Allow breaking threads using --no-parent

It is a common request to be able to get a partial thread in case
someone submitted an auxiliary standalone patch in the middle of a
larger patch series. Passing the msgid of the start of the thread along
with --no-parent should tell b4 to break the thread at the start of the
message-id specified and only consider that message and its children.

Suggested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/tools/YpTI9lhCfA7shi6j@sirena.org.uk/
Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>

5 files changed, 250 insertions, 112 deletions

diff --git a/b4/__init__.py b/b4/__init__.py
index 1ac7eb1..bc4dd36 100644
--- a/b4/__init__.py
+++ b/b4/__init__.py
@@ -2148,8 +2148,9 @@ def get_msgid(cmdargs) -> Optional[str]:
     return msgid
 
 
-def get_strict_thread(msgs, msgid):
+def get_strict_thread(msgs, msgid, noparent=False):
     want = {msgid}
+    ignore = set()
     got = set()
     seen = set()
     maybe = dict()
@@ -2157,6 +2158,8 @@ def get_strict_thread(msgs, msgid):
     while True:
         for msg in msgs:
             c_msgid = LoreMessage.get_clean_msgid(msg)
+            if c_msgid in ignore:
+                continue
             seen.add(c_msgid)
             if c_msgid in got:
                 continue
@@ -2168,7 +2171,16 @@ def get_strict_thread(msgs, msgid):
                 msgrefs += email.utils.getaddresses([str(x) for x in msg.get_all('in-reply-to', [])])
             if msg.get('References', None):
                 msgrefs += email.utils.getaddresses([str(x) for x in msg.get_all('references', [])])
+            # If noparent is set, we pretend the message we got passed has no references, and add all
+            # parent references of this message to ignore
+            if noparent and msgid == c_msgid:
+                logger.info('Breaking thread to remove parents of %s', msgid)
+                ignore = set([x[1] for x in msgrefs])
+                msgrefs = list()
+
             for ref in set([x[1] for x in msgrefs]):
+                if ref in ignore:
+                    continue
                 if ref in got or ref in want:
                     want.add(c_msgid)
                 elif len(ref):
@@ -2206,7 +2218,7 @@ def get_strict_thread(msgs, msgid):
         return None
 
     if len(msgs) > len(strict):
-        logger.debug('Reduced mbox to strict matches only (%s->%s)', len(msgs), len(strict))
+        logger.debug('Reduced thread to requested matches only (%s->%s)', len(msgs), len(strict))
 
     return strict
 
@@ -2266,7 +2278,8 @@ def get_pi_thread_by_url(t_mbx_url, nocache=False):
     return list(deduped.values())
 
 
-def get_pi_thread_by_msgid(msgid, useproject=None, nocache=False, onlymsgids: Optional[set] = None):
+def get_pi_thread_by_msgid(msgid: str, useproject: Optional[str] = None, nocache: bool = False,
+                           onlymsgids: Optional[set] = None) -> Optional[list]:
     qmsgid = urllib.parse.quote_plus(msgid)
     config = get_main_config()
     loc = urllib.parse.urlparse(config['midmask'])
diff --git a/b4/command.py b/b4/command.py
index 6d3c899..aa307da 100644
--- a/b4/command.py
+++ b/b4/command.py
@@ -55,6 +55,8 @@ def cmd_am_common_opts(sp):
                          '"-P *globbing*" to match on commit subject)')
     sp.add_argument('--cc-trailers', dest='copyccs', action='store_true', default=False,
                     help='Copy all Cc\'d addresses into Cc: trailers')
+    sp.add_argument('--no-parent', dest='noparent', action='store_true', default=False,
+                    help='Break thread at the msgid specified and ignore any parent messages')
     sp.add_argument('--allow-unicode-control-chars', dest='allowbadchars', action='store_true', default=False,
                     help='Allow unicode control characters (very rarely legitimate)')
 
diff --git a/b4/mbox.py b/b4/mbox.py
index c2e6319..4ac2c29 100644
--- a/b4/mbox.py
+++ b/b4/mbox.py
@@ -656,12 +656,9 @@ def get_msgs(cmdargs) -> Tuple[Optional[str], Optional[list]]:
             sys.exit(1)
 
         pickings = set()
-        try:
-            if cmdargs.cherrypick == '_':
-                # Just that msgid, please
-                pickings = {msgid}
-        except AttributeError:
-            pass
+        if 'cherrypick' in cmdargs and cmdargs.cherrypick == '_':
+            # Just that msgid, please
+            pickings = {msgid}
         msgs = b4.get_pi_thread_by_msgid(msgid, useproject=cmdargs.useproject, nocache=cmdargs.nocache,
                                          onlymsgids=pickings)
         if not msgs:
@@ -693,6 +690,9 @@ def get_msgs(cmdargs) -> Tuple[Optional[str], Optional[list]]:
             logger.critical('Mailbox %s does not exist', cmdargs.localmbox)
             sys.exit(1)
 
