Accepting the new error output

cabal-testsuite/PackageTests/ConditionalAndImport/cabal.out

@@ -11,8 +11,10 @@ Building executable 'some-exe' for some-exe-0.0.1.0...
 Installing executable some-exe in <PATH>
 Warning: The directory <ROOT>/cabal.dist/home/.cabal/store/ghc-<GHCVER>/incoming/new-<RAND><ROOT>/cabal.dist/home/.cabal/store/ghc-<GHCVER>/<PACKAGE>-<HASH>/bin is not in the system search path.
 # cabal v2-build
-Error: cabal: Error parsing project file <ROOT>/cabal-cyclical.project:3:
+Error: [Cabal-7090]
+Error parsing project file <ROOT>/cabal-cyclical.project:3:
 cyclical import of cabal-cyclical.project
 # cabal v2-build
-Error: cabal: Error parsing project file <ROOT>/cabal-bad-conditional.project:
+Error: [Cabal-7090]
+Error parsing project file <ROOT>/cabal-bad-conditional.project:
 Cannot set compiler in a conditional clause of a cabal project file

cabal-testsuite/PackageTests/ConfigFile/T7705/cabal.out

 # cabal info
 Config file path source is commandline option.
-Error: cabal: Config file not found: does.not.exist
+Error: [Cabal-7084]
+Config file not found: does.not.exist
 (Config files can be created via the cabal-command 'user-config init'.)
 # cabal info
 Config file path source is environment variable CABAL_CONFIG.
-Error: cabal: Config file not found: absent.file
+Error: [Cabal-7084]
+Config file not found: absent.file
 (Config files can be created via the cabal-command 'user-config init'.)

cabal-testsuite/PackageTests/Get/T7248/cabal.out

 # cabal get
 Warning: <ROOT>/cabal.config: Unrecognized stanza on line 3
 Warning: The package list for 'repo.invalid' does not exist. Run 'cabal update' to download it.
-Error: cabal: There is no package named 'a-b-s-e-n-t'. 
+Error: [Cabal-7100]
+There is no package named 'a-b-s-e-n-t'. 
 You may need to run 'cabal update' to get the latest list of available packages.

cabal-testsuite/PackageTests/MultiRepl/NotEnabledFail/cabal.multirepl-a.out

 # cabal v2-repl
 Resolving dependencies...
-Error: cabal: Cannot open a repl for multiple components at once. The targets 'pkg-a' and 'pkg-b' refer to different components..
+Error: [Cabal-7076]
+Cannot open a repl for multiple components at once. The targets 'pkg-a' and 'pkg-b' refer to different components..
 
 Your compiler supports a multiple component repl but support is not enabled.
 The experimental multi repl can be enabled by

cabal-testsuite/PackageTests/NewBuild/CmdRun/ExeAndLib/cabal.out

@@ -7,4 +7,5 @@ Configuring executable 'foo' for ExeAndLib-1.0...
 Preprocessing executable 'foo' for ExeAndLib-1.0...
 Building executable 'foo' for ExeAndLib-1.0...
 # cabal v2-run
-Error: cabal: The run command is for running executables, but the target 'ExeAndLib' refers to the library ExeAndLib from the package ExeAndLib-1.0.
+Error: [Cabal-7070]
+The run command is for running executables, but the target 'ExeAndLib' refers to the library ExeAndLib from the package ExeAndLib-1.0.

