com>

Anything that defines multiple git sources should have the largest value
taken when calculating the SOURCE_DATE_EPOCH for a package.

The previous iteration actually introduced some degree of randomness, as
it would stop on the first git repository reported by os.walk, which
does not assure any specific ordering by default.

Signed-off-by: Randolph Sapp <rs@ti.com>
---

v2: Use os.walk method as opposed to glob to avoid infinite recursion when
navigating symbolic links

v3: Cover submodule / worktree related cases by using -C and checking for .git
files.

 meta/lib/oe/reproducible.py | 66 ++++++++++++++++---------------------
 1 file changed, 29 insertions(+), 37 deletions(-)

diff --git a/meta/lib/oe/reproducible.py b/meta/lib/oe/reproducible.py
index 0270024a83..a80376010a 100644
--- a/meta/lib/oe/reproducible.py
+++ b/meta/lib/oe/reproducible.py
@@ -74,52 +74,44 @@ def get_source_date_epoch_from_known_files(d, sourcedir):
         bb.debug(1, "SOURCE_DATE_EPOCH taken from: %s" % newest_file)
     return source_date_epoch

-def find_git_folder(d, sourcedir):
-    # First guess: UNPACKDIR/BB_GIT_DEFAULT_DESTSUFFIX
-    # This is the default git fetcher unpack path
+def find_git_repositories(d, sourcedir):
     unpackdir = d.getVar('UNPACKDIR')
-    default_destsuffix = d.getVar('BB_GIT_DEFAULT_DESTSUFFIX')
-    gitpath = os.path.join(unpackdir, default_destsuffix, ".git")
-    if os.path.isdir(gitpath):
-        return gitpath
-
-    # Second guess: ${S}
-    gitpath = os.path.join(sourcedir, ".git")
-    if os.path.isdir(gitpath):
-        return gitpath
-
-    # Perhaps there was a subpath or destsuffix specified.
-    # Go looking in the UNPACKDIR
-    for root, dirs, files in os.walk(unpackdir, topdown=True):
-        if '.git' in dirs:
-            return os.path.join(root, ".git")
+    git_repositories = []

-    for root, dirs, files in os.walk(sourcedir, topdown=True):
-        if '.git' in dirs:
-            return os.path.join(root, ".git")
+    for mainpath in (sourcedir, unpackdir):
+        for root, dirs, files in os.walk(mainpath, topdown=True):
+            if '.git' in dirs or '.git' in files:
+                git_repositories.append(root)

-    bb.warn("Failed to find a git repository in UNPACKDIR: %s" % unpackdir)
-    return None
+    if not git_repositories:
+        bb.warn('Failed to find any git repositories in UNPACKDIR or S')
+
+    return git_repositories

 def get_source_date_epoch_from_git(d, sourcedir):
     if not "git://" in d.getVar('SRC_URI') and not "gitsm://" in d.getVar('SRC_URI'):
         return None

-    gitpath = find_git_folder(d, sourcedir)
-    if not gitpath:
-        return None
+    # Get an epoch from all valid git repositories
+    source_dates = []
+    for repo_path in find_git_repositories(d, sourcedir):
+        # Check that the repository has a valid HEAD; it may not if subdir is used
+        # in SRC_URI
+        p = subprocess.run(['git', '-C', repo_path, 'rev-parse', 'HEAD'],
+                           check=False, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+        if p.returncode != 0:
+            bb.debug(1, "%s does not have a valid HEAD: %s" % (repo_path, p.stdout.decode('utf-8')))
+            continue
+
+        bb.debug(1, "git repository: %s" % repo_path)
+        p = subprocess.run(['git', '-C', repo_path, 'log', '-1', '--pretty=%ct'],
+                           check=True, stdout=subprocess.PIPE)
+        source_dates.append(int(p.stdout.decode('utf-8')))
+
+    if source_dates:
+        return max(source_dates)

-    # Check that the repository has a valid HEAD; it may not if subdir is used
-    # in SRC_URI
-    p = subprocess.run(['git', '--git-dir', gitpath, 'rev-parse', 'HEAD'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
-    if p.returncode != 0:
-        bb.debug(1, "%s does not have a valid HEAD: %s" % (gitpath, p.stdout.decode('utf-8')))
-        return None
-
-    bb.debug(1, "git repository: %s" % gitpath)
-    p = subprocess.run(['git', '-c', 'log.showSignature=false', '--git-dir', gitpath, 'log', '-1', '--pretty=%ct'],
-                       check=True, stdout=subprocess.PIPE)
-    return int(p.stdout.decode('utf-8'))
+    return None

 def get_source_date_epoch_from_youngest_file(d, sourcedir):
     if sourcedir == d.getVar('UNPACKDIR'):
--
2.52.0