+    if msgid and 'noparent' in cmdargs and cmdargs.noparent:
+        msgs = b4.get_strict_thread(msgs, msgid, noparent=True)
+
     if not msgid and msgs:
         for msg in msgs:
             msgid = msg.get('Message-ID', None)
diff --git a/man/b4.5 b/man/b4.5
index b83d5c5..7d4a62e 100644
--- a/man/b4.5
+++ b/man/b4.5
@@ -1,8 +1,5 @@
 .\" Man page generated from reStructuredText.
 .
-.TH B4 5 "2021-09-01" "0.9.0" ""
-.SH NAME
-B4 \- Work with code submissions in a public-inbox archive
 .
 .nr rst2man-indent-level 0
 .
@@ -30,6 +27,9 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .in \\n[rst2man-indent\\n[rst2man-indent-level]]u
 ..
+.TH "B4" 5 "2021-09-01" "0.9.0" ""
+.SH NAME
+B4 \- Work with code submissions in a public-inbox archive
 .SH SYNOPSIS
 .sp
 b4 {mbox,am,shazam,attest,pr,ty,diff} [options]
@@ -49,7 +49,7 @@ precursor to Lore and Data in the Star Trek universe.
 .IP \(bu 2
 \fIb4 am\fP: Create an mbox file that is ready to git\-am
 .IP \(bu 2
-\fIb4 shazam\fP: Similar to \fIam\fP, but lets you apply patches directly
+\fIb4 shazam\fP: Similar to \fIam\fP, but lets you treat patch series similar to pull requests
 .IP \(bu 2
 \fIb4 pr\fP: Work with pull requests
 .IP \(bu 2
@@ -64,13 +64,13 @@ precursor to Lore and Data in the Star Trek universe.
 .SH OPTIONS
 .INDENT 0.0
 .TP
-.B \-h\fP,\fB  \-\-help
+.B  \-h\fP,\fB  \-\-help
 show this help message and exit
 .TP
-.B \-d\fP,\fB  \-\-debug
+.B  \-d\fP,\fB  \-\-debug
 Add more debugging info to the output (default: False)
 .TP
-.B \-q\fP,\fB  \-\-quiet
+.B  \-q\fP,\fB  \-\-quiet
 Output critical information only (default: False)
 .UNINDENT
 .SH SUBCOMMAND OPTIONS
@@ -78,41 +78,40 @@ Output critical information only (default: False)
 .INDENT 0.0
 .TP
 .B usage:
-b4 mbox [\-h] [\-o OUTDIR] [\-p USEPROJECT] [\-c] [\-n WANTNAME] [\-m LOCALMBOX] [msgid]
+b4 mbox [\-h] [\-p USEPROJECT] [\-m LOCALMBOX] [\-C] [\-o OUTDIR] [\-c] [\-n WANTNAME] [\-M] [\-f] [msgid]
 .TP
 .B positional arguments:
 msgid                 Message ID to process, or pipe a raw message
 .TP
-.B optional arguments:
+.B options:
 .INDENT 7.0
 .TP
-.B \-h\fP,\fB  \-\-help
+.B  \-h\fP,\fB  \-\-help
 show this help message and exit
 .TP
+.BI \-p \ USEPROJECT\fR,\fB \ \-\-use\-project \ USEPROJECT
+Use a specific project instead of default (linux\-mm, linux\-hardening, etc)
+.TP
+.BI \-m \ LOCALMBOX\fR,\fB \ \-\-use\-local\-mbox \ LOCALMBOX
+Instead of grabbing a thread from lore, process this mbox file (or \- for stdin)
+.TP
+.B  \-C\fP,\fB  \-\-no\-cache
+Do not use local cache
+.TP
 .BI \-o \ OUTDIR\fR,\fB \ \-\-outdir \ OUTDIR
 Output into this directory (or use \- to output mailbox contents to stdout)
 .TP
-.BI \-p \ USEPROJECT\fR,\fB \ \-\-use\-project \ USEPROJECT
-Use a specific project instead of guessing (linux\-mm, linux\-hardening, etc)
-.TP
-.B \-c\fP,\fB  \-\-check\-newer\-revisions
+.B  \-c\fP,\fB  \-\-check\-newer\-revisions
 Check if newer patch revisions exist
 .TP
 .BI \-n \ WANTNAME\fR,\fB \ \-\-mbox\-name \ WANTNAME
-Filename to name the mbox file
-.TP
-.BI \-m \ LOCALMBOX\fR,\fB \ \-\-use\-local\-mbox \ LOCALMBOX
-Instead of grabbing a thread from lore, process this mbox file
-(or use \- for stdin)
+Filename to name the mbox destination
 .TP
-.B \-C\fP,\fB  \-\-no\-cache
-Do not use local cache
+.B  \-M\fP,\fB  \-\-save\-as\-maildir
+Save as maildir (avoids mbox format ambiguities)
 .TP
-.B \-f\fP,\fB  \-\-filter\-dupes
+.B  \-f\fP,\fB  \-\-filter\-dupes
 When adding messages to existing maildir, filter out duplicates
-.TP
-.B \-M\fP,\fB  \-\-save\-as\-maildir
