# Could GIT manage revision headers embedded in code ? 4 messages from 2017-05-02 to 2017-05-02. Participants: Delanoe Eric, Christian Couder, Johannes Schindelin. Thread: https://gitlist.dev/t/45849 ## Delanoe Eric, 2017-05-02 11:48 Subject: Could GIT manage revision headers embedded in code ? Message-ID: <135C7A92C7D64E488B830ADC2970C70132AE6407@SVGEA-EMAIL.gea.fr> URL: https://gitlist.dev/e/135C7A92C7D64E488B830ADC2970C70132AE6407%40SVGEA-EMAIL.gea.fr ``` Hello, We need a great deal of traceability for our source, made of many scripts in interpreted languages, spread in many "independent" modules, as far as can be ;-). In particular, somebody troubleshooting a script in production should be able to know exactly the revision or commit ID (or tag label) of a given file, and its location in the GIT source directory tree. Our old CVS... let's say it was its only advantage... was doing this with keywords embedded in code comments: $Header$, $Id$, $Rev$, $File$ etc... When a file was committed, its $Header$ keyword was expanded into a rich piece of "version" information like '' $Header: /cvsstore/SourcesOracle/Install/COMMUN/CST.sql,v 1.69.2.10 2017/04/14 09:38:48 edelanoe $". Could this kind of "keyword expansion" feature be added into GIT ? Focusing on the goal: enable the identification of a file and its revision(*) inside the committed code itself. (*) the "revision" information or a commit ID. The tag(s) attached at commit time would be less reliable, as a tag can be moved between revisions. Thank you in advance for any answer, Best regards, E.Delanoë Grenobloise d'Electronique et d'Automatismes Inovallée - 12, Chemin de Malacher 38243 MEYLAN CEDEX FRANCE ``` ## Christian Couder, 2017-05-02 12:11 Subject: Re: Could GIT manage revision headers embedded in code ? Message-ID: URL: https://gitlist.dev/e/CAP8UFD0NrTyGYgHeEOWpUH5v0ejKvcKu%2BMzd8_scYbvzL4b4zg%40mail.gmail.com In-Reply-To: <135C7A92C7D64E488B830ADC2970C70132AE6407@SVGEA-EMAIL.gea.fr> ``` Hi, On Tue, May 2, 2017 at 1:48 PM, Delanoe Eric wrote: > Hello, > > We need a great deal of traceability for our source, made of many scripts in interpreted languages, spread in many "independent" modules, as far as can be ;-). > In particular, somebody troubleshooting a script in production should be able to know exactly the revision or commit ID (or tag label) of a given file, and its location in the GIT source directory tree. > > Our old CVS... let's say it was its only advantage... was doing this with keywords embedded in code comments: $Header$, $Id$, $Rev$, $File$ etc... When a file was committed, its $Header$ keyword was expanded into a rich piece of "version" information like '' $Header: /cvsstore/SourcesOracle/Install/COMMUN/CST.sql,v 1.69.2.10 2017/04/14 09:38:48 edelanoe $". > > Could this kind of "keyword expansion" feature be added into GIT ? You can already do it with "smudge" and "clean" filters. Look for "Keyword Expansion" in: https://git-scm.com/book/en/v2/Customizing-Git-Git-Attributes ``` ## Delanoe Eric, 2017-05-02 13:33 Subject: RE: Could GIT manage revision headers embedded in code ? Message-ID: <135C7A92C7D64E488B830ADC2970C70132AE7442@SVGEA-EMAIL.gea.fr> URL: https://gitlist.dev/e/135C7A92C7D64E488B830ADC2970C70132AE7442%40SVGEA-EMAIL.gea.fr In-Reply-To: ``` Thank you for your quick answer. And great answer ! I'm looking forward to try this. Thanks again and best regards, E.Delanoë -----Message d'origine----- De : Christian Couder [mailto:christian.couder@gmail.com] Envoyé : mardi 2 mai 2017 14:11 À : Delanoe Eric Cc : git@vger.kernel.org Objet : Re: Could GIT manage revision headers embedded in code ? Hi, On Tue, May 2, 2017 at 1:48 PM, Delanoe Eric wrote: > Hello, > > We need a great deal of traceability for our source, made of many scripts in interpreted languages, spread in many "independent" modules, as far as can be ;-). > In particular, somebody troubleshooting a script in production should be able to know exactly the revision or commit ID (or tag label) of a given file, and its location in the GIT source directory tree. > > Our old CVS... let's say it was its only advantage... was doing this with keywords embedded in code comments: $Header$, $Id$, $Rev$, $File$ etc... When a file was committed, its $Header$ keyword was expanded into a rich piece of "version" information like '' $Header: /cvsstore/SourcesOracle/Install/COMMUN/CST.sql,v 1.69.2.10 2017/04/14 09:38:48 edelanoe $". > > Could this kind of "keyword expansion" feature be added into GIT ? You can already do it with "smudge" and "clean" filters. Look for "Keyword Expansion" in: https://git-scm.com/book/en/v2/Customizing-Git-Git-Attributes ``` ## Johannes Schindelin, 2017-05-02 15:54 Subject: Re: Could GIT manage revision headers embedded in code ? Message-ID: URL: https://gitlist.dev/e/alpine.DEB.2.20.1705021751250.3480%40virtualbox In-Reply-To: <135C7A92C7D64E488B830ADC2970C70132AE6407@SVGEA-EMAIL.gea.fr> ``` Hi Eric, On Tue, 2 May 2017, Delanoe Eric wrote: > Could this kind of "keyword expansion" feature be added into GIT ? Back in the days, it was decided that this should be part of the "export as zip" functionality, see the `export-subst` feature in git-archive's and gitattributes' documentation. In reality, what most projects do is to generate a header or some such as part of their build process. Git itself may serve as a case in point: https://github.com/git/git/blob/master/GIT-VERSION-GEN used in https://github.com/git/git/blob/v2.12.2/Makefile#L390-L392 Ciao, Johannes ```