style: don't use capital letter for constant For better or worse, our coding do not use all caps for constants. We rename constant name introduced in a5009789960c.

tests-subrepo-git: use "f" to dump pwned.txt, for portability Rather than sometimes using a complicated shell construct to dump pwned.txt (if it wasn't expected to exist, but might, if something were broken) or just cat (if it was expected to exist), just use the "f" utility, which will be consistent in its behavior across different platforms. Also make sure that *something* gets put into pwned.txt, even if we ended up typoing the message variable.

bundle2: don't assume ordering of heads checked after push Usually, the heads will have the same ordering in handlecheckheads. Insisting on the same ordering is however an unnecessary constraint that in some custom cases can cause pushes to fail even though the actual heads didn't change. This caused production issues for us in combination with the current version of https://bitbucket.org/Unity-Technologies/hgwebcachingproxy/ .

sslutil: print the fingerprint from the last hash used Before, we would always print the unprefixed SHA-1 fingerprint when fingerprint comparison failed. Now, we print the fingerprint of the last hash used, including the prefix if necessary. This helps ensure that the printed hash type matches what is in the user configuration. There are still some cases where this can print a mismatched hash type. e.g. if there are both SHA-1 and SHA-256 fingerprints in the config, we could print a SHA-1 hash if it comes after the SHA-256 hash. But I'm inclined to ignore this edge case. While I was here, the "section" variable assignment has been moved to just above where it is used because it is now only needed for this error message and it makes the code easier to read.

sslutil: make cert fingerprints messages more actionable The previous warning and abort messages were difficult to understand. This patch makes them slightly better. I think there is still room to tweak the messaging. And as we adopt new security defaults, these messages will certainly change again. But at least this takes us a step in the right direction. References to "section" have been removed because if no fingerprint is defined, "section" can never be "hostfingerprints." So just print "hostsecurity" every time.

sslutil: refactor code for fingerprint matching We didn't need to use a temporary variable to indicate success because we just return anyway. This refactor makes the code simpler. While we're here, we also call into formatfingerprint() to ensure the fingerprint from the proper hashing algorithm is logged.

sslutil: print SHA-256 fingerprint by default The world is starting to move on from SHA-1. A few commits ago, we gained the ability to define certificate fingerprints using SHA-256 and SHA-512. Let's start printing the SHA-256 fingerprint instead of the SHA-1 fingerprint to encourage people to pin with a more secure hashing algorithm. There is still a bit of work to be done around the fingerprint messaging. This will be addressed in subsequent commits.

sslutil: move and change warning when cert verification is disabled A short time ago, validatesocket() didn't know the reasons why cert verification was disabled. Multiple code paths could lead to cert verification being disabled. e.g. --insecure and lack of loaded CAs. With the recent refactorings to sslutil.py, we now know the reasons behind security settings. This means we can recognize when the user requested security be disabled (as opposed to being unable to provide certificate verification due to lack of CAs). This patch moves the check for certificate verification being disabled and changes the wording to distinguish it from other states. The warning message is purposefully more dangerous sounding in order to help discourage people from disabling security outright. We may want to add a URL or hint to this message. I'm going to wait until additional changes to security defaults before committing to something.

sslutil: add devel.disableloaddefaultcerts to disable CA loading There are various tests for behavior when CA certs aren't loaded. Previously, we would pass --insecure to disable loading of CA certs. This has worked up to this point because the error message for --insecure and no CAs loaded is the same. Upcoming commits will change the error message for --insecure and will change behavior when CAs aren't loaded. This commit introduces the ability to disable loading of CA certs by setting devel.disableloaddefaultcerts. This allows a testing backdoor to disable loading of CA certs even if system/default CA certs are available. The flag is purposefully not exposed to end-users because there should not be a need for this in the wild: certificate pinning and --insecure provide workarounds to disable cert loading/validation. Tests have been updated to use the new method. The variable used to disable CA certs has been renamed because the method is not OS X specific.

sslutil: store flag for whether cert verification is disabled This patch effectively moves the ui.insecureconnections check to _hostsettings(). After this patch, validatesocket() no longer uses the ui instance for anything except writing messages. This patch also enables us to introduce a per-host config option for disabling certificate verification.