cabal-testsuite/PackageTests/NewBuild/CmdRun/MultipleExes/cabal.out

@@ -14,10 +14,13 @@ Configuring executable 'bar' for MultipleExes-1.0...
 Preprocessing executable 'bar' for MultipleExes-1.0...
 Building executable 'bar' for MultipleExes-1.0...
 # cabal v2-run
-
 # cabal v2-run
-Error: cabal: The run command is for running a single executable at once. The target '' refers to the package MultipleExes-1.0 which includes
+Error: [Cabal-7070]
+The run command is for running a single executable at once. The target '' refers to the package MultipleExes-1.0 which includes 
 - executables: bar and foo
+
 # cabal v2-run
-Error: cabal: The run command is for running a single executable at once. The target 'MultipleExes' refers to the package MultipleExes-1.0 which includes
+Error: [Cabal-7070]
+The run command is for running a single executable at once. The target 'MultipleExes' refers to the package MultipleExes-1.0 which includes 
 - executables: bar and foo
+

cabal-testsuite/PackageTests/NewBuild/CmdRun/MultiplePackages/cabal.out

@@ -24,8 +24,10 @@ Building executable 'foo-exe' for bar-1.0...
 # cabal v2-run
 Error: cabal: No targets given and there is no package in the current directory. Specify packages or components by name or location. See 'cabal build --help' for more details on target options.
 # cabal v2-run
-Error: cabal: The run command is for running a single executable at once. The target 'bar' refers to the package bar-1.0 which includes
+Error: [Cabal-7070]
+The run command is for running a single executable at once. The target 'bar' refers to the package bar-1.0 which includes 
 - executables: bar-exe and foo-exe
+
 # cabal v2-run
 Error: cabal: Ambiguous target 'foo-exe'. It could be:
     bar:foo-exe (component)
@@ -34,3 +36,4 @@ Error: cabal: Ambiguous target 'foo-exe'. It could be:
 # cabal v2-run
 Error: cabal: Unknown target 'foo:bar-exe'.
 The package foo has no component 'bar-exe'.
+

cabal-testsuite/PackageTests/NewBuild/CmdRun/RunMainBad/cabal.out

 # cabal v2-run
 Resolving dependencies...
-Error: cabal: The run command can only run an executable as a whole, not files or modules within them, but the target 'Main.hs' refers to the file Main.hs in the executable foo.
+Error: [Cabal-7070]
+The run command can only run an executable as a whole, not files or modules within them, but the target 'Main.hs' refers to the file Main.hs in the executable foo.

cabal-testsuite/PackageTests/NewBuild/CmdRun/Single/cabal.out

@@ -11,4 +11,5 @@ Building executable 'foo' for Single-1.0...
 # cabal v2-run
 # cabal v2-run
 # cabal v2-run
-Error: cabal: Cannot run the package bar, it is not in this project (either directly or indirectly). If you want to add it to the project then edit the cabal.project file.
+Error: [Cabal-7070]
+Cannot run the package bar, it is not in this project (either directly or indirectly). If you want to add it to the project then edit the cabal.project file.

cabal-testsuite/PackageTests/Outdated/outdated-project-file.out

@@ -7,4 +7,5 @@ base ==3.0.3.2 (latest: 4.0.0.0)
 Outdated dependencies:
 base ==3.0.3.2 (latest: 4.0.0.0)
 # cabal outdated
-Error: cabal: --project-dir and --project-file must only be used with --v2-freeze-file.
+Error: [Cabal-7103]
+--project-dir and --project-file must only be used with --v2-freeze-file.

cabal-testsuite/PackageTests/Outdated/outdated_freeze.out

@@ -23,6 +23,7 @@ Outdated dependencies:
 template-haskell ==2.3.0.0 (latest: 2.3.0.1)
 binary ==0.8.5.0 (latest: 0.8.6.0)
 # cabal outdated
-Error: cabal: Couldn't find a freeze file expected at: <ROOT>/cabal.project.missing.freeze.freeze
+Error: [Cabal-7104]
+Couldn't find a freeze file expected at: <ROOT>/cabal.project.missing.freeze.freeze
 
 We are looking for this file because you supplied '--project-file' or '--v2-freeze-file'. When one of these flags is given, we try to read the dependencies from a freeze file. If it is undesired behaviour, you should not use these flags, otherwise please generate a freeze file via 'cabal freeze'.