-Save as maildir (avoids mbox format ambiguities)
 .UNINDENT
 .UNINDENT
 .sp
@@ -121,84 +120,159 @@ Save as maildir (avoids mbox format ambiguities)
 .INDENT 0.0
 .TP
 .B usage:
-b4 am [\-h] [\-o OUTDIR] [\-p USEPROJECT] [\-c] [\-n WANTNAME] [\-m LOCALMBOX] [\-v WANTVER] [\-t] [\-T] [\-s] [\-l] [\-Q] [msgid]
+b4 am [\-h] [\-p USEPROJECT] [\-m LOCALMBOX] [\-C] [\-o OUTDIR] [\-c] [\-n WANTNAME] [\-M] [\-v WANTVER] [\-t] [\-S] [\-T] [\-s] [\-l] [\-P CHERRYPICK] [\-\-cc\-trailers] [\-\-no\-parent] [\-\-allow\-unicode\-control\-chars] [\-Q] [\-g] [\-b GUESSBRANCH [GUESSBRANCH ...]] [\-\-guess\-lookback GUESSDAYS] [\-3] [\-\-no\-cover] [\-\-no\-partial\-reroll] [msgid]
 .TP
 .B positional arguments:
 msgid                 Message ID to process, or pipe a raw message
 .TP
-.B optional arguments:
+.B options:
 .INDENT 7.0
 .TP
-.B \-h\fP,\fB  \-\-help
+.B  \-h\fP,\fB  \-\-help
 show this help message and exit
 .TP
+.BI \-p \ USEPROJECT\fR,\fB \ \-\-use\-project \ USEPROJECT
+Use a specific project instead of default (linux\-mm, linux\-hardening, etc)
+.TP
+.BI \-m \ LOCALMBOX\fR,\fB \ \-\-use\-local\-mbox \ LOCALMBOX
+Instead of grabbing a thread from lore, process this mbox file (or \- for stdin)
+.TP
+.B  \-C\fP,\fB  \-\-no\-cache
+Do not use local cache
+.TP
 .BI \-o \ OUTDIR\fR,\fB \ \-\-outdir \ OUTDIR
 Output into this directory (or use \- to output mailbox contents to stdout)
 .TP
-.BI \-p \ USEPROJECT\fR,\fB \ \-\-use\-project \ USEPROJECT
-Use a specific project instead of guessing (linux\-mm, linux\-hardening, etc)
-.TP
-.B \-c\fP,\fB  \-\-check\-newer\-revisions
+.B  \-c\fP,\fB  \-\-check\-newer\-revisions
 Check if newer patch revisions exist
 .TP
 .BI \-n \ WANTNAME\fR,\fB \ \-\-mbox\-name \ WANTNAME
-Filename to name the mbox file
-.TP
-.BI \-m \ LOCALMBOX\fR,\fB \ \-\-use\-local\-mbox \ LOCALMBOX
-Instead of grabbing a thread from lore, process this mbox file
-(or use \- for stdin)
+Filename to name the mbox destination
 .TP
-.B \-M\fP,\fB  \-\-save\-as\-maildir
+.B  \-M\fP,\fB  \-\-save\-as\-maildir
 Save as maildir (avoids mbox format ambiguities)
 .TP
-.B \-C\fP,\fB  \-\-no\-cache
-Do not use local cache
-.TP
 .BI \-v \ WANTVER\fR,\fB \ \-\-use\-version \ WANTVER
 Get a specific version of the patch/series
 .TP
-.B \-t\fP,\fB  \-\-apply\-cover\-trailers
+.B  \-t\fP,\fB  \-\-apply\-cover\-trailers
 Apply trailers sent to the cover letter to all patches
 .TP
-.B \-S\fP,\fB  \-\-sloppy\-trailers
+.B  \-S\fP,\fB  \-\-sloppy\-trailers
 Apply trailers without email address match checking
 .TP
-.B \-T\fP,\fB  \-\-no\-add\-trailers
+.B  \-T\fP,\fB  \-\-no\-add\-trailers
 Do not add or sort any trailers
 .TP
-.B \-s\fP,\fB  \-\-add\-my\-sob
+.B  \-s\fP,\fB  \-\-add\-my\-sob
 Add your own signed\-off\-by to every patch
 .TP
-.B \-l\fP,\fB  \-\-add\-link
-Add a lore.kernel.org/r/ link to every patch
-.TP
-.B \-Q\fP,\fB  \-\-quilt\-ready
-Save patches in a quilt\-ready folder
+.B  \-l\fP,\fB  \-\-add\-link
+Add a Link: with message\-id lookup URL to every patch
 .TP
 .BI \-P \ CHERRYPICK\fR,\fB \ \-\-cherry\-pick \ CHERRYPICK
-Cherry\-pick a subset of patches (e.g. "\-P 1\-2,4,6\-", "\-P _" to use just the msgid specified, or "\-P *globbing*" to match on commit subject)
+Cherry\-pick a subset of patches (e.g. "\-P 1\-2,4,6\-", "\-P _" to use just the msgid specified, or "\-P \fIglobbing\fP" to match on commit subject)
+.TP
+.B  \-\-cc\-trailers
+Copy all Cc\(aqd addresses into Cc: trailers
 .TP
-.B \-g\fP,\fB  \-\-guess\-base
+.B  \-\-no\-parent
+Break thread at the msgid specified and ignore any parent messages
