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authorKevin Pulo <kevin.pulo@mongodb.com>2020-10-26 17:11:18 +1100
committerEvergreen Agent <no-reply@evergreen.mongodb.com>2020-11-02 09:58:44 +0000
commit7d8e64df2d2d56a821f638ef88aa619403d03d31 (patch)
tree6ada2d481c56b9754ec7848caf146cd94149148f /docs
parent4d2dea00415bf02d2b32d0474c93d251ce6568cc (diff)
downloadmongo-7d8e64df2d2d56a821f638ef88aa619403d03d31.tar.gz
SERVER-44570 Add tripwire assertions (tassert)
Diffstat (limited to 'docs')
-rw-r--r--docs/exception_architecture.md12
1 files changed, 10 insertions, 2 deletions
diff --git a/docs/exception_architecture.md b/docs/exception_architecture.md
index 09f89e16837..105319774f3 100644
--- a/docs/exception_architecture.md
+++ b/docs/exception_architecture.md
@@ -3,6 +3,8 @@
MongoDB code uses the following types of assertions that are available for use:
- `uassert` and `internalAssert`
- Checks for per-operation user errors. Operation-fatal.
+- `tassert`
+ - Like uassert, but inhibits clean shutdown.
- `massert`
- Checks per-operation invariants. Operation-fatal.
- `fassert`
@@ -18,9 +20,9 @@ The following types of assertions are deprecated:
- `verify`
- Checks per-operation invariants. A synonym for massert but doesn't require an error code.
- Do not use for new code; use invariant or fassert instead.
+ Process fatal in debug mode. Do not use for new code; use invariant or fassert instead.
- `dassert`
- - Calls `verify` but only in debug mode. Do not use!
+ - Calls `invariant` but only in debug mode. Do not use!
MongoDB uses a series of `ErrorCodes` (defined in [mongo/base/error_codes.yml][error_codes_yml]) to
identify and categorize error conditions. `ErrorCodes` are defined in a YAML file and converted to
@@ -41,6 +43,12 @@ mistakenly using these assertions midway through mutating process state. Example
`fassert` failures will terminate the entire process; this is used for low-level checks where
continuing might lead to corrupt data or loss of data on disk.
+`tassert` is a hybrid - it will fail the operation like `uassert`, but also triggers a
+"deferred-fatality tripwire flag". If this flag is set during clean shutdown, the process will
+invoke the tripwire fatal assertion. This is useful for ensuring that operation failures will cause
+a test suite to fail, without resorting to different behavior during testing, and without allowing
+user operations to potentially disrupt production deployments by terminating the server.
+
Both `massert` and `uassert` take error codes, so that all assertions have codes associated with
them. Currently, programmers are free to provide the error code by either using a unique location
number or choose from existing `ErrorCodes`. Unique location numbers are assigned incrementally and