Merge branch 'jk/fast-export-anonym-alt'

"git fast-export --anonymize" learned to take customized mapping to
allow its users to tweak its output more usable for debugging.

* jk/fast-export-anonym-alt:
  fast-export: use local array to store anonymized oid
  fast-export: anonymize "master" refname
  fast-export: allow seeding the anonymized mapping
  fast-export: add a "data" callback parameter to anonymize_str()
  fast-export: move global "idents" anonymize hashmap into function
  fast-export: use a flex array to store anonymized entries
  fast-export: stop storing lengths in anonymized hashmaps
  fast-export: tighten anonymize_mem() interface to handle only strings
  fast-export: store anonymized oids as hex strings
  fast-export: use xmemdupz() for anonymizing oids
  t9351: derive anonymized tree checks from original repo

1 files changed, 29 insertions, 0 deletions

diff --git a/Documentation/git-fast-export.txt b/Documentation/git-fast-export.txt
index e8950de3ba..1978dbdc6a 100644
--- a/Documentation/git-fast-export.txt
+++ b/Documentation/git-fast-export.txt
@@ -119,6 +119,11 @@ by keeping the marks the same across runs.
 	the shape of the history and stored tree.  See the section on
 	`ANONYMIZING` below.
 
+--anonymize-map=<from>[:<to>]::
+	Convert token `<from>` to `<to>` in the anonymized output. If
+	`<to>` is omitted, map `<from>` to itself (i.e., do not
+	anonymize it). See the section on `ANONYMIZING` below.
+
 --reference-excluded-parents::
 	By default, running a command such as `git fast-export
 	master~5..master` will not include the commit master{tilde}5
@@ -238,6 +243,30 @@ collapse "User 0", "User 1", etc into "User X"). This produces a much
 smaller output, and it is usually easy to quickly confirm that there is
 no private data in the stream.
 
+Reproducing some bugs may require referencing particular commits or
+paths, which becomes challenging after refnames and paths have been
+anonymized. You can ask for a particular token to be left as-is or
+mapped to a new value. For example, if you have a bug which reproduces
+with `git rev-list sensitive -- secret.c`, you can run:
+
+---------------------------------------------------
+$ git fast-export --anonymize --all \
+      --anonymize-map=sensitive:foo \
+      --anonymize-map=secret.c:bar.c \
+      >stream
+---------------------------------------------------
+
+After importing the stream, you can then run `git rev-list foo -- bar.c`
+in the anonymized repository.
+
+Note that paths and refnames are split into tokens at slash boundaries.
+The command above would anonymize `subdir/secret.c` as something like
+`path123/bar.c`; you could then search for `bar.c` in the anonymized
+repository to determine the final pathname.
+
+To make referencing the final pathname simpler, you can map each path
+component; so if you also anonymize `subdir` to `publicdir`, then the
+final pathname would be `publicdir/bar.c`.
 
 LIMITATIONS
 -----------