+.TP
+.B  \-\-allow\-unicode\-control\-chars
+Allow unicode control characters (very rarely legitimate)
+.TP
+.B  \-Q\fP,\fB  \-\-quilt\-ready
+Save patches in a quilt\-ready folder
+.TP
+.B  \-g\fP,\fB  \-\-guess\-base
 Try to guess the base of the series (if not specified)
+.UNINDENT
+.INDENT 7.0
 .TP
-.B \-3\fP,\fB  \-\-prep\-3way
-Prepare for a 3\-way merge (tries to ensure that all index blobs exist by making a fake commit range)
+.B \-b GUESSBRANCH [GUESSBRANCH ...], \-\-guess\-branch GUESSBRANCH [GUESSBRANCH ...]
+When guessing base, restrict to this branch (use with \-g)
+.UNINDENT
+.INDENT 7.0
+.TP
+.BI \-\-guess\-lookback \ GUESSDAYS
+When guessing base, go back this many days from the patch date (default: 2 weeks)
 .TP
-.B \-\-cc\-trailers
-Copy all Cc\(aqd addresses into Cc: trailers, if not already present
+.B  \-3\fP,\fB  \-\-prep\-3way
+Prepare for a 3\-way merge (tries to ensure that all index blobs exist by making a fake commit range)
 .TP
-.B \-\-no\-cover
+.B  \-\-no\-cover
 Do not save the cover letter (on by default when using \-o \-)
 .TP
-.B \-\-no\-partial\-reroll
+.B  \-\-no\-partial\-reroll
 Do not reroll partial series when detected
 .UNINDENT
 .UNINDENT
 .sp
 \fIExample\fP: b4 am \fI\%20200313231252.64999\-1\-keescook@chromium.org\fP
 .SH B4 SHAZAM
+.INDENT 0.0
+.TP
+.B usage:
+b4 shazam [\-h] [\-p USEPROJECT] [\-m LOCALMBOX] [\-C] [\-v WANTVER] [\-t] [\-S] [\-T] [\-s] [\-l] [\-P CHERRYPICK] [\-\-cc\-trailers] [\-\-no\-parent] [\-\-allow\-unicode\-control\-chars] [\-H] [\-\-guess\-lookback GUESSDAYS] [msgid]
+.TP
+.B positional arguments:
+msgid                 Message ID to process, or pipe a raw message
+.TP
+.B options:
+.INDENT 7.0
+.TP
+.B  \-h\fP,\fB  \-\-help
+show this help message and exit
+.TP
+.BI \-p \ USEPROJECT\fR,\fB \ \-\-use\-project \ USEPROJECT
+Use a specific project instead of default (linux\-mm, linux\-hardening, etc)
+.TP
+.BI \-m \ LOCALMBOX\fR,\fB \ \-\-use\-local\-mbox \ LOCALMBOX
+Instead of grabbing a thread from lore, process this mbox file (or \- for stdin)
+.TP
+.B  \-C\fP,\fB  \-\-no\-cache
+Do not use local cache
+.TP
+.BI \-v \ WANTVER\fR,\fB \ \-\-use\-version \ WANTVER
+Get a specific version of the patch/series
+.TP
+.B  \-t\fP,\fB  \-\-apply\-cover\-trailers
+Apply trailers sent to the cover letter to all patches
+.TP
+.B  \-S\fP,\fB  \-\-sloppy\-trailers
+Apply trailers without email address match checking
+.TP
+.B  \-T\fP,\fB  \-\-no\-add\-trailers
+Do not add or sort any trailers
+.TP
+.B  \-s\fP,\fB  \-\-add\-my\-sob
+Add your own signed\-off\-by to every patch
+.TP
+.B  \-l\fP,\fB  \-\-add\-link
+Add a Link: with message\-id lookup URL to every patch
+.TP
+.BI \-P \ CHERRYPICK\fR,\fB \ \-\-cherry\-pick \ CHERRYPICK
+Cherry\-pick a subset of patches (e.g. "\-P 1\-2,4,6\-", "\-P _" to use just the msgid specified, or "\-P \fIglobbing\fP" to match on commit subject)
+.TP
+.B  \-\-cc\-trailers
+Copy all Cc\(aqd addresses into Cc: trailers
+.TP
+.B  \-\-no\-parent
+Break thread at the msgid specified and ignore any parent messages
+.TP
+.B  \-\-allow\-unicode\-control\-chars
+Allow unicode control characters (very rarely legitimate)
+.TP
+.B  \-H\fP,\fB  \-\-make\-fetch\-head
+Attempt to treat series as a pull request and fetch it into FETCH_HEAD
+.TP
+.BI \-\-guess\-lookback \ GUESSDAYS
+(use with \-H) When guessing base, go back this many days from the patch date (default: 3 weeks)
+.UNINDENT
+.UNINDENT
 .sp
-TBD.
+\fIExample\fP: b4 shazam \-H \fI\%20200313231252.64999\-1\-keescook@chromium.org\fP
 .SS b4 attest
 .sp
 usage: b4 attest [\-h] patchfile [patchfile ...]
@@ -230,7 +304,7 @@ msgid                 Message ID to process, or pipe a raw message
 .B optional arguments:
 .INDENT 7.0
 .TP
-.B \-h\fP,\fB  \-\-help
+.B  \-h\fP,\fB  \-\-help
 show this help message and exit
 .TP
 .BI \-g \ GITDIR\fR,\fB \ \-\-gitdir \ GITDIR
@@ -239,16 +313,16 @@ Operate on this git tree instead of current dir
 .BI \-b \ BRANCH\fR,\fB \ \-\-branch \ BRANCH
 Check out FETCH_HEAD into this branch after fetching
 .TP
-.B \-c\fP,\fB  \-\-check
+.B  \-c\fP,\fB  \-\-check
 Check if pull request has already been applied
 .TP
-.B \-e\fP,\fB  \-\-explode
+.B  \-e\fP,\fB  \-\-explode
 Convert a pull request into an mbox full of patches
 .TP
 .BI \-o \ OUTMBOX\fR,\fB \ \-\-output\-mbox \ OUTMBOX
 Save exploded messages into this mailbox (default: msgid.mbx)
 .TP
-.B \-l\fP,\fB  \-\-retrieve\-links
+.B  \-l\fP,\fB  \-\-retrieve\-links
 Attempt to retrieve any Link: URLs (use with \-e)
 .TP
 .BI \-f \ MAILFROM\fR,\fB \ \-\-from\-addr \ MAILFROM
@@ -266,7 +340,7 @@ b4 ty [\-h] [\-g GITDIR] [\-o OUTDIR] [\-l] [\-t THANK_FOR [THANK_FOR ...]] [\-d
 .B optional arguments:
 .INDENT 7.0
 .TP
-.B \-h\fP,\fB  \-\-help
+.B  \-h\fP,\fB  \-\-help
 show this help message and exit
 .TP
 .BI \-g \ GITDIR\fR,\fB \ \-\-gitdir \ GITDIR
@@ -275,7 +349,7 @@ Operate on this git tree instead of current dir
 .BI \-o \ OUTDIR\fR,\fB \ \-\-outdir \ OUTDIR
 Write thanks files into this dir (default=.)
 .TP
-.B \-l\fP,\fB  \-\-list
+.B  \-l\fP,\fB  \-\-list
 List pull requests and patch series you have retrieved
 .TP
 .BI \-t \ THANK_FOR\fR,\fB \ \-\-thank\-for \ THANK_FOR
@@ -284,7 +358,7 @@ Generate thankyous for specific entries from \-l (e.g.: 1,3\-5,7\-; or "all")
 .BI \-d \ DISCARD\fR,\fB \ \-\-discard \ DISCARD
 Discard specific messages from \-l (e.g.: 1,3\-5,7\-; or "all")
 .TP
-.B \-a\fP,\fB  \-\-auto
+.B  \-a\fP,\fB  \-\-auto
 Use the Auto\-Thankanator gun to figure out what got applied/merged
 .TP
 .BI \-b \ BRANCH\fR,\fB \ \-\-branch \ BRANCH
@@ -293,10 +367,10 @@ The branch to check against, instead of current
 .BI \-\-since \ SINCE
 The \-\-since option to use when auto\-matching patches (default=1.week)
 .TP
-.B \-S\fP,\fB  \-\-send\-email
+.B  \-S\fP,\fB  \-\-send\-email
 Send email instead of writing out .thanks files
 .TP
-.B \-\-dry\-run
+.B  \-\-dry\-run
 Print out emails instead of sending them
 .UNINDENT
 .UNINDENT
@@ -325,7 +399,7 @@ optional arguments:
 .INDENT 3.5
 .INDENT 0.0
 .TP
-.B \-h\fP,\fB  \-\-help
+.B  \-h\fP,\fB  \-\-help
 show this help message and exit
 .TP
 .BI \-g \ GITDIR\fR,\fB \ \-\-gitdir \ GITDIR
@@ -334,7 +408,7 @@ Operate on this git tree instead of current dir
 .BI \-p \ USEPROJECT\fR,\fB \ \-\-use\-project \ USEPROJECT
 Use a specific project instead of guessing (linux\-mm, linux\-hardening, etc)
 .TP
-.B \-C\fP,\fB  \-\-no\-cache
+.B  \-C\fP,\fB  \-\-no\-cache
 Do not use local cache
 .UNINDENT
 .INDENT 0.0
@@ -344,13 +418,13 @@ Compare specific versions instead of latest and one before that, e.g. \-v 3 5
 .UNINDENT
 .INDENT 0.0
 .TP
-.B \-n\fP,\fB  \-\-no\-diff
+.B  \-n\fP,\fB  \-\-no\-diff
 Do not generate a diff, just show the command to do it
 .TP
 .BI \-o \ OUTDIFF\fR,\fB \ \-\-output\-diff \ OUTDIFF
 Save diff into this file instead of outputting to stdout
 .TP
-.B \-c\fP,\fB  \-\-color
+.B  \-c\fP,\fB  \-\-color
 Force color output even when writing to file
 .UNINDENT
 .INDENT 0.0
@@ -373,7 +447,7 @@ msgid                 Message ID to process, or pipe a raw message
 .B optional arguments:
 .INDENT 7.0
 .TP
-.B \-h\fP,\fB  \-\-help
+.B  \-h\fP,\fB  \-\-help
 show this help message and exit
 .TP
 .BI \-p \ USEPROJECT\fR,\fB \ \-\-use\-project \ USEPROJECT
@@ -382,10 +456,10 @@ Use a specific project instead of guessing (linux\-mm, linux\-hardening, etc)
 .BI \-m \ LOCALMBOX\fR,\fB \ \-\-use\-local\-mbox \ LOCALMBOX
 Instead of grabbing a thread from lore, process this mbox file (or \- for stdin)
 .TP
-.B \-C\fP,\fB  \-\-no\-cache
+.B  \-C\fP,\fB  \-\-no\-cache
 Do not use local cache
 .TP
-.B \-\-show\-keys
+.B  \-\-show\-keys
 Show all developer keys from the thread
 .UNINDENT
 .UNINDENT
diff --git a/man/b4.5.rst b/man/b4.5.rst
index 217e145..739e196 100644
--- a/man/b4.5.rst
+++ b/man/b4.5.rst
@@ -29,7 +29,7 @@ SUBCOMMANDS
 -----------
 * *b4 mbox*: Download a thread as an mbox file
 * *b4 am*: Create an mbox file that is ready to git-am
-* *b4 shazam*: Similar to *am*, but lets you apply patches directly
+* *b4 shazam*: Similar to *am*, but lets you treat patch series similar to pull requests
 * *b4 pr*: Work with pull requests
 * *b4 diff*: Show range-diff style diffs between patch versions
 * *b4 ty*: Create templated replies for processed patches and pull requests
@@ -47,55 +47,57 @@ SUBCOMMAND OPTIONS
 b4 mbox
 ~~~~~~~
 usage:
-  b4 mbox [-h] [-o OUTDIR] [-p USEPROJECT] [-c] [-n WANTNAME] [-m LOCALMBOX] [msgid]
+  b4 mbox [-h] [-p USEPROJECT] [-m LOCALMBOX] [-C] [-o OUTDIR] [-c] [-n WANTNAME] [-M] [-f] [msgid]
 
 positional arguments:
   msgid                 Message ID to process, or pipe a raw message
 
-optional arguments:
+options:
   -h, --help            show this help message and exit
+  -p USEPROJECT, --use-project USEPROJECT
+                        Use a specific project instead of default (linux-mm, linux-hardening, etc)
+  -m LOCALMBOX, --use-local-mbox LOCALMBOX
+                        Instead of grabbing a thread from lore, process this mbox file (or - for stdin)
+  -C, --no-cache
+                        Do not use local cache
   -o OUTDIR, --outdir OUTDIR
                         Output into this directory (or use - to output mailbox contents to stdout)
-  -p USEPROJECT, --use-project USEPROJECT
-                        Use a specific project instead of guessing (linux-mm, linux-hardening, etc)
   -c, --check-newer-revisions
                         Check if newer patch revisions exist
   -n WANTNAME, --mbox-name WANTNAME
-                        Filename to name the mbox file
-  -m LOCALMBOX, --use-local-mbox LOCALMBOX
-                        Instead of grabbing a thread from lore, process this mbox file
-                        (or use - for stdin)
-  -C, --no-cache        Do not use local cache
-  -f, --filter-dupes    When adding messages to existing maildir, filter out duplicates
+                        Filename to name the mbox destination
   -M, --save-as-maildir
                         Save as maildir (avoids mbox format ambiguities)
+  -f, --filter-dupes
+                        When adding messages to existing maildir, filter out duplicates
+
 
 *Example*: b4 mbox 20200313231252.64999-1-keescook@chromium.org
 
 b4 am
 ~~~~~
 usage:
-  b4 am [-h] [-o OUTDIR] [-p USEPROJECT] [-c] [-n WANTNAME] [-m LOCALMBOX] [-v WANTVER] [-t] [-T] [-s] [-l] [-Q] [msgid]
+  b4 am [-h] [-p USEPROJECT] [-m LOCALMBOX] [-C] [-o OUTDIR] [-c] [-n WANTNAME] [-M] [-v WANTVER] [-t] [-S] [-T] [-s] [-l] [-P CHERRYPICK] [--cc-trailers] [--no-parent] [--allow-unicode-control-chars] [-Q] [-g] [-b GUESSBRANCH [GUESSBRANCH ...]] [--guess-lookback GUESSDAYS] [-3] [--no-cover] [--no-partial-reroll] [msgid]
 
 positional arguments:
   msgid                 Message ID to process, or pipe a raw message
 
-optional arguments:
+options:
   -h, --help            show this help message and exit
+  -p USEPROJECT, --use-project USEPROJECT
+                        Use a specific project instead of default (linux-mm, linux-hardening, etc)
+  -m LOCALMBOX, --use-local-mbox LOCALMBOX
+                        Instead of grabbing a thread from lore, process this mbox file (or - for stdin)
+  -C, --no-cache
+                        Do not use local cache
   -o OUTDIR, --outdir OUTDIR
                         Output into this directory (or use - to output mailbox contents to stdout)
-  -p USEPROJECT, --use-project USEPROJECT
-                        Use a specific project instead of guessing (linux-mm, linux-hardening, etc)
   -c, --check-newer-revisions
                         Check if newer patch revisions exist
   -n WANTNAME, --mbox-name WANTNAME
-                        Filename to name the mbox file
-  -m LOCALMBOX, --use-local-mbox LOCALMBOX
-                        Instead of grabbing a thread from lore, process this mbox file
-                        (or use - for stdin)
+                        Filename to name the mbox destination
   -M, --save-as-maildir
                         Save as maildir (avoids mbox format ambiguities)
-  -C, --no-cache        Do not use local cache
   -v WANTVER, --use-version WANTVER
                         Get a specific version of the patch/series
   -t, --apply-cover-trailers
@@ -104,28 +106,75 @@ optional arguments:
                         Apply trailers without email address match checking
   -T, --no-add-trailers
                         Do not add or sort any trailers
-  -s, --add-my-sob      Add your own signed-off-by to every patch
-  -l, --add-link        Add a lore.kernel.org/r/ link to every patch
-  -Q, --quilt-ready     Save patches in a quilt-ready folder
+  -s, --add-my-sob
+                        Add your own signed-off-by to every patch
+  -l, --add-link
+                        Add a Link: with message-id lookup URL to every patch
   -P CHERRYPICK, --cherry-pick CHERRYPICK
-                        Cherry-pick a subset of patches (e.g. "-P 1-2,4,6-", "-P _" to use just the msgid specified, or "-P \*globbing\*" to match on commit subject)
+                        Cherry-pick a subset of patches (e.g. "-P 1-2,4,6-", "-P _" to use just the msgid specified, or "-P *globbing*" to match on commit subject)
+  --cc-trailers
+                        Copy all Cc'd addresses into Cc: trailers
+  --no-parent
+                        Break thread at the msgid specified and ignore any parent messages
+  --allow-unicode-control-chars
+                        Allow unicode control characters (very rarely legitimate)
+  -Q, --quilt-ready
+                        Save patches in a quilt-ready folder
   -g, --guess-base
                         Try to guess the base of the series (if not specified)
+
+  -b GUESSBRANCH [GUESSBRANCH ...], --guess-branch GUESSBRANCH [GUESSBRANCH ...]
+                        When guessing base, restrict to this branch (use with -g)
+
+  --guess-lookback GUESSDAYS
+                        When guessing base, go back this many days from the patch date (default: 2 weeks)
   -3, --prep-3way
                         Prepare for a 3-way merge (tries to ensure that all index blobs exist by making a fake commit range)
-  --cc-trailers
-                        Copy all Cc'd addresses into Cc: trailers, if not already present
   --no-cover
                         Do not save the cover letter (on by default when using -o -)
   --no-partial-reroll
                         Do not reroll partial series when detected
 
-
 *Example*: b4 am 20200313231252.64999-1-keescook@chromium.org
 
+
 b4 shazam
 ---------
-TBD.
+usage:
+  b4 shazam [-h] [-p USEPROJECT] [-m LOCALMBOX] [-C] [-v WANTVER] [-t] [-S] [-T] [-s] [-l] [-P CHERRYPICK] [--cc-trailers] [--no-parent] [--allow-unicode-control-chars] [-H] [--guess-lookback GUESSDAYS] [msgid]
+
+positional arguments:
+  msgid                 Message ID to process, or pipe a raw message
+
+options:
+  -h, --help            show this help message and exit
+  -p USEPROJECT, --use-project USEPROJECT
+                        Use a specific project instead of default (linux-mm, linux-hardening, etc)
+  -m LOCALMBOX, --use-local-mbox LOCALMBOX
+                        Instead of grabbing a thread from lore, process this mbox file (or - for stdin)
+  -C, --no-cache        Do not use local cache
+  -v WANTVER, --use-version WANTVER
+                        Get a specific version of the patch/series
+  -t, --apply-cover-trailers
+                        Apply trailers sent to the cover letter to all patches
+  -S, --sloppy-trailers
+                        Apply trailers without email address match checking
+  -T, --no-add-trailers
+                        Do not add or sort any trailers
+  -s, --add-my-sob      Add your own signed-off-by to every patch
+  -l, --add-link        Add a Link: with message-id lookup URL to every patch
+  -P CHERRYPICK, --cherry-pick CHERRYPICK
+                        Cherry-pick a subset of patches (e.g. "-P 1-2,4,6-", "-P _" to use just the msgid specified, or "-P *globbing*" to match on commit subject)
+  --cc-trailers         Copy all Cc'd addresses into Cc: trailers
+  --no-parent           Break thread at the msgid specified and ignore any parent messages
+  --allow-unicode-control-chars
+                        Allow unicode control characters (very rarely legitimate)
+  -H, --make-fetch-head
+                        Attempt to treat series as a pull request and fetch it into FETCH_HEAD
+  --guess-lookback GUESSDAYS
+                        (use with -H) When guessing base, go back this many days from the patch date (default: 3 weeks)
+
+*Example*: b4 shazam -H 20200313231252.64999-1-keescook@chromium.org
 
 b4 attest
 ~~~~~